báo cáo_2-6
TRANSCRIPT
Trng H M - a Cht DANH MC BNG
N TT NGHIP
Trang Bng 2.1. Thng s vt l ca Anatase v Rutile...Error: Reference source not found Bng 2.2. c trng ca ph nh nng mt tri (trong ngy khng my).........Error: Reference source not found Bng 2.3. Cc ng dng ca xc tc quang ha TiO2 [12. Kaneko M., Okura I. (2002), Photocatalysis: Science and Technology, Springer-Verlag Berlin Heidelberg New York, Japan]...............................Error: Reference source not found Bng 4.1 Bng nh gi kh nng x l ca cc loi vt liu........Error: Reference source not found Bng 5.1. Chi ph cho vic thit k test box.......54Error: Reference source not found DANH MC HNH Hnh 2.1 Cu trc ca rutile v anatase ..............Error: Reference source not found Hnh 2.2 Minh ha qu trnh kch thch trong xc tc quang ha....Error: Reference source not found Hnh 3.1. Quy trnh tm ph nano TiO2 ln bng thch anh..Error: Reference source not found Hnh 3.2. Knh hin vi in t qut S4800..............Error: Reference source not found Hnh 4.1. Anh chp cua bng thch anh...............Error: Reference source not found Hnh 4.2 Gian XRD ca SiO2............................Error: Reference source not found Hnh 4.4. Gian XRD ca vt liu so snh - mu 2......Error: Reference source not found Hnh 4.5. nh SEM ca mu 1- do ti ch to. Error: Reference source not found Hnh 4.6. nh SEM ca mu 2- mu chun ca Php....Error: Reference source not found Hnh 4.7. Mu TiO2/SiO2 sau 1 ln tm ph: (A) ca ti; (B): mu i chng; v (C): chiu dy lp ph......................................Error: Reference source not found Hnh 4.8. S test box........................................Error: Reference source not found Hnh 4.9 Kho st s thay i nng aldehyt i vi cc loi vt liu ch to khi c ngun nh sng kch hot............................Error: Reference source not found
Sinh vin : Trng H
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Lp : a Sinh Thi K51
Trng H M - a Cht
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M UX l nhim khng kh nc ta t trc n nay t c quan tm nghin cu trin khai. Hu ht cc cng ngh x l nhim mi trng ch tp trung vo lm sch nc, x l nc thi m cha thc s u t vo lm sch mi trng khng kh mc d nhim khng kh n mc bo ng. Cc bin php nh tuyn truyn gio dc, tng cng din tch cy xanh, quy hoch hp l cc cng trnh dn sinh ch gim thiu mt phn nhim khng kh. V vy, cc bin php cng ngh nh qu trnh oxy ha kh kt hp, hp ph, lc kh cn thit phi p dng. Trong , cc gii php ch to cc mng lc vt liu kch thc nano va c kh nng hp ph li va c kh nng xc tc dit khun, nm mc, x l ngun kh thi phn tn trong khng kh rt hiu qu v tim nng. Hiu ng quang xc tc ca vt liu nano, c bit l nano Titandioxit TiO2 c coi l c s khoa hc y trin vng cho cc gii php k thut x l nhim khng kh. Vt liu nano TiO2 c sn xut i tr trn th gii vi gi thnh khng t (vi chc la/kg), cng ngh ch to khng i hi cc trang thit b t tin nn c th thc thi trong iu kin thc t Vit Nam. TiO2 l cht bt mu trng, rt bn, khng c v r tin. TiO2 vi cu trc tinh th nano t 5 -50 nanomet c hot tnh quang xc tc mnh, c nghin cu ng dng trong x l cc cht c hi trong mi trung vi u im ni bt hn so vi cc qu trnh khc l : S phn hy cc cht hu c c th t n mc v c ha hon ton. Chi ph u t v vn hnh thp.
Qu trnh oxy ha c thc hin trong iu kin nhit v p sut bnh thng. Hu ht cc cht c hu c u c th b oxy ha thnh sn phm cui cng
l H2O v CO2. TiO 2 ph ln cc cht mang (gch men, cc thit b v sinh, knh ca s) bng cng ngh sol-gel hay mt s cng ngh khc c kh nng lm sch, dit vi khun, nm mc, kh mi hi v phn hy cc kh c hi NOx, SOx, VOCs. Trong s cc cht mang c k n l si bng thch anh c b mt xp mu trng c din tch b mt tip xc rt ln (trng lng ring 200 g/m2, b mt ring 40 m2/g) l vt liu rt ph hp cho mc ch tm ph TiO2 x l cc cht nhim, cc mi hi trong mi trng khng kh.
Sinh vin : Trng H
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Lp : a Sinh Thi K51
Trng H M - a Cht
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Cc mi hi pht sinh trong vn phng, cng ty ch yu l foocmaldehyt v cc hp cht ca n. Foocmaldehyt c sinh ra t cc ni tht nh bn, gh, t gy mi kh chu, nng cao nh hng ti h thn kinh. S dng vt liu TiO2 x l l vn cn thit. Chnh v vy ti Nghin cu ch to vt liu TiO2/si SiO2 x l aldehyt trong mi trng khng kh c thc hin. Sn phm mang tnh cng ngh cao, thc s c ngha nng cao hiu qu lm sch mi trng khng kh. ng thi mang tnh kinh t - x hi, s dng vt liu r tin, gi c ph hp vi thc t Vit Nam nhng cht lng khng thua km sn phm nc ngoi. y l cc vn ln u tin c trin khai dng nghin cu v th nghim thc t. Ni dung chnh ca ti bao gm: Nghin cu, ch to vt liu TiO2/SiO2.
nh gi cc hot tnh quang xc tc ca vt liu ch to qua x l cc cht nhim trong khng kh (x l mi hi: aldehyt) do cc dng gy nn trong vn phng. Nghin cu ch to m hnh th nghim (test box) vi dung tch 1m3
(1mx1mx1m) th nghim kh nng x l aldehyt vi nng pht thi tng ng vi mi trng thc t.
Sinh vin : Trng H
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Lp : a Sinh Thi K51
Trng H M - a Cht LI CM N
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Ti xin by t lng cm n su sc ti TS. Nguyn Th Hu - Vin ph Vin Cng ngh mi trng - Trng phng phn tch Cht lng Mi trng Vin Cng ngh mi trng - Vin Khoa hc v Cng ngh Vit Nam v TS. Vn Bnh Trng b mn a Sinh Thi & Cng ngh Mi trng Trng i hc M - a cht hng dn tn tnh, chu o v to mi iu kin tt nht cho ti hon thnh n tt nghip ny. Ti cng chn thnh cm n tp th cn b phng phn tch Cht lng Mi trng Vin Cng ngh mi trng - Vin Khoa hc v Cng ngh Vit Nam v cc thy c gio trong B mn a sinh thi to iu kin thun li v gip ti trong qu trnh lm thc nghim. Trong qu trnh thc hin ti do trnh v thi gian cn hn ch nn khng trnh khi sai st mong c cc kin ng gp ca thy c gio v cc bn. Ti xin chn thnh cm n! H Ni, ngy thng nm 2011 Sinh vin
Trng H
Sinh vin : Trng H
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Lp : a Sinh Thi K51
Trng H M - a Cht
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PHN I PHN CHUNG V CHUYN MN
Sinh vin : Trng H
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Lp : a Sinh Thi K51
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CHNG 1: TNG QUAN V NHIM KHNG KH V ALDEHYT 1.1. nhim khng kh v aldehyt 1.1.1. nh ngha : Hin nay nhim khng kh ang l mt vn bc xc i vi mi trng th, cng nghip v cc lng ngh nc ta hin nay. nhim khng kh c tc ng xu n sc khe con ngi c bit l cc bnh v h hp. Ngoi ra nhim khng kh cn gy nh hng n cc h sinh thi v bin i kh hu (ma axit, hiu ng nh knh, suy gim tng ozon). Qu trnh cng nghip ha v th ha pht trin cng mnh th ngun gy nhim khng kh cng nhiu lm cho cht lng khng kh ngy cng xu i do vy vn bo v mi trng khng kh cng tr nn cp thit. nh ngha v nhim khng kh: nhim khng kh l s c mt ca cc cht kh trong bu kh quyn do hot ng ca con ngi hoc t nhin c nng ln v thi gian lu tc ng n con ngi v mi trng. Tuy nhin, chng ta thng ngh rng nhim khng kh ch l vn gy ra bi cng nghip hoc giao thng - v iu ng - nhng cn vn nhim trong nh th sao? Trong khong 30 nm tr li y, ngi ta quan tm nhiu hn n vic gim nhim trong nh, nhng ch gn y cng ng khoa hc quc t lo lng v vic gim nhim khng kh ca nhng mi trng khp kn. Cc nghin cu ca M v chu u cho thy, con ngi cc nc cng nghip dnh hn 90% thi gian ca h trong nh. Nng ca nhiu cht nhim trong nh vt nng ca chng ngoi tri. C quan Bo v mi trng M nghin cu s phi nhim ca con ngi i vi cc cht nhim trong khng kh ch ra rng, nng trong nh ca cc cht nhim c th cao hn 2-5 ln v i khi cao hn 100 ln so vi nng ngoi tri. Theo nghin cu ca T chc Y t Th gii (WHO), nhim khng kh trong nh ch yu gy ra bi vic t nhin liu rn, c c tnh lm cht hn 50.000 tr em hng nm (di 4 tui) ti chu u. Vy nhim trong nh l g? nhim trong nh l s nhim khi "c s hin din ca cc cht nhim c tnh cht vt l, ha hc hoc sinh hc trong khng kh ca cc mi trng b gii hn, m cc cht ny khng hin din mt cch t nhin vi s lng ln trong khng kh ngoi tri ca h sinh thi" (B Mi trng , 1991). 1.1.2. Tc hi ca nhim mi trng khng kh. Sinh vin : Trng H6
Lp : a Sinh Thi K51
Trng H M - a Cht
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nhim mi trng khng kh thng gy ra mt s bnh v ng h hp v h tun hon nh vim phi, bnh ngoi da, mt. Theo c tnh, mi nm c khong 3 triu ngi b cht v ht phi kh c trong cc cn h cht chi. Bi mn gy cc bnh nh hen suyn, vim ph qun mn tnh, ung th phi. Tr em v ngi gi d b cc bnh ny. Theo d on ca T chc Y t Th gii (WHO) mi nm c khong 865.000 trng hp t vong do nhim mi trng khng kh gy nn. Qua iu tra 2.239 h gia nh vi hn 1 vn thnh vin gia nh trong c 6.021 hc sinh v 1.368 cn b ang hc tp v cng tc ti 3 nhm ngnh ngh da giy v vt liu xy dng ti 4 cng ty trn a bn H Ni, cho kt qu nh sau: bnh ti mi hng chim t l cao nht 21,4% sau n vim mi d ng 10,7%, hen ph qun 9,9%, cm cm 8,9% vim phi, vim ph qun 8,3%, cc bnh ngoi da v mt 3 -5%. Cc triu chng ng h hp chim t l cao nht l tc ngt mi (16%), chy nc mi (13,6%), vim hng (9,8%), ho (7,4%). Thi im c du hiu tn thng ng h hp nhiu nht l lc tnh dy, chim 63,9%. iu tra mt s qun huyn trn a bn thnh ph H Ni, kt qu cho thy, qun Hong Mai c t l cao nht, chim 26,6 -33,9%, thp nht l qun Hon Kim (2,9 -7,6%). Ngoi ra, c ti 4,1% ngi tng mc cc bnh da liu, 11,4% mc cc bnh v mt, trong cao nht l qun Hong Mai, ng a, Thanh Xun. Theo , nhng ngi c thi gian sng H Ni trn 10 nm c t l mc cc bnh mn tnh v tai mi hng (24,5%) cao hn nhng ngi sng di 3 nm (12,5%); cc bnh cp tnh nh cm cm, trn 10 nm l 11,5% v di 3 nm ch chim 5,8%. Nh vy, thi gian sng cng lu th xu hng mc cc bnh cp tnh v mn tnh v tai mi hng, cm cm cao hn nhng ngi c thi gian sng t hn (di 3 nm, t l mc bnh hen ph qun l 2,3%, t 3 n 10 nm l 13,3%). Trong , cc bnh hay gp nht l hen ph qun, vim xoang, vim mi d ng v vim ph qun chim t 3,5% - 7,9%. 1.1.3. Cc iu kin nh hng n s pht tn ca cc cht trong khng kh a, Tc gi nh hng n tc lan truyn ca cc cht nhim trong mi trng khng kh. Vi vn tc gi ln th kh nng lan truyn cht nhim xa v c c tc dng pha long nhanh i vi khng kh sch. Tuy nhin, khi vn tc gi nh cc cht nhim khng b pht tn nng cc cht nhim trong khng kh cao. b, Lng ma Sinh vin : Trng H7
Lp : a Sinh Thi K51
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Ma c tc dng ha tan v cun theo lng cht nhim c trong khng kh, chuyn mt phn cht nhim vo trong mi trng nc qua lm gim nng ca cht nhim trong khng kh. Ni cch khc ma cng l mt phng php lm sch khng kh. c, S nghch o nhit Qu trnh nghch o ca nhit cng lm bin i nng ca cc cht trong khng kh, bi n nh hng n qu trnh lan truyn ca cc cht nhim trong khng kh v lm nh hng n qu trnh tc ng ca cc cht nhim n mi trng v c th sinh vt v con ngi. d, Rng cy Cy xanh c kh nng hp th mt s loi cht nhim c trong khng kh, ng thi vic quang hp ca cy xanh to ra O2 cng lm cho khng kh tr nn sch hn. Tuy nhin, cng phi k n qu trnh h hp to ra CO2 ca cy xanh c th lm tng nguy c gy hi cho mi trung khng kh khi c cc tc nhn nhim. e, a hnh Yu t a hnh c nh hng n vn tc gi, nhit v phng thc lan truyn ca cht nhim trong khng kh: c th ngn cn s pht tn ca cc cht nhim hoc l tch t cc cht gy nhim. 1.2. Hin trng nhim aldehyt 1.2.1. Tng quan v aldehyt Thng thng aldehyt hay c biu th bng foocmaldehyt cho nn ti tp trung vo xc nh v x l foocmaldehyt. Foocmaldehyt c gi bng nhiu cch khc nhau nh methanal, methylene, oxymethylen, oxomethane v formic aldehyde. nhit phng foocmaldehyt l cht kh khng mu, d chy, tnh cht ha hc mnh v d dng polime ha. Nhit lng khi t chat foocmaldehyt l 4.47 Kcal/gam. Hp cht ny tan c trong nc, ethanol, diethylether v acetone. Trong nc, foocmaldehyt dng methylen glycol [CH2(OH)2] v glycol polymethylen [H(CH2O)OH]. Foocmaldehyt thng mi thng dng dng lng 37% trong nc, c gi l foocmalin, vi 10% methanol l cht n nh. Foocmaldehyt phn hy t t thnh methanol v CO nhit trn 1500C. Khi foocmaldehyt ngoi tri, n xy ra phn ng quang ha to ra CO2. Foocmaldehyt c cng thc ha hc l CH2O; phn t lng l 30,03g/mol; t trng so vi khng kh (khng kh = 1): 1,04 g/L; nhit chy ( 0C): -92; nhit si (0C): -21; t trng 200C: 0,815g/ml. Ngng gy mi: trong nc c nng Sinh vin : Trng H8
Lp : a Sinh Thi K51
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50 ppm v trong mi trng khng kh: 0,5 1 ppm. Foocmaldehyt tan trong nc sch n 55% v trong dung mi nh ete, alcohol, acetone, benzene. p sut bay hi 25oC: 3,883 mm Hg. Thi gian bn phn hy di nh sang mt tri to ra H 2, CO, H- v HCO-: 1,6 gi n 19 gi. 1.2.2. Ngun pht sinh Foocmaldehyt c hnh thnh ch yu trong qu trnh t chy cc cht hu c do hot ng ca con ngi v trong t nhin. Ngoi ra, foocmaldehyt cn c to ra do s oxi ha cc hp cht hu c d bay hi (VOCs) t nhin cng nh nhn to trong khng kh. a, Ngun t nhin: Foocmaldehyt tn ti trong mi trng v l sn phm ca nhiu qu trnh trong t nhin khc nhau nh chy rng, s chiu sang than bn trong nc bi nh sng mt tri. - T cc phn ng trong kh quyn : Hng ngn cc hp cht hu c c thi vo kh quyn t cc ngun sinh vt. Theo Atkinson v Arey, cc hp cht hu c ny bao gm: isopren, monoterpenes, .v cc sn phm oxi ha khc. Trong tng i lu, chng phn ng vi gc Hydroxyl, gc Nitrat, Ozone v ng vai tr quan trng trong cc phn ng di tng i lu. Nng tng i cao ca Formaldehyde ngoi tri c th c tm thy trong khng kh cc th b nhim nng. y, foocmaldehyt trc tip c pht thi vo bu kh quyn hoc do phn ng quang ha pha kh ca gc Hydroxyl . - T s t chy bn ngoi: S t chy g cng l mt ngun t nhin ca formaldehyde. Hedberg nghin cu qu trnh t chy cy bch dng v ch ra rng, t l pht thi formaldehyde l 180-710 mg/kg g. Ngun nhn to: T chc Y t th gii WHO ch ra rng, pht thi Formaldehyde cng nghip c th xy ra bt c giai on no ca sn xut, lu tr, s dng, vn chuyn, hoc loi b sn phm vi lng d formaldehyde. S pht thi Formaldehyde c pht hin t cc nh my ha cht, nh my sn xut giy v bt giy, nh my lp xe, cao su, sn xut oto.theo bo co ca Hoa k nm 1993, h cung cp cc phn tch sau y c lng kh Formaldehyde pht thi vo khng kh ngoi tri : Giao thng (70%), my bay (11%), vn ti (7%) , cng nghip ch bin formaldehyde (10%), my mc thit b v thiu t cht thi (1%). Foocmaldehyt nhn to c hnh thnh do t chy nhin liu, s dng trc tip foocmaldehyt trong cng nghip v sinh ra t cc vt liu xy dng v sn phm tiu dng. Mc d foocmaldehyt khng c trong thnh phn ca xng, du Sinh vin : Trng H9
Lp : a Sinh Thi K51
Trng H M - a Cht
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nhng n li l sn phm ca qu trnh t chy khng hon ton v vy n c pht ra t cc ng c t trong. Lng pht thi ph thuc ch yu vo thnh phn nhin liu, loi ng c, nhit , tui v tnh trng ca phng tin vn hnh. Ngoi ra, foocmaldehyt cn c hnh thnh do qu trnh t chy t l t ci, un nu, l si, t trong nng nghip, l t rc, khi thuc. c bit foocmaldehyt cn c pht hin trong cc sn phm g nh vecni bn g, sn, thm, si v nha. Ngun gc cc cht nhim trong nh: Cc cht nhim trong nh c ngun gc ch yu t: - Vt liu xy dng, thit b si m, my lnh, hot ng un nu, c; vt liu che ph (sn tng, vc-ni, tm lt nn nh...). - Sn phm bo tr v ty ra (bt git, thuc tr su, v.v); s dng khng gian v cc hot ng thc hin trong khng gian . - Khi thuc l, bi v lng t th vt, phn hoa, mt, mc, nm v vi khun. Nhit v m cao cng c th lm tng nng ca mt s cht nhim. - Cht nhim khng kh ngoi tri cng c th gy vn cho khng kh bn trong, c bit vo nhng ngy p tri hoc nng nng khi cc ca s c m ra. 1.2.3. Tc ng ca aldehyt n mi trng v sc khe ca con ngi v sinh vt Mt s hin tng khi tip xc vi foocmaldehyt: Ht phi: Gy au nhc c hng, ho v th ngn. Gy rt v d ng h h hp. Liu lng t 25 n 30 ppm gy tn thng h h hp nng dn n ph v vim phi. Gy bnh mn tnh nng cao. Nut phi: Gy au bng, nn ma d di, nhc u v tiu chy. Liu ln gy gim than nhit, nh hng n h tiu ha, kh th, mch khng u gy bt tnh v dn n t vong. Tip xc da: Foocmaldehyt l mt cht kch thch v gy d ng da nghim trng. Tip xc trc tip lm da bc mu trng, gy cm gic nhc nhi. Tip xc mt: Hi foocmaldehyt lm rt, mt, au v bng. Foocmaldehyt vng vo mt hay mt tip xc nhiu gy nguy nhim lu di. Tip xc thng xuyn: nh hng foocmaldehyt thng xuyn v lu di dn n vim da. Tip xc foocmaldehyt trc tip vi da thng xuyn v lu di gy d ng da, suy yu th lc. Phi nhim HCHO ln c th gy cht ngi, HCHO chuyn ha thnh axit focmic lm tng hot ng ca tim, lm gim thn nhit dn n hn m v t vong. Nm 2004, C quan quc t Nghin cu ung th (IARC) phn loi formaldehyde l cht gy ung th cho con ngi (nhm 1). nh gi ny da trn cc thng tin v Sinh vin : Trng H10
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mi quan h gia bnh ung th vm hng v bnh bch cu lin quan n vic tip xc vi formaldehyde. T nm 1991, U.S.EPA (United States Environmental Protection Agency) quan tm n formaldehyde nh l mt cht gy ung th ca con ngi. 1.2.4. ng dng ca aldehyt Formaldehyde l mt nguyn liu ha cht cho rt nhiu qu trnh cng nghip. N cng c dng lm cht bo qun, thuc kh trng v cht dit khun. V th, n c lin quan ti mi trng trong nh, n c s dng nh l mt thnh phn kt dnh ca nha phn ng nhit. Cht kt dnh Ure Formaldehyde (UF) (cn c gi l aminoplast) l nhng sn phm ph bin nht c s dng trong sn xut g v ni tht do n c th khc phc li mt cch nhanh chng, hiu qu v gi thnh thp. Melamine urea Formaldehyde (MUF) l mt cht kt dnh tng t nh UF. N c sn xut bng cch trn hn hp UF vi melamine formaldehyde (MF) hoc bng cch c c tt c monome cng mt lc. Cht kt dnh Phenol- Formaldehyde (PF) rt n nh v c kh nng chu nc, v kh nng kt dnh cao i vi g. Trc , nha lm bng PF cng c bit n nh l Bakelite (nha tng hp), c s dng lm v bc cho in thoi, radio. Cht kt dnh Melamine-urea phenol- formaldehyde (MUPF) c s dng sn xut g chng m v vt liu xy dng. Sau y l tm tt v ng dng ca formaldehyde c s dng trong sn xut : - Sn xut cc sn phm g (tm vn, g dn.) - Sn phm vn bng giy cch nhit v cch m - Cc vt liu cch in c lm t UF - Sn phm giy - Ph vt liu, sn, sn mi c cha formaldehyde l cht bo qun - Dt may - Thuc kh trng v cht bo qun - Qu trnh quang ha ha hc M phm 1.3. Cc phng php x l aldehyt ang p dng Vit Nam v trn Th gii nh hng chung ca Vit Nam v Th gii trong lnh vc x l nhim khng kh : Tuyn truyn gio dc tp qun sinh hot, sn xut cng nh quy hoch hp l cc cng trnh dn sinh, nh my gy nhim v tng cng din tch ph xanh ca cy ci gim thiu ngun t nhin gy nhim. Sinh vin : Trng H11
Lp : a Sinh Thi K51
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Ban hnh lut kim sot nhim khng kh v thc hin chin lc kim
sot nhim khng kh, a ra tiu chun cht lng khng kh v chng trnh quan trc cht lng khng kh. Tng cng s dng nhng cng ngh sn xut tin tin, thay th cc cng ngh lc hu gy nhim, ch to v s dng cc th h ng c nhin liu sch nhm gim thiu ngun to ra kh c hi gy nhim khng kh. S dng cc thnh tu khoa hc, cng ngh v vt liu mi to ra gii php k thut ch ng x l ngun khng kh b nhim. a, Trn Th gii Nm 1987, M nghin cu cng ngh sol-gel ch to TiO2 dng mng v dng si [4]. Nm 1993, cc nh khoa hc H Lan ch to loi gch men c lp TiO2 trn b mt lm sch mi trng khng kh. Chng c nh gi l rt hiu qu phn hy cht bn v dit khun. Nm 2001, cc nh khoa hc M s dng TiO2 dng sn ph trn b mt vt liu kh hp cht hexadecan, kt qu nghin cu cho thy 98,2% hp cht ny b kh trong thi gian 72 gi. Nm 2006, Vin Cng ngh Mi trng, i hc i Loan, Trung Quc dng bt Degussa P25 TiO2 trong cc b lc kh kh toluen v foocmaldehyt [5]. Nm 2007, i hc Paris, cng ha Php, nghin cu ra loi sn arcylic TiO 2 x l kh NO v NO2, hiu qu t 19% - 20% vi thi gian chiu sng trong 5 gi, tc phn ng t 0,05-0,13 g.m-2.s-1 [6]. TiO2 rt hiu qu trong vic phn hy clorofooc v ur, thuc tr su gc ln hu c dimetylphotphat. Cyanua c th b phn hy nhanh chng trong mi trng c cha 5% TiO 2 v chiu sng vi ngun sng c bc sng 390nm [7]. Qu trnh quang xc tc xy ra vi bc x c bc sng nh hn 4200 to nn oxy hot tnh phn hy hon ton cc cht thi hu c thnh CO2 v H2O. Nht Bn nghin cu ch to v ng dng TiO2 dng mng, sn hoc bt cho hiu qu rt tt trong x l nhim khng kh. Vi ngun sng 40W, khong cch chiu sng 150 cm, TiO2 c th kh H2S, amoni, trimethylamin t 30 ppm xung cn 1,9-2,0 ppm trong 2 gi. Kh c hi trong nh pht sinh t vt liu trang tr (decoration material) v ni tht cha methyl, methyl hydrosulfit, H2S v amonia, foocmaldehyt, acetaldehyde... cc cht ny u c th b phn hy v oxy ha bng phn ng quang xc tc. Nng ban u t 10 - 12 ppm gim n 2ppm sau 120 pht v n 0 ppm sau 300 - 400 pht [8]. Ngoi ra, trong lnh vc x l mi trng cc nh khoa hc ti Nht Bn ch to c dung dch hn hp cha TiO2 v mang tm thnh cng ln cc vt liu, c nhiu tc dng nh: dit khun, Sinh vin : Trng H12
Lp : a Sinh Thi K51
Trng H M - a Cht
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kh nm mc, loi b cc kh NOx, SOx. Cc kh nng trn ca TiO2 c gi l kh nng lm sch ca vt liu. Cc sn phm ny c p dng rng ri ngoi thc t. Mt s hng sn xut vt liu ph TiO2 ni ting ti Nht Bn nh: Ishihara Sangyo, Kaisha, Kogyo Kabushika Kaisha, Tto v Sakai Chemical. Vic s dng cc loi vt liu mi nhm nng cao c hiu qu ca cc phng php x l kh thi c cc nc pht trin ch trng t lu. T vic ch to thnh cng cc vt liu nano, tng c din tch b mt, th cc cng ngh nano c p dng nhanh chng vo lnh vc mi trng v em li hiu qu cao. i u trong cng ngh nano nh M, Nht, Nga c nhng thit b x l kh thi, nc thibng cc vt liu ng dng cng ngh nano. Rt nhiu cc sn phm mi ra i nh gch men c kh nng t lm sch v dit vi khun dng cho cc bnh vin, knh t lm sch bng vic ph mt lp vt liu ln knh, h thng lc nc s dng nh sng t ngoi v TiO2 kh cc cht c hu c cn st li trong nc sau khi x l bng cc phng php thng thng, thit b lm sch khng kh v mi b, Vit Nam Hin nay Vit Nam th cng c s u t v cc dy chuyn hoc thit b nhm lm gim thiu c s hnh thnh v pht tn cc cht kh gy nhim khng kh. Ch yu vn dng cc bin php nh s dng cc cht hp ph thu v x l cc kh, theo phng php thu hi v x l. Tuy nhin hiu qu x l ca cc phng php khng cao. Vic p dng cc k thut cng ngh cao cng c ch nhm nng cao c hiu sut x l ca thit b cng nh l hiu qu x l cc cht gy nhim. Bt u t vic s dng than hot tnh hp th cc kh c c trong khng kh. Nm 1996, cc vin thuc Trung tm Khoa hc t nhin v Cng ngh quc gia, gm Vin cng ngh Mi Trng, Vin Vt l ng dng v Thit b khoa hc, Vin Ha hc, Phn vin Vt liu ti TP HCM, Vin K thut nhit i hp tc s dng cng ngh nano nghin cu vt liu bn dn ny. ti tp trung vo nghin cu cng ngh ch to lp ph TiO2 c kch thc ht nano ln mt s loi vt liu khc nhau, dng phn hy cc hp cht hu c gy nhim nh khi thi xe c, khi thuc l v cc ha cht c trong nc thi, thuc tr su... nh tc ng khuch tn ca nh sng. Da trn cc kt qu nghin cu c bn, hin nay, cc nh khoa hc thit k v ch th thnh cng tm panen quang xc tc TiO 2 c cu trc nano xp a vo mt s thit b lm sch mi trng nh my kh mi, lm sch khng kh, Sinh vin : Trng H13
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
h thng lc nc.TiO2 l vt liu rt bn, khng c hi, r tin v c th ch to Vit Nam. Vt liu ny c s dng rng ri trong cuc sng. Tuy vy, vic s dng tnh cht quang xc tc ca TiO2 ht siu mn (ht c kch thc vi chc nano) lm sch mi trng cn l vn rt mi nc ta. Vic xc nh c chnh xc ngun gy nhim aldehyt th cng c nhng gii php nhm gim thiu ti a s pht thi v s tc ng ca aldehyt n mi trng v con ngi. i vi s pht thi t qu trnh t chy nhin liu ha thch: tm kim
ngun nhin liu thay th sch hn (sn xut xng Etanol, s dng nng lng mt tri), nng cao hiu sut t chy, thay th cc loi ng c c, trang b thm cc b x l kh thi trc khi thi ra mi trng. i vi s pht thi t cc vt c foocmaldehyt: hn ch s dng
foocmaldehyt lm cht n, ph gia trong qu trnh sn xut. i vi nhng khu nh, vn phng c cc vt c kh nng pht thi foocmaldehyt th nn trang b thm cc thit b lm sch khng kh, tng cng s trao i khng kh nhm gim nng kh c trong phng, nhng cng nn lu c th c s tc ng t cc cht kh bn ngoi n mi trng khng kh trong nh. Mt s sn phm cng ngh nano Vit Nam: - Trung tm Quc t Nghin cu v o to Khoa hc Vt liu (ITIMS); Nghin cu vt liu v tnh cht TiO2 trong cc qu trnh ha hc chng n mn ang c trin khai ti Khoa Ha, Trng i hc Khoa hc T nhin, HQG H Ni [10]. - Nghin cu v ng dng nano TiO2 cho sensor quang hc ti Khoa Vt l, Trng i hc KHTN - HQG H Ni, Ch to in cc trong sut cho pin mt tri; ch to sn TiO2 c tc dng dit khun; mng nano TiO2 c kh nng t lm sch, phn hy cht c, chng nm mc, dit khun, tnh cht siu u nc ca Vin Vt l ng dng v Thit b Khoa hc, Vin Khoa hc v Cng ngh Vit Nam. Hi tho quc t gia Vin Khoa hc v Cng ngh Vit Nam v Trng i hc Tng hp Cng ngh Tokyo t chc ti H Ni 01/2003 v Khoa hc v ng dng ca nano TiO2 cho mi trng bn vng" nh du bc pht trin ca Vit Nam v cng ngh nano. Nhng kt qu nghin cu v tnh cht quang xc tc v kh nng ng dng cho x l nhim mi trng ca nano TiO2 trong ti cp Vin Khoa hc v Cng ngh Vit Nam (2002-2003) ca Vin Cng ngh Mi trng v Vin Vt l ng dng cho thy tnh kh thi ca nhng ch phm t nano TiO 2 [11]. Mng TiO2 ph ln vi than hot tnh, vi thy tinh cho hiu qu dit khun v kh mi kh tt (kt qu c kim nghim ti Vin V sinh Dch t Trung ng). TiO 2 Sinh vin : Trng H14
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
ph ln cc mang to ra cc b lc ch ng quang xc tc trong mu thit b kh mi, c cng b trong ti hp tc quc t vi Malaysia nm 2005 [12]. Ch to b lc ch ng quang xc tc nano TiO2 c p dng trong my th cho bnh nhn nhim H5N1 ca Vin Cng ngh, B Khoa hc Cng ngh [13].
Sinh vin : Trng H
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Lp : a Sinh Thi K51
Trng H M - a Cht
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CHNG 2: VT LIU NANO TiO2 V HIU NG QUANG XC TC 2.1. Vt liu nano TiO2 Cu trc TiO2 v tnh cht vt l Titandioxide (TiO2) l mt loi vt liu rt ph bin trong cuc sng hng ngy ca chng ta. Chng c s dng nhiu trong vic pha ch to mu sn, mu men, m phm v c trong thc phm. Ngy nay lng TiO2 c tiu th hng nm ln ti hn 3 triu tn. TiO2 cn c bit n trong vai tr ca mt cht xc tc quang ha. TiO2 tn ti dng bt, thng c mu trng tuyt iu kin thng, khi nung nng c mu vng. Khi lng phn t l 79,87 g/mol, trng lng ring t 4,13 - 4,25 g/cm3; nng chy nhit cao 18700C; khng tan trong nc; khng tan trong cc axit nh axit sunfuric, clohydric... ngay c khi un nng. Tuy nhin, vi kch thc nanomet, TiO2 c th tham gia mt s phn ng vi axit v kim mnh. Cc dng oxit, hydroxit v cc hp cht ca Ti (IV) u c tnh bn dn. Bng 2.1. Thng s vt l ca Anatase v Rutile Tnh cht H tinh th Nhm khng gian Thng s mng a Thng s mng c Khi lng ring khc x cng (thang Mox) Hng s in mi Nhit nng chy Anatase Tetragonal I4 1 /amd 3,78A 9,49A 3,895g/cm 3 2,52 5,5 6,0 31 Nhit cao chuyn thnh rutile Rutile Tetragonal P4 2 /mnm 4,58A 2,95A 4,25 2,71 6,0 7,0 114 1858 0 C
Tinh th TiO2 c nhiu dng th hnh trong c 2 dng th hnh chnh l: Anatase v Rutile. Cu trc ca chng c th hin trong hnh 2.1.
Sinh vin : Trng H
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Lp : a Sinh Thi K51
Trng H M - a Cht
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Hnh 2.1 Cu trc ca rutile v anatase Cu trc ca dng tinh th anatase v rutile thuc h tinh th tetragonal C 2 dng tinh th trn u c to nn t cc a din phi tr TiO 6 cu trc theo kiu bt din (hnh v), cc a din phi tr ny sp xp khc nhau trong khng gian. Tuy nhin trong tinh th Anatase cc a din phi tr 8 mt b bin dng mnh hn so vi Rutile, khong cch Ti-Ti ngn hn v khong cch Ti-O di hn. iu ny nh hng n cu trc in t ca hai dng tinh th, ko theo s khc nhau v cc tnh cht vt l v ha hc. Trong t nhin dng tinh th Anatase v Rutile thng ph bin hn cc dng khc. Qu trnh phn ng xc tc ca vt liu ph TiO 2 xy ra khi c cc ngun chiu sng t nhin v nhn to c th [14]. - Ngun nh sng nhn to Cc vt liu mang tm ph TiO2 s dng ngun UV nhn to ca nh sng hunh quang c hiu qu chuyn in nng thnh photon nh sng cao. Loi n ny chuyn phn ln in nng thnh nhit v nh sng kh kin, gi thnh cao v thi gian s dng thp, khong 1000 gi so vi n UV hunh quang c hiu sut chuyn ha in nng thnh photon cao v thi gian s dng t 4000 n 14000 gi. - Ngun nh sng t nhin nh sng to ra t mt tri l ngun sng c ph a sc, bc sng tri di t min t ngoi n hng ngoi vi cng bc x cc i khong 580Wm-2 Sinh vin : Trng H17
Lp : a Sinh Thi K51
Trng H M - a Cht
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bc sng 400-800 nm, l vng nh sng trng thy (VIS). c trng ca ph nh nng mt tri trong ngy khng my c trnh by trong bng 2.2. Bng 2.2. c trng ca ph nh nng mt tri (trong ngy khng my) Di UV C UV B UC A UV A2 VIS IR A IR B IR C Tng cng Bc sng, nm < 280 280 -320 320 360 360 400 400 800 800 1400 1400 3000 > 3000 Cng , Wm-2 0 5 27 36 580 329 143 1120 T l, % 0 0,5 2,4 3,2 51,8 29,4 12,7 100
Ngun nng lng thin nhin ny l v tn v c bit phong ph quanh nm i vi nhng nc vng nhit i nh Vit Nam. Tuy phn bc x tng ng vi bc sng UV khng ln, khong 5% trong tng s bc x ca nh nng mt tri nhng hon ton c th v cn tn dng ngun UV thin nhin ny thc hin cc qu trnh quang ho hc, c bit cc qu trnh oxi ho quang ho hc nng cao. Vi nhng nc nm gia 35o v bc v 35o v nam, bc x UV ca mt tri ni chung > 0,015 mW cm-1, nng lng ny thc hin qu trnh quang xc tc [15]. Trong ph cc di nng lng mt tri c di UV A tng ng vi bc sng di 400nm, tng ng vi mc nng lng ln hn 3.2eV, ph hp vi mc nng lng cn thit thc hin qu trnh quang xc tc trn TiO 2. UV B c bc sng 280 315nm. UV C c bc sng t 200 315nm, UV C thng c c trng bi bc sng 254nm. Cc thit b s dng ngun UV nhn to c ch to ty theo trng thi cht xc tc s dng. Nh vy, vi vt liu ph TiO2 c th s dng c c hai ngun chiu sng nhn to v t nhin. Vit Nam thuc vng nhit i gi ma nn vic ng dng cc sn phm ph TiO2 s tn dng c ngun nng lng c sn, ng thi hn ch c vi sinh vt gy bnh trong mi trng khng kh. 2.2. Phn ng quang xc tc TiO2 C ch xc tc quang ca TiO2. Khi Titandioxyt TiO2 dng tinh th Anatase c hot ha bi nh sng c bc sng (lamda) thch hp th xy ra s chuyn in t t vng ha tr ln vng dn, ti vng ha tr c s hnh thnh cc gc OH* v RX+: Sinh vin : Trng H18
Lp : a Sinh Thi K51
Trng H M - a Cht
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Ti vng dn c s hnh thnh ca cc gc O2-, HO2*:
Nh vy, s hp th photon lm sinh ra electron v l trng chnh l yu t then cht ca qu trnh xc tc quang ha. Tuy nhin, c mt qu trnh khc cng xy ra trn b mt cht xc tc, i lp vi s kch thch quang lm sinh ra cp electron-l trng. l s ti kt hp ca electron v l trng. y l yu t chnh lm hn ch hiu qu ca qu trnh xc tc quang ha v gy lng ph nng lng cung cp bi cc photon. Phng trnh m t s ti kt hp c th coi l ngc li vi phng trnh : e- + h+ (SC) + E Trong (SC) l tm bn dn trung ho v E l nng lng c gii phng ra di dng mt photon (bc x nh sng) hoc phonon (nhit). Qu trnh ny c th din ra di hnh thc ti kt hp b mt hoc ti kt hp th tch.
Hnh 2.2 Minh ha qu trnh kch thch trong xc tc quang ha (A) Ti kt hp b mt; (B) Ti kt hp th tch (C) Qu trnh kh; (D) Qu trnh oxy ha Sinh vin : Trng H19
Lp : a Sinh Thi K51
Trng H M - a Cht
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Vy s khc bit l do dng anatase c kh nng kh O 2 thnh O2 (tr) cn rutile th khng (thc t v dng anatase c tnh xc tc mnh hn nn khi nghin cu v tnh cht ny u tp trung v dng anatase nn rutil b coi nh. Thc t th h photo-catalyst c dng nhiu nht trong cng nghip hin nay c 80% anatase v 20% rutile, l P25 (DEGUSTA). Khi trn anatase vi rutile c th tng bn ca h v thm ch cn c th tng hot tnh na.) Do anatase c kh nng nhn ng thi oxy v hi nc t khng kh cng nh sng t ngoi phn hy cc hp cht hu c. Tinh th Anatase di tc dng ca nh sng t ngoi ng vai tr nh mt cu ni trung chuyn in t t H2O sang O2, chuyn hai cht ny thnh dng O2 (tr) v OH* l hai dng c hot tnh oxy ha cao c kh nng phn hy cht hu c thnh H2O v CO2.
Hnh 2.3. Minh ha c ch xc tc quang ha ca TiO2 Song song vi tnh cht quang xc tc, khi c chiu nh sng t ngoi dng TiO2-anatase cn th hin mt tnh cht na cng rt c bit, l tnh cht siu thm t. Tnh cht ny c dng ch to cc vt liu t lm sch nh: Knh t lm sch, vt liu x l nc, vt liu dng trong y hc... 2.3. Cc yu t nh hng n tc ca phn ng quang xc tc 2.3.1. Cht xc tc i vi c hai h xc tc quang ha (huyn ph v c nh), tc ti a ca phn ng u t l thun vi khi lng xc tc. Tuy nhin c mt gi tr mmax m ti nu tip tc thay i khi lng cht xc tc th tc ca phn ng khng thay i. Khi lng mmax ph thuc vo 2 yu t: - Dng hnh hc ca vt liu. - iu kin tin hnh ca thit b phn ng quang ha Sinh vin : Trng H20
Lp : a Sinh Thi K51
Trng H M - a Cht
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Mmax: - xp x 1,3 mg TiO2/cm2 i vi h c nh - 2,5g TiO2/l i vi h huyn ph Vi iu kin thc hin l phng th nghim th nng tt nht l TiO2: 0,25g/l (thc hin trong bnh c nh, cn trong mt h thng tun hon dung dch ch cn TiO2 l 0,2g/l). 2.3.2. Bc sng ca n Tc phn ng ph thuc vo bc sng ca n, i vi TiO 2 khong cch gia vng dn v vng ha tr c nng lng E =3,2eV tng ng vi bc sng 380 nm. 2.3.3. Nng C0 ban u nh hng ca nng tun theo m hnh ng hc LangmuirHinshelwood. 2.3.4. Nhit Do phn ng quang ha nn khng i hi v nhit ( c th tin hnh iu kin nhit thng). Ni chung iu kin phn ng 20 -80 0C. V trong khong nng lng hot ha ca cc qu trnh quang ha s nh nht (khong 12kJ/mol). Nu nhit thp qu (di 00C) Ea s tng ln. Nu nhit ln hoan 800C s khng tt cho qu trnh hp ph cc cht ln b mt xc tc do tc ca phn ng s gim. 2.3.5. Dng photon Vn tc phn ng t l bc nht vi dng photon (). Dng cng ln th cp e t do- l trng cng nhiu do tc phn ng s tng. Tuy nhin, trong iu kin phng th nghim th dng gii hn khong 25mW/cm2 tc phn ng s t l vi 1/2. 2.3.6. Hiu sut lng t Hiu sut lng t: c nh ngha l t l gia tc phn ng quang ha -1 (mol.s ) v tc dng photon. V vy trn thc t vi cc phn ng quang ha xc tc phn hy cc cht hu c th lun tn ti cc giai on phn ng trung gian nn hiu sut lng t thng nh hn 1. 2.4. iu kin ca phn ng quang xc tc Phn ng quang xc tc ch xy ra khi c cc yu t sau: - Vt liu c tnh xc tc - nh sng - Cht nhim
Sinh vin : Trng H
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Lp : a Sinh Thi K51
Trng H M - a Cht
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Bn cht ca phn ng quang xc tc l qu trnh ti to li kh nng oxi ha ca vt liu. N chuyn i nng lng ca nh sng thnh ha nng v th nguyn tc lm vic l v tn. Tuy nhin, trn thc t th thi gian lm vic ca vt liu cng c hn, tuy nhin ln hn rt nhiu ln so vi cc phng php khc. TiO2 c hot tnh tt v c nhiu u im hn so vi cc loi vt liu bn dn khc: - Oxi ha hon ton cc cht c (VOC v Bicarosol) thnh CO2 v H2O. - ng dng cho nhiu cht hu c v hiu sut cao. - Cc sn phm ph, sn phm cui cng khng gy hi ti mi trng. - C th s dng ngun UV nhn to hoc tn dng ngun nh sng t nhin nn c th tit kim nng lng. - Thc hin trong c iu kin nhit v p sut bnh thng, thm ch c iu kin m cao. - Bo dng r v d dng. - Thi gian lm vic ca sn phm lu. Mt s ng dng ca vt liu nano TiO2 c trnh by trong bng 2.3.
Sinh vin : Trng H
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Lp : a Sinh Thi K51
Trng H M - a Cht
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Bng 2.3. Cc ng dng ca xc tc quang ha TiO2 [12. Kaneko M., Okura I. (2002), Photocatalysis: Science and Technology, Springer-Verlag Berlin Heidelberg New York, Japan]. c tnh T lm sch Phm vi ng dng Vt liu nh v vn Gch ngoi tht, linh kin nh bp v phng phng tm, c ni tht, b mt nha, xy dng, mn ca, n chiu sng trong Chp n trong sut, vt liu ph ln nh v ngoi tri bng n hunh quang v n cao p Vt liu cng trnh giao Vt liu ph ng hm, n tn hiu, thng gng phn x Khc Vt liu lm lu, qun o bnh vin, ng phc, sn xe Lm sch Trong nh My iu ha khng kh kt hp xc tc khng kh quang ha, x l kh c trong nh Ngoi tri B tng lm ng, gch lt va h, tng hm, tng nh Lm sch nc Nc ung Khc iu tr ung th Bnh vin Khc X l nc mt, nc ngm, lm b cha nc B c, cng thot nc Cc thit b ni soi Gch lt nn v tng phng m, ng silicone thng tiu, qun o bnh vin Gch lt nh tm, phng nui ng vt
Chng khi u Kh trng
2.5. Tng quan v phng php sol- gel Phng php sol-gel l mt phng php tng hp vt liu hin i, nh kh nng iu khin tnh cht sn phm thng qua tc ng vo bc to sol hoc gel, nn sol-gel l mt phng php t ra rt u vit tng hp nhng vt liu c kch c nano hay nhng mng siu mng. Bn cht ca phng php sol - gel l da trn cc phn ng thy phn v ngng t ca cc tin cht bng cch iu chnh tc ca hai phn ng thy phn v ngng t chng ta s t c vt liu mong mun. T dung dch bao gm cc cht a vo phn ng c ha tan vi nhau, qua cc phn ng thy phn v ngng t ta thu c gel.23
Sinh vin : Trng H
Lp : a Sinh Thi K51
Trng H M - a Cht
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Qu trnh sol - gel c th cho ta gel cha ton b cc cht tham gia phn ng v dung mi ban u, hoc kt ta gel tch khi dung mi v c khi l c cc cht sau phn ng. Vi a s cc phn ng th tc phn ng thy phn thng ln hn tc phn ng ngng t. V vy cn nghin cu v ng hc phn ng iu chnh tc ca hai phn ng xy ra thch hp vi tnh cht sn phm cui. Qu trnh sol - gel thc cht xy ra qua hai giai on sau: - Thy phn to sol (kch thc ht keo nm trong vng kch thc t 1nm 100nm). Phn ng chung xy ra nh sau:Dung mi hu c M(OH) + xHO xROH M(OH)(OR) +
- Ngng t to gel: Qu trnh hnh thnh gel l qu trnh trng ngng loi nc v ROH, ng thi ngng t cc alcolat b thy phn to thcc lin kt kim loi - oxi. Ta c th biu qu trnh gel ha qua cc giai on nh sau:
Sinh vin : Trng H
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Lp : a Sinh Thi K51
Trng H M - a Cht
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* Ngng t cc monome Alcolat hnh thnh cc ht polime -M-OH- + HO-M-M-O-M -M-OH + RO-M-M-O-M-
+ +
H2 O ROH
* Cc ht polyme pht trin dn ln v kch thc. Cc ht nh lin kt thnh mch, sau hnh thnh mng khng gian n mt lc no nht tng ln t ngt v ton b h bin thnh gel. Dung mi s nm trong cc l trng ca gel. Qu trnh thy phn v ngng t thng c iu khin bng cch thm axit, baz iu chnh pH. iu chnh tc thy phn nh vic thay i pH, thm bt H2O, thm dung mi hoc thm cc phi t to phc cng nh axetylaxeton, axit acetic. Hai qu trnh trn cng xy ra chm th kch thc ht cng nh phi t to phc cng nh axetyl axeton, axit axetic.... Vic tm ra mt dung mi thch hp c th iu khin c qu trnh thy phn v ngng t l vn ht sc cn thit khi ta tin hnh iu ch cc ht c kch thc c nano theo phng php sol - gel, bn cht ca dung mi s quyt nh phn ln n sn phm hnh thnh. Khi hnh thnh gel ta ch mi thu c mt loi sn phm m trong cc nguyn t kim loi v oxy lin kt vi nhau thnh mng khng gian (khng phi l mng tinh th) v gia cc khong trng ca mng khng gian s cha cc phn t dung mi. Gel c hnh thnh nh vy s c dng mt khi mm, cu trc d dng b ph v khi tc ng bi lc bn ngoi. thu c cu trc bn th gel hnh thnh phi c x l qua giai on sau: - Lm kh: L qu trnh lm bay hi nc v dung mi to thnh b khung xerogel. Xerogel vn cha l cu trc cui cng, n vn l trng thi v nh hnh c hnh thnh bi mng bao gm cc lin kt kim loi v oxi, cc phn t dung mi bay hi ht. - Nung: Gel sau khi c lm kh vn gi nguyn trng thi v nh hnh, chuyn thnh dng tinh th cn phi tri qua giai on nung, y l giai on ht sc quan trng c vai tr quyt nh n trng thi v kch c ht hnh thnh, ng thi khi nung s phn hy cc cht hu c cn li v dung mi cn d t cc l trng ca mng khng gian, ph v khung hnh thnh cc ht c kch c nano, v nh hnh li cu trc ca vt liu thu c sn phm cui cng. Qu trnh phn hy v bay hi ca dung mi s hnh thnh nn cc ht nh hn t cc ht ban u, kch c ca chng t ti kch thc vi chc nanomet ty thuc vo iu kin hnh thnh gel ban u v iu kin nung. [3] Nhng u im ca phng php sol - gel Sinh vin : Trng H25
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
- C th to ra s lin kt vng chc gia cht nn kim loi v lp ph pha trn - C th to ra nhng mng vi dy nht nh c kh nng ngn chn s n mn - Phng php sol - gel l phng php c th trn ln qui m nguyn t, tnh ng nht ca sn phm cao, tinh khit ha hc cao, cc giai on phn ng c th iu khin c to c sn phm mong mun, khng gy nhim mi trng. - Nhit thiu kt thp, thng 200 0 C - 600 0 C - Cch lm n gin, r tin, phng php t hiu qu cht lng cao. Nhc im ca phng php sol - gel - tinh khit ca sn phm d b nh hng. Sn phm cui cng tng hp bng phng php ny rt d b ln cc tp cht c th do cc cht a vo ban u cha phn ng trit hoc do tp cht l sn phm ca qu trnh phn ng ph. - dy ti a c th to c l 5m, khi kh nng rn nt l khng th trnh khi. - S kt ta khng mong mun trong bt k giai on no ca qu trnh tng hp ny s dn n s thay i v thnh phn cng nh tnh cht ca vt liu. - Kh nng ng dng vo sn xut cng nghip cn hn ch do iu kin phn ng c bit. Phn loi cc qu trnh sol - gel Da vo vt liu ban u s dng cho qu trnh tng hp ngi ta c th chia phng php sol - gel thnh ba dng chnh: - Sol -gel i t thy phn mui trong dung dch nc - Sol - gel i t thy phn phc cht - Sol - gel i t thy phn alkoxide kim loi Qu trnh sol - gel i t thy phn mui: qu trnh sol - gel i t thy phn mui trong dung dch nc thng s dng cc mui ca axit nitric hoc axit clohydric, do cc mui ny d tan trong nc. u im ca phng php ny l cc mui c s dng thng r tin do gi thnh sn phm rt r so vi cc phng php khc. Phng php ny c s dng trong thc t sn xut Fe2O3, Al2O3, SiO2 . Tuy nhin, do cc mui nitrat hay clorua thng l cc cht in gii mnh, tng tc ion sau phn ng d xc tc qu trnh ln ln ca mm, v vy kh iu chnh c ht c kch thc nanomet. Qu trnh sol - gel i t thy phn phc cht: phc cht thng c dng y l phc ca cation kim loi vi cc phi t hu c. Cc phi t hu c c s dng thng l cc axit cacboxylic nh axit citric, axit tartric, axit oleic, axit Sinh vin : Trng H26
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
naphtanic. Cc hng dn s dng phng php ny tng hp vt liu bao gm: gm siu dn cht in mi v cc dng vt liu c cu trc perovskite. Lin kt gia cc phi t trong phc cht l cc lin kt phi tr, nng lng lin kt phi tr thng nh hn nng lng lin kt ion, tnh phn cc gim do vy d t c s ha trn phn t gia cc thnh phn phn ng, v vy sn phm phn ng phn b u v kch thc ht nh. Qu trnh sol - gel i t thy phn alkoxide kim loi: y l phng php s dng vt liu ban u l cc alkoxide, nhng sn phm cui cng thu c thng c cht lng cao, do t tin cht (precusor) c th thc hin ng thi hai qu trnh phn li (thy phn) v kt t (ngng t) to mch v li ha. Do phng php ny c nghin cu rng ri trong nhng nm gn y. Phng trnh tng qut ca phn ng thy phn v ngng t cc alkoxide kim loi c th vit nh sau: M(OH) n + xOH [M(OR) n x (OX) x ] + xROH Trong X c th l nguyn t hydro i vi phn ng thy phn, l nguyn t kim loi i vi phn ng ngng t v thm ch l cc phi t v c hoc hu c i vi phn ng to phc.H HO: + MOR | H (a) \ R / HOMO MOH + ROH \ (c) H (d)
O: MOR / H (b)
Nhng phn ng ny xy ra theo c ch th nucleophin lng phn t (S N 2) nh sau: Bc 1: (a) a tc nhn i nhn (H 2 O) vo nguyn t kim loi mang in dng dn n trng thi chuyn tip (b), trng thi ny s phi t ca M tng thm mt. Bc 2: l bc chuyn proton trong (b) dn n trng thi trung gian trung gian (c). Proton t phn t nc c chuyn ti oxi tch in m ca nhm OR. Bc 3: l qu trnh tch nhm mang tnh dng in nht trng thi (c) chuyn n trng thi (d). C hai phn ng thy phn v ngng t u tham gia vo s bin i alkoxide thnh khung oxit, do cu trc hnh thi hc ca cc oxit thu c ph thuc rt nhiu vo kh nng phn ng ca hai phn ng ny. Hin nay trn th gii c rt nhiu cng trnh nghin cu to mng mng titan dioxit theo phng php sol - gel trn mang l cc vt liu tr nh thy tinh Sinh vin : Trng H27
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
hoc vt liu hp ph nh laterit, cc oxit kim loi... Cc cng trnh nghin cu ny hu ht cho kt qu rt kh quan trong x l cht hu c kh phn hy sinh hc. S dng TiO 2 theo phng php ny c u im l khng cn cng on tch v thu hi, tin li cho s dng; tuy vy nhc im l k thut gn cht xc tc trn mang di dng mng mng phc tp. Hn na, mng xc tc c xu hng b bong tri theo thi gian s dng nn phi ti to nh k.
Sinh vin : Trng H
28
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
CHNG 3: PHNG PHP NGHIN CU 3.1. Phng php thu thp Thu thp, nghin cu v phn tch, k tha cc ti liu c trn th gii v Vit Nam v phng php ch to vt liu nano TiO2, cch ph dung dch sol TiO2 ln bng thch anh v ng dng ca chng trong x l kh thi aldehyt (HCHO) trong mi trng khng kh. Tin hnh thu thp ti liu t cc ngun sau: + T Vin Cng ngh mi trng - Vin Khoa hc v Cng ngh Vit Nam. + Lin h vi cc thy c trong b mn cng nh trong nh trng thu thp thm cc ti liu c lin quan n ni thc tp v phc v cho vic vit n. + Tm kim cc thng tin v cc ti liu qua cc phng tin bo tr, sch bo v internet + Ngoi ra cc ti liu cn c thu thp t cc bn sinh vin khc 3.2. Phng php nghin cu Ch to vt liu TiO2/SiO2 bng phng php sol- gel (sol C) a, Ha cht o Tetrabutylorthotitanate - Ti(OC4H9)4o Ethanol - C2H5OH o Diethanolamine - NH(C2H4OH)2 vit tt (DEA) o Tt c cc ha cht u c ngun gc t Merck c.
o Nc ct s dng trong qu trnh ch to l nc ct hai ln. b, Thit b o L nung Carbolite (c) c chng trnh iu khin nhit , nhit 1000oC lp ph TiO2 o T sy o Bp gia nhit Jenway -1000 (Anh) c khuy (Hotplace and Stirrer) s dng gia nhit trong qu trnh ch to sol-gel v dng un dung dch HCHO khi th nghim. o Cn ADAM (M) chnh xc 10-4 mg v 10-2 mg s dng cn ha cht. - Thit b kim tra v x l mu: My chp XRD (X-Ray Diffraction): nhn din nhanh v chnh xc cc
pha tinh th, ng thi c th s dng nh lng pha tinh th v kch thc ht vi tin cy cao. Knh hin vi in t qut - SEM (scanning electron microscope): xc nh b
mt mu vt. Sinh vin : Trng H29
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
Knh hin vi in t truyn qua - TEM (Transmission electron microscopy):
Xc nh cu trc tinh th ca vt liu. Test box: Dng th nghim kh nng x l ca vt liu ch to. Bm KIMOTO HS7 (Handy Sampler) tc ti a ca my: 2,5 l/pht v
mc nh nht l 0,1 l/pht. S dng trong qu trnh th nghim vt liu s dng hp th HCHO vo trong nc ct xc nh nng HCHO trong test box. My phn tch UV- Vis : Xc nh nng HCHO trong khng kh.
Ngoi ra cc dng c trong cn dng nh cc thy tinh, a, kp,bp... cng c s dng trong qu trnh nghin cu. Qu trnh to lp ph TiO2 trn vt liu SiO2 (TiO2/SiO2), qua 3 cng on nh sau: 1. Pha ch sol TiO2 bng phng php sol- gel 2. Phun ph vt liu 3. Thiu kt nhit cao c, iu ch dung dch sol- gel Ngoi ra, to c lp ph TiO2 nano bm dnh tt trn mang ta c th a vo sol TiO2 mt lng bt nano TiO2 - P25 thch hp. tch cc cm ht P25 thnh cc ht TiO2 ring l, hn hp sol TiO2 vi P25 c khuy mnh nhit phng, sau rung siu m cho n khi P25 phn tn u thnh dung dch TiO 2 huyn ph mu trng sa. Huyn ph TiO2 c dng ph ln bng thch anh hoc knh. Sau mu c thiu kt 5000-5500C trong vng 1 gi. dy mng c xc nh bng phng php anpha step hoc tnh t khi lng ring, din tch v trng lng. Mt ln ph mng cho dy c 0,4 micro mt i vi mng sol gel v c 3 micro mt vi mng t bt TiO2-P25. Quy trnh tm ph TiO2 ln bng thch anh c m t nh hnh 3.1.
Sinh vin : Trng H
30
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
Ti(OC4H9)4, C2H5OH DEA
C2H5OH, H2O
Ti(OC4H9)4, C2H5OH, DEA, H2Os
TiO2
Sol TiO2
Dung dch huyn ph Phun ph mng
Thiu kt 5500C trong l Bng thch anh tm ph TiO2Hnh 3.1. Quy trnh tm ph nano TiO2 ln bng thch anh Bc 1: Pha 23ml TBOT v 7,1ml DEA vo 140 ml Ethanol. Bc 2: Khuy k dung dch trn nhit phng trong thi gian 3 gi trn my khuy t, ta thu c hn hp 1. Bc 3: Pha 1,3 ml H2O vo 10 ml ethanol. Bc 4: Khuy k dung dch trn nhit phng trong 15 pht ta thu c hn hp 2. Bc 5: Khuy mnh hn hp 1 trn my khuy t v nh git hn hp 2 vo hn hp 1. Bc 6: Khuy mnh dung dch trn trong 1 gi. Kt qu thu c dung dch trong sut v n nh (sol TiO2). Bc 7: a 1 g TiO2 nano thng mi P25 DEGUSSA vo 30 ml sol TiO2 Sinh vin : Trng H31
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
Bc 8: Khuy mnh hn hp sol v P25 nhit phng v rung siu m cho n khi P25 phn tn u. Ta thu c huyn ph sol TiO2. Bc 9: Dung dch bc 6 v bc 8 trn c s dng to mng TiO2 trn mang bng thch anh. Bc 10: S dng my phun sn to lp ph sol TiO2 ln mang l bng thch anh. Bc 11: Sy bng thch anh ph sn TiO 2 trong t sy 60 0 C trong 12 gi. Bc 12: Thiu kt bng thch anh ph sol TiO 2 550 0 C trong 1 gi. Bc 13: Bc cng ngh lp li t cc bc 10 n bc 13 t c dy ca lp ph thch hp. thu c dy mong mun c th tip tc lp li qu trnh trn nhiu ln.
Hnh 4.2. Vt liu bng thch anh trc Hnh 4.3. Vt liu bng thch anh ang khi phun ph. c phun. Tin hnh chp SEM xc nh c cu trc ca vt liu, tnh ton ra thi gian ti u nht( b mt vt liu l ln nht). Th nghim vt liu bng vic xy dng test box vi th tch 1m 3, s dng bng n UV lm xc tc quang nng.
Sinh vin : Trng H
32
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
3.4. Phng phap xc nh cu trc ca lp ph a) Phng php xc nh dng hin vi in t qut SEM SEM l mt trong nhng phng php phn tch ph bin nht dng xc nh c tnh ca vt liu, cu trc vi tinh th v s phn b kch thc. phn gii ca phng php ny t n vi nanomet, cho php iu chnh phng i t 10 n trn 1.000.000 ln. SEM khng nhng cung cp thng tin v phn b hnh th bng nh hin vi quang hc m cn cung cp thnh phn ha hc ca hn hp cht phn tch gn b mt. Nguyn tc hot ng: To chm tia in t mnh v iu khin chm ny qut theo hng, theo ct trn mt din tch rt nh ca b mt mu. Chm in t kch thch mu pht in t th cp, in t tn x ngc, tia X. Mi loi in t, tia cho mt thng tin no v mu phn nh mt tnh cht no ch in t p vo mu. Vt liu nano TiO2/SiO2 sau khi c a vo thit b knh hin vi in t qut (Scanning electronic microscope - SEM), xc nh cu trc v mt s tnh cht vt l ca vt liu. Trong qu trnh nghin cu mt s mu vt liu nano TiO2/SiO2 c gi n phng th nghim ca Vin khoa hc vt liu - Vin khoa hc Vit Nam chp nh SEM xc nh kich thc hat TiO2 v chiu day lp mang TiO2. S cu to v nguyn tc hot ng c trnh by hnh bn:
Sinh vin : Trng H
33
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
Hnh 3.2. Knh hin vi in t qut S4800 b) Phng php nhiu x tia X (X-Ray difraction - XRD) Vi cc cht c cu trc mng tinh th u n th mi mt mng nh mt lp phn x cc tia X khi chng c chiu vo cc mt ny. Chm tia X chiu vo tinh th to vi mt tinh th gc . y l phng php dng xc nh cu trc v thnh phn pha ca cht xc tc. N rt cn thit v quan trng v thnh phn, cu trc b mt xc tc TiO2 c nh hng mnh m n tnh cht l ha ca chng, c bit l hot tnh quang ha. Ngoi ra, phng php XRD cn c th xc nh c v tr ca cc nguyn t trong nhng cu trc phn t phc tp.
Sinh vin : Trng H
34
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
1 2
+
+
Hnh 3.3. S nhiu x tia X t mt s hu hn cc mt phng (p mt phng) Vt liu nano TiO2/SiO2 cng c a vo thit b nhiu x Rn-ghen xc nh cu trc mng tinh th ca cc ht TiO2 bm trn b mt si nhm oxit. Phng php ny da trn hin tng phn x v giao thoa ca cc tia X khi lan truyn trong mng tinh th. Phng php xc nh ny cng c thc hin ti phng th nghim ca Vin khoa hc vt liu - Vin khoa hc Vit Nam xc nh cu trc tinh th ca ht trn thit b Siemens D5000. Phn tch cu trc bng XRD c tin hnh bng cch chiu ln mu nghin cu chm tia X vi bc sng t vi phn trm n vi chc angstron, sau ghi nhn v phn tch nh nhiu x t mu. Ph nhiu x tia X ca TiO2 anatase s cho cc cc i 2 = 25,3o(mt 101), 37,8o (mt 004), v 48o (mt 200). Ph nhiu x tia X ca TiO2 rutile s cho cc cc i 2 = 27,4o(mt 110), 36,1o(mt 111), v 54,3o (mt 211). 3.5 Thc nghim a) Phng php to kh HCHO S dng ha cht l Fomandehit nng 37%. Mun to kh foocmaldehyt, ly 50l HCHO 37%, t ln bp Hotplate & Stirrier v t vo bn trong Testbox c qut i lu. b) Phng php xc nh nng kh aldehyt trong test box S dng thit b KIMOTO hp th hi foocmaldehyde trong 60 pht bng 10ml dng dch hp th ( nc ct). Mu c ly ra v o bng phng php so mu vi thuc th Phenyl hydrazin 1% trong nc ct. Tin hnh o mt quang bc sng 519 nm, t tnh ton c nng ca aldehyde theo cng thc : C=ab vVo
trong : C Nng foocmaldehyde trong khng kh (mg/l) Sinh vin : Trng H35
...p
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
a -Lng formol trong ng phn tch ng vi ng thang mu b Dung dch hp th (ml) v- Dung dch hp th ly ra phn tch (ml) Vo- Th tch khng kh ly mu qui v iu kin tiu chun (l) Xc nh c nng aldehyt trong test box, t nh gi c kh nng x l ca vt liu.
Sinh vin : Trng H
36
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
PHN II PHN KT QU, THIT K V TNH TON KINH PH
Sinh vin : Trng H
37
Lp : a Sinh Thi K51
Trng H M - a Cht CHNG 4 : KT QU NGHIN CU
N TT NGHIP
4.1 Kt qu th nghim Vt liu mang tm TiO2 c s dng trong ti nghin cu l si bng thch anh (SiO2). la chon vt liu phu hp vi tinh cht mang tm, cn khao sat tnh nng c ly nh bn, tnh chiu nhit va kha nng thay i cu trc tinh th .Tinh cht nay rt quan trong quyt inh bn cua vt liu. Bng thch anh dng si, xp, mu trng c din tch b mt tip xc rt ln (trng lng ring 200 g/m2, b mt ring 40 m2/g) do vy rt ph hp lm vt liu mang tm TiO2. Bng thch anh c cu trc v nh hnh, khi nhit cao d gin, gy v vy TiO2 ph ln vt liu ny thng lm theo cng ngh phun ph hn l ngm tm trong dung dch sol. Hnh 4.2 l gin nhiu x tia X (XRD) ca vt liu TiO2/SiO2. Hnh 4.1 l nh chp ca bng thch anh.
Hnh 4.1. Anh chp cua bng thch anh
Sinh vin : Trng H
38
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
Hnh 4.2 Gian XRD ca SiO2 4.2. Kt qu xc nh cu trc lp ph 4.2.1. Kho st tnh cht lp ph TiO2/SiO2 i vi thnh phn sol ch to Vt liu c ch to vi t l mol thnh phn sol cc cht TBOT: DEA: H2O: EtOH theo t l 1: 1: 1: 38 (k hiu l mu 1) c so snh vi vt liu chun ca Php c tm ph TiO2 (mu 2). Kt qu phn tch gin nhiu x tia X trong hnh 4.3 v 4.4 cho thy:
Hnh 4.3. Gian XRD ca vt liu t ch to mu 1
Sinh vin : Trng H
39
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
Hnh 4.3 l gin XRD ca bng thch anh (di) v ca mu 1 (trn) c pic c trng ca tinh th A-TiO2 ti 2 = 25,18o, bng thch anh tn ti dng v nh hnh. Mu 2 ca Php (hnh 4.4) c gian nhiu x c trng gc 25o rt r.
Hnh 4.4. Gian XRD ca vt liu so snh - mu 2 Hnh 4.5 l anh chup SEM i vi vt liu TiO2/SiO2 trn mu 1. Cc ht TiO2 c kch thc t 25 30 nm va anatase TiO2 ph u trn b mt vt liu. Mu 2 (hnh 4.6) cac ht TiO2 cung c kch thc khong 30 nm. So snh hai mu ny nhn thy s tng ng v kch thc ht, cc ht TiO2 trong mu ti ch to c dng ht u nhau hn nhng b mt vt liu mu 2 c phn mn v ph u trn b mt mang.
Hnh 4.5. nh SEM ca mu 1- do ti ch to
Sinh vin : Trng H
40
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
Hnh 4.6. nh SEM ca mu 2- mu chun ca Php 4.2.2. Kho st chiu dy lp ph TiO2 trn cc loi vt liu Xc nh chiu dy lp ph TiO2 trn si bng thch anh
Hnh 4.7. Mu TiO2/SiO2 sau 1 ln tm ph: (A) ca ti; (B): mu i chng; v (C): chiu dy lp ph Dung dch sol C c s dng tm ph ln bng thch anh, hnh 4.7 (A) l TiO2 tm ph ln si bng thch anh cua ti, chiu dy mi ln ph khong 1 micro mt (4.7 - C). Hnh 4.7 B, l mu so snh ca Php. S dng huyn ph TiO2 c th to c lp phu c dy c micro mt se khc phc c kh khn do bng thch anh gin, d gy khi tm ph nhiu ln. Mu c ch to c tnh cht tng ng vi mu ca Php. 4.3 M hnh th nghim (testbox) Bung th nghim co h thng van khi vao, h thng en UV, motor hut gio, h thng in. Cac thng s cua h o: lu lng khi, tc dong khi, cng en chiu sang, ch thoat khi thai. anh gia hiu qua cua vt liu quang xuc tac x ly nhim khng khi cn phai xy dng bung th nghim thc hin cac phep o tng ng t hin trng cua cac phng tin giao thng, cac tram ng kim v quy m phong thi nghim.41
Sinh vin : Trng H
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
Bung th nghim c ch tao bng vt liu Inox am bao bn hoa hoc, khng bi n mon, co kin cao va khng tham gia vao cac qua trinh bin i ly hoc va hoa hoc. Kich thc bung th nghim 1m 1m 1m la tao ra mt th tich khng gian la 1m3 th tich khng khi. 4.3.1.1 Cu tao bung th nghim 1m 1m 1m (Test Box) a, Bn ngoai: Toan b bung th nghim c lam bng Inox bao gm khung Inox va Inox tm bao boc bn ngoai, phia trc co ca quan sat kich thc (600 400) mm, co th m khi cn thao tac bn trong. Co ng dn in vao, chn co banh xe y khi cn co th di chuyn c. Bn trai bung th nghim phia di co h thng van va ng ng dn khi vao. Bn phai bung th nghim phia trn co h thng van va ng ng dn khi ra. b, Bn trong: a) H thng in: Bn trong bung th nghim c lp t h thng en chiu sang va quat i lu nn h thng in c thit k tng ng bao gm: 1 bang in 4 cm c ni vi ngun bn ngoai trong o: + 1 cm quat i lu cng sut 30W + 3 cm 2 gian en, mi gian en co 3 bong va mi bong co cng tc ring. b) H thng gian en: + Mt ay c lp t 3 en tup 60 co cng sut 20W/en, vi tri cac en cach nhau nh trn hinh ve. + Mt inh cung c lp t 3 n tup 60 co cng sut 20W/en vi tri i din tng ng vi mt ay va co khoang cach nh trn hinh ve. c) H thng khe va moc cai vt liu: Vt liu cn nghin cu c lp vao cac tm li Inox co kich thc (370370) mm. Mt ay co 4 hang inh moc treo tm vt liu song song va xen ke vi 3 mang en tup. Khoang cach va vi tri nh trn hinh ve. 4.2.2 Chc nng bung th nghim 4.2.2.1 H thng van iu tit khi vao va khi ra Bung th nghim c s dung khao sat qua trinh x ly cac loai kim khi bng vt liu quang xuc tac di tac dung cua cac loai en co bc song khac nhau. Chinh vi vy Bung th nghim c kt ni vi: h phan ng bng cac ng dn Sinh vin : Trng H42
Lp : a Sinh Thi K51
Trng H M - a Cht
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co van iu tit khi vao va khi ra, vi tri cac ng dn va van iu tit c m ta trn hinh ve. 4.2.2.2 H thng gian en Trong bung th nghim lp t 2 gian en, mi gian co 3 mang en. en c s dung trong nghin cu la en tup dai 60 cm cng sut 20W/en. Co 3 loai en khac nhau: - en anh sang trng - en UV co bc song 254 nm - en UV co bc song 365 nm Tuy tng thi nghim co th lp t 1 6 en va co th thay cac loai en khac nhau. 4.2.2.3 Quat i lu Bung th nghim la h kin, khi 1 lng khi c tao ra a vao bung th nghim mun tao s ng nht phai khuy trn. Quat i lu lp t nhm tao ra s ng nht v nng khi trong 1 th tich la 1m3. Cng sut quat i lu la 30W. 4.2.2.4 H thng in H thng in bn trong bung th nghim c lp t co cng tc tng va cng tc ring cho tng gian en, cho tng en, cho quat i lu. Tuy tng thi nghim co th bt hoc tt ring bt ky cng tc nao. H thng in bn trong c ni vi mang in bn ngoai bng ng dn nh trn hinh 4.8.
Sinh vin : Trng H
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Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
B n g n t u p
in h m c t m v t l iu v an kh
n g c m in dn kh
t m v t l iu q u t i l u
k h e c i v t l i u
Hnh 4.8. S test box Vic tin hnh cc th nghim to phn ng sinh kh v th nghim kh nng x l kh ca cc vt liu khc nhau c tin hnh mt cch cn thn v c s gim st nhm m bo cc thng s l ph hp v chnh xc nh mong mun ng thi cng m bo khng xy ra s c khi thc hin. 4.3 nh gi kh nng kh aldehyt ca cc vt liu ch to
Foocmaldehyt c a vo h th nghim vi nng ban u khong 8 mg/m3. Qua nh gi, sau 28 gi nng foocmaldehyt hu nh khng thay i khi khng c ngun nh sng kch hot v c s dng cc loi vt liu ch to (hnh 4.9). Th nghim ban u vi nng foocmaldehyt trong test box l 8 mg/m3 vi cc iu kin: khng n khng vt liu, mnh vt liu mu 1 v mnh vt liu mu 2. Kt qu th nghim c th hin bng 4.1.
Sinh vin : Trng H
44
Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
Thi gian 0 1 2 4 8 16 24 28
Khng n + Khng vt liu 8 7.7 7.7 7.7 7.6 7.6 7.6 7.6
Vt liu mu 1 + Vt liu mu 2 + khng n khng n 8 8 7.7 7.2 7.6 7.1 7.6 7 7.5 7 7.4 7 7.4 7 7.4 7
Bng 4.1. kt qu th nghim ca test box trong cc iu kin khc nhau
Hnh 4.9. Kho st s thay i nng kh khi khng c n Vi ngun sng 20 W, bc sng 365 nm. Kha nng x li aldehyt cua vt liu cung khc nhau. Hnh 4.10 cho thy, hiu sut x l ca mu 1 t 83,5 % v mu 2 chun ca Php l 92 %. Kh nng x l foocmaldehyt ca vt liu ch to trn bng thch anh cho kh nng x l kh quan nht. nh gi kh nng x l ca vt liu TiO2/SiO2 ca ti ch to v mu chun ca Php c th hin bng 4.2.
Sinh vin : Trng H
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Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
Thi gian 0 1 2 4 8 16 24 28 % X l
n + Vt liu (mu 1) 8 6.33 5.67 4.33 3.67 2.67 2.33 1.33 83
n + Vt liu (mu 2) 8 5.67 4.47 4.24 3.67 2.67 1.33 0.67 92
Bng 4.2 Bng nh gi kh nng x l ca cc loi vt liu trong iu kin c n.9 8 7 6 5 4 3 2 1 0 0 1 2 4 8 16 24 28 n + Vt liu (mu 1) n + Vt liu (mu 2- mu chun Php)
Hnh 4.10. Kho st s thay i nng aldehyt i vi cc loi vt liu ch to khi c ngun nh sng kch hot
Sinh vin : Trng H
46
Lp : a Sinh Thi K51
Trng H M - a Cht CHNG 5: TNH TON CHI PH
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5.1 C s tnh ton Cn c Ngh nh s 205/2004/N-CP ngy 14/12/2004 ca Chnh ph quy nh h thng thang lng, bng lng v ch ph cp lng trong cc cng ty nh nc. Cn c Ngh nh s 94/2006/N-CP ngy 07/09/2006 ca Chnh ph v vic iu chnh mc lng ti thiu chung. Cn c Thng t s 12/2006/TT-BLTBXH ngy 14/09/2006 ca b Lao ng thng binh v x hi v vic hng n thc hin iu chnh tin lng v ph cp lng trong doanh nghip theo ngh nh s 94/2006/N-CP ngy 07/09/2006 ca chnh ph. Cn c vo gi th trng v mt s vn bn khc c lin quan, t tnh ra c chi ph cho ton b qu trnh. a) Chi ph vt liu L gi tr vt liu chnh, vt liu ph cn thit trc tip thc hin v hon thnh mt n v khi lng cng vic. Gi vt liu kho st xy dng trong n gi tnh theo Bng gi vt liu n chn cng trnh trn a bn H Ni theo mt bng gi qu I nm 2011 v cha bao gm thu gi tr gia tng. b) Chi ph nhn cng Chi ph nhn cng: L s lng ngy cng lao ng ca k s, cng nhn trc tip (bao gm c nhn cng iu khin my) cn thit thc hin v hon thnh mt n v khi lng cng tc kho st xy dng. Chi ph nhn cng trong n gi bao gm lng c bn, cc khon ph cp c tnh cht lng v cc chi ph theo ch m c th khon trc tip cho ngi lao ng tnh ton cho mt ngy cng nh mc. Theo nguyn tc ny chi ph nhn cng trong n gi kho st xy dng. Chi ph nhn cng trong n gi c tnh vi mc lng ti thiu l 730.000 ng/thng t 01/05/2010 theo Ngh nh s 94/2006/N-CP ngy 07/09/2006 ca Chnh ph v vic iu chnh mc lng ti thiu chung. c) Chi ph my v thit b L chi ph s dng cc loi my v thit b trc tip cn thit thc hin v hon thnh mt n v khi lng cng tc .
Sinh vin : Trng H
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Lp : a Sinh Thi K51
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Chi ph my v thit b kho st trong n gi kho st xy dng khng bao gm chi ph tin lng th iu chnh my (v chi ph ny c tnh trong chi ph nhn cng ca n gi kho st xy dng). Nh vy th chi ph tnh cho qu trnh th nghim vt liu c tnh: (s tin cng tr cho nhn vin + tin chi ph thu my mc thit b cn thit) x Thi gian tin hnh th nghim. 5.2. Chi ph thit k ch to m hnh th nghim (test box): Da trn c s tnh ton chi ph th chi ph cn thit cho vic thit k test box c th hin bng 5.1.
Sinh vin : Trng H
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Lp : a Sinh Thi K51
Trng H M - a Cht
N TT NGHIP
Loi vt liu S lng x n gi Vt liu nhm: 18kg x80.000/kg Inox bt ngoi loi 0,5 29 kg x65.000/kg mm: Dy inox =4 Li inox kh 1 mx4 m Mng n n UV 365mn H thng van kh Ph kin khc: cm, qut in, phch cm, bng dn, inh vt,.. Ph kin lm thng hnh hp kch thc 1 mx 1m x1m(bn l, ke gc, inh tn, goong m,...) 60.000/m 6 ci x 30.000/ci 6 ci x 500.000/ci
Thnh tin =1,440.000 =1,885.000 =100.000 =240.000 =180.000 = 3,000.000 = 1,000.000
=400.000
=750.000
Chi ph khc Cng th Thu vn chuyn Tng chi ph 14 cng x150.000/cng
=200.000 = 2100.000 = 100.000 =11,207.000 Bng 5.1. Chi ph cho vic thit k test box
Sinh vin : Trng H
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Lp : a Sinh Thi K51
Trng H M - a Cht
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5.3. Chi ph ch to vt liu TiO2/SiO2 dng tm Tm vt liu c kch thc: 47cm x 47cm x 1cm.Bao gm: Chi ph ha cht v chi ph nhn cng ch to ra vt liu. - TiO2 degusa P25: 75.000 - TBOT: 3.000.000/L x 25 ml =35.000 - DEA: 1.000.000 x 10 ml = 5.000 - Cn: 150 mL x 40.000/L = 3.000 - in, nc: = 2.500 - Bng thch anh: = 25.000 - Nhn cng, ph ph : = 10.000 Tng: = 155.500 5.4. Chi ph cho cng tc th nghim vt liu Cp bc tin lng theo bng lng A.1 thang lng 7 bc, Ngnh 8 nhm II - Xy dng c bn ban hnh theo Ngh nh s 205/2004/N-CP ngy 14/12/2004 ca chnh ph. Ph cp lu ng mc 20% tin lng ti thiu, mt khon lng ph (ngh l, tt, php...) bng 12% lng c bn v mt s chi ph c th khon trc tip cho ngi lao ng tnh bng 4% so vi tin lng c bn. Da vo bng n gi nhn cng ta c th tnh n gi nh bng 5.2. Lao ng STT Lng c bn v cc khon ph cp c tnh cht lng Bc 3/7 Bc 4/7 Bc 3,5/7 H s lng theo ngh nh 25/CP v 1 26/CP 2,16 2,55 2,36 2 Lng ti thiu 730.000 730.000 730.000 3 Lng thng ti thiu 1.576.800 1.861.500 1.722.800 4 Ph cp theo lng ti thiu + Ph cp lu ng (20%) 146.000 146.000 146.000 5 Ph cp tnh theo lng c bn + Phc cp khng n nh (10%) 157.680 186.150 172.280 + Lng ph (l, tt,) (12%) 189.216 186.150 206.736 + Mt s khon khc (4%) 63,072 74,460 68.912 Cng lng thng 2.132.768 2.454.260 2.316.728 S ngy cng/thng 26 26 26 n gi mt ngy cng (ng/cng) 82.029 94.394 89.104 Bng 5.2. n gi nhn cng Tin hnh th nghim kho st, nh gi kh nng x l kh ca vt liu. Do 2 k s thc hin. Thi gian d kin 6 thng ti phng phn tch Cht lng Mi trng Vin Cng ngh mi trng - Vin Khoa hc v Cng ngh Vit Nam. Sinh vin : Trng H50
Lp : a Sinh Thi K51
Trng H M - a Cht
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Da vo bng 5.2 ta c th tnh c chi ph lm th nghim nh sau: TT 1 2 Danh mc Thi gian n UV 6 thng Tin thu my 6 thng v phng th nghim S lng n gi (ng) 6 bng 800.000/1 bng - my o kh t 15.000.000/thng ng my KIMOTO - ha cht 2 ngi 2.454.260/thng (bc 4/7) 2 bng 10.000/bng Tng (ng) 4.800.000 90.000.000
3 4 Tng
Nhn cng n thng tup
6 thng
14.725.560 20.000 109.545.560
Bng 5.2. Chi ph cng tc th nghim trong phng Cc khon chi ph khc STT Loi chi ph 1 2 Thi S gian lng Tin in thoi, 6 thng in, nc Vn phng phm 6 thng (bt vit, mc in, giy in) n gi 2.000.000/thng 1.500.000/ thng Tng (n ng) 12.000.000 9.000.000 v:
Tng
21.000.000
5.5. nh gi hiu qu kinh t: Sau khi tng hp , nh gi cc kt qu d ton, ta a ra c chi ph chung cho ton d n nh sau:
Sinh vin : Trng H
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Lp : a Sinh Thi K51
Trng H M - a Cht Bng 5.3 Tng chi ph chung cho ton d n Loi cng tc Lm test box Cc khon chi ph khc Th nghim trong phng Chi ph ch to vt liu Tng n gi (ng) 11.207.000 21.000.000 109.545.560 155.500 142.908.060
N TT NGHIP
Ngoi ra trong d n cn phi chi ph cc loi sau: Chi ph chung bng 7,5% chi ph thc t. Vy chi ph chung l:
142.908.060 x 7,5% = 107.181.045 (ng) Chi ph d phng bng 10% chi ph thc t. Vy chi ph d phng l: 142.908.060 x 10% = 14.290.806 (ng) Chi ph cho li nh mc bng (chi thc t + chi ph chung + chi ph d phng) x 9%. vy chi ph cho li nh mc bng: (142.908.060 + 107.181.045+14.290.806) x 9%= 23.794.192 (ng) Vy chi ph cho ton d n trong 6 thng l: 142.908.060 + 107.181.045+14.290.806 +23.794.192 = 288.174.103 (ng) Chi ph tnh trung bnh mt thng : 288.174.103/ 6 =48.029.017 (ng) nh gi hiu qu kinh t ca d n: Chi ph khong 48 triu ng/1 thng cho vic ch to vt liu v th nghim
vt liu ch to l mt mc gi hp l. Nhm la chn c iu kin ti u trong qu trnh ch to v th nghim. T ch to cc vt liu nh vy s dng trong cc thit b x l kh p ng c nhu cu v cc thit b lm sch khng kh ca th trng. Test box l thit b th nghim kh nng x l kh ca cc vt liu c
ch to. N c bn cao, vic s dng n gin, c th ng dng th nghim nhiu vt liu khc nhau. Khng ch s dng trong ti ny m cn c th ng dng trong rt nhiu d n tng t khc. Test box l thit b th nghim khng th thiu nh gi tc dng ca cc vt liu ch to. Gi thnh ch to khong 11 triu cho test box l mt mc gi hp l. Chi ph ch to cho 1 tm vt liu TiO2/SiO2 khong 150 nghn ng l mt
mc chi ph hp l cho mt loi vt liu x l nhim trong khng kh. D n c hiu qu kinh t cao v n l c s khng nh kh nng x l
kh ca vt liu v c th i vo thng mi ha bng vic sn xut khi lng ln v cc sn phm s dng vt liu nano TiO2/SiO2. Sinh vin : Trng H52
Lp : a Sinh Thi K51
Trng H M - a Cht KT LUN V KIN NGH KT LUN
N TT NGHIP
ti nghin cu, ch to thnh cng vt liu nano TiO2 tm ph trn trn bng thch anh v ng dng vo x l aldehyt trong mi trng khng kh (kh thi c hi pht sinh t cc ni tht trong vn phng v nh ). Cc kt qu chnh t c nh sau: 1. Xc nh c ngun pht sinh aldehyt trong mi trng vn phng v nh , cc tc ng ca aldehyt n sc khe con ngi. 2. nghin cu, ch to c vt liu nano TiO2/SiO2 bng k thut phun ph huyn phu TiO2 degusa - P25. Vt liu c to bi huyn ph cho tinh th anatase dng nano kch thc trung bnh t 25nm 30 nm, chiu dy n lp khong 1m va c s tng ng v kch thc ht vi vt liu ca Php. Vt liu c pic c trng ca tinh th SiO2 ti 2 = 25,18o. 3. ch to h th nghim (test box) dung tch 1mx1mx1m bng vt liu inox vi cc h thng n, qut thng gi, h thng in, vi h thng sinh kh s dng nh gi cc vt liu ch to trong x l kh aldehyde. Nng kh foocmaldehyt = 8mg/m3.Sau vi gi chiu sng (en c bc sng 365nm, 20W, khong cch t ngun sng n vt liu l 50 cm), kh b kh gn nh hon ton. Vt liu TiO2/SiO2 c kh nng x l nhanh v hiu qu gn tng ng vi vt liu ca Php. Hiu sut x l aldehyt ca vt liu TiO2/SiO2 do ti ch to t 83%. 4. xy dng c qui trnh cng ngh phun ph nano TiO 2 trn b mt si bng thch anh bng vic s dng my phun sn. Quy trnh ny c tnh kh thi, n nh cao v c kh nng ng dng trin khai nhiu ni vi chi ph thp. KIN NGH Vi cc kt qu nghin cu v sn phm ch to c, cc thnh vin thc hin ti mong mun: 1. c tip tc pht trin hng nghin cu mc hon thin hn cc quy trnh cng ngh p dng trong sn xut lng ln v trin khai quy m thc t ti mt a danh c th.
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Lp : a Sinh Thi K51
Trng H M - a Cht
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2. Ch to cc thit b lc kh c s dng vt liu TiO 2/SiO2 lm b lc nng
cao hiu qu x l cc kh c hi. 3. Nghin cu p dng s dng vt liu TiO2/SiO2 x l cc cht nhim khc nh: CO, NO, cc VOCs khc v p dng trong cc mi trng khc nhau nh: cng xng sn xut, khu vc bo qun ha cht 4. Tip tc u t nghin cu v kh nng hp ph ti a ca vt liu, kh nng phc hi ca vt liu theo thi gian, thi gian thay th vt liu.
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Lp : a Sinh Thi K51
Trng H M - a Cht Ti liu tham kho
N TT NGHIP
1. Nguyn Th Ngc Anh (2007), "Nghin cu ch to xc tc quang xc tc quang TiO2/UV v ng dng vo vic x l nc thi cha cc hp cht hu c kh phn hy sinh hc" kha lun tt nghip c nhn Khoa hc mi trng, HKH T nhin, HQG HN. 2. Trn Ngc Bin, Nghin cu thit k ch to my th s cu bnh nhn H 5N1 ti tuyn huyn, Trung tm Cng ngh Laser, ti c lp cp nh nc, 20052006. 3. o Khc An My x l khng kh nhim dit khun, dit nm mc da theo hiu ng quang xc tc vi b lc TiO2, Bo co tng kt nghim thu ti ngh nh th Vit Nam Malaysia (2006). 4. TS Nguyn Th Hu Nghin cu x l nhim khng kh bng vt liu sn nano TiO2/Apatite, TiO2/Al2O3 v TiO2/bng thch anh, Vin Cng ngh mi trng . 5. Trn Th c, Nguyn Th Hu Nghin cu ch to cc loi mng xc tc quang ha TiO2 x l cc cht c hi trong khng kh v nc. Bo co tng kt ti cp Vin Khoa hc v Cng ngh Vit Nam, H Ni, 11/2003. 6. Cao Th H (2006), Nghin ch to xc tc quang ha trn c s bn dn TiO2
x l cc cht nhim hu c, Bo co khoa hc cp quc gia.
7. Trn Mnh Tr (2005), S dng nng lng mt tri thc thc hin qu trnh quang xc tc x l nc v nc thi cng nghip, Tp ch khoa hc v cng ngh Tp 43 s 2. 8. GS TSKH Trn Mnh Tr, TS Trn Mnh Trung, Cc qu trnh oxi ho nng cao trong x l nc v nc thi c s khoa hc v ng dng, NXB khoa hc v k thut. 9. Lisa. C, Klein. Sol-gel technology for thin films, fibers, preforms, electronic and specialty shapes. Noyes publicatin, USA,1987. Yu. KP, Lee. GW, Huang. WM, Wu. CC, Lou. CL, Yang. S, J. Air Waste Manag Assoc. 56(5): 666-74 (2006). 10. Th. Maggo, J.G. Bartzis, M. Liakou, C. Gobin, Photocatalytic degradation of NOx gases using TiO2-containing paint, Journal of Hazardous Materials ,146, 3, 668-673 (2007). 11. Carey and Oliver (1980),[20] Nemerow v Dasgupta (1991). 12. Ulrike Deibold, The surface science of TiO2, Surface Science report,Vol. 48, Sinh vin : Trng H55
Lp : a Sinh Thi K51
Trng H M - a Cht
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52-229 (2003). 13.T. Nonami et all. Mat. Sci. Forum, 439, 337-343, (2003). 14. Phm Vn Nho v cng s, Pin mt tri trn c s in cc TiO 2 nano xp, K yu Hi ngh Vt ly cht rn ton quc (2003). 15. http://www.congnghehoahoc.org/forum/showthread.php?t=845-Din n cng ngh ha hc.
Sinh vin : Trng H
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Lp : a Sinh Thi K51
Trng H M - a Cht Ph lc 1:
N TT NGHIP
Thit b
Sinh vin : Trng H
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Lp : a Sinh Thi K51