kumar 2015

Ecotoxicology and Environmental Safety ∎ (∎∎∎∎) ∎∎∎–∎∎∎

Contents lists available at ScienceDirect

Ecotoxicology and Environmental Safety

http://d0147-65

n CorrE-m

Pleasappli

journal homepage: www.elsevier.com/locate/ecoenv

Fabrication of zirconia composite membrane by in-situ hydrothermaltechnique and its application in separation of methyl orange

R. Vinoth Kumar, Aloke Kumar Ghoshal, G. Pugazhenthi n

Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India

a r t i c l e i n f o

Article history:Received 2 December 2014Received in revised form4 May 2015Accepted 6 May 2015

Keywords:Zirconia membraneMethyl orangeHydrothermal treatmentDye removal

x.doi.org/10.1016/j.ecoenv.2015.05.00613/& 2015 Elsevier Inc. All rights reserved.

esponding author. Fax: þ91 361 2582291.ail address: [email protected] (G. Pugazhenth

e cite this article as: Kumar, R.V., etcation in separation of methyl orang

a b s t r a c t

The main objective of the work was preparation of zirconia membrane on a low cost ceramic supportthrough an in-situ hydrothermal crystallization technique for the separation of methyl orange dye. Toformulate the zirconia film on the ceramic support, hydrothermal reaction mixture was prepared usingzirconium oxychloride as a zirconia source and ammonia as a precursor. The synthesized zirconia powderwas characterized by X-ray diffractometer (XRD), N2 adsorption/desorption isotherms, Thermogravi-metric analysis (TGA), Fourier transform infrared analysis (FTIR), Energy-dispersive X-ray (EDX) analysisand particle size distribution (PSD) to identify the phases and crystallinity, specific surface area, porevolume and pore size distribution, thermal behavior, chemical composition and size of the particles. Theporosity, morphological structure and pure water permeability of the prepared zirconia membrane, aswell as ceramic support were investigated using the Archimedes’ method, Field emission scanningelectron microscopy (FESEM) and permeability. The specific surface area, pore volume, pore size dis-tribution of the zirconia powder was found to be 126.58 m2/g, 3.54 nm and 0.3–10 mm, respectively. Theporosity, average pore size and pure water permeability of the zirconia membrane was estimated to be42%, 0.66 mm and 1.44�10�6 m3/m2 s kPa, respectively. Lastly, the potential of the membrane was in-vestigated with separation of methyl orange by means of flux and rejection as a function of operatingpressure and feed concentration. The rejection was found to decrease with increasing the operatingpressure and increases with increasing feed concentrations. Moreover, it showed a high ability to rejectmethyl orange from aqueous solution with a rejection of 61% and a high permeation flux of2.28�10�5 m3/m2 s at operating pressure of 68 kPa.

& 2015 Elsevier Inc. All rights reserved.

1. Introduction

The annual global productions of dyes are calculated to be morethan ten thousand tons. In that, around 15% quantity is lost duringthe industrial processes, such as dyeing, textiles printing and dyemanufacturing (Forgacs et al., 2004). These industrial processesutilize several synthetic chemical dyes for a variety of purposes.Textile dyeing is among the most environmentally unfriendly in-dustrial processes owing to the large quantities of water de-manded and the strongly colored wastewater produced, pollutedwith dyes and other chemical auxiliaries. The highly colored ef-fluents dye streams could pose serious detrimental effects to theenvironment and thus to human health (Zaghbani et al., 2007;Jana et al., 2010). Specifically, Azo dyes can be toxic upon de-gradation and this class of dye is widely used in many industriesby virtue of present unique properties and technical

i).

al., Fabrication of zirconiae. Ecotoxicol. Environ. Saf.

characteristics. Among several varieties of dyes, methyl orange(MO) is considered as a model compound for ordinary water so-luble azo dyes, which is extensively utilized in chemical, textileand paper industries. Furthermore it is dangerous to the en-vironment (Shiue et al., 2012). The majority of the azo dyes andtheir breakdown products are toxic and carcinogenic to animalsand humans (Weisburger, 2002). Hence, this effluent is necessaryto be treated before discharging from the industries. The con-ventional methods employed for separation of dyes from coloredwastewater are flocculation/coagulation (Zahrim and Hilal, 2013),adsorption (Qiao et al., 2009), chemical oxidation (Turgay et al.,2011) and photocatalytic processes (Velusamy et al., 2014), reac-tion with ozone (Sharma et al., 2013) and biological treatment(Nilesh and Chaudhari, 2006). In flocculation, coagulation andadsorption treatment methods, effluents are converted from theliquid state to a solid state and this way creates secondary

composite membrane by in-situ hydrothermal technique and its(2015), http://dx.doi.org/10.1016/j.ecoenv.2015.05.006i

www.sciencedirect.com/science/journal/01476513

www.elsevier.com/locate/ecoenv

http://dx.doi.org/10.1016/j.ecoenv.2015.05.006



mailto:[email protected]





R.V. Kumar et al. / Ecotoxicology and Environmental Safety ∎ (∎∎∎∎) ∎∎∎–∎∎∎2

pollution. Chemical techniques such as photocatalytic and reactionwith ozone method need bulk quantity of costly chemicals as wellas generating huge amount of waste slurry. The by-products fromchemical degradation are also colored and even toxic. Further-more, biological degradation is inexpensive technique, harmless tothe environment and also not generates massive quantities ofsludge; however it is selective and time taking. Hence it is un-suitable for many dyes (Tan et al., 2006).

Membrane separation process could be ecofriendly and anauspicious alternative for the separation of dyes. The pressure-driven membrane processes, especially reverse osmosis, nanofil-tration, ultrafiltration and microfiltration are being increasinglyutilized in the removal of dyes (Al-Bastaki, 2004; Kim et al., 2005;Al-Aseeri et al., 2007; Mo et al., 2008). Within these techniques,ceramic membranes are better than polymeric membranes due toexcellent thermal, chemical and mechanical properties (Jedidiet al., 2009). However, nanofiltration and reverse osmosis techni-ques are described by higher energy utilization. Therefore lowerpressure membrane techniques such as microfiltration and ultra-filtration could be inexpensively more favorable for dye separa-tion. Besides, ceramic membranes are made up of a compositeformation with an active top layer, which typically decide its se-paration characteristics. Mostly the active top layers are made byinorganic oxides fabricated via the sol–gel method, dip-coating,hydrothermal crystallization with a controlled particle size. In-itially, the research on inorganic membranes was focused to thefabrication of alumina membranes, which is of higher cost andused most widely (Yang et al., 1998). Nevertheless, in recent times,various other porous membrane materials, such as zirconia, titaniaand silica were used. Amongst these, zirconia is especially attrac-tive material for making the ceramic membranes. The excellentcharacteristics of zirconia membrane are elevated chemical stabi-lity and cleaning actions can be done in the range of 0–14 pH,superior permeability and higher flux in separation owing to itsspecific surface characteristics, and excellent thermal resistance(Bhave, 1991).

In order to improve the flux of the membrane, the hydrophilicadaptation in microfiltration is an excellent choice, which providesan enhanced hydrophilic character to the membrane surface (Ko-cherginsky et al., 2003). Nano-scale ZrO2, TiO2/Al2O3, Al2O3 andSiO2 have been used to enhance the hydrophilic character and itcreates the charge on the surface of the membrane (Chang et al.,2014). Several investigations on zirconia membrane have indicatedits superior performance in the separation due to its special sur-face character (Zhou et al., 2010). These hydrophilic and chargedmembranes facilitate to attain a higher flux with good separationefficiency even though utilizing a realistically larger range of poresize membranes. However, the difficulty of modification of ceramicmembranes leads in the way of adding nano-particles uniformlyinto the porous ceramic membrane without blocking the mem-brane pores. Several preparation methods have been developed,such as in situ hydrothermal synthesis, vapor phase transportmethod, secondary growth method for the deposition of nano-materials on the ceramic matrix (Xu et al., 2004). Amongst these,hydrothermal technique has become basic route for the mod-ification of membrane surface by the deposition of nanomaterial(Kalantari et al., 2015).

In this present study, an inexpensive zirconia compositemembrane on a porous ceramic support has been synthesized. Thetop layer of zirconia is prepared through in-situ hydrothermalcrystallization technique by controlling growth of zirconia particleon the porous ceramic support. The separation potential of themembrane is investigated with separation of methyl orange var-ious operating pressure and feed concentration.

Please cite this article as: Kumar, R.V., et al., Fabrication of zirconiaapplication in separation of methyl orange. Ecotoxicol. Environ. Saf.

2. Materials and methods

2.1. Chemicals

Clays (ball clay, feldspar, kaolin, pyrophyllite and quartz) usedfor synthesis of ceramic support were of mineral grade and ob-tained in the vicinity (Kanpur, India). Zirconium Oxychloride(ZrOCl2 �H2O), Calcium Carbonate and Polyvinyl Alcohol (PVA)were supplied by Loba Chemie (Mumbai). Ammonium hydroxidesolution (NH4OH, 25 wt%) and methyl orange (C14H14N3NaO3S)were procured form from Merck (I) Ltd. (Mumbai).

2.2. Preparation of zirconia–ceramic composite membrane

The procedure followed for the preparation of ceramic supportand its composition were explained in our earlier publication(Monash and Pugazhenthi, 2011a). The zirconia–ceramic compo-site membrane was prepared through in-situ hydrothermalsynthesis by controlling growth of zirconia particle on the porousceramic support. The reaction mixture for hydrothermal reactionwas prepared by dissolving 5 g of zirconium oxychloride in 100 mLof water. Then the pH was adjusted to 10.0 with addition of aqu-eous ammonia (25%) under stirring condition at room tempera-ture. After that the reaction mixture was stirred vigorously for5 min, and then transferred to Teflon coated stainless steel auto-clave reactor (capacity 200 mL) for in-situ hydrothermal crystal-lization and a prepared porous ceramic support having 43 mmdiameter and 4.5 mm thickness was placed inside the reactor. Thereaction mixture was subjected to hydrothermal crystallization at90 °C for 60 h. After that, the membrane was recovered and wa-shed several times with Millipore water and dried at 90 °C for 24 hfollowed by calcined at 400 °C for 6 h in air atmosphere.

2.3. Methods for characterization

2.3.1. Characterization of zirconia powderAs-synthesized zirconia powder was collected from the bottom

of the autoclave reactor. Then, the zirconia powder was washed,dried and calcined at the same condition adopted for the com-posite membrane. Precise powder diffraction data of zirconia wasmeasured on a machine (Bruker AXS D8 advanced) with Cu Kα(λ¼1.5406 Å) radiation. The patterns were obtained in the 2θrange of 5–75° with a scan speed of 0.05° s�1. N2 adsorption/desorption isotherm was computed at �196 °C in a surface areaanalyzer (make: Beckman-Coulter; model: SA™ 3100). Thermo-gravimetric (TGA) analysis of the zirconia powder (before calci-nation) was carried out in a instrument of Mettler Toledo withmodel No.TGA/SDTA 851s in flowing nitrogen atmosphere at aheating rate of 10 °C min�1 from 25 to 900 °C. FTIR spectra wererecorded using a Shimadzu IRAffinity-1 model Spectrometer in thewavenumber range of 4000–500 cm�1. The particle size dis-tribution (PSD) of the zirconia powder was measured using amachine Malvern Mastersizer 2000 (APA 5005s model, hydroMU) in wet dispersion mode.

2.3.2. Characterization of zirconia ceramic composite membraneThe morphology of the prepared ceramic support and zirconia

composite membrane was investigated with an instrument FESEM(JEOL JSM-5600LV). Energy-dispersive X-ray (EDX) was carried outusing SEM (LEO 1430 VPs Oberkochen, Germany). In order todetermine the porosity, the membrane was dried at 120 °C for 3 hand measured the dry weight of the membrane (MD). Then themembrane was placed in Millipore water for 24 h. After which, thewet weight (MW) of the membrane was determined after remov-ing all visible water from the surface of the membrane with tissuepaper. Then the membrane was immersed in water, the pore filled





10 20 30 40 50 60 70

0

10

20

30

40

50

monoclinic- ZrO2 tetragonal- ZrO2

tetragonal- ZrO2

Inte

nsity

2θ (Degrees)

Fig. 1. XRD pattern of zirconia powder.

R.V. Kumar et al. / Ecotoxicology and Environmental Safety ∎ (∎∎∎∎) ∎∎∎–∎∎∎ 3

with water saturated weight of the membrane (MA) was measured(A refers to Archimedes). The porosity of the membrane was es-timated according to the below expression (Monash and Pug-azhenthi, 2011b).

M MM M 1

W D

W Aε =

−− ( )

2.3.3. Pure water permeability and microfiltration of methyl orange(MO)

The in-house made dead-end filtration setup with capacity of250 ml was used to determine the water flux and pure waterpermeability presented as supplementary data (see Fig. S1). Itconsists of two parts, a cylindrical top part and a base plate with aprovision to keep a membrane. The membrane was placed on aperforated casing and then kept in the bottom compartment. Theupper compartment of the batch cell was pressurized using ni-trogen gas by setting a desired pressure through regulator at-tached with the nitrogen cylinder. The water flux was calculated atvarious applied pressures. At every applied pressure, the collectionof first 50 mL of permeate was disposed and time taken for col-lection of following 50 mL of permeate was noted for the de-termination of flux. The following relations were used to calculatethe water flux and pure water permeability.

JT

L PQ

A 2W p=Δ

= Δ ( )

where, JW is the water flux (ms�1), Q is the volume of waterpermeated (m3), A is the effective membrane area (m2), ΔT is thesampling time (s). LP is water permeability (ms�1 kPa�1) andΔP isapplied pressure (kPa).

The average pore size was determined using Hagen Poiseuilleexpression assuming that pores are cylindrical in shape (Almandozet al., 2004; Bowen et al., 1997; Kumar et al., 2015).

Jr P

lL P

8 3W

2

pε

μτ= Δ = Δ

( )

where, ε is the porosity of the membrane, r is the pore radius ofthe membrane, l is the pore length, τ is the tortuosity factor and μis the viscosity of water.

The separation potential of the membrane was evaluated byundertaking the separation tests of methyl orange using the samesetup filled with 100 mL of the feed solution. In order to determinethe permeate flux at fixed operating pressure, initial 10 mL of thecollected permeate was disposed and the time needed to collectsubsequent 10 mL of permeate was calculated. The observed re-jection was evaluated by the following expression.

RC C

C100

4f P

f=

−×

( )

where, R is the observed rejection (%), Cf is the concentration ofthe feed solution and Cp is the concentration of the permeate so-lution. After carrying out a preliminary calibration procedure, theprecise concentration of dye was determined by measuring theabsorbance of the dye at a wavelength of 472 nm using a UV–visspectrophotometer (Spectrascan, UV 2300) (Monash and Pug-azhenthi, 2014). After every experimental run, the membrane wasthoroughly washed with Millipore water, followed by flushingwith Millipore water at higher pressure to regain the original purewater flux.


3. Results and discussion

3.1. Characterization of zirconia powder

X-ray diffraction analysis of fumed zirconia powder shows thetetragonal phase along with some small peaks of the monoclinicphase (Fig. 1). The patterns with a wide base line illustrate thepresence of amorphous zirconia. As a whole, zirconia powder ispacked with both amorphous and nano-crystals. Crystallite size ofthe zirconia powder is calculated by Debye–Scherrer formula(D¼Kλ/β cos θ), in which K (¼0.90) stands for shape factor, λ(¼0.15406 nm) represents the wave length of X-rays, β is the fullwidth of diffraction peak at half-maximum intensity in radians,and θ is the Bragg angle. The crystallite size of the zirconia is foundto be in the range of 5.54–14.31 nm. The bigger crystal size is dueto the thermally activated crystal growth. This result is in ac-cordance with previous results published in the literature (Wu andCheng, 2000; Etienne et al., 1994; Gestel et al., 2006). N2 adsorp-tion–desorption isotherm is depicted in Fig. 2(a). It clearly re-presents type IV adsorption isotherm with H-2 hysteresis loopaccording to IUPAC classification and associated with capillarycondensation in the mesopores (Sangwichien et al., 2002). Thepore size distribution of the zirconia is calculated from desorptionbranch of isotherm by BJH model. In Fig. 2(b), the distributioncurve indicates that the most of the pores are present with a sizesmaller than 10 nm and the sample possesses a relatively narrowsize distribution. BET surface area and pore diameter are estimatedto be 126.58 m2/g, and 3.54 nm, respectively.

Thermogravimetric analysis is carried out for the as-synthe-sized zirconia powder (figure not shown). The total weight loss isestimated to be approximately 21%. In general, the weight loss attemperature below 150 °C is owing to elimination of weekly ad-hered water molecule that was absorbed by the sample. Theweight loss at higher temperature is attributed to removal ofstructural hydroxyl groups. Moreover, the weight loss of the par-ticle after 450 °C is found to be insignificant. This justifies theselection of calcination temperature for the synthesis membrane.Fig. 3 demonstrates the FTIR spectra of zirconia (both before andafter calcination). Before calcination, OH stretching and bendingband appear at around 3400 and 1600 cm�1, respectively. Thesebands are related to adsorbed water, and illustrate the [ZrO(OH)2]n �H2O polymer structure. A sharp band at 1000 cm�1 describes Zr¼Ogroup stretching vibration, indicating that Zr¼O bond is not





0.0 0.2 0.4 0.6 0.8 1.00

20

40

60

80

100

Volu

me

adso

rbed

[cc

g-1

(STP

)]

Relative pressure P/Po

Adsorption Isotherm Desorption Isotherm

10 100

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

d(V

P)/d

(DP

) (m

l/g.n

m)

Pore diameter (nm)

Fig. 2. (a) N2 adsorption–desorption isotherms and (b) BJH pore size distribution ofzirconia.

4000 3500 3000 2500 2000 1500 1000 5008

10

12

14

16After calcination

Wavenumbers (cm-1) Tr

ansm

ittan

ce (a

.u.) 7

8

9Before calcination

Fig. 3. FTIR analysis of zirconia powder.


converted into Zr–O bond. The calcined zirconia shows absorptionpeak around at 800 cm�1, which is typically monoclinic zirconia. Zr–O bonds exhibit bands at 450–520 cm�1 whereas a broad infraredband at 520 cm�1 exhibits tetragonal ZrO2 phase (Chandra et al.,2010; Wong et al., 2002). The particle size distribution analysis wasmeasured for the synthesized zirconia powder. It is found that thesize of the particles is in the ranges of 0.3–10 mm as shown in sup-plementary data (see Fig. S2). Moreover, the volume median dia-meter (d0.5) is calculated to be 2.237 mm.

3.2. Characterization of ceramic support and zirconia compositemembrane

The porosity of the prepared ceramic support and zirconiacomposite membrane is measured to be 44%, and 42%, respec-tively. The average pore size is estimated to be 0.969 mm and0.66 mm for support and composite membrane, respectively. It isinferred from these values that, the porosity and pore radius of thezirconia membrane are reduced after hydrothermal treatmentowing to the deposition of zirconia particles on the surface of thesupport. Fig. 4(a), illustrates the FESEM image of fabricated sup-port and it is apparent that the uniform surface is highly porous


and crack free. Fig. 4(b) shows the deposition of fumed zirconia onto the surface of the membrane. It indicates that the film of zir-conia is deposited on the pore of ceramic support. Hence it can beconcluded that the ziconia is formed on the surface of the mem-brane support with smooth consistent surface. In addition, thepore density of the membrane is estimated from SEM micrographsusing Image J software. In order to minimize errors of imageanalysis, three SEM micrographs are analyzed for each sample. Thepore density of the ceramic support and zirconia membrane isfound to be 2.34�106 and 3.80�105 pore/mm2, respectively. Thedecreased pore density for the zirconia membrane is due to theblockage of pores by the formation of zirconia particles on thesurface of ceramic support.

Fig. 4(b) (inside) depicts an EDX spectrum, which quantitativelydetects the constituent elements. The spectrum shows Zr peakssignifying the existence of zirconia on the composite membrane.Other peaks detected in the EDX spectrum include oxygen, whichalso derived from the deposition of ziconia. Fig. 5 depicts the purewater flux of ceramic support along with zirconia membrane. Asexpected water flux increases linearly with an increase of appliedpressure and follows Darcy's law. It is observed that the water fluxis lower than that of ceramic support, which is accredited by re-duction in pore radius on hydrothermal treatment. As a result, thepure water permeability of zirconia membrane reduces resultingin lower flux. The pure water permeability (Lp) for support andzirconia membrane is found to be 3.63�10�6 and1.44�10�6 m3/m2 s kPa, respectively.

Table S1 (presented as supplementary data) summarizes theoverall properties of the fabricated ceramic support and zirconiamembrane. As stated above, the porosity, water permeability,mean pore size and pore density of the zirconia membrane isdecreased (see Table S1), which is obviously due to the in-corporation of the zeolite particles on the ceramic support byhydrothermal treatment.

3.3. Microfiltration of methyl orange

3.3.1. Effect of operating pressureThe flux and rejection trend of MO solution with different op-

erating pressures (69–207 kPa) at a fixed concentration





Fig. 4. (a) FESEM image of ceramic support and (b) zirconia–ceramic composite membrane with EDX.

0 50 100 150 200 250 300 3500.0000

0.0002

0.0004

0.0006

0.0008

0.0010

Wat

er fl

ux (m

3 /m2 s)

Applied pressure (kPa)

Zirconia-ceramic membrane Ceramic support

Fig. 5. Variation of water flux with applied pressure for support and zirconiamembrane.

Fig. 6. (a) Effect of operating pressure and (b) feed concentration on methyl orangeseparation.


(1000 ppm) is shown in Fig. 6(a). The permeate flux increases withincreasing operating pressure, due to the increase of driving forceacross the membrane. However, the permeate flux is lesser thanthat of pure water flux. This may be due to various aspects such asadsorption of dye particles on the surface of membrane and pores,and concentration polarization. The dye particles are settled on themembrane surface or into the pores, which raise membranefouling and resulting in reduction in permeate flux (Benitez et al.,2009). The observed rejection slightly decreases with an increaseof applied pressure. It means that the membrane properties havelittle effect on the dye removal with operating pressure. The re-moval of MO dye is perhaps due to the surface charge of zirconiamembrane. The isoelectric point (IEP) of zirconia is reported to be4 (Seshadri et al., 1998; Tsuru et al., 1998). It signifies that thezirconia membrane is positively charged at pHo4 and negativelycharged at pH44. Therefore the prepared composite membrane isnegatively charged as the natural pH of dye solution used in thiswork is 5.7. It can be clarified that the repulsion between mem-brane surface and the anionic dye molecule in the aqueous solu-tion causes the removal of MO in the permeate.

3.3.2. Effect of feed concentrationThe effect of feed concentrations (1000–3000 ppm) of MO on


the permeate flux and rejection was investigated at a constantpressure of 69 kPa and the obtained results are depicted in Fig. 6(b). As anticipated, the flux decline is high at higher concentrationas the feed concentration raises the membrane fouling severely.






An increase in dye adsorption on the membrane surface andconcentration polarization might be the responsible factors for thisobservation (Cassano et al., 2008). The obtained rejection data atthese concentrations demonstrate that the rejection slightly in-creases with increasing the feed concentration. At higher con-centration, the transportation of MO through the membrane isreduced due to the retention of MO in the deposit on the mem-brane surface. MO agglomerates more rapidly when the con-centration of MO in the feed solution is high (Monash et al., 2010);as a result, concentration of MO in the permeate declines.

4. Conclusions

The zirconia–ceramic composite membrane has been success-fully prepared by in-situ hydrothermal crystallization with con-trolled growth of zirconia particle on the porous ceramic support.XRD analysis of zirconia powder calcined at 450 °C reveals thepresence of tetragonal phase along with some small peaks of themonoclinic phase of zirconia. EDX spectrum demonstrates thepresence of the zirconia in the membrane FESEM image verifiesthat the zirconia particles adhere on the surface of the membrane.Moreover, porosity, average pore size and pure water permeabilityof the zirconia membrane is estimated to be 42%, 0.66 mm and1.44�10�6 m3/m2 s kPa, respectively. Separation potential of theprepared membrane is investigated on the effect of parameterssuch as operating pressure and feed concentration and its influ-ences on both permeate flux and MO removal is discussed.Moreover, the highest separation (61%) is obtained with thepermeate flux of 2.28�10�5 m3/m2 s at 68 kPa for the feed con-centration of 3000 ppm.

Acknowledgment

We would like to thank the Central Instrument Facility, IITGuwahati for helping us to perform FESEM analysis. This work wasfinancially supported by a research grant under the Fast TrackScheme (SR/FTP/ETA-44/2010) from Department of Science andTechnology (DST), Government of India.

Appendix A. Supplementary information

Supplementary data associated with this article can be found inthe online version at http://dx.doi.org/10.1016/j.ecoenv.2015.05.006.

References

Al-Aseeri, M., Bu-Ali, Q., Haji, S., Al-Basataki, N., 2007. Removal of acid red andsodium chloride from aqueous solutions using nanofiltration. Desalination 206,407–413.

Al-Bastaki, N., 2004. Removal of methyl orange dye and Na2SO4 salt from syntheticwaste water using reverse osmosis. Chem. Eng. Process. 43, 1561–1567.

Almandoz, M.C., Marchese, J., Pradanos, P., Palacio, L., Hernandez, A., 2004. Pre-paration and characterization of non-supported microfiltration membranesfrom aluminosilicates. J. Membr. Sci. 241, 95–103.

Benitez, F.J., Acero, J.L., Real, F.J., Garcia, C., 2009. Removal of phenyl-urea herbicidesin ultrapure water by ultrafiltration and nanofiltration processes. Water Res. 43,267–276.

Bhave, R.R., 1991. Inorganic Membranes Synthesis, Characteristics and Applications.Van Nostrand Reinhold, New York.

Bowen, W.R., Mohammad, A.W., Hilal, N., 1997. Characterisation of nanofiltrtationmembranes for predictive purposes-use of salts uncharged solutes and atomicforce microscopy. J. Membr. Sci. 126, 91–105.

Cassano, A., Mecchia, A., Drioli, E., 2008. Analyses of hydrodynamic resistances andoperating parameters in the ultrafiltration of grape must. J. Food Eng. 89,171–177.


Chandra, N., Singh, D.K., Sharma, M., Upadhyay, R.K., Amriphale, S.S., Sanghi, S.K.,2010. Synthesis and characterization of nano-sized zirconia powder synthe-sized by single emulsion-assisted direct precipitation. J. Colloid Interface Sci.342, 327–332.

Chang, Q., Zhou, J., Wang, Y., Liang, J., Zhang, X., Cerneaux, S., Wang, X., Zhu, Z.,Dong, Y., 2014. Application of ceramic microfiltration membrane modified bynano-TiO2 coating in separation of a stable oil-in-water emulsion. J. Membr. Sci.456, 128–133.

Etienne, J., Larbot, A., Julbe, A., Guizard, C., Cot, L., 1994. A microporous zirconiamembrane prepared by the sol–gel process from zirconyl oxalate. J. Membr. Sci.86, 95–102.

Forgacs, E., Cserhati, T., Oros, G., 2004. Removal of synthetic dyes fromwastewaters:a review. Environ. Int. 30, 953–971.

Gestel, T.V., Kruidhof, H., Blank, D.H.A., Bouwmeester, H.J.M., 2006. ZrO2 and TiO2

membranes for nanofiltration and pervaporation Part 1. Preparation andcharacterization of a corrosion-resistant ZrO2 nanofiltration membrane with aMWCOo300. J. Membr. Sci. 284, 128–136..

Jana, S., Purkait, M.K., Mohanty, K., 2010. Removal of crystal violet by advancedoxidation and microfiltration. Appl. Clay Sci. 50, 337–341.

Jedidi, I., Saidi, S., Khemakhem, S., Larbot, A., Elloumi-Ammar, N., Fourati, A., Charfi,A., Salah, A.B., Amar, R.B., 2009. Elaboration of new ceramic microfiltrationmembranes from mineral coal fly ash applied to waste water treatment. J.Hazard. Mater. 172, 152–158.

Kalantari, N., Vaezi, M.J., Yadollahi, M., Babaluo, A.A., Bayati, B., Kazemzadeh, A.,2015. Synthesis of nanostructure hydroxy sodalite composite membranes viahydrothermal method: support surface modification and synthesis methodeffects. Asia–Pac. J. Chem. Eng. 10, 45–55.

Kim, T.H., Park, C., Kim, S., 2005. Water recycling from desalination and purificationprocess of reactive dye manufacturing industry by combined membrane fil-tration. J. Clean. Prod. 13, 779–786.

Kocherginsky, N.M., Tan, C.L., Lu, W.F., 2003. Demulsification of water-in-oilemulsion via filtration through a hydrophilic polymer membrane. J. Membr. Sci.220, 117–128.

Kumar, R.V., Basumatary, A.K., Ghoshal, A.K., Pugazhenthi, G., 2015. Performanceassessment of an analcime–C zeolite–ceramic composite membrane by removalof Cr(VI) from aqueous solution. RSC Adv. 5, 6246–6254.

Mo, J.H., Lee, Y.H., Kim, J., Jeong, J.Y., Jegal, J., 2008. Treatment of dye aqueous so-lutions using nanofiltration polyamide composite membranes for the dyewastewater reuse. J. Dyes Pigm. 76, 429–434.

Monash, P., Majhi, A., Pugazhenthi, G., 2010. Separation of bovine serum albumin(BSA) using γ-Al2O3–clay composite ultrafiltration membrane. J. Chem. Technol.Biotechnol. 85, 545–554.

Monash, P., Pugazhenthi, G., 2011. Development of ceramic supports derived fromlow-cost raw materials for membrane applications and its optimization basedon sintering temperature. Int. J. Appl. Ceram. Technol. 8, 227–238.

Monash, P., Pugazhenthi, G., 2011. Effect of TiO2 addition on the fabrication ofceramic membrane supports: a study on the separation of oil droplets andbovine serum albumin (BSA) from its solution. Desalination 279, 104–114.

Monash, P., Pugazhenthi, G., 2014. Utilization of calcined Ni-Al layered double hy-droxide (LDH) as an adsorbent for removal of methyl orange dye from aqueoussolution. Environ. Prog. Sustain. Energy 33, 153–159.

Nilesh, P.T., Chaudhari, S., 2006. Degradation of azo dyes by sequential Fenton’soxidation and aerobic biological treatment. J. Hazard. Mater. B 136, 698–705.

Qiao, S., Hu, Q., Haghseresht, F., Hu, X., Lu, G.Q., 2009. An investigation on the ad-sorption of acid dyes on bentonite based composite adsorbent. Sep. Purif.Technol. 67, 218–225.

Sangwichien, C., Aranovich, G.L., Donohue, M.D., 2002. Density functional theorypredictions of adsorption isotherms with hysteresis loops. Colloids Surf. A 206,313–320.

Seshadri, K.S., Ahamed, J., Kesavamoorthy, R., Srinivasan, M.P., Krishnasamy, V.,1998. Estimation of pore charge on zirconia membrane prepared by sol–gelroute using zeta potential measurement. J. Mater. Sci. Technol. 14, 425–428.

Sharma, S., Buddhdev, J., Patel., M., Ruparelia, J.P., 2013. Studies on degradation ofreactive red 135 dye in wastewater using ozone. Procedia Eng. 51, 451–455.

Shiue, A., Ma, C., Ruan., R., Chang, C., 2012. Adsorption kinetics and isotherms forthe removal methyl orange from wastewaters using copper oxide catalystprepared by the waste printed circuit boards. Sustain. Environ. Res. 22,209–215.

Tan, X., Kyaw, N.N., Teob, W.K., Li, K., 2006. Decolorization of dye-containing aqu-eous solutions by the polyelectrolyte-enhanced ultrafiltration (PEUF) processusing a hollow fiber membrane module. Sep. Purif. Technol. 52, 110–116.

Tsuru, T., Takezoe, H., Asaeda, M., 1998. Ion separation by porous silica–zirconiananofiltration membranes. AIChE J. 44, 765–768.

Turgay, O., Ersoz, G., Atalay, S., Forss., J., Welander., U., 2011. The treatment of azodyes found in textile industry wastewater by anaerobic biological method andchemical oxidation. Sep. Purif. Technol. 79, 26–33.

Velusamy, P., Pitchaimuthu, S., Rajalakshmi, S., Kannan, N., 2014. Modification of thephotocatalytic activity of TiO2 by b-cyclodextrin in decoloration of ethyl violetdye. J. Adv. Res. 5, 19–25.

Weisburger, J.H., 2002. Comments on the history and importance of aromatic andheterocyclic amines in public health. Mutat. Res. Fundam. Mol. Mech. Mutagen.506–507, 9–20.

Wong, M.S., Huang, H.C., Ying, J.Y., 2002. Supramolecular-templated synthesis ofnanoporous zirconia–silica catalysts. Chem. Mater. 14, 1961–1973.

Wu, J.C., Cheng, L., 2000. An improved synthesis of ultrafiltration zirconia mem-branes via the sol–gel route using alkoxide precursor. J. Membr. Sci. 167,




http://refhub.elsevier.com/S0147-6513(15)00229-8/sbref1







































































































































































253–261.Xu, X., Bao, Y., Song, C., Yang, W., Liu, J., Lin, L., 2004. Microwave-assisted hydro-

thermal synthesis of hydroxy-sodalite zeolite membrane. Microporous Meso-porous Mater. 75, 173–181.

Yang, C., Zhang, G., Xu, N., Shi, J., 1998. Preparation and application in oil–waterseparation of ZrO2/α-Al2O3 MF membrane. J. Membr. Sci. 142, 235–243.

Zaghbani, N., Hafiane, A., Dhahbi, M., 2007. Separation of methylene blue fromaqueous solution by micellar enhanced ultrafiltration. Sep. Purif. Technol. 55,117–124.


Zahrim, A.Y., Hilal, N., 2013. Treatment of highly concentrated dye solution bycoagulation/flocculation–sandfiltration and nanofiltration. Water Resour. Ind. 3,23–34.

Zhou, J., Chang, Q., Wang, Y., Wang, J., Meng, G., 2010. Separation of stable oil–wateremulsion by the hydrophilic nano-sized ZrO2 modified Al2O3 microfiltrationmembrane. Sep. Purif. Technol. 75, 243–248.








































kumar 2015

Documents