laporan akhir penelitian hi-impact dana its 2020
TRANSCRIPT
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LAPORAN AKHIR
PENELITIAN HI-IMPACT
DANA ITS 2020
(Biojetfuel Range Alkanes Production From Minyak Kemiri
Sunan (Reutealiss trisperm Oil) Via Hydrodeoxygenation Reaction
By Metal/Aluminosilicates From Local Source)
Tim Peneliti :
Prof. Didik Prasetyoko, M.Sc (Kimia/FSAD)
Dr. Yuly Kusumawati, M.Si (Kimia/FSAD)
DIREKTORAT RISET DAN PENGABDIAN KEPADA MASYARAKAT
INSTITUT TEKNOLOGI SEPULUH NOPEMBER
SURABAYA
2020
Sesuai Surat Perjanjian Pelaksanaan Penelitian No: 836/PKS/ITS/2020
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Daftar Isi
Daftar Isi ........................................................................................................................................................ i
Daftar Tabel .................................................................................................................................................. ii
Daftar Gambar ............................................................................................................................................. iii
Daftar Lampiran............................................................................................................................................ v
BAB I RINGKASAN ................................................................................................................................... 1
BAB II HASIL PENELITIAN ...................................................................................................................... 3
BAB III STATUS LUARAN ...................................................................................................................... 23
BAB IV PERAN MITRA (Untuk Penelitian Kerjasama Antar Perguruan Tinggi) ..................................... 24
BAB V KENDALA PELAKSANAAN PENELITIAN .............................................................................. 25
BAB VI RENCANA TAHAPAN SELANJUTNYA .................................................................................. 26
BAB VII DAFTAR PUSTAKA.................................................................................................................. 27
BAB VIII LAMPIRAN .............................................................................................................................. 29
LAMPIRAN 1 Tabel Daftar Luaran ........................................................................................................... 29
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Daftar Tabel
Tabel 1 Jumlah situs asam Bronsted dan Lewis menggunakan adsorpsi piridin.............................16
Tabel 2 Pergeseran kimia dan rasio Si/Al dari 29Si NMR…………………….…………………..17
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Daftar Gambar
Hal
Gambar 1. Spektra IR katalis aluminosilikat dari redmud (a) aluminosilikat H+-
Ni, (b) aluminosilikat H+, (c) aluminosilikat Na+Ni, (d) aluminosilikat
Na+
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Gambar 2. Difraktogram katalis aluminosilikat dari redmud (a) aluminosilikat H+-
Ni, (b) aluminosilikat H+, (c) aluminosilikat Na+Ni, (d) aluminosilikat
Na+
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Gambar 3. N2 adsorpsi-desorpsi katalis aluminosilikat redmud (a) dan distribusi
ukuran pori menggunakan metode DFT (b)
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Gambar 4. Foto TEM katalis aluminosilikat redmud 6
Gambar 5. Komposisi Produk Biojetfuel Minyak Kemiri Sunan dengan Reaksi
Hidrodeoksigenasi menggunakan katalis Aluminosilikat redmud
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Gambar 6. Distribusi Produk Biojetfuel Minyak Kemiri Sunan dengan Reaksi
Hidrodeoksigenasi menggunakan katalis Aluminosilikat redmud
Gambar 7. Spektra FTIR ZSM-5 3 jam, ZSM-5 6 jam, ZSM-5 9 jam
Gambar 8. Difraksi sinar X ZSM-5 3 jam, ZSM-5 6 jam, ZSM-5 9 jam
Gambar 9. Foto SEM katalis ZSM-5 3 jam (a), ZSM-5 6 jam (b) dan ZSM-5 9 jam
(c)
Gambar 10. Kurva TGA sampel ZSM-5 3jam (a), ZSM-5 6 jam (b) dan ZSM-5 9
jam (c)
Gambar 11. Distribusi komposisi biofuel hasil reaksi hirodeoksigenasi minyak
kemiri sunan dengan katalis ZSM-5
Gambar 12. Spektra FTIR (a) dan adsorpsi piridin (b) pada kaolin, Al-MCM-41,
ZSM-5 yang disintesis menggunakan TPAOH (T-ZSM-5) dan ZSM-5
yang disintesis menggunakan silikalit (S-ZSM-5)
Gambar 13. (a) sudut panjang dan (b) sudut pendek XRD dari kaolin, Al-MCM-41,
T-ZSM-5 dan S-ZSM-5
Gambar 14. Spektra dekonvolusi 29Si NMR dari S-ZSM-5 (a), T-ZSM-5 (b) dan
Al-MCM-41 (c)
Gambar 15. Distribusi rantai hidrokarbon pada reaksi deoksigenasi JCO
Gambar 16. Hasil konversi JCO (a) dan selektivitas hidrokarbon pada Al-MCM-41
dengan variasi waktu reaksi deoksigenasi. Komposisi hidrokarbon
dibagi menjadi dua fraksi yakni fraksi gasoline (C8-10) dan fraksi diesel
(C11-18)
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9
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11
12
13
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18
20
21
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Gambar 17. Spektra FTIR dari JCO dan produk cair (a) dan analisis produk gas
pada reaksi deoksigenasi JCO (b)
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Daftar Lampiran
Lampiran 1. Tabel Daftar Luaran ……………………………………………………………..25
Lampiran 2. Bukti Abstrak Submitted pada Seminar ICCME 2020 dan paper submitted ……27
Lampiran 3. Manuscript paper publikasi ……………………………………………………...28
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BAB I RINGKASAN
.
Penelitian yang dilakukan memiliki tujuan untuk menghasilkan produk senyawa alkana
dalam range bio jet-fuel dari bahan baku minyak nabati non-edible Kemiri Sunan (Reutealis
trisperm) menggunakan material katalis aluminosilikat dari sumber alam lokal dalam rangka
mendukung subtitusi bahan bakar yang berkelanjutan. Bio jet-fuel dari konversi minyak nabati
non-edible Reutealis trisperm atau Kemiri Sunan merupakan alternatif pengganti bahan bakar
fosil yang potensial untuk dikembangkan karena faktor kelimpahan yang tinggi dan tidak
menimbulkan persaingan dengan sektor pangan dan pertanian. Dengan meningkatnya
kebutuhan energi dalam bidang transportasi dari tahun ke tahun, mengakibatkan penelitian
tentang teknologi subtitusi bahan bakar maupun pengembangan material maju sebagai katalis
reaksi konversi minyak nabati menjadi bio jet-fuel menjadi perhatian banyak peneliti.
Peningkatan performa bahan bakar jenis biodiesel menjadi bio jet-fuel karena keunggulan sifat
fisik dan kimianya untuk aplikasi pada mesin kendaraan darat dan udara, melibatkan
penggunaan katalis yang spesifik dan selektif dalam reaksi konversi energi baru terbarukan.
Inovasi modifikasi katalis konversi untuk menghasilkan senyawa hidrokarbon alkana
dalam range bio jet-fuel sangat berperan untuk mencapai hasil akhir reaksi konversi katalitik
dengan tingkat selektifitas dan konversi yang tinggi. Dalam penelitian ini modifikasi
permukaan katalis aluminosilikat dilakukan dengan penambahan logam aktif nikel serta variasi
interaksi logam dan support dalam framework aluminosilikat. Material aluminosilikat dalam
penelitian ini disintesis dari sumber alam lokal seperti limbah bauksit (Red mud) dan kaolin
juga merupakan keterbaruan dalam penelitian produksi bio jet-fuel melalui reaksi
hidrodeoksigenasi. Selain itu pemanfaatan limbah bauksit juga menjadi salah satu solusi
permasalahan lingkungan yang dapat diintegrasikan dengan pengembangan material untuk
energi dan lingkungan.
Sintesis aluminosilikat dilakukan dengan metode hidrotermal dengan tahapan dua kali
kristalisasi (two steps crystallization) dengan logam aktif Ni sebagai katalis reaksi
hidrodeoksigenasi minyak Kemiri Sunan. Karakterisasi fisika dan kimia katalis dalam
penelitian ini dilakukan dalam rangka mengetahui efektivitas dan selektivitas katalis berbasis
sumber lokal pada produksi senyawa alkana dalam range bio jet-fuel. Karakterisasi material
yang dilakukan meliputi FTIR, XRD, TGA, SEM, TEM, N2 adsorpsi desorpsi dan FTIR piridin.
Uji katalitik reaksi hidrodeoksigenasi selanjutnya dilakukan dalam skala laboratorium
menggunakan feedstock minyak Kemiri Sunan dan asam oleat (model compound) dalam reaktor
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semi-batch dengan variasi parameter reaksi jenis katalis, suhu dan waktu reaksi untuk
mendapatkan data tentang konversi dan selectivitas produk senyawa alkana range bio jet-fuel.
Analisis produk hasil reaksi hidrodeoksigenasi dilakukan menggunakan GC-MS.
Luaran yang ditargetkan dalam penelitian ini yaitu artikel ilmiah yang dipublikasikan pada
jurnal internasional teindeks Scopus Q1. Luaran tambahan dalam penelitian ini adalah presentasi
pada seminar internasional. Status luaran wajib dalam penelitian ini adalah ter-submit dengan status
under review pada jurnal Microporous and Mesoporous Materials (Q1) dengan H Index Jurnal 151
Impact factor 4.551, citation score 7,7dan luaran tambahan yakni telah dilaksanakan seminar
internasional ICCME Universitas Diponegoro.
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Ringkasan penelitian berisi latar belakang penelitian,tujuan dan tahapan metode
penelitian, luaran yang ditargetkan, kata kunci
BAB II HASIL PENELITIAN
Hasil penelitian yang telah dilakukan meliputi sintesis katalis aluminosilikat berbasis
sumber lokal red mud/kaolin, karakterisasi katalis aluminosilikat, uji aktivitas katalis melalui reaksi
hidrodeoksigenasi minyak kemiri sunan dan asam oleat
1. Sintesis aluminosilikat dari Redmud
Sintesis aluminosilikat dengan sumber silika dan alumina dari Redmud pulau Bintan dilakukan dengan
metode hidrotermal melalui 2 tahap kristalisasi pada suhu 80 °C selama 24 jam dan 28 °C selama 4 jam serta
dan sumber silika kaolin Bangka Belitung yang dilakukan dengan metode hidrotermal melalui 2 tahap
kristalisasi pada suhu 80 °C selama 12 jam dan 150 °C selama 24 jam . Padatan aluminosilikat yang terbentuk
selanjutnya dicuci dengan aquades hingga pH netral. Katalis aluminosilikat selanjutnya dilakukan proses
kalsinasi untuk menghilangkan template CTABr yang berperan dalam proses pembentukan mesopori. Katalis
yang terbentuk selanjutnya dimodifikasi struktur permukaannya untuk mengetahui sisi aktif yang berperan
dalam reaksi hidrodeoksigenasi melalui beberapa cara yaitu impregnasi logam Ni menghasilkan katalis
aluminosilikat bentuk Na+-Ni, pertukaran kation Na+ pada aluminosilikat dengan H+ menghasilkan katalis
aluminosilikat H+, serta pertukaran kation dan impregnasi logam Ni menghasilkan katalis aluminosilikat H+-
Ni. Masing-masing katalis selanjutnya dikarakterisasi menggunakan FTIR, XRD, N2 adsorpsi-desorpsi,
TEM.
2. Karakterisasi Katalis
2.1 FTIR
Katalis aluminosilikat dikarakterisasi dengan FTIR untuk mengetahui gugus fungsional dari material
yang telah disintesis. Gambar 1 menunjukkan spektra FTIR dari katalis aluminosilikat awal dan yang telah
dimodifikasi struktur permukaannya. Seluruh katalis yang telah disintesis menunjukkan puncak serapan
karakteristik dari aluminosilikat, yaitu puncak serapan pada bilangan gelombang 3452, 3525, dan 3622
cm-1 yang merupakan puncak serapan khas dari vibrasi ulur –OH [1], sedangkan puncak serapan
pada bilangan gelombang 1629 cm-1 menandakan adanya vibrasi tekuk –OH. Puncak serapan khas
untuk vibrasi tekuk Si-O-Si, dan Si-O-Al terlihat pada daerah bilangan gelombang 1012, dan 1031
cm-1. Vibrasi ulur Si-O pada tetrahedral SiO4 menunjukkan puncak serapan pada bilangan
gelombang 746, 798, dan 914 cm-1 [2]. Puncak serapan pada bilangan gelombang 450 cm-1 yang
dihasilkan karena adanya vibrasi ikatan T-O-T (T adalah atom Al atau Si). Pada bilangan gelombang 550
cm-1 menunjukkan adanya vibrasi stretching asimetri dari D5R (double five-membered ring) yang merupakan
karakteristik dari struktur zeolite pentasil tipe MFI. Sedangkan pada bilangan gelombang 795 dan 1225 cm-
1 merupakan vibrasi streching eksternal simetri dan asimetri dari T-O-T.
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Gambar 1. Spektra IR katalis aluminosilikat dari redmud (a) aluminosilikat H+-Ni, (b) aluminosilikat H+,
(c) aluminosilikat Na+Ni, (d) aluminosilikat Na+
Karakterisasi FTIR pada ZSM-5 dari sumber mineral kaolin juga dilakukan untuk mengetahui
terbentuknya gugus fungsi ZSM-5.
2.2 XRD
Katalis aluminosilikat dikarakterisasi menggunakan XRD untuk mengetahui fasa yang terbentuk dari
material yang telah disintesis. Gambar 2 menunjukkan difraktogram dari katalis yang telah disintesis. Pola
difraktogram pada aluminasilika hasil sintesis (ASM) menunjukkan adanya hump (gundukan) pada
range 2θ = 15-30° tanpa adanya puncak. Menurut Xu dkk., (2011) adanya hump merupakan
karakteristik dari fasa amorf suatu padatan, sehingga dapat disimpulkan bahwa ASM hasil sintesis
memiliki fasa amorf [1]. .Hasil yang sama juga dilaporkan oleh Qoniah dkk dan Hartati, Prasetyoko,
dkk. [2,3]. Berdasarkan hasil tersebut, dapat disimpulkan bahwa ASM telah berhasil disintesis dari
red mud dan fasa yang dihasilkan adalah amorf.
a
b
c
d
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Gambar 2. Difraktogram katalis aluminosilikat dari redmud (a) aluminosilikat H+-Ni, (b) aluminosilikat H+,
(c) aluminosilikat Na+Ni, (d) aluminosilikat Na+
2.3 N2 adsorpsi-desorpsi
Karakterisasi menggunakan N2 adsorpsi-desorpsi dilakukan pada sampel katalis aluminosilikat dari
redmud awal. Karakterisasi ini bertujuan untuk mengetahui sifat textural dari material yang telah disintesis
seperti luas permukaan meso, mikro, ukuran pori dan volume pori. Gambar 3 menunjukkan grafik isoterm
dan distribusi ukuran pori katalis aluminosilikat. Pola isoterm ASM hasil sintesis menunjukkan pola
isoterm tipe IV dimana terjadi adsorpsi molekul nitrogen dalam jumlah rendah pada tekanan relatif
(P/P0) 0,0 sampai 0,3 yang ditandai dengan pola isoterm yang naik. Hal ini disebabkan pada tekanan
relatif 0,01 – 0,3 molekul nitrogen yang teradsorp memenuhi permukaan padatan sehingga
terbentuk lapisan tunggal atau monolayer. Pada tekanan relatif (P/P0) 0,4 – 0,9 mengindikasikan
terbentuknya multilayer dengan adanya penambahan volume molekul nitrogen yang teradsorpsi
(Chorkendorff dan Niemantsverdriet, 2017). Data distribusi ukuran pori dari sampel aluminosilikat
mesorpori dengan metode BJH (Barret, Joiner, Halenda). Berdasarkan gambar tersebut terlihat
bahwa distribusi pori sampel aluminosilikat memiliki ukuran pori pada radius sekitar 1,53 – 15,57
nm (diameter pori 3,1 – 31 nm) (Tabel 4.2) dengan luas permukaan total 404 m2/g.
a
b
c
d
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Gambar 3. N2 adsorpsi-desorpsi katalis aluminosilikat redmud (a) dan distribusi ukuran pori menggunakan
metode DFT (b)
Berdasarkan analisis N2 adsorpsi- desorpsi dapat dsimpulkan bahwa katalis aluminosilikat dari
sumber redmud memiliki karakteristik padatan mesopri interpartikel.
2.4 TEM
Karakterisasi TEM pada katalis aluminosilikat dilakukan untuk mengetahui sebaran pori meso dan
ukuran pori katalis. Gambar 4 menunjukkan hasil foto TEM katalis aluminosilikat dari redmud.
Berdasarkan gambar TEM terlihat bahwa pori dari ASM memiliki bentuk pori spherical dan tidak
teratur dengan ukuran pori ~1 nm. Hal ini dapat dilihat dari pembentukan sistem penghubung yang
terjadi secara acak. Hasil yang sama juga dilaporkan oleh Qoniah dkk., (2015) dimana dihasilkan
aluminosilikat dengan bentuk pori yang tidak teratur pada material aluminosilikat. Hasil analisa
TEM ini juga mengkonfirmasi adanya mesopori yang terbentuk pada interpartikel.
Gambar 4. Foto TEM katalis aluminosilikat redmud
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3 Uji Aktivitas Katalitik Aluminosilikat dengan Minyak Kemiri Sunan
Uji aktivitas katalitik katalis aluminosilikat dilakukan pada reaksi hidrodeoksigenasi minyak kemiri
sunan dengan kondisi reaksi 3% katalis, temperatur reaksi 300 oC, waktu reaksi 1 jam, dan aliran gas
hydrogen 50 dan 100 mL/menit sebagai studi pendahuluan. Hasil analisis biojetfuel dari reaksi
hidrodeoksigenasi minyak kemiri sunan dengan instrument GC-MS menunjukkan hasil komposisi produk
biojetfuel meliputi, aromatic, siklik, oksigenate dan hidrokarbon.
Gambar 5. Komposisi Produk Biojetfuel Minyak Kemiri Sunan dengan Reaksi Hidrodeoksigenasi
menggunakan katalis Aluminosilikat redmud
Gambar 6. Distribusi Produk Biojetfuel Minyak Kemiri Sunan dengan Reaksi Hidrodeoksigenasi
menggunakan katalis Aluminosilikat redmud
Berdasarkan hasil analisis terhadap aktivitas katalitik katalis aluminosilikat dari sumber alam,
menunjukkan bahwa hasil produk biojetfuel yang dihasilkan didominasi oleh senyawa aromatic yang sesuai
dengan karakter jet fuel yang ditetapkan oleh IATA dan standar jet A. Komposisi senyawa aromatic telah
memenuhi range standar senyawa aromatic untuk jetfuel. Oleh karena itu penelitian ini memiliki potensi
untuk pengembangan biojetfuel dari minyak kemiri sunan menggunakan katalis aluminosilikat berbasis
sumber alam lokal.
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4 Sintesis ZSM-5 dari sumber kaolin
Untuk mengetahui pengaruh sumber mineral pada produksi biojetfuel, sintesis aluminosilikat dalam
bentuk ZSM-5 dari kaolin juga dilakukan dengan metode hidrotermal dengan melakukan variasi waktu
hidrotermal tahap pertama dan juga variasi template. Variasi waktu hidrotermal yang dilakukan pada
penelitian ini adalah 3 jam, 6 jam dan 9 jam. Variasi template seperti silicalite dan TPAOH dilakukan untuk
mengetahui pada terbentuknya struktur mesopori pada material aluminosilikat.
Variasi terhadap waktu hidrotermal tahap pertama dilakukan untuk mengetahui karakteristik ZSM-
5 yang dihasilkan berdasarkan pengaruh transformasi material sumber silica alumina yang digunakan.
Metode sintesis aluminosilikat dari kaolin menggunakan precursor ludox dan pengarah struktur CTABr.
Pada penelitian ini sintesis ZSM-5 mesopori dilakukan pada pH basa karena pada pH tersebut di
dalam larutan akan terjadi polimerisasi ion-ion pembentuk zeolit. Pada pH > 6 terbentuk anion
Al(OH)4- atau AlO2
- yang merupakan anion pembentuk zeolit yang berasal dari sumber alumina.
Namun apabila larutan dalam keadaan asam yaitu pada pH 1 sampai 4 bentuk aluminium yang
dominan adalah [Al(H2O)6]3+. Keberadaan kation [Al(H2O)6]
3+tersebut akan menghambat
pembentukan kerangka aluminosilikat dari zeolit. Kerangka zeolit juga dipengaruhi oleh
keberadaan anion dari silikat. Pada pH > 12, akan terbentuk ion Si(OH)4-, yang merupakan ion
utama dalam proses pembentukan kerangka zeolite. Ludox (silika kolid) ditambahkan sebagai
sumber silika tambahan. Hal itu dikarenakan sumber silika yang dibutuhkan belum mencukupi
untuk terbentuknya ZSM-5. Aquades ditambahkan kembali ke dalam campuran tersebut sambil
diaduk selama 8 jam pada suhu kamar agar distribusi partikel merata. Aquades memiliki peranan
penting sebagai pelarut, mengubah sifat fisik dan kimia reaktan dan produk, serta mempercepat
reaksi.
Setelah di aduk selama 8 jam kemudian campuran di aging pada 70°C selama 6 jam. Aging
merupakan suatu proses yang mengacu antara pembentukan gel aluminosilikat dan tahap
kristalisasi. Aging memiliki efek penting pada pembentukan gel yang mempengaruhi nukleasi dan
kinetika pertumbuhan kristal zeolite. Proses aging berfungsi untuk meningkatkan nukleasi,
mengurangi waktu induksi dan kristalisasi. Selain itu, aging juga berperan dalam penataan ulang
ikatan dan struktur kimia dari fasa padat dan cair.
Tahap selanjutnya adalah proses kristalisasi pertama dengan metode hidrotermal pada 80°C
selama 3, 6, dan 9 jam. Proses tersebut terjadi secara kontinyu diawali dengan reaksi kondensasi
dan diikuti oleh polimerisasi larutan jenuh membentuk ikatan Si-O-Al. Selama proses hidrotermal
terjadi pembentukan jaringan ikatan Si-O-Al dan menghasilkan klaster (prekursor ZSM-5) yang
berukuran nano (nanokristal). Nanoklaster ini kemudian akan mengalami penataan menjadi
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aggregat yang lebih besar melalui pemanasan. Setelah melalui proses hidrotermal maka proses
kristalisasi pertama dihentikan agar pertumbuhan kristal tidak terus berlangsung yang dapat
menyebabkan terbentuknya partikel ZSM-5 yang lebih besar. Penggabungan partikel-partikel
tersebut akan semakin sulit untuk pembentukan mesostruktur dengan adanya penambahan surfaktan
CTABr, sehingga pada proses kristalisasi tahap pertama sangat berpengaruh terhadap pembentukan
pori yang berukuran meso pada tahap selanjutnya. Dengan mevariasi waktu hidrotermal tahap
pertama diharapkan dapat menghasilkan strukturmeso yang lebih banyak.
Penambahan surfaktan CTABr selanjutnya dilakukan dengan rasio mol Si/CTABr =3,85.
Setelah penambahan CTABr campuran dipanaskan pada suhu 150°C selama 24 jam untuk
kristalisasi tahap kedua. Surfaktan CTABr berfungsi sebagai pengarah struktur mesopori. Proses
kristalisasi kedua merupakan tahap kristalisasi pembentukan pori berukuran meso dimana terjadi
interaksi antara surfaktan dengan nanopartikel aluminosilikat. Setelah proses kristalisasi tahap
kedua selesai, padatan yang terbentuk dicuci dengan aquades dengan cara disaring sampai hasil
filtratnya mempunyai pH netral. Selanjutnya, padatan tersebut dipanaskan pada suhu 60ºC selama
24 jam untuk menghilangkan air. Penghilangan air pada suhu rendah dilakukan agar air keluar
secara perlahan sehingga tidak merusak kerangka Si-O-Al yang sangat rapuh. Padatan yang
terbentuk kemudian dikalsinasi pada suhu 550 ºC selama 1 jam dengan kenaikan suhu 2ºC/menit
menggunakan aliran gas nitrogen agar dekomposisi templat berlangsung perlahan sehingga tidak
merusak struktur kerangka dan memperkuat pembentukan ikatan aluminosilikat (Si-O-Al) yang
rapuh. Selanjutnya dikalsinasi pada suhu 550 °C selama 1 jam dengan aliran N2 dan 6 jam pada
udara bebas untuk menghilangkan templat organik (karbon) dan menguatkan jaringan Si-O-Al.
5 Karakterisasi material ZSM-5 dengan variasi waktu
5.1 FTIR
Material ZSM-5 hasil sintesis dengan variasi waktu hidrotermal pertama 3, 6 dam 9 jam dilakukan
karakterisasi FTIR untuk mengetahui gugus fungsi ZSM-5. Hasil karakterisasi FTIR ZSM-5 disajikan pada
Gambar 7. Berdasarkan spectra FTIR ZSM-5 pada gambar 7 diketahui bahwa pada semua variasi waktu
hidrotermal pertama 3, 6 dan 9 jam telah terbentuk gugus fungsi khas ZSM-5. Seluruh katalis yang telah
disintesis menunjukkan puncak serapan karakteristik dari aluminosilikat, yaitu puncak serapan pada
bilangan gelombang sekitar 3400-3500 cm-1 yang merupakan puncak serapan khas dari vibrasi ulur
–OH [1], sedangkan puncak serapan pada bilangan gelombang 1629 cm-1 menandakan adanya
vibrasi tekuk –OH. Puncak serapan khas untuk vibrasi tekuk Si-O-Si, dan Si-O-Al terlihat pada
daerah bilangan gelombang 1012, dan 1031 cm-1. Vibrasi ulur Si-O pada tetrahedral SiO4
menunjukkan puncak serapan pada bilangan gelombang 746, 798, dan 914 cm-1 [4]. Puncak serapan
pada bilangan gelombang 450 cm-1 yang dihasilkan karena adanya vibrasi ikatan T-O-T (T adalah atom Al
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atau Si). Pada bilangan gelombang 550 cm-1 menunjukkan adanya vibrasi stretching asimetri dari D5R
(double five-membered ring) yang merupakan karakteristik dari struktur zeolite pentasil tipe MFI.
Sedangkan pada bilangan gelombang 795 dan 1225 cm-1 merupakan vibrasi streching eksternal simetri dan
asimetri dari T-O-T.
Secara umum semua ZSM-5 dengan variasi waktu hidrotermal 3, 6, 9 jam terdapat puncak serapan
pada 910 cm-1 yang menunjukkan adanya serapan pengarah struktur yaitu CTABr yang memungkinkan
terbentiknya struktur meso pada ZSM-5.
Gambar 7 Spektra FTIR ZSm-5 3 jam, ZSM-5 6 jam, ZSM-5 9 jam
5.2 XRD
Pola difraksi sinar-X ZSM-5 dari kaolin dengan variasi waktu hidrotermal 3,6 dan 9 jam
ditunjukkan pada Gambar 8 . Hasil karakterisasi XRD dari sampel ZSM-5 3, 6, dan 9 jam
menunjukkan puncak- puncak karakteristik dari kaolin pada 2θ disekitar 12°, 20°-25° dan 35°-40°
telah hilang yang menunjukkan bahwa telah terbentuk ZSM-5. Puncak-puncak karakteristik dari
kaolin muncul pada 2θ di sekitar 12° yang merupakan fase kaolinit, puncak di sekitar 20° yang
merupakan fase musqovit, puncak tinggi di sekitar 25° yang merupakan fase kaolinit serta puncak
di sekitar 35°- 40° merupakan fase musqovit dan kaolinit. Puncak karakteristik dari kaolin tidak
terdapat pada semua ZSM-5 3 jam, ZSM-5 6 jam dan ZSM-5 9 jam. Hal ini mengindikasikan bahwa
11
kaolin telah bereaksi dan mengalami transformasi menjadi ZSM-5. Puncak karakteristik difraksi
dari semua sampel pada 2θ sekitar 7,89°; 8,8°; 23,04°; 23,87° dan 24,32° merupakan karakteristik
ZSM-5 dengan struktur MFI [5].
Berdasarkan gambar difraksi sinar X pada gambar 8, terlihat bahwa pada sampel ZSM-5 3 jam
terdapat gundukan (hump) puncak pada 2θ sekitar 23°. Hal ini menunjukkan bahwa pada ZSM-5
dengan variasi waktu hidrotermal pertama 3 jam memiliki fasa amorf. Pada sampel ZSM-5 6 jam
dan 9 jam fasa yang terbentuk lebih kristalin dan tidak terdapat hump pada 2θ 23°. Semakin lama
waktu hidrotermal pertama, maka kristalinitas ZSM-5 semakin tinggi. Puncak pada 2θ 20-23° yang
lebih tinggi intensitasnya dibandingkan dengan puncak pada 2θ 7-9° pada semua variasi waktu
hidrotermal pertama pada katalis ZSM-5 mengkonfirmasi adanya kemungkinan simetri ortorombik
pada ZSM-5 [6].
Gambar 8. Difraksi sinar X ZSM-5 3 jam, ZSM-5 6 jam, ZSM-5 9 jam
5.3 Karakterisasi SEM-EDX ZSM-5
Katalis ZSM-5 dari sumber kaolin juga dikarakterisasi dengan SEM-EDX untuk mengetahui
morfologi dan bentuk partikel dari ZSM-5 hasil sintesis. Hasil SEM-EDX sampel ZSM-5 ditunjukkan pada
Gambar 9. Berdasarkan gambar 9 dapat diketahui pada semua sampel ZSM-53 jam, ZSM-5 6 jam dan ZSM-
5 9 jam memiliki distribusi partikel yang cukup merata dan tidak tampak agregat partikel. Perbedaan
12
kristalinitas dari sampel ZSM-5 pada variasi waktu hidrotermal pertama 3 jam, 6 jam dan 9 jam tidak terlihat
secara signifikan. Pada sampel ZSM-5 3 jam terlihat distribusi partikel yang lebih merata dibandingkan
dengan sampel ZSM-5 6 jam dan ZSM-5 9 jam. Hal ini menunjukkan bahwa semakin pendek waktu
hidrotermal pertama akan semakin menghasilkan struktur mesopori yang seragam. Selain itu lebih sedikitnya
pembentukan agregat pada sampel ZSM-5 3 jam dibandingkan dengan sampel ZSM-5 6 jam dan 9 jam juga
memungkinkan semakin terbentuknya pori intrapartikelyang lebih banyak dengan waktu hidrotermal yang
lebih pendek. Hal ini sejalan dengan hasil penelitian Chen, et al., (2017) yang menunjukkan bahwa semakin
lama waktu hidrotermal maka akan semakin meningkatkan agregasi partikel [7]
Gambar 9. Foto SEM katalis ZSM-5 3 jam (a), ZSM-5 6 jam (b) dan ZSM-5 9 jam (c)
a b
c
13
Gambar 10. Kurva TGA sampel ZSM-5 3jam (a), ZSM-5 6 jam (b) dan ZSM-5 9 jam (c)
14
5.4 TGA
Analisis terhadap penghilangan berat katalis ZSM-5 dilakukan dengan metode analisis TGA-DTA..
Karakterisasi TGA-DTA juga bertujuan untuk mengetahui jumlah TPAOH yang masuk atau terinkoporasi
ke dalam ZSM-5 [8]. Hasil karakterisasi TGA-DTA disajikan pada Gambar 10. Berdasarkan hasil analisis
TGA-DTA sampel ZSM-5 seperti ditunjukkan pada gambar 10, terlihat bahwa ketiga sampel ZSM-5 hasil
sintesis dengan variasi waktu hidrotermal 3 jam, 6 jam dan 9 jam memiliki tiga tahap penurunan berat yaitu
pada suhu antara 30-110 oC, 110-350 oC dan 350-550 oC. Penurunan berat pada range suhu 30-110
merupakan penghilangan air yang teradsorb secara fisik pada permukaan ZSM-5. Penurunan berat kedua
pada suhu sekitar 110-350 oC menunjukkan penghilangan template organik dan kristal air. Penghilangan
template organic pada penurunan berat keduaini berasal dari ion TPA+ yang terikat dalam struktur defek Si-
O [9]. Penurunan berat ketiga pada suhu 350-550 oC merupakan indikasi penghilangan template organic
kation TPA+ di dalam channel/jaringan ZSM-5.
Dari data TGA pada gambar 10, diketahui bahwa ZSM-5 3 jam mengalami penurunan persen berat
sebesar 15% pada suhu sekitar 150 oC, sedangkan ZSM-5 6 jam mengalami penurunan persen berat sebesar
10% dan ZSM-5 9 jam mengalami penurunan persen berat sebesar 12%. Hal ini menunjukkan bahwa ZSM-
5 3 jam mengandung lebih banyak TPAOH dalam struktur ZSM-5 yang menandakan kemungkinan
membentuk struktur mesopori yang lebih besar dibandingkan ZSM-5 6 jam dan ZSM-5 9 jam.
6. Uji Aktivitas Katalitik ZSM-5 dengan Minyak Kemiri Sunan
Uji aktivitas katalitik katalis ZSM-5 variasi waktu hidrotermal 3 jam dan 6 jam dilakukan pada reaksi
hidrodeoksigenasi minyak kemiri sunan dengan kondisi reaksi 3% katalis, temperatur reaksi 350 oC, waktu
reaksi 1 jam,dan aliran gas hydrogen 100 mL/menit sebagai studi pendahuluan. Hasil analisis biojetfuel
menggunakan instrument GC-MS dari reaksi hidrodeoksigenasi minyak kemiri sunan dengan katalis ZSM-
5 menunjukkan hasil komposisi produk biojetfuel meliputi, aromatic, cyclic, oksigenate dan hidrokarbon.
Data persen komposisi sampel katalis ZSM-5 3 jam dan 6 jam disajikan pada gambar 11.
Gambar 11. Distribusi komposisi biofuel hasil reaksi hirodeoksigenasi minyak kemiri sunan dengan
katalis ZSM-5
7. Karakterisasi Aluminosilikat dengan variasi template
7.1 FTIR
15
Spektroskopi inframerah digunakan untuk menentukan gugus fungsional yang terdapat pada
sampel yang telah disintesis. Kaolin sebagai sumber silika dan alumina menunjukkan adanya
serapan pada bilangan gelombang 538 cm-1 yang merupakan vibrasi karakteristik dari ikatan Al-O
pada Al[O(OH)]6, serapan pada 789 and 914 cm-1 menunjukkan adanya vibrasi dari ikatan (Al-O)-
H pada Al[O(OH)]6. Vibrasi ikatan Si-O dari from SiO4 terdapat pada bilangan gelombang 430,
470, 752, 795, 1032 and 1114 cm-1. Spektra FTIR dari semua sampel menunjukkan serapan
karakteristik yang sama dengan ZSM-5 pada bilangan gelombang 450,550, 795, 1100 and 1225 cm-
1. Pita serapan pada bilangan gelombang 450 cm-1 dihasilkan dari vibrasi tekuk T-O-T (T adalah
atom Al atau Si); 550 cm-1 merupakan vibrasi stretching asimetris dari cincin D5R yang merupakan
karakteristik struktur zeolit tipe-pentasil MFI; 795 dan 1225 cm-1 masing-masing berkontribusi
terhadap peregangan simetris eksternal dan stretching asimetris; dan pita pada 1100 cm -1 berasal
dari vibrasi stretching asimetris internal T-O-T (antara tetrahedral TO4) [9,10]. Spektra IR pada
Gambar 1 menunjukkan bahwa pita serapan Al-MCM-41 pada 550 cm-1 memiliki intensitas
terendah. Menurut Chen et al., pita serapan pada 550 cm-1 merupakan pita serapan karakteristik dari
cincin D5R ZSM-5 [11]. Somani et al., melaporkan bahwa peningkatan intensitas pita serapan 550
cm-1 menunjukkan peningkatan konsentrasi fase MFI dan kristalinitas [12]. Hasil ini sesuai dengan
hasil XRD seperti yang ditunjukkan pada Gambar 13.
Spektrum inframerah piridin yang diadsorpsi semua sampel aluminosilikat ditunjukkan pada
Gambar 12 dan jumlah situs asam dirangkum dalam Tabel 1. Adsorpsi piridin dalam temperatur
berbeda dilakukan untuk menentukan kekuatan asam dan jumlah keasaman dalam sampel padatan.
Pita absorpsi pada bilangan gelombang sekitar 1450 dan 1540 cm-1 berkontribusi terhadap
keberadaan nitrogen piridin yang terikat secara koordinatif dengan situs asam Lewis dan diserap
secara kimia pada situs asam Brønsted pada permukaan katalis [13]. Sementara itu, penyerapan
puncak sekitar 1488 cm-1 berhubungan dengan piridin teradsorpsi pada situs asam Lewis dan
Brønsted [2]. Seperti yang ditampilkan pada Gambar 1 dan Tabel 1, sampel T-ZSM-5 memiliki
jumlah situs asam Brønsted terbesar yang akan meningkatkan rasio Brønsted/Lewis (B / L),
kemudian diikuti oleh S-ZSM-5 dan Al-MCM-41. Seperti yang dilaporkan dalam penelitian
sebelumnya oleh Zhang et al (2017) peningkatan konsentrasi ion TPA + akan secara signifikan
meningkatkan situs asam Brønsted [14]. Hasil ini menunjukkan bahwa template TPAOH yang
digunakan dalam sintesis akan mempengaruhi pembentukan situs asam karena terbentuknya
extraframework tetrahedral alumina.
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Tabel 1. Jumlah situs asam Bronsted dan Lewis menggunakan adsorpsi piridin
Sampel
Jumlah situs asam
(mmol/g) B/L L/B
Brønsted Lewis B+L
S-ZSM-5 (150 0C) 0.072 0.158 0.230 0.455 2.194
S-ZSM-5 (300 0C) 0.038 0.089 0.127 0.426 2.342
T-ZSM-5 (150 0C) 0.108 0.284 0.392 0.380 2.629
T-ZSM-5 (300 0C) 0.073 0.198 0.271 0.369 2.712
Al-MCM-41 (150
0C) 0.054
0.296 0.350 0.182 5.481
Al-MCM-41 (300
0C) 0.014
0.234 0.248 0.059 16.710
Gambar 12. Spektra FTIR (a) dan adsorpsi piridin (b) pada kaolin, Al-MCM-41, ZSM-5 yang
disintesis menggunakan TPAOH (T-ZSM-5) dan ZSM-5 yang disintesis menggunakan silikalit (S-
ZSM-5).
b. XRD
Pola difraktogram ditampilkan pada Gambar 13 digunakan untuk mengidentifikasi fasa dari semua
sampel yang telah disintesis. Pola difraktogram dari kaolin menunjukkan adanya fasa kaolinit
17
dengan munculnya puncak pada 2θ = 12.3, 19.7, 20.3, 24.8, 26.6, 34.9, 36.1, 37.5, 38.2, 39 dan
45.2°. Hasil ini sesuai dengan hasil penelitian sebelumnya yang dilaporkan oleh Hartanto et al.,
(2016) [9]. Fasa amorf dari aluminosilikat seperti MCM-41 diperoleh pada sampel Al-MCM-41.
Puncak melebar pada 2θ = 15-30° mengindikasikan terbentuknya struktur amorf silika seperti
MCM-41 seperti yang telah dilaporkan oleh Tran et al., (2016) [15]. Pola XRD sudut pendek
menunjukkan adanya tiga puncak difraksi yang merupakan difraksi bidang (100), (110) and (200)
yang menunjukkan terbentuknya struktur heksagonal yang teratur dari aluminosilikat [16,17].
Sedangkan pada sampel S-ZSM-5 dan T-ZSM-5 terdapat puncak karakteristik dari ZSM-5 pada 2θ
= 7.8, 8.7, 23, 23.8 dan 24° dengan intensitas yang tinggi. Pada sampel S-ZSM-5 hanya memiliki
satu puncak dengan intensitas yang rendah bidang difraksi (100) yang menunjukkan jumlah pori
teratur yang lebih sedikit (Li et al., 2013). Hasil ini menunjukkan bahwa adanya template organik
seperti TPAOH dan silicate seed-1 akan mempengaruhi terbentuknya struktur ZSM-5.
Gambar 13. (a) sudut panjang dan (b) sudut pendek XRD dari kaolin, Al-MCM-41, T-ZSM-5 dan
S-ZSM-5.
c. 29Si-NMR
Analisis dari 29Si MAS NMR memberikan informasi mengenai interaksi atom silika pada
framework aluminosilikat. 29Si MAS NMR dari S-ZSM-5 menunjukkan adanya 3 puncak
dekonvolusi pada pergeseran kimia -86, -97 dan -110 ppm (Gambar 14). Sinyal yang muncul pada
-110 dan -97 ppm merupakan sinyal Q4 dari ikatan Si(SiO)4 [18] dan situs Si(OSi)3OAl [19,20].
Pada T-ZSM-5, terjadi pergeseran puncak menjadi -111 dan -101 ppm yang diasumsikan dari
kristalinitasnya yang tinggi dibandingkan dengan S-ZSM-5 [21]. S-ZSM-5 menunjukkan adanya
18
puncak resonansi yang lemah pada -86 ppm yang merupakan sinyal Q3 situs Si(OSi)3OH dari fase
amorf ZSM-5. Sinyal 29Si MAS NMR dari Al-MCM-41 muncul pada pergeseran kimia -83 dan -
89 yang merupakan situs Q3 dari Si(OSi)3(OH) dan Q4 Si(OSi)3Al. Adanya resonansi Q3
menunjukkan adanya transformasi parsial dari Si(SiO)3Al menjadi Si(SiO)3(OH). Al-MCM-41
menunjukkan puncak resonansi broad akibat adanya overlapping dari puncak ganda pada
pergeseran kimia -97 dan -108 ppm yang merupakan situs Q4 unit Si(SiO)4. Komposisi elemen dari
Si dan Al ditentukan menggunakan data dekonvolusi dari 29Si MAS NMR yang ditampilkan pada
Tabel 2. Rasio Si/Al dari katalis ZSM-5 dan Al-MCM-41 berada pada range 22-26.
Gambar 14. Spektra dekonvolusi 29Si NMR dari S-ZSM-5 (a), T-ZSM-5 (b) dan Al-MCM-41 (c)
Tabel 2. Pergeseran kimia dan rasio Si/Al dari 29Si NMR
Samples
Pergeseran kimia (ppm) dan luas puncak dekonvolusi (%)
Si/Al Q4 (4Si, 0Al) Q4 (4Si, 0Al) Q4 (3Si, 1Al) Q3 (3Si, 1OH)
S-ZSM-5 -110 (84.87)
- -97 (13.09) -86 (2.04) 26.44
- 24.46
19
T-ZSM-5 -111 (83.65) - -101 (16.35)
Al-MCM-
41 -108 (42.86) -97 (28.95) -89 (14.92) -83 (13.27) 22.61
2. Reaksi deoksigenasi Jatropha Curcas Oil (JCO) menggunakan katalis aluminosilikat
Reaksi deoksigenasi dari JCO dilakukan pada temperatur 350 ℃ selama 1 jam menggunakan
atmosfir nitrogen. Hasil reaksi deoksigenasi JCO pada katalis S-ZSM-5, T-ZSM-5 dan Al-MCM-
41 ditampilkan pada Tabel 3. Al-MCM-41 memberikan konversi yang paling tinggi yakni 20,04%
dibandingkan katalis T-ZSM-5 dan S-ZSM-5 sebesar 9,97% dan 6,73%. Produk cair yang diperoleh
selanjutnya dianalisis menggunakan GC-MS. Reaksi deoksigenasi menggunakan katalis S-ZSM-5
menghasilkan produk dominan oksigenat sebesar 48,16% dan hidrokarbon sebesar 45,94%.
Senyawa oksigenat meliputi asam karboksilat, aldehid dan eter. Sedangkan diperoleh sikloalkana
sebesar 3.25%. Selektivitas hidrokarbon semakin meningkat menjadi 65,78% ketika menggunakan
katalis T-ZSM-5 dan menurunkan komposisi oksigenat menjadi 26,37%. Al-MCM-41 memberikan
selektivitas yang tinggi pada terbentuknya komponen hidrokarbon yakni 83,68% dan oksigenat
4,77%. Peningkatan mesoporositas pada ZSM-5 ketika menggunakan silikalit sebagai template
akan menurunkan aktivitas katalitik reaksi deoksigenasi dan hanya diperoleh nilai konversi yang
rendah. S-ZSM-5 memiliki konsentrasi asam yang rendah jika dibandingkan dengan T-ZSM-5 dan
Al-MCM-41. Hal ini mengindikasikan bahwa reaksi deoksigenasi merupakan reaksi katalisis asam
sehingga peningkatan situs asam akan meningkatkan konversi minyak menjadi hidrokarbon.
Table 3. Konversi dan selektivitas produk pada reaksi deoksigenasi JCO
Catalysts Xoils, %
Selektivitas
Hidrokarbon, %
Selektivitas
Sikloalkana, % Oksigenat, %
S-ZSM-5 6.73 45.94 3.25 48.19
T-ZSM-5 9.97 65.78 6.35 26.37
Al-MCM-41 20.04 83.68 11.52 4.77
20
Gambar 15. Distribusi rantai hidrokarbon pada reaksi deoksigenasi JCO
Analisis komposisi JCO menunjukkan adanya 70% asam lemak tidak jenuh yang tersusun atas
campuran asam oleat (C18:1) dan asam linoleat (C18:2), 20% asam lemak jenuh palmitat (C16:0)
[22]. Selanjutnya, analisis mengenai hidrokarbon yang dihasilkan dari reaksi deoksigenasi JCO
ditampilkan pada Gambar 15. Al-MCM-41 menunjukkan selektivitas yang tinggi pada n-C15+n-
C17. Reaksi deoksigenasi JCO akan menghasilkan rantai hidrokarbon paraffin dengan jumlah atom
karbon adalah n-1 dimana n adalah jumlah rantai karbon dari asam lemak JCO. Terbentuknya fraksi
hidrokarbon (C8-14) diperoleh saat menggunakan katalis S-ZSM-5 dan T-ZSM-5 yang akan
menurunkan selektivitas pada terbentuknya fraksi diesel hidrokarbon (n-C15+n-C17). Rantai
hidrokarbon pendek dihasilkan dari reaksi hydrocracking rantai asam lemak JCO.
Selanjutnya, reaksi deoksigenasi JCO dilakukan pada temperatur 350 ℃ dengan variasi waktu 1-4
jam pada katalis Al-MCM-41. Konversi JCO menjadi produk cair semakin meningkat dari 20%
menjadi 45% pada waktu reaksi selama 4 jam (Gambar 16). Komposisi hidrokarbon dibagi menjadi
dua yakni range diesel (C11-18) dan range gasoline (C8-10). Selektivitas hidrokarbon n-C11-18
mencapai 90% pada reaksi deoksigenasi JCO.
21
Gambar 16. Hasil konversi JCO (a) dan selektivitas hidrokarbon pada Al-MCM-41 dengan variasi
waktu reaksi deoksigenasi. Komposisi hidrokarbon dibagi menjadi dua fraksi yakni fraksi gasoline
(C8-10) dan fraksi diesel (C11-18)
JCO dan produk cair selanjutnya dikarakterisasi menggunakan FTIR untuk mengetahui
tahap/mekanisme terjadinya reaksi deoksigenasi (Gambar 17a). Spektra FTIR JCO menunjukkan
adanya vibrasi –CH stretching dari rantai alifatik pada 2925 cm-1, vibrasi stretching ester –C=O
pada 1735 cm-1, vibrasi stretching C-O-C pada 1161 cm-1, vibrasi bending –CH alkane dan =CH
alkena pada 1453 dan 717 cm-1. Pita serapan absorpsi pada ester –C=O dan karbonil C-O-C
merupakan karakteristik dari spesi oksigenat trigliserida yang dapat digunakan untuk mengetahui
mekanisme reaksi deoksigenasi [23]. Terjadi pergeseran serapan vibrasi stretching –C=O dari
produk cair dari 1735 cm-1 (grup ester) menjadi 1700 cm-1 (grup asam karboksilat) setelah 1 jam
reaksi. Hal ini mengindikasikan terjadinya disosiasi ikatan ester untuk membentuk senyawa
intermediate asam lemak [24]. Analisa menggunakan FTIR juga mendukung terjadinya eliminasi
ikatan C-O-C pada gugus karbonil JCO yang dibuktikan dengan hilangnya serapan pada 1161 cm-
1[25]. Hasil analisis FTIR ini menunjukkan bahwa pada tahap awal terjadi transformasi trigliserida
menjadi asam lemak yang terjadi pada katalis asam. Seiring dengan bertambahnya waktu reaksi
menjadi 4 jam, terjadi pengurangan intensitas serapan pada –C=O yang menunjukkan terjadinya
eliminasi fragmen karboksilat dari asam lemak. Produk gas yang dihasilkan selama reaksi
deoksigenasi JCO selanjutnya dikarakterisasi menggunakan GC-TCD untuk mengetahui jenis gas
yang terlibat dalam reaksi. Hasil analisa gas ditampilkan pada Gambar 17b. Pada 1 jam reaksi
dihasilkan gas CO2 yang menunjukkan terjadinya reaksi dekarboksilasi. Penambahan waktu reaksi
akan menurunkan jumlah CO2 yang dihasilkan dan meningkatkan jumlah gas CO. Hal ini
mengindikasikan bahwa reaksi dekarbonilasi mendominasi reaksi dan dihasilkan hidrokarbon
dengan rantai ikatan tidak jenuh.
22
Gambar 17. Spektra FTIR dari JCO dan produk cair (a) dan analisis produk gas pada reaksi
deoksigenasi JCO (b)
23
BAB III STATUS LUARAN
Status luaran yang ditargetkan pada penelitian ini yaitu luaran wajib pada jurnal ilmiah internasional
masih dalam tahap under review pada jurnal Microporous and Mesoporous Materials (Q1). Luaran tambahan
yaitu seminar internasional telah dilaksanakan pada 6-7Oktober 2020 pada forum ICCME 2020 (The 4th
International Chemical Conference on Material and Engineering) yang diselenggarakan oleh Universitas
Diponegoro.
24
BAB IV PERAN MITRA (UntukPenelitian Kerjasama Antar Perguruan Tinggi)
Penelitian ini tidak memiliki mitra.
25
BAB V KENDALA PELAKSANAAN PENELITIAN
Kendala yang dihadapi selama pelaksanaan penelitian adalah adanya pandemi Covid-19 di Indonesia
yang menyebabkan kegiatan penelitian di laboratorium sedikit terhambat dan terkendala layanan analisis
instrument untuk karakterisasi material dan uji aktivitas katalitik yang belum beroperasi maksimal sehingga
data eksperimen belum mencapai target. Hambatan lainnya yaitu keterbatasan alat yang digunakan untuk
reaksi hidrodeoksigenasi yang membuthkan waktu lama untuk membuat reaktor. Lamanya waktu yang
diperlukan untuk analisa material, hal ini dikarenakan terbatasnya jumlah instrument analisis material di
Indonesia untuk karakterisasi seperti N2 adsorpsi desorpsi dan TEM, banyaknya antrian menyebabkan waktu
yang diperlukan untuk analisis menjadi lama. Karakterisasi material menggunakn N2 adsorpsi dilakukan di
UII dan ITS diperlukan waktu 1-2 bulan. Karakterisasi material menggunakan TEM di Indonesia hanya bisa
dilakukan di ITB, waktu tunggu hingga mendapat jadwal karakterisasi antara 2 minggu – 1 bulan. Penelitian
tentang produksi biojetfuel dari minyak kemiri sunan ini termasuk topik penelitian baru di dalam Grup Riset
Material dan Energi, sehingga diperlukan setting alat dan pemahaman mengenai desain dan rangkaian
reaktor. Banyak kendala yang dialami dalam tahapan ini, diantaranya kesulitan dalam menyusun rangkaian
alat hingga kendala kebocoran gas.Kesulitan lain yang dihadapi adalah dalam penulisan paper publikasi,
dikarenakan kurangnya media yang dapat memfasilitasi dalam penulisan artikel ilmiah yang baik.
26
BAB VI RENCANA TAHAPAN SELANJUTNYA
Rencana tahapan penelitian selanjutnya adalah melanjutkan sintesis katalis dari sumber kaolin serta
uji aktivitas katalitik menggunakan minyak kemiri sunan dengan variasi parameter kondisi reaksi yang
berbeda. Selain itu juga akan dilakukan penyempurnaan penyusunan draf artikel imiah untuk publikasi pada
jurnal internasional.
27
BAB VII DAFTAR PUSTAKA
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Seed-assisted, template-free synthesis of ZSM-5 zeolite from natural aluminosilicate
minerals, Appl. Clay Sci. 158 (2018) 177–185. https://doi.org/10.1016/j.clay.2018.03.025.
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(2019) 53–60. https://doi.org/10.1016/j.micromeso.2018.12.014.
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by microwave radiation: Synthesis of ZSM-5, Mater. Chem. Phys. 82 (2003) 538–545.
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[13] H. Li, Y. Wang, F. Meng, H. Chen, C. Sun, S. Wang, Direct synthesis of high-silica nano
ZSM-5 aggregates with controllable mesoporosity and enhanced catalytic properties, RSC
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[14] C. Zhang, H. Chen, X. Zhang, Q. Wang, TPABr-grafted MWCNT as bifunctional template
to synthesize hierarchical ZSM-5 zeolite, Mater. Lett. 197 (2017) 111–114.
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guaiacol on Al-MCM-41 supported Ni and Co catalysts, Appl. Catal. A Gen. 512 (2016) 93–
100. https://doi.org/10.1016/j.apcata.2015.12.021.
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C18 fatty acids over HAlMCM-41 molecular sieve, Biomass Convers. Biorefinery. 8 (2018)
159–167. https://doi.org/10.1007/s13399-017-0263-9.
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[17] D. Li, H. Min, X. Jiang, X. Ran, L. Zou, J. Fan, One-pot synthesis of Aluminum-containing
ordered mesoporous silica MCM-41 using coal fly ash for phosphate adsorption, J. Colloid
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[18] T.C. Hoff, D.W. Gardner, R. Thilakaratne, J. Proano-Aviles, R.C. Brown, J.P. Tessonnier,
Elucidating the effect of desilication on aluminum-rich ZSM-5 zeolite and its consequences
on biomass catalytic fast pyrolysis, Appl. Catal. A Gen. 529 (2017) 68–78.
https://doi.org/10.1016/j.apcata.2016.10.009.
[19] E.C. Santos, L.S. Costa, E.S. Oliveira, R.A. Bessa, A.D.L. Freitas, C.P. Oliveira, R.F.
Nascimento, A.R. Loiola, Al-MCM-41 synthesized from kaolin via hydrothermal route:
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Chem. Soc. 29 (2018) 2378–2386. https://doi.org/10.21577/0103-5053.20180115.
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sulfide catalysts for HYD and HDS via in situ hydrogen generation through a WGSR, Catal.
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[21] S. Mintova, V. Valtchev, T. Onfroy, C. Marichal, H. Knözinger, T. Bein, Variation of the
Si/Al ratio in nanosized zeolite Beta crystals, Microporous Mesoporous Mater. 90 (2006)
237–245. https://doi.org/10.1016/j.micromeso.2005.11.026.
[22] N. Asikin-Mijan, H. V Lee, G. Abdulkareem-alsultan, A. Afandi, Production of green diesel
via cleaner catalytic deoxygenation of Jatropha curcas oil, J. Clean. Prod. 167 (2017) 1048–
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[23] M. Safa Gamal, N. Asikin-Mijan, M. Arumugam, U. Rashid, Y.H. Taufiq-Yap, Solvent-free
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29
BAB VIII LAMPIRAN
LAMPIRAN 1. Tabel Daftar Luaran
Program :
Nama Ketua Tim : Prof. Dr. Didik Prasetyoko, M.Sc
Judul : Biojetfuel Range Alkanes Production From Minyak Kemiri
Sunan (Reutealiss trisperm Oil) Via Hydrodeoxygenation
Reaction By Metal/Aluminosilicates From Local Source
1.Artikel Jurnal
No Judul Artikel Nama Jurnal Status Kemajuan*)
1. The effect of structure directing
agents on micro/mesopore
structures of aluminosilicates from
Indonesian kaolin as deoxygenation
catalysts
Microporous and
Mesoporous Materials
(Q1, IF: 4.551)
Under review
*) Status kemajuan: Persiapan, submitted, under review, accepted, published
2. Artikel Konferensi
No Judul Artikel Nama Konferensi (Nama
Penyelenggara, Tempat,
Tanggal)
Status Kemajuan*)
1 Biojetfuel Production From
Reutealis Trisperm Oil Over
Indonesian Red Mud Based
Catalyst
ICCME 2020, Undip
Semarang, 6-7 Oktober
2020
Terdaftar
*) Status kemajuan: Persiapan, submitted, under review, accepted, presented
3. Paten
No Judul Usulan Paten Status Kemajuan
*) Status kemajuan: Persiapan, submitted, under review
4. Buku
No Judul Buku (Rencana) Penerbit Status Kemajuan*)
*) Status kemajuan: Persiapan, under review, published
5. Hasil Lain
30
No Nama Output Detail Output Status Kemajuan*)
*) Status kemajuan: cantumkan status kemajuan sesuai kondisi saat ini
6. Disertasi/Tesis/Tugas Akhir/PKM yang dihasilkan
No Nama Mahasiswa NRP Judul Status*)
*) Status kemajuan: cantumkan lulus dan tahun kelulusan atau in progress
31
Lampiran 2. Bukti Abstrak Submitted pada Seminar ICCME 2020 dan paper submitted
Mmllml
Biojetfuel Production From Reutealis Trisperm Oil Over Indonesian Red Mud Based
Catalyst
D. Prasetyoko a*, D.K.Maharani a, Y. Kusumawati a
a Department of Chemistry, Faculty of Science and Analytical Data, Sepuluh Nopember Institute of
Technology , Surabaya, East Java, 59323, Indonesia. (Email:[email protected];
[email protected]; [email protected]; [email protected]
*Corresponding author
D.Prasetyoko, Department of Chemistry, Faculty of Science and Analytical Data, Sepuluh Nopember
Institute of Technology, Surabaya, East Java, 59323, Indonesia. (Email: [email protected])
Abstract
Redmud is one of caustic waste generated from by product of alumina by production. Composition
of redmud are Fe2O3, SiO2, Al2O3, TiO2 and other minor components [1-3]. Indonesian redmud
has been studied for hydrodeoxygenation reaction (HDO) of Reutalis trisperm oil which is non-
edible feedstock as potential catalyst for bio jet-fuel production. Aluminosilicates were synthesized
from Indonesian redmud has mesoporous structure with uniform particle size as confirmed by
TEM image and nitrogen adsorption isotherm data. Catalytic study of aluminosilicates mesopore
on HDO of Reutealis trisperm oil resulted in jetfuel range liquid product consist of hydrocarbon,
aromatic, cyclic and oxygenates component. Change in HDO liquid product composition were
confirmed on different structure of aluminosilicates mesopore form. At H+ form of aluminosilicates
mesopore catalyst, oxygenates product yield were 54.1% indicating slight decreased compared
to that 66.1% Na form. Ni loading on aluminosilicates mesopore of H+ form increase the aromatic
product into 31.8% and also reduce oxygenates content. This result was in accordance with
previouse study that state increasing Ni loading on redmud catalyst produced higher hydrocarbon
component in HDO of Pinyon janiper oil. Aromatic content in biojetfuel produced from this
research was fulfill the standart of JetA (ASTM) and JetA (IATA) which mean it has a possibility
for jet fuel commercial uses.
Keywords: biojetfuel; hydrodeoxygenation; redmud; aluminosilicates mesopore; Reutealis
trisperm oil
ICCME 2020 Abstract Template
32
33
Lampiran 3. Bukti paper tersubmit pada jurnal internasional
Microporous and Mesoporous Materials
The effect of structure directing agents on micro/mesopore structures ofaluminosilicates from Indonesian kaolin as deoxygenation catalysts
--Manuscript Draft--
Manuscript Number:
Article Type: Full length article
Keywords: Kaolin; hierarchical ZSM-5; Al-MCM-41, structure directing agents; bio-oildeoxygenation
Corresponding Author: Didik PrasetyokoInstitut Teknologi Sepuluh NopemberSurabaya, INDONESIA
First Author: Reva E Nugraha
Order of Authors: Reva E Nugraha
Didik Prasetyoko
Nurul Asikin-Mijan
Hasliza Bahruji
Suprapto Suprapto
Yun Hin Taufiq-Yap
Aishah Abdul Jalil
Abstract: Indonesian kaolin was successfully transformed into aluminosilicates (ALS) via twosteps hydrothermal method using different structure directing agents (SDA). Thecomparison of structure, porosity and catalytic activity of ALS produced using silicaliteseed and tetrapropyl ammonium hydroxide (TPAOH) as SDA were determined ascatalyst for deoxygenation of bio-oil. Cetyltrimethyl ammonium bromide (CTAB) wasadded during the second hydrothermal method to induce mesopores. Silicaliteproduced ZSM-5 with hierarchical structures, TPAOH obtained mainly microporesmeanwhile in the absence of SDA formed mesoporous Al-MCM-41. ZSM-5 frameworkwas rapidly formed when using TPAOH compared to silicalite, which has prevented theformation of mesostructure in the second crystallization processes. The variation ofsurface area, porosity and surface acidities of ALS affected the catalytic activity fordeoxygenation of bio-oil to hydrocarbon. The selectivity towards long-chain (C 11 -C18 ) hydrocarbon were significantly improved when increasing the mesoporosity ofALS.
Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation
1
The effect of structure directing agents on micro/mesopore structures 1
of aluminosilicates from Indonesian kaolin as deoxygenation catalysts 2
3
Reva Edra Nugraha1, Didik Prasetyoko1,*, Nurul Asikin-Mijan2, Hasliza Bahruji3, 4
Suprapto Suprapto1, Yun Hin Taufiq-Yap4,5, Aishah Abdul Jalil6,7 5
6
1Department of Chemistry, Faculty of Sciences, Institut Teknologi Sepuluh Nopember, 7
Keputih Sukolilo, Surabaya 60111, Indonesia 8
2Department of Chemical Sciences, Faculty of Science and Technology, Universiti 9
Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia 10
3Centre of Advanced Material and Energy Sciences, Universiti Brunei Darussalam, 11
Jalan Tungku Link, BE 1410, Brunei 12
4Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400, UPM 13
Serdang, Selangor, Malaysia 14
5Chancellery Office, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Sabah 15
6Department of Chemical Engineering, Faculty of Chemical and Energy Engineering, 16
Universiti Teknologi Malaysia, 81310, Skudai, Johor Bahru, Johor, Malaysia 17
7Centre of Hydrogen Energy, Institute of Future Energy, Universiti Teknologi Malaysia, 18
81310, Skudai, Johor Bahru, Johor, Malaysia 19
20
*Corresponding author: [email protected]; [email protected] 21
Telp. +62-31-5943353; fax: +62-31-5928314 22
23
Manuscript Click here to access/download;Manuscript;Manuscript MicmatReva.docx
Click here to view linked References
2
Abstract 24
Indonesian kaolin was successfully transformed into aluminosilicates (ALS) via two 25
steps hydrothermal method using different structure directing agents (SDA). The 26
comparison of structure, porosity and catalytic activity of ALS produced using silicalite 27
and tetrapropyl ammonium hydroxide (TPAOH) as SDA were determined as catalyst 28
for deoxygenation of bio-oil. Cetyltrimethyl ammonium bromide (CTAB) was added 29
during the second hydrothermal method to induce mesopores. Silicalite produced ZSM-30
5 with hierarchical structures, TPAOH obtained mainly micropores meanwhile in the 31
absence of SDA formed mesoporous Al-MCM-41. ZSM-5 framework was rapidly 32
formed when using TPAOH compared to silicalite, which has prevented the formation 33
of mesostructure in the second crystallization processes. The variation of surface area, 34
porosity and surface acidities of ALS affected the catalytic activity for deoxygenation of 35
bio-oil to hydrocarbon. The selectivity towards long-chain (C11-C18) hydrocarbon were 36
significantly improved when increasing the mesoporosity of ALS. 37
38
Keyword: Kaolin; hierarchical ZSM-5; Al-MCM-41, structure directing agents; bio-oil 39
deoxygenation 40
41
1. Introduction 42
Development of renewable energy is recognised as route to fulfil the increasing energy 43
demand and to tackle the environmental issue associated with the fossil fuel 44
consumption. Integrated catalytic conversion of biomass as carbon feedstock to fuel has 45
received tremendous attention since the development of the first generation biodiesel in 46
3
2008 [1]. Biodiesel is consisted of fatty acid methyl ester (FAME) produced from 47
transesterification reaction of oil from plant or animal [2]. However, FAME consisted 48
of high oxygen content that contributed to the low heat value of biodiesel (HV) [3–7]. 49
Biodiesel also exhibited poor oxidation and cold-flow properties that affected the 50
performance in the conventional engine [8,9]. Green diesel with petrodiesel-like 51
structures with C12-22 of hydrocarbons composition exhibits enhanced properties than 52
biodiesel [1]. Green diesel was produced from deoxygenation reaction via elimination 53
of carboxyl group in fatty acid. The reaction occurred under H2-free atmosphere and 54
produced hydrocarbon with one atom carbon shorter than the corresponded fatty acid 55
(C(n-1)) [10,11]. Jathropa curcas oil (JCO) as non-edible oil can be cultivated on 56
marginal land with low rainfall areas, and showed high durability to withstand pest and 57
drought [12]. JCO is consisted of saturated and unsaturated long chain fatty acids that 58
was ideal for deoxygenation to green diesel [13,14]. Deoxygenation reaction were often 59
performed in the presence of organic solvent like decalin, dodecane, hexane and 60
methanol [13,15–19]. Solvent free deoxygenation reaction reduced the cost of product 61
purification and waste disposal. Activated carbon [4,20], multi-walled carbon nanotube 62
(MWCNT) [10,16,21], mesoporous SiO2 [22,23], mesoporous TiO2 [24,25], ZrO2 [26], 63
CaO [3,27], Al2O3 [15], Al-MCM-41 [5,11,28], SBA-15 [1,29], ZIF-67 [30] and 64
zeolites [2,31–35] have been investigated as catalysts for deoxygenation reaction. 65
However porous aluminosilicates catalysts such as zeolite and mesoporous 66
alumina/silica were the ideal candidates due to the synergistic effects between porosity 67
and acidity [35–38]. Microporous zeolite as catalysts for deoxygenation reaction 68
suffered from steric hindrance and diffusion limitation that reduced the accessibility of 69
large molecules reactant towards the acid sites [39]. Hierarchical ZSM-5 zeolite 70
4
exhibited two levels of porosity i.e. micropore and mesopore that enhanced the 71
diffusion and reduced the mass transfer limitation of products and reactants. 72
Conventional method for the synthesis of hierarchical zeolite employed the desilication 73
or the dealumination of the microporous zeolite, that often contributed to the destruction 74
of zeolite framework and altered the acidity of the zeolite [40–43]. Two-step 75
crystallization method with the presence of mesopore template provided efficient route 76
for the formation of hierarchical zeolite. Utilization of naturally occurring mineral as 77
silica and alumina sources such fly ash, rice husk and clay reduced the carbon footprint 78
of catalyst production [44,45]. Clay minerals like montmorilonite [46], palygorskite 79
[47], bentonite [48], perlite [49], illite [50] and halloysite [51] required pretreatment 80
meanwhile kaolin can be directly used for synthesis aluminosilicate materials [52–54]. 81
Kaolin is a sedimentary rock consisted of primarily a hydrated aluminosilicate kaolinite, 82
Al4(OH)8(Si4O10) with high Si/Al ratios and has been explored as starting material for 83
zeolite synthesis [55]. 84
Catalyst design holds the key for efficient deoxygenation of oil into green diesel. 85
Deoxygenation reaction required the catalysts to selectively produced hydrocarbon 86
olefin through the removal of carbonyl group in fatty acid, while simultaneously 87
inhibited the secondary cracking reaction. Catalytic cracking reaction produced short-88
chain hydrocarbon that compromised the selectivity towards large hydrocarbons. This 89
research aimed to investigate the activity of hierarchical aluminosilicate synthesized 90
using Indonesian kaolin toward deoxygenation of JCO to hydrocarbon with green diesel 91
composition (C11-C18). Al-MCM-41 is a mesoporous aluminosilicate consisted of one-92
dimensional cylindrical mesopores, synthesized using CTABr as mesopore template. 93
The effect of large mesopore and unidirectional channel of Al-MCM-41 was compared 94
5
with microporous ZSM-5 and hierarchical ZSM-5. ZSM-5 consists of zigzag pore 95
channel with narrow intersection was synthesized using TPAOH as template. 96
Hierarchical ZSM-5 with enhanced mesoporosity was synthesized using silicate as 97
structure directing agent in order to increase the pore diameter that ideally will enhance 98
the diffusion of reactants and products. The competition between deoxygenation and 99
secondary hydrocracking reactions were correlated with the aluminosilicate framework 100
structure, the mesoporosity and the acidity of the catalysts. 101
2. Experimental 102
2.1 Materials 103
Kaolin Al4(OH)8(Si4O10) was obtained from Bangka Belitung consisted of 57% 104
SiO2 and 22% Al2O3 [56]. Jatropha curcas oil (JCO) was purchased from Bionas Sdn 105
Bhd, Malaysia. NaOH (assay 99%) was obtained from Merck, Germany. LUDOX® 106
HS-40 colloidal silica (30% silica in water) and TPAOH (40%) were purchased from 107
Sigma Aldrich, Germany. CTABr (C19H42BrN, assay 99%) was purchased from 108
Applichem. All materials used in this work were analytical grade. Silicalite was 109
synthesized in the laboratory prior to the ZSM-5 synthesis. 110
2.2 Synthesis of hierarchical aluminosilicate 111
Hierarchical ZSM-5 was synthesized following the modified method [57,58] at 112
molar composition of 10Na2O:100SiO2: 2Al2O3:1800H2O. CTABr was added at 113
SiO2/CTABr ratio of 3.85 in order to form mesopore structure. NaOH was dissolved in 114
demineralized water and stirred for 30 min. Kaolin as alumina and silica sources was 115
added gradually into NaOH with continuous stir. Ludox was added slowly into the 116
mixture to form gel under vigorous stirring. Demineralized water was added into the 117
mixture and stirred for another 8 h. The gel was left to age for 6 h at 70 ℃ followed by 118
6
the addition of silicalite at 1% w/w to the solution and stirred for another 30 min. The 119
first hydrothermal process was carried out at 80 ℃ for 12 h and then the autoclave was 120
cooled down under water to stop the crystallization process. CTABr 121
(SiO2/CTABr=3.85) was added slowly to the synthesis mixture and stirred for 1 h. 122
Hydrothermal process was continued at 150 ℃ for 24 h. The resulting solid was washed 123
thoroughly with distilled water until the pH reached 7 and then dried in air oven at 60 ℃ 124
for 24 h. The dried solid was then calcined at 550 ℃ under N2 flow (flow rate of 2 125
℃/min) for 1 h followed by air flow for 6 h. The catalyst obtained denoted as S-ZSM-5. 126
Similar procedure was repeated however silicalite was replaced with TPAOH and the 127
product was denoted as T-ZSM-5. The third sample was synthesized without the 128
addition of both TPAOH and silicalite seed, however following the similar method and 129
denoted as Al-MCM-41. 130
2.3 Catalyst characterization 131
The phase transformation of kaolin to aluminosilicate structure was analysed by 132
wide angle X-Ray Diffraction (XRD) characterization using PHILIPS-binary XPert 133
with MPD diffractometer with Cu Kα radiation operated at 30 mA and 40 kV. Low 134
angle X-Ray Diffraction (XRD) was carried out using Bruker type D2 Phaser using 135
KFL Cu 2K radiation at 10 mA and 30 kV. Fourier Transform Infra-Red (FTIR) (ranges 136
400 – 1400 cm-1) measurement was recorded using FTIR Shimadzu Instrument 137
Spectrum One 8400S. The specific surface area of each catalyst was determined by N2 138
Adsorption Desorption by Quantachrome Touchwin v1.11 instrument at 363 K using 139
Brunauer–Emmet–Teller (BET) method. The pore size distributions further determined 140
by DFT method using Quantachrome ASiQwin instrument. The Brønsted and Lewis 141
acidity were measured by pyridine adsorption using FTIR spectrometer. Approximately, 142
7
14 mg of catalyst was pressed to form pellet and placed in the homemade glass 143
transmmission cell and calcined at 400 °C for 4 h under N2 flow. The cooled to ambient 144
temperature prior to contact with ca. 2 mbar of pyridine. Physically adsorbed pyridine 145
was removed by degassing at 150 ℃ for 3 h. The low resolution and high resolution 146
transmission electron microscope (TEM) images of all catalysts were recorded using 147
Hitachi HT-7700 TEM and Hitachi HR-9500 TEM. The acceleration voltage of 100 kV 148
and 300 kV were applied at HT-7700 TEM and Hitachi HR-9500 TEM respectively. 149
The catalyst further analyzed using 29Si MAS NMR coupled with Varian Unity INOVA 150
400 MHz spectrometer, at pulse length of 3.0 µs, recycle delay of 12 s and spinning rate 151
of 9 kHz. The Si/Al framework ratio were quantified from the integrated areas of the 152
deconvoluted peak by using Eq. 1 153
154
The carbonaceous coke formation on spent catalysts were determined using 155
thermogravimetric analysis (TGA) by Linseis STA PT-1000. The analysis was carried 156
out under air atmosphere from room temperature up to 900 ℃ with heating rate 10 157
℃/min. The functional group and physical changes on spent catalyst also further 158
observed by FTIR and low angle XRD analysis. The analysis was conducted within IR 159
range of 500-4000 cm-1 and the resolution was 4 cm-1. Low angle-XRD was carried out 160
using Bruker type D2 Phaser using KFL Cu 2K radiation at 10 mA and 30 kV. 161
2.4 Catalytic deoxygenation of JCO 162
Deoxygenation reaction of JCO was performed in 100 mL three-necked flask 163
connected with distillation step-up equipped with stirred heating mantle. 3% wt/wt of 164
catalyst was added into 10 g JCO and purged with N2 gas prior to the reaction to provide 165
Eq. 1
8
inert environment during the reaction. Subsequently, the mixture was stirred and heated 166
to 350 ℃ and the reaction was maintained for 1 h under constant flow of N2 at flow rate 167
of 20 cc/min. Liquid product was collected in a cold vessel at 18 oC to facilitate the 168
condensation. The deoxygenated liquid product was further analysed using GC-FID, 169
GC-MS and FTIR spectroscopy. The gaseous products were collected by gas sampling 170
bag and analysed using offline GD-TCD (Shimadzu GC-8 A) with molecular sieve 171
packed column. 172
2.5 Deoxygenated liquid product and gas analysis 173
Liquid product obtained from deoxygenation reaction was analysed using gas 174
chromatography equipped with FID detector (Shimadzu GC-14B) and capillary column 175
HP-5MS (length: 30 m × inner diameter: 0.32 mm × film thickness: 0.25 µm). 176
Hydrocarbons were identified using alkane and alkene standard (C8-C20) obtained from 177
Sigma Aldrich, and 1-bromohexane was used as internal standard for the quantitative 178
analysis. 1 µL of liquid sample was injected into GC column with N2 as carrier gas. The 179
initial temperature was set for 40 ℃ and held for 6 min, then increase to 270 ℃ at 180
heating rate of 7 ℃. The liquid product distribution was qualitatively identified using 181
gas chromatography-mass spectroscopy (HP 6890 GC) with capillary column HP-5MS 182
(length: 30 m × inner diameter: 0.25 mm × film thickness: 0.25 µm). The hydrocarbon 183
yield (X) was calculated by GC-FID using Eq. 2. 184
(Eq. 2) 185
where, no = peak area of alkanes, ni= peak area of alkenes, nz= peak area of the total 186
products. The selectivity of the hydrocarbon products was determined by Eq. 3. 187
(Eq.3) 188
9
where, ci= peak area of desired hydrocarbon, nz= peak area of total hydrocarbon. 189
The functional group of deoxygenated liquid products were identified using FTIR 190
spectrometer (Perkin Elmer (PC) Spectrum 100). The spectra were recorded within IR 191
range of 500-4000 cm-1 and the resolution was 4 cm-1. 192
3. Results and Discussion 193
3.1 Characterization of catalysts 194
XRD analysis 195
XRD analysis in Fig 1a-b showed the low and wide angles diffraction pattern of 196
the catalysts. Kaolin showed the presence of kaolinite phase with high intensity peaks 197
appeared at 2θ = 12.4°, 23.7°, 24.9° and 38.4° (JCPDS No. 14-0164) (Fig. 1a). 198
Significant changes on the diffraction pattern were observed following hydrothermal 199
synthesis, with both S-ZSM-5 and T-ZSM-5 showed the diffraction peaks corresponded 200
to the ZSM-5 at 2θ = 7.8°, 8.7°, 23.0°, 23.8° and 24.0° (JCPDS No. 44-0003). For Al-201
MCM-41, a broad diffraction peak appeared at 2θ = 15-30° corresponded to the 202
amorphous phase of Al-MCM-41 [59]. The low angle XRD analysis (Fig. 1b) of Al-203
MCM-41 showed three diffraction peaks within 2θ = 2-6° corresponded to the (100), 204
(110) and (200) diffraction planes. The peaks confirmed the formation of highly ordered 205
hexagonal mesostructures of Al-MCM-41 [11,60]. S-ZSM-5 synthesized using silicalite 206
as structure directing agent showed a weak diffraction peak at 2θ=2.1o that 207
corresponded to the (100) diffraction plane. The presence of this peak implied the 208
formation of a lower ordered mesostructure within the ZSM-5 framework [60]. When 209
T-ZSM-5 was synthesized using TPAOH, the peaks associated with the ordered 210
mesostructure were negligible. In general, the mesoporosity of ZSM-5 was enhanced 211
when silicalite was used as seeding template during the two-steps crystallization of 212
10
kaolin. The mesoporosity of aluminosilicate was further enhanced when the synthesis 213
was carried out in the absence MFI as structure directing agent, however the framework 214
structure was transformed into Al-MCM-41. 215
Fig. 1a-b 216
FTIR analysis 217
FTIR analysis of kaolin showed the absorption bands at 538 cm-1, 789 cm-1 and 218
914 cm-1 that were corresponded to the vibrations of Al-O and (Al-O)-H bonds in 219
Al[O(OH)]6 (Fig. 2a). Kaolin also showed absorption bands at 430, 470, 752, 795, 1032 220
and 1114 cm-1, which were assigned to the Si-O bonds from SiO4. The absence of 221
absorption band associated with kaolin on S-ZSM-5, T-ZSM-5 and Al-MCM-41 222
indicated the phase transformation of kaolinite to silica-based materials framework. All 223
the catalysts derived from kaolin showed the characteristics absorption of zeolite 224
framework at 450 cm-1 due to the vibration of T-O-T (T is Al or Si atom). The catalysts 225
also showed the adsorption bands at 795 and 1225 cm-1 assigned to the internal and the 226
external asymmetric stretching, respectively; and the band at 1100 cm-1 ascribed to 227
internal asymmetric stretching mode of T-O-T (between TO4 tetrahedral) [61]. S-ZSM-228
5 and T-ZSM-5 catalysts showed the formation of 550 cm-1 band which was the 229
characteristic of MFI structure [62]. Meanwhile the absence of 550 cm-1 band on Al-230
MCM-41 further confirmed the formation of Al-MCM-41 framework [63]. The 231
vibrational peak appeared at 960 cm-1 from Al-MCM-41 corresponded to Si-O 232
stretching vibration of Si-O-H group [64]. 233
Fig. 2a-b 234
11
Surface acidity of the catalysts were analyzed using FTIR spectroscopy while 235
employing pyridine as probe molecule (Fig 2b). Pyridine was adsorbed onto the 236
catalysts at room temperature and subsequently evacuated at 150 ℃ and 300 ℃ in order 237
to provide information on the acidity strength and the number of Brønsted (B) and 238
Lewis (L) sites. The absorption band appeared at 1450 cm-1 was corresponded to the 239
Brønsted acidity, meanwhile the band at 1540 cm-1 was assigned to the Lewis acidity 240
[65]. The adsorption band observed at 1488 cm−1 was originated from adsorbed pyridine 241
on both types of acidity [52]. Table 1 summarized the calculated acidity of 242
aluminosilicate catalysts. Al-MCM-41 showed the highest number of Lewis acid at 243
0.296 mmol/g followed by T-ZSM-5 at 0.284 mmol/g and S-ZSM-5 at 0.158 mmol/g. 244
The number of Lewis and Brønsted acid sites were reduced following evacuation at 300 245
℃, which implied the presence of both weak and medium strength acidity on the 246
catalysts. T-ZSM-5 showed a higher Brønsted sites at 0.108 mmol/g followed by S-247
ZSM-5 at 0.072 mmol/g and Al-MCM-41 at 0.054 mmol/g. ZSM-5 produced from 248
TPAOH and silicalite seed showed a different concentration of acid sites despite similar 249
initial Si/Al ratios. The results implied the influence of organic template TPAOH for the 250
formation of surface acidity in ZSM-5. TPA+ was reported to facilitate the formation of 251
zeolite-like aluminium sites via the arrangement of tiny aluminosilicate clusters with 252
tetrahedrally coordinated aluminium, which in return significantly enhanced the acidity 253
of ZSM-5 [66,67]. 254
Table 1 255
N2 adsorption-desorption analysis 256
12
The textural properties of the catalysts were analyzed using nitrogen adsorption-257
desorption method (Fig. 3a and Table 2). N2 adsorption analysis also provided 258
evidences on the presence of both microporous and mesoporous characteristics of 259
hierarchical zeolite. All the catalysts exhibited different type of isotherms. However, at 260
low relative pressure (P/P0<0.1), all the catalysts showed significant increase of N2 261
adsorption that was due to the presence of micropores. Similar trend was also observed 262
at high relative pressure (0.9<P/P0<1), due to the multilayer adsorption and capillary 263
condensation of N2. For Al-MCM-41, a sharp increase of N2 uptake at P/P0= 0.3-0.4 264
was observed as the typical characteristic of Al-MCM-41 mesoporosity. Al-MCM-41 265
also exhibited the largest surface area of 739 m2/g with the total pore volume of 0.85 266
cc/g. Al-MCM-41 also showed narrow distribution of mesopores with a very intense N2 267
adsorption volume centered at 3.8 nm due to the formation of intra-particle mesopores 268
[50] (Fig. 3b). T-ZSM-5 synthesized using TPAOH exhibited type I isotherm 269
corresponded to the microporous zeolite. The pore size was also measured at ~ 4.5-6.0 270
nm, however the mesopores were originated from inter-particles interaction. S-ZSM-5 271
produced using silicalite showed the combination of type I and type IV isotherms 272
suggesting the formation of hierarchical structures of ZSM-5. The presence of intra-273
particle mesopores in S-ZSM-5 was confirmed by the increased of N2 adsorption at 274
P/P0= 0.3-0.4. However, the N2 volume was significantly lower than Al-MCM-41. The 275
surface area of T-ZSM-5 was determined at 220 m2/g with the total pore volume was 276
measured at 0.37 cc/g. When ZSM-5 was synthesized using silicalite as a seed, the 277
surface area of S-ZSM-5 was significantly enhanced to 439 m2/g and the total pore 278
volume increased to 0.52 cc/g. 279
Fig. 3a-b 280
13
Table 2 281
Morphology analysis using SEM and TEM 282
SEM analysis provided information on the morphology of the catalysts 283
synthesized using different types of structure directing agent. S-ZSM-5 (Fig 4a) showed 284
the formation of agglomerated particles that were dominated by the prismatic structures 285
with the particle size of 0.86-1.09 µm. Meanwhile, T-ZSM-5 catalyst (Fig. 4b) showed 286
the formation of cubic-shaped structure with the particle size of 0.90-1.04 µm. The 287
synthesis of porous Al-MCM-41 in the absence of structure directing agent showed the 288
formation of non-uniform crystallite structures with the average particle size of 0.50-289
1.05 µm (Fig. 4c). 290
Fig. 4a-c 291
HR-TEM analysis of S-ZSM-5 (Fig 5a) revealed the formation of hexagonal 292
crystallite structures with corrugated surfaces in agreement with the SEM analysis. The 293
presence of well-ordered parallel mesopores channel was observed with the pore 294
diameters were estimated at 3.32 nm (Fig 5b). TEM analysis of T-ZSM-5 showed the 295
formation of cubical crystalline structure with the size was determined at ~ 400 nm (Fig 296
5c). The presence of mesoporous channel in T-ZSM-5 was less evident in comparison 297
to the S-ZSM-5, which confirmed the results from N2 adsorption-desorption and low 298
angle XRD (Fig. 5d). TEM analysis of Al-MCM-41 exhibited the formation of intra-299
particulate one dimensional mesopores with the average pore size of 3.49 nm (Fig 5e-f). 300
The formation of parallel mesopore channel was more pronounced in Al-MCM-41 that 301
indicated the highly-ordered mesopore channel was developed during the synthesis 302
14
without the use of MFI structure directing agent. The presence of CTABr as mesopore 303
template controlled the growth of parallel mesopores in Al-MCM-41. 304
Fig. 5a-f 305
29Si MAS NMR analysis 306
29Si MAS NMR analysis provided information of the silica environment in 307
aluminosilicate at molecular level. 29Si MAS NMR spectra of S-ZSM-5 showed three 308
deconvoluted peaks centered at -86, -97 and -110 ppm (Fig 6a). The signal appeared at -309
110 and -97 ppm were corresponded to the Q4 linkage of Si(SiO)4 [68] and Si(OSi)3OAl 310
sites, respectively [69,70]. In T-ZSM-5, these peaks were slightly shifted to -111 and -311
101 ppm presumably due to the high crystallinity of T-ZSM-5 compared to S-ZSM-5 312
[71]. S-ZSM-5 showed the presence of weak resonance peak at -86 ppm, which was 313
corresponded to the Q3 Si(OSi)3(OH) sites from the amorphous phase of ZSM-5. The 314
29Si MAS NMR signal for Al-MCM-41 appeared at chemical shift of -83 and -89 ppm 315
which were assigned to Q3 Si(OSi)3(OH) and Q4 Si(OSi)3OAl sites, respectively. The 316
presence of Q3 resonances implied the partial transformation of Si(SiO)3OAl to 317
Si(SiO)3(OH). Al-MCM-41 also showed a broad resonance peak due to the overlapping 318
of multiple peaks at chemical shift of -97 and -108 ppm corresponded to the silicon sites 319
Q4 Si(OSi)4 unit. The elemental composition of Si and Al determined from 29Si MAS 320
NMR deconvoluted data (Table 3) showed the Si/Al ratios of the catalysts were 321
determined at ~22 – 26. 322
Fig. 6a-c 323
Table 3 324
3.2 Catalytic deoxygenation of JCO 325
15
Deoxygenation of JCO was carried out at 350 ℃ for 1 h under N2 flow using S-ZSM-326
5, T-ZSM-5 and Al-MCM-41 (Table 4). Al-MCM-41 showed high oil conversion at 327
20.04%, which was significantly higher than T-ZSM-5 at 9.97% and S-ZSM-5 at 328
6.73%. Analysis of the liquid products from S-ZSM-5 revealed the selectivity of 329
hydrocarbon at 45.94% and oxygenates compound at 48.16%. Oxygenates were 330
consisted of carboxylic acid, aldehyde and ether compounds. Cycloalkane was also 331
observed at 3.25% selectivity. The selectivity of hydrocarbon was increased to 65.78% 332
when using T-ZSM-5 with significant reduction of oxygenates compound to 26.37%. 333
When Al-MCM-41 was used as catalyst, hydrocarbons was produced at 83.68% of 334
selectivity, and the formation oxygenates was significantly reduced to 4.77%. It is 335
interesting to note that increasing the mesoporosity of ZSM-5 when using silicalite as 336
template was detrimental towards deoxygenation reaction evident by the low conversion 337
of oil at 6.73%. S-ZSM-5 also exhibited low concentration of acidity in comparison to 338
T-ZSM-5 and Al-MCM-41. The results suggested that the deoxygenation of JCO is an 339
acid catalyzed reaction and therefore the number of acid sites significantly enhanced the 340
conversion of oil to hydrocarbon. 341
Table 4. 342
Analysis of JCO composition showed the presence of 70% of unsaturated fatty acid 343
which was consisted of a mixture of oleic acid (C18:1) and linoleic acid (C18:2); with 344
another 20% was saturated fatty palmitic acid (C16:0) [10]. Therefore, detail analysis 345
of the hydrocarbon resulted from the reaction provided insight into the pathway of 346
deoxygenation reaction. Fig 7 showed the distribution of hydrocarbon based on the 347
number of carbon chain, in which Al-MCM-41 showed high selectivity towards n-348
C15+n-C17 hydrocarbons. Deoxygenation produced oxygen-free hydrocarbons with one 349
16
atom carbon shorter than the parent fatty acid. The formation of n-C15+n-C17 350
hydrocarbons indicated that the JCO oil underwent deoxygenation reaction when using 351
Al-MCM-41. The formation of light hydrocarbons fraction (C8-C14) were observed on 352
S-ZSM-5 and T-ZSM-5 catalysts that reduced the selectivity of deCOx products (n-353
C15+n-C17 hydrocarbons). Light hydrocarbon was produced presumably due to the 354
secondary hydrocracking reaction of the resulting hydrocarbons or the fatty acids in 355
JCO. 356
Fig. 7 357
3.2 Effect of reaction time on deoxygenation of JCO over Al-MCM-41 358
The effect of reaction time on the conversion and the selectivity of hydrocarbon 359
was investigated using Al-MCM-41 catalysts. The conversion was increased from 20% 360
to 45% in 4h (Fig 8a). The composition of hydrocarbon was further divided into n-C11-361
18 which was within the diesel hydrocarbon range, and n-C8-10 for gasoline range (Fig. 362
8b). n-C11-18 hydrocarbon n was dominated the product throughout the reaction at ~ 363
90% of selectivity. The appearance of n-C8-10 fraction was corresponded to the 364
competing hydrocracking reaction of JCO or the resulted hydrocarbon with acid sites on 365
the catalysts [72]. 366
Fig. 8a-b 367
JCO and liquid product from deoxygenated reaction were further characterised 368
using FTIR analysis in order to provide insight into the mechanistic steps of the reaction 369
(Fig. 9a). The FTIR spectra of JCO showed the presence of –CH stretching of the 370
aliphatic chain absorption band at 2925 cm-1, the –C=O stretching of ester at 1735 cm-1, 371
the C-O-C stretching at 1161 cm-1, the –CH alkane and the =CH alkene bending 372
17
vibrations at 1453 and 717 cm-1 respectively. The absorption band of –C=O (ester) and 373
C-O-C (carbonyl) stretching were the characteristics of oxygenates species in 374
triglycerides that were used to evaluate the progress of deoxygenation reaction [20]. The 375
stretching vibration of –C=O in liquid product was slightly shifted from 1735 cm-1 376
(ester group) to 1700 cm-1 (carboxylic acid group) after 1h of reaction, indicated the 377
dissociation of ester bond to form intermediates fatty acid [73]. The observation was 378
also supported by the elimination of C-O-C band of the carbonyl group in JCO evident 379
by the disappearance of the absorption band at 1161 cm-1 [74]. FTIR analysis indicated 380
that the first step of reaction involved the transformation of triglycerides to fatty acids 381
that occurred on acid catalysts. As the reaction time increased to 4 h, the reduction of–382
C=O peak intensity was observed which confirmed the elimination of carboxylate 383
fragments of the free fatty acids. It is also interesting to see that the C-O adsorption 384
band was disappeared within the first 1h of the reaction, meanwhile the C=O band only 385
showed significant reduction after 4h of reaction. Considering the deoxygenation 386
involved removal of OCO group, we believe the differences of the intensity of the C-O 387
and C=O absorption bands provided crucial information on the mechanism of the 388
reaction that will be discussed in section 3.5. 389
Fig. 9a-b 390
3.4 Reusability and stability Al-MCM-41 catalyst 391
The stability Al-MCM-41 were evaluated based on the reusability of the catalyst 392
and the formation of coke deposits. The catalyst was filtered of 2h of reaction and 393
reactivated by washing with hexane until the filtration become colourless. The 394
reactivated catalyst was subsequently used under similar reaction condition for five 395
times. Fig. 10 showed the conversion and the selectivity hydrocarbon that indicated the 396
18
Al-MCM-41 catalyst was active up to five reaction cycles with consistent hydrocarbon 397
selectivity ~91%. However, hydrocarbon selectivity reduced after 5th cycle at 80%, and 398
therefore the catalyst was further characterized using TGA and XRD analysis to provide 399
information on the cause of deactivation (Fig. 11a-c). TGA-DTG-DSC analysis 400
showed the presence of 28% of coke on the catalysts that may have blocked the active 401
sites of the reaction [75]. TGA-DTG-DSC analysis also indicated the decomposition of 402
carbon to CO2 at 300-500 ℃ in which suggested the coke was consisted of a mixture of 403
soft and hard carbon. Coke can be classified into soft/thermal coke deposit which 404
decomposed at temperature below 400 ℃, and hard/catalytic coke that decomposed at 405
temperature above 400 ℃ [14,76,77]. XRD analysis of the used catalysts showed the 406
hexagonal porous characteristic peak at 2θ= 2.3o (100) was slightly reduced (Fig. 11c) 407
that suggested the coke deposited within the hexagonal pores array of Al-MCM-41 408
framework and reduced the diffusion of molecules reactant [78]. 409
Fig. 10 410
Fig. 11a-c 411
3.5 Discussion 412
Selective deoxygenation of JCO under inert condition eliminated the carboxylate 413
fragments of fatty acid via decarboxylation and/or decarbonylation pathways. JCO was 414
consisted of 20 % of free fatty acid and 70% of triglycerides. In the presence of acid 415
catalysts, triglycerides was hydrolysed to form palmitic acid, oleic acid, stearic acid and 416
linoleic acid (C16 and C18 fatty acids) [14]. The resulting fatty acids were further 417
deoxygenated to form n-C15 and n-C17 hydrocarbons. The presence of strong acid sites 418
was important due to the deoxygenation reaction was carried out at high temperatures 419
~350 oC. Pyridine adsorption analysis showed that Al-MCM-41 has high number of 420
19
Lewis acid sites in comparison to the ZSM-5. S-ZSM-5 showed approximately 43% 421
reduction of Lewis acidity at temperature above 300 oC meanwhile Al-MCM-41 only 422
showed 20 % reduction of Lewis acidity. Although the mesoporosity of S-ZSM-5 was 423
significantly improved when using silicate as template, the deficiency of high strength 424
Lewis acid sites significantly reduced the conversion of oil into hydrocarbons. 425
Analysis of the hydrocarbons composition from Al-MCM-41 and ZSM-5 426
indicated that the deoxygenation reaction of JCO was in competition with 427
hydrocracking reaction. Deoxygenation eliminated carbonyl group in the fatty acid in 428
order to form hydrocarbon with one atom carbon shorter than the parent structures (C15 429
and C17 hydrocarbons). Both deoxygenation and hydrocracking reactions required an 430
acid catalyst to dissociate the C-C bond for high conversion of oil to hydrocarbon. 431
Cracking reaction of hydrocarbon generally required a strong acid catalyst with high 432
concentration of Brønsted acidity [31,79], meanwhile deoxygenation occurred 433
predominantly on Lewis acidity [72]. The ratio between Lewis to Brønsted acidity 434
indicated that Al-MCM-41 have a high number of Lewis acidity than the S-ZSM-5 and 435
T-ZSM-5. However, the porosity of catalysts also affected the conversion towards 436
deoxygenation reaction. High selectivity towards short-chain hydrocarbons fraction (C8-437
10) were observed when using S-ZSM-5 and T-ZSM-5. The result indicated the reaction 438
underwent secondary cracking pathway on S-ZSM-5 and T-ZSM-5. Catalytic cracking 439
into short-chain hydrocarbon can occur on the fatty acids, or the resulting hydrocarbons 440
from deoxygenation reaction, which consequently reduced the selectivity of 441
hydrocarbon within the green diesel composition (C11-18). The confined spaces of the 442
zigzag pore structure and the narrow channel intersection of ZSM-5 restricted the 443
diffusion of molecular substrate, hence prolonged the interaction between acid sites and 444
20
hydrocarbon for secondary cracking reaction. Al-MCM-41 catalyzed deoxygenation 445
reaction of JCO to favor high production of nC15+17 hydrocarbon and simultaneously 446
suppressed the formation of light chained hydrocarbon from secondary hydrocracking 447
reaction. Efficient diffusion of hydrocarbons prevented further cracking reaction to light 448
chained hydrocarbon. The narrow diameter of ZSM-5 pores that was generally consisted 449
of a zigzag and a straight channel connected via a narrow intersection restricted the 450
diffusion of fatty acids into the pores and therefore it can be suggested that catalytic 451
cracking reaction may utilized acid sites on the surface of the catalyst. 452
Fig. 12 illustrated the proposed mechanism of deoxygenation reaction of JCO 453
over Al-MCM-41 catalyst. Deoxygenation of JCO occurred via decarboxylation of fatty 454
acid evident by the production of CO2 gas. Analysis of the gas product from 455
deoxygenation of JCO using GC-TCD (Fig 9b) indicated the domination of CO2 with 456
100% selectivity within 1h of reaction. Increasing the reaction time significantly 457
reduced the selectivity of CO2 but enhanced the formation of CO suggested that fatty 458
acids underwent decarbonylation reaction to release CO. Traces amount of CH4 was also 459
observed presumably due to the methanation reaction between CO and CO2 gas under 460
the presence of H2. Since the reaction was carried out in the absence of H2, there is a 461
possibility that H2 was produced from the catalytic cracking reaction. 462
Fig. 12 463
4. Conclusions 464
Kaolin was transformed into highly selective hierarchical aluminosilicate catalysts for 465
deoxygenation of Jatropha Curcas oil into green diesel. Aluminosilicates in the form of 466
mesoporous Al-MCM-41, hierarchical ZSM-5 and microporous ZSM-5 were produced 467
21
when different structure directing agent were employed during the two steps 468
hydrothermal synthesis. High conversion and selectivity towards deoxygenation 469
reaction was observed on Al-MCM-41 meanwhile ZSM-5 showed the competition 470
between deoxygenation and catalytic hydrocracking reaction. Lewis acidity was 471
responsible for high conversion of JCO. Highly ordered mesoporous Al-MCM-41 with 472
one-dimensional hexagonal pore arrays facilitated the diffusion of deoxygenated 473
products that prevented the secondary cracking reaction, consequently enhanced the n-474
C15+n-C17 hydrocarbon yield. Al-MCM-41 also displayed high stability and reusability 475
up to five cycles with consistent hydrocarbon selectivity. 476
477
Acknowledgement 478
The authors would like to acknowledge the Ministry of Research, Technology and 479
Higher Educaction of Republic Indonesia under PMDSU scholarship with contract 480
number 1290/PKS/ITS/2020 and local ITS grant no. 836/PKS/ITS/2020 for funding the 481
research. 482
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791
792
793
Table Captions 794
Table 1. Number of Brønsted and Lewis acid sites of the catalysts from pyridine 795
adsorption 796
Table 2. Physicochemical properties of all samples 797
Table 3. Chemical shifts and Si/Al ratio from 29Si NMR 798
Table 4. Conversion and selectivity of liquid products from catalytic deoxygenation of 799
JCO 800
801
36
Table 1. 802
Sample
Number of acid site (mmol/g)
B/L L/B
Brønsted Lewis B+L
S-ZSM-5 (150 0C) 0.072 0.158 0.230 0.455 2.194
S-ZSM-5 (300 0C) 0.038 0.089 0.127 0.426 2.342
T-ZSM-5 (150 0C) 0.108 0.284 0.392 0.380 2.629
T-ZSM-5 (300 0C) 0.073 0.198 0.271 0.369 2.712
Al-MCM-41 (150 0C) 0.054 0.296 0.350 0.182 5.481
Al-MCM-41 (300 0C) 0.014 0.234 0.248 0.059 16.710
803
804
37
Table 2. 805
No Template
SBET
(m2/g)a
Surface
area
(m2/g)
Pore volume (cc/g) Dmeso
(nm) d
Product
e
Smeso Smicc Vmeso
b Vmicc Vtotal
1
Silicalite+
CTABr
439 149 289 0.38 0.14 0.52
3.6;
5.6
ZSM-5
2
TPAOH
+CTABr
220 118 102 0.34 0.03 0.37 5.1 ZSM-5
3 CTABr 739 260 478 0.56 0.29 0.85 3.8
Al-
MCM-
41
a SBET (Total surface area) by BET method. 806
b Vmeso by DFT method 807
c Smicro and Vmicro (micropore volume) by t-plot method 808
d Dmeso by DFT method 809
e Product by XRD technique 810
811
38
Table 3. 812
Samples
Chemical shift (ppm) and area (%) deconvoluted peak
Si/Al
Q4 (4Si,
0Al)
Q4 (4Si,
0Al)
Q4 (3Si,
1Al) Q3 (3Si, 1OH)
S-ZSM-5 -110 (84.87)
- -97 (13.09) -86 (2.04) 26.44
T-ZSM-5
-111 (83.65)
-
-101 (16.35) - 24.46
Al-
MCM-41 -108 (42.86) -97 (28.95) -89 (14.92) -83 (13.27) 22.61
813
814
39
Table 4. 815
Catalysts Xoils, %
Selectivity
Hydrocarbon, %
Selectivity
Cycloalkane,
%
Oxygenates
compound, %
S-ZSM-5 6.73 45.94 3.25 48.19
T-ZSM-5 9.97 65.78 6.35 26.37
Al-MCM-
41
20.04 83.68 11.52 4.77
816
817
40
Figure Captions 818
Fig. 1. (a) Wide angle and (b) low angle XRD analysis of kaolin, Al-MCM-41, ZSM-5 819
synthesized using TPAOH (T-ZSM-5) and hierarchical ZSM-5 synthesized 820
using silicate (S-ZSM-5). 821
Fig. 2. FTIR framework (a) and pyridine adsorption (b) spectra of kaolin, Al-MCM-41, 822
ZSM-5 synthesized using TPAOH (T-ZSM-5) and hierarchical ZSM-5 823
synthesized using silicate (S-ZSM-5). 824
Fig. 3. N2 adsorption-desorption isotherm (a) and pore size distribution by DFT method 825
of Al-MCM-41, ZSM-5 synthesized using TPAOH (T-ZSM-5) and hierarchical 826
ZSM-5 synthesized using silicate (S-ZSM-5) (b)\ 827
Fig. 4. SEM images of the S-ZSM-5 (a), T-ZSM-5 (b) and Al-MCM-41 (c) 828
Fig. 5. TEM images of the S-ZSM-5 (a,b), T-ZSM-5 (c,d) and Al-MCM-41 (e,f) 829
Fig. 6. 29Si NMR deconvoluted spectra of S-ZSM-5 (a), T-ZSM-5 (b) and Al-MCM-41 830
(c) 831
Fig. 7. Hydrocarbon distribution from catalytic deoxygenation reaction of JCO on Al-832
MCM-41, ZSM-5 synthesized using TPAOH (T-ZSM-5) and hierarchical ZSM-5 833
synthesized using silicate (S-ZSM-5). 834
Fig. 8. Conversion of JCO (a) and Selectivity of hydrocarbon on Al-MCM-41 catalyst 835
as a function of time (b). Hydrocarbon composition was divided into gasoline fractions 836
(C8-10) and diesel fraction (C11-18) 837
Fig. 9. FTIR spectra of JCO and liquid deoxygenated products over 4h of reaction (a) 838
and gas products analyzed from JCO reaction (b) 839
41
Fig. 10. Reusability investigation of JCO deoxygenation reaction over Al-MCM-41 840
using 3 wt.% catalyst loading at 350 ℃ within 2 h under inert atmosphere. (a) 841
Conversion of JCO, and (b) selectivity of hydrocarbon from liquid product 842
Fig. 11. TG-DTG-DSC profile of fresh (a) and spent catalyst (b) and low angle XRD 843
pattern of fresh and spent catalyst (c) 844
Fig. 12. Reaction pathway of JCO deoxygenation 845
846
42
847
Fig. 1. 848
849
43
850
Fig 2. 851
852
44
853
Fig. 3. 854
45
855
Fig 4. 856
46
857
858
Fig 5. 859
47
860
Fig. 6. 861
48
862
Fig. 7. 863
864
49
865
Fig. 8. 866
867
50
868
Fig. 9. 869
870
51
871
Fig. 10. 872
873
52
874
Fig. 11. 875
876
53
877
Fig. 12. 878
Declaration of interests
☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
☐The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:
Declaration of Interest Statement