A Comparative Study of Immobilization Techniques for Photocatalytic Degradation of Rhodamine B using...

A Comparative Study of Immobilization Techniquesfor Photocatalytic Degradation of Rhodamine B usingNanoparticles of Titanium Dioxide

Jatinder Kumar & Ajay Bansal

Received: 31 October 2012 /Accepted: 15 January 2013 /Published online: 7 February 2013# Springer Science+Business Media Dordrecht 2013

Abstract The use of aqueous suspension of nano-particles of titanium dioxide for photocatalytic re-moval of pollutants is not suitable for industrialapplications due to the inconvenient and expensiveseparation of nanoparticles of titanium dioxide forreuse. The nanosized titanium dioxide needs to beimmobilized on the support for improving the effi-ciency and economics of the photocatalytic process.In the present paper, nanoparticles of titanium di-oxide have been immobilized on the surface of thesupport using three different techniques. The immo-bilized films of titanium dioxide have been charac-terized using X-ray diffraction and scanningelectron microscopy to notice any change in thephase composition and photocatalytic properties ofthe titanium dioxide after immobilization on thesupport. A photocatalytic test has been performedunder similar reaction conditions to compare thephotocatalytic performance of the films of immobi-lized titanium dioxide prepared using differenttechniques.

Keywords Advanced oxidation processes (AOPs) .

Photocatalysis . Titanium dioxide . Photocatalyticactivity

1 Introduction

Air and water pollution is a serious problem throughoutthe world. To overcome this problem, many convention-al physical, chemical, and biological technologies areavailable (Linsebigler et al. 1995). The conventionalmethods of control of pollution include adsorption byactivated carbon, thermal oxidation, filtration, coagula-tion, chemical precipitation and electrocoagulation, etc.These conventional methods have some associateddrawbacks. Adsorption on activated carbon is the mostwidely used process. The primary drawback to thismethod is that the pollutant still needs to be disposedoff once the adsorbent is exhausted. Additionally, theprocess of manufacturing activated carbon is a pollutionhazard itself (Bayer et al. 2005). Thermal oxidation maybe valuable but surely not cost-effective, particularly atlow contamination values, due to the added fuel con-sumption; further, it contributes to massive carbon di-oxide production. Biological treatment provides a lowenergy approach to treat a variety of challenging pollu-tants (Ang et al. 2005). The main disadvantage of bio-logical treatment is that the microbial community maybe difficult to maintain, and may not be effective intreating a water stream with large transient fluctuationsin nutrients or pollutants. Furthermore, biological treat-ment may not be effective for toxic and bioresistantcompounds (Parra et al. 2000). One common difficultywith all of the conventional methods is that they are notdestructive but only transfer the contaminants from onephase to another. Therefore, a new different kind of

Water Air Soil Pollut (2013) 224:1452DOI 10.1007/s11270-013-1452-1

J. Kumar (*) :A. BansalDepartment of Chemical Engineering,Dr. B. R. Ambedkar National Institute of Technology,Jalandhar 144011 Punjab, Indiae-mail: [email protected]

secondary pollution is faced and further treatments aredeemed necessary (Tunay et al. 1996; Slokar andMarechal 1998; Galindo et al. 2001; Daneshvar et al.2006; Toor et al. 2006; Natarajan et al. 2011a, b).Moreover, the conventional methods often do not suc-cessfully deal with the persistent organic pollutants.

In recent years, advanced oxidation processes (AOPs)have been proposed as an alternative to conventionalmethods. AOPs oxidize quickly and non-selectively abroad range of organic pollutants (Kitano et al. 2007;Sano et al. 2008). Heterogeneous photocatalysis viacombination of nanoparticles of TiO2 and UV light isconsidered to be one of the promising advanced oxida-tion processes for destruction of water-soluble organicpollutants found in water and wastewater (Mishra et al.2010; Tayade et al. 2006; Toor et al. 2006). When a lightwith λ<390 nm illuminates TiO2 particles, an electron(eˉ) is excited out of its energy level and consequentlyleaves a hole (h+) in the valence band. Indeed, electronsare promoted from the valence band to the conductionband of TiO2 to give electron–hole pairs (Pirkanniemiand Sillanpaa 2002; Yates and Thompson 2006;Fujishima and Zhang 2006; Alinsafi et al. 2007)

TiO2 þ hv λ < 390nmð Þ ! e� þ hþ ð1Þ

The valence band potential is positive enough togenerate hydroxyl radicals at the surface on TiO2, andthe conduction band potential is negative enough toreduce molecular oxygen. The hydroxyl radical is apowerful oxidizing agent, and attacks organic pollu-tants present at or near the surface of TiO2. It causes,ultimately, complete decomposition of toxic and bio-resistant compounds into harmless species such asCO2, H2O, etc. (Kitano et al. 2007; Chen and Mao2007; Herrmann 2005).

Photocatalysis using semiconductors such as TiO2

has been demonstrated to be an inexpensive and ef-fective method for treating a wide range of pollutants,including alkanes, alcohols, carboxylic acids, alkenes,phenols, dyes, aromatic hydrocarbons, halogenatedalkanes, surfactant, and pesticides, in both water andair (Fox and Dulay 1993; Hoffmann et al. 1995; Millsand Hunte 1997; Litter 1999; Alfano et al. 2000;Tayade et al. 2006; Natarajan et al. 2011a, b; Sun etal. 2011). Most of the literature studies related tophotodegradation have been carried out using the sus-pension of nanocrystals of TiO2 in aqueous solution.The use of aqueous suspension is not suitable for

industrial applications due to the inconvenient andexpensive separation of nanoparticles of titanium di-oxide for reuse. Moreover, suspension of fine particleslimits the penetration of light leading to reduced effi-ciency of photodegradation. As such, there is a need toimmobilize the photocatalyst onto an appropriate inertsupport in an efficient way. It will eliminate the needof filtration of catalyst for reuse. It is very important toprepare immobilized TiO2 films that are capable ofharvesting incident light to a great extent, and have ahigh surface area and porosity to increase the rate ofreaction between photogenerated species and the pol-lutants. So, the porous TiO2 thin and thick films withlarge specific surface area have attracted more andmore attention nowadays. The production of nanostruc-tured films is a topic of interest for the researchers, andthe films of nanoparticles of TiO2 are among the materi-als routinely produced on lab scale. Many researchershave produced immobilized films of TiO2 by differenttechniques (Noorjahan et al. 2003; Khataee et al. 2009;Kumar and Bansal 2012; Natarajan et al. 2011a, b). Thecharacterization and evaluation of photoactivity of theprepared films have also been performed. The photo-catalytic activity of the prepared films has been studiedindividually and independently in literature using differ-ent model pollutants and different reaction conditions. Itis very difficult to make a comparison of efficiency andperformance of available immobilization techniques byjust reviewing the literature as individual studies havebeen performed at different conditions. Photocatalyticactivity test, of the titanium dioxide films prepared bydifferent techniques, needs to be performed under sim-ilar reaction conditions in order to compare the perfor-mance of different immobilization techniques.

In the present paper, a quantitative comparison ofphotoactivity of titanium dioxide immobilized bythree different immobilization techniques has beenmade for the selection of best technique for furtheruse. The studied immobilization techniques utilize thecommercially available nanoparticles of titanium di-oxide for immobilization. The use of nanopowderedtitanium dioxide facilitates the process of immobiliza-tion for its possible extension to industrial level ascompared to the sol–gel process. The immobilizedfilms of nano-crystals of TiO2 have been prepared byheat treatment technique (Khataee et al. 2009), acrylicemulsion method (Noorjahan et al. 2003), and poly(vinyl formal) method (Kumar and Bansal 2012). Thefilms obtained have been characterized by X-ray

1452, of 11 Water Air Soil Pollut (2013) 224:1452

diffraction (XRD) and scanning electron microscopy(SEM). The photocatalytic degradation of aqueoussolution of Rhodamine B using the prepared filmswas also studied to evaluate the photocatalytic activityof the films. The photocatalytic degradation experi-ments were performed under similar reaction condi-tions so that a comparison of the photocatalyticactivity of the prepared films of nanaoparticles oftitanium dioxide be made. The films were repeatedlyutilized for photocatalytic degradation for 16 h tocheck the repeatability of the prepared films for indus-trial applications. Rhodamine B was selected as modelpollutant. It is a complex organic dye and can be easilyassessed using a UV-visible spectrophotometer. It iswidely used as test chemical in engineering and bio-logical applications.

2 Materials and Methods

2.1 Materials

Polyvinyl alcohol LR, formaldehyde LR, and RhodamineB (C28H31C1N2O3) dye powder were obtained from s dFine-Chem Ltd, Mumbai. Acrylic binder was obtainedfrom Golden Chemical Works, Delhi. Degussa P25(TiO2) catalyst provided by Evonik Industries, Germanywas used throughout the current investigation. Accordingto manufacturer’s specifications, its BET surface area was55±15 m2/g, average particle size was around 30 nm,purity was 97 %, and anatase to rutile ratio was 80:20.The chemicals in this study were used as purchased.

2.2 Preparation of Degussa P25 (TiO2) Film UsingHeat Treatment Technique

The catalyst (TiO2) was immobilized on the micro-scope glass slide (75×50 mm) using heat treatmentmethod according to the process mentioned byKhataee et al. 2009, with some modifications. Thetitanium dioxide suspension was prepared by adding5 % (w/v) Degussa P25 in doubled distilled water. Theresulting suspension was stirred continuously for halfan hour to form a milky solution that is stable forseveral hours. The suspension was then applied onthe one side of microscope glass slide with the helpof a brush to provide a coat of titanium dioxide on it.The coated surface was then dried in an oven for 1 h at108 °C. After drying, the surface was visually

examined to check the uniformity of coating.Another coat was then given, and drying process wasrepeated. It was observed that one to two coats provideuniform deposition of titanium dioxide. The driedsurface was then calcined at 500 °C for 3–4 h. Aftercalcinations at high temperature, the coated samplewas cooled to room temperature. The heating andcooling processes were performed gradually to avoidcracking of film/coating of immobilized titanium di-oxide on the surface. The prepared titanium dioxidefilm was then flushed with water to remove the looselybound catalyst particles. The immobilized film ofTiO2, thus prepared, on the glass surface by heattreatment technique was given an identity F1.

2.3 Preparation of Degussa P25 (TiO2) Film UsingAcrylic Emulsion

The TiO2 film on microscope glass slide (75×50 mm)using acrylic emulsion was prepared according to themethod explained by Noorjahan et al. (2003). Onegram of TiO2 was added in 25 ml of water followedby addition of 1 ml of acrylic emulsion under vigorousstirring for proper mixing. The resultant emulsion wasthen applied on one side of the microscope glass slide(75×50 mm) with the help of a brush. The coated filmwas left for air-drying. Coating was repeated twice toget a uniform film without pin holes. This preparedfilm of immobilized titanium dioxide was given anidentity F2.

2.4 Preparation of Degussa P25 (TiO2) Film UsingPolyvinyl Alcohol-Formaldehyde(Polyvinyl Formal) Binder

The P25 (TiO2) film was prepared on a fiberglassslide (75×50 mm) using poly(vinyl formal) resin asbinder according to the procedure mentioned by theauthor elsewhere (Kumar and Bansal 2012). TiO2

suspension was prepared by adding 1 g of TiO2 in25 ml of double distilled water followed by contin-uous stirring for 1 h to ensure homogeneity. A6.25 %w/v polyvinyl alcohol-formaldehyde binderwas prepared under constant stirring in a 70 °Cwater bath until a transparent, sticky polymer glue(Polyvinyl formal) was formed. The binder waskept in a sealed bottle to prevent it from rapidhardening. The fiberglass slide (75×50 mm) wasfirst applied with a thin layer of binder on one side

Water Air Soil Pollut (2013) 224:1452 of 11, 1452

of the slide. The TiO2 suspension was then brushedonto the layer of binder to immobilize it. The filmprepared by this method was given an identity F3.

2.5 Characterization of Prepared Films

The morphology of the immobilized titanium dioxidewas studied using SEM. The sample was coated withgold before analyzing in scanning electron microscopeJSM 6100 (JEOL) operated at 25 kV.

The XRD analysis of immobilized titanium dioxidewas done by plate XRD technique to study the crystal-line structure. The X-ray diffraction pattern wasobtained on a Phillips PW-1710 X-ray diffractometerusing Cu-Kα radiation as X-ray source at an angle of 2θranging from 20° to 80°. The measurement was carriedout at a scanning rate of 0.034 (2θ)/s.

2.6 Photocatalytic activity test

All of the prepared films were used for photo-catalytic degradation of Rhodamine B to evaluatetheir photocatalytic activity. Photocatalytic degra-dation experiments were carried out in a batchphotocatalytic reactor containing two 15-W UV

lamps (F15T8/GL, Phillips) as shown in Fig 1. Adye solution of 50 ml with concentration of10 ppm was poured into a beaker having across-sectional area of 86.6 cm2. The slide carry-ing film of TiO2 was placed on the bottom thebeaker in such a manner that the total availablesurface of photocatalyst was 50×75 mm. The bea-ker was then placed onto the working area of thephotocatalytic reactor. A magnetic stirrer was usedto provide mixing. Two UV light sources werethen switched on, and the solution was irradiatedwith the ultraviolet light. The incident light inten-sity on the catalyst surface was measured usingradiometer (UV Power Puck II, EIT), and foundto be 1.1 mW/cm2. The cooling fan was switchedon in order to maintain the temperature of thephotocatalytic chamber. The concentration of theRhodamine B at different reaction times was de-termined by measuring the absorbance intensity atλmax=554 nm with the help of the UV–vis spec-trophotometer. The decrease in concentration of thedye was plotted with respect to time for analysis.The experiment was conducted for all kinds ofprepared TiO2 films. All the experiments were per-formed under similar operating conditions of initial

Fig. 1 Batch photocatalyticreactor

Fig. 2 XRD patterns of aF1 film, b F2 film, and cF3 film


concentration of dye=10 ppm, volume of solution=50ml, light intensity=1.1mW.cm-2, and catalyst surfacearea=75×50 mm. The photocatalytic degradationexperiments were repeated for four times for all theprepared films to evaluate the use of films for longtimes.

It has been agreed that the kinetics of photocatalyticdegradation using irradiated TiO2 follows theLangmuir–Hinshelwood (L-H) law of heterogeneousphotocatalytic reactions (Fox and Dulay 1993).According to the L-H model, when initial concentra-tion C0 is very small, the following pseudo-first-orderrate equation is followed.

lnC

Co

� �¼ �kt ð2Þ

where, k is pseudo-first-order rate constant and C isthe concentration at time t. A plot of ln C

Co

� �versus

time represents a straight line, the slope of which uponlinear regression equals the pseudo-first-order rateconstant (k).

3 Results and Discussion

3.1 Characterization of Immobilized TitaniumDioxide Films

The XRD studies were made to notice any changein the phase composition and photocatalytic prop-erties of the titanium dioxide after immobilizationon the support. The XRD measurements were donedirectly on immobilized catalyst resulting in noisypatterns. The XRD patterns of immobilized titania(TiO2) films are presented in Fig. 2a–c. The XRDpatterns of the immobilized titania did not showany variation in the structure and phase composi-tion due to immobilization process. The diffractionpeaks observed at 2θ=25.28°, 37.8°, 48.05°,53.89°, 55.06°, and 62.69° correspond to theknown diffraction maxima of anatase phase of tita-nium dioxide. The peaks at 2θ=27.46°, 36.1°,41.66°, 54.34°, and 56.6° correspond to rutile phaseof titania. The intensity of the peaks reveals that themajor phase available in the immobilized titania isanatase while the rutile is the minor phase. Theanatase titania is necessary to achieve the requiredelectronic band gap of 3.2 eV. The anatase phase is

also supposed to be the most active one for thephotocatalytic reactions (So et al. 2001; Xu et al.2006).

To study the morphology, the SEM images of allthe prepared films were taken at ×10,000 magnifica-tions, and shown in Fig. 3a–c. SEM images demon-strate the nanostructure of the catalyst, and rough

Fig. 3 SEM images of a F1 film, b F2 film, and c F3 film


surface of the films, which is quite necessary for thegood photocatalytic activity of the films. It is obviousfrom the micrographs that TiO2 (white spots) is moreuniformly distributed on the surface of F1 and F3

films as compared to F2 film. Moreover, more whitespots on the surface of F1 film are indicative of avail-ability of larger surface area of titanium dioxide forphotocatalytic reactions as compared to other films.

Fig. 4 Photocatalytic degra-dation of Rhodamine B forfirst run. a Time effect ondegradation. b Kinetics ofdegradation

Table 1 Half-life time and rateconstant Film

identityImmobilizationtechnique

Half-life time, h Rate constant, h−1

Run1

Run2

Run3

Run4

Run1

Run2

Run3

Run4

F1 Heat treatment 1.96 2.36 2.51 2.57 0.35 0.30 0.28 0.27

F2 Acrylic binder 4.81 7.29 10.50 28.87 0.14 0.10 0.07 0.02

F3 Poly(vinylformal)

3.12 4.62 6.79 12.83 0.22 0.15 0.10 0.05


3.2 Photocatalytic activity of prepared films

Before evaluating the photocatalytic activity, all theprepared films were kept in a magnetically stirred vesselcontaining water for 4 h to check the film adherence tothe supports. The films were physically examined to seeany kind of deterioration. All the films showed a goodadherence strength as a little peeling of films from thesupport was observed. The photocatalytic degradationof Rhodamine B was then performed with films F1, F2,and F3 separately for a period of 4 h in each case. Thedecrease in concentration of dye was recorded withrespect to time and shown in Fig. 4a. The error barsrepresent the standard deviation obtained with triplicate

runs. The recorded data were best fitted by exponentialequations with regression coefficient as high as 0.983,0.993, and 0.996 for F1, F2, and F3 films, respectively.It was observed that there was 74.0 % decrease in theconcentration of dye after 4 h of UV light illumination incase of F1 film. A decrease of 44.0 and 59.0 % of dyeconcentration was monitored for the same period ofillumination in case of F2 and F3 films, respectively.The values of half-life time for the degradation ofRhodamine B for F1, F2, and F3 films were calculated,and tabulated in Table 1. The ln C

Co

� �values were cal-

culated and plotted with respect to time for all theprepared films as shown in Fig. 4b. The plotted datafor all types of films were best fitted by straight lines of

Fig. 5 Photocatalytic degra-dation of Rhodamine B forsecond run. a Time effect ondegradation. b Kinetics ofdegradation


different slopes which indicate that the reactions fol-lowed pseudo-first-order kinetics according to the L-Hlaw. The pseudo-first-order reaction rate constants weredetermined from the slopes of the plot of ln C

Co

� �versus

time for all the prepared films. Table 1 shows the valuesof pseudo-first-order reaction rate constant for F1, F2,and F3 films.

The half-life time and reaction constant for the firstrun for the F1 film were obtained as 1.96 h and0.35 h−1, respectively. The same values for F2 andF3 films were obtained as 4.81 h and 0.10 h−1, and3.12 h and 0.15 h−1, respectively. The lowest half-lifetime and highest reaction constant for the first runwere obtained for F1 film which is an indicative of

highest photocatalytic activity. It is obvious fromFig. 4a, b and Table 1 that the F1 film formed by heattreatment method showed fastest photocatalytic deg-radation of Rhodamine B among the prepared filmsfollowed by F3 film prepared from polyvinyl alcohol-formaldehyde binder. The film formed by acrylicemulsion (F2) depicted the slowest photocatalytic deg-radation among all the three types of films. The F2 andF3 films have considerably lower activity than filmformed by heat treatment method (F1 film). One of themain reasons for the remarkable difference could bethe solid–liquid interface between the TiO2 particlesand the aqueous solution. The F1 film contained phys-ically attached TiO2 aggregates on the support without

Fig. 6 Photocatalytic degra-dation of Rhodamine B forthird run. a Time effect ondegradation. b Kinetics ofdegradation


any added reagent leading to a large exposed area ofTiO2. The F2 and F3 films were less active because thelayer of binder (acrylic emulsion in case of F2 film andpolyvinyl alcohol-formaldehyde in case of F3 film)might have partly covered the TiO2 particles resultingin less surface area available for solid liquid contact.The F3 film showed better performance as comparedto F2 film as the formaldehyde (a large portion of thebinder) in case of F3 films gets evaporated at roomtemperature providing more TiO2 surface area fordegradation. The acrylic binder does not evaporate atroom temperature leading to availability of less sur-face area of titanium dioxide for the photocatalyticreaction.

The photocatalytic degradation experiments were re-peated four times for all the prepared films to evaluate thereusability of the films for industrial applications. Theresults of the second, third, and fourth runs of the experi-ments for individual films under similar operating con-ditions have been presented in Figs. 5a,b, 6a, b, and 7a, b,respectively. The corresponding values of the half-lifetime and rate constant have been shown in Table 1. It isobserved that there is a drastic decrease in performance ofthe F2 and F3 for the subsequent runs after the first use.The decrease in rate constants for the F2 and F3 films forthe second run was obtained as 28.6 and 31.8 %, respec-tively, in comparison to a decrease in 14.3 % for the F1film. The corresponding increase in half-life times for F2

Fig. 7 Photocatalytic degra-dation of Rhodamine B forfourth run. a Time effect ondegradation. b Kinetics ofdegradation


and F3 films for the second run was obtained as 34.0 and32.5 %, respectively, in comparison to an increase in16.9 % for the F1 film. It is deduced from the results thatF1 film showed a better performance for the second runalso in comparison to F2 and F3 films. It was alsoobserved that although F3 film showed a better perfor-mance than F2 film, still there is more decrease in theperformance of F3 film as compared to F2 film. Theforemost reason for the same may be that titanium diox-ide particles are loosely bound in F3 film leading todetachment of TiO2 particles from the support duringthe subsequent experiments. It is obvious from the resultsof the third and fourth run that there is a negligible changein the performance of the F1 film even after 16 h of use,whereas a significant decrease in the performance of theF2 and F3 films has been observed. So, based on theexperimental observation, it is inferred that F1 filmshowed a better photocatalytic efficiency, adherence,and reusability as compared to F2 and F3 films.

4 Conclusion

A comparison of photocatalytic activity of films ofnanoparticles of titanium dioxide prepared using threedifferent techniques has been made. Among the threeimmobilization techniques (heat treatment method,acrylic emulsion method, and poly(vinyl formal)method), it is found that film prepared by heat treat-ment technique (F1 film) showed better photocatalyticacitvity as compared to films prepared by other meth-ods (F2 and F3 films). The reusability study of thefilms showed that there is a negligible change in theperformance of the film prepared using heat treatmenttechnique (F1 film), while the other films (F2 and F3films) showed a remarkable decrease in their perfor-mance. The present study concludes the applicabilityof the films prepared by heat treatment technique (F1film) to the commercial level.

Nomenclature

l Wavelength (nm)v Frequency (s−1)h Plank’s constant (eV-s)eˉ Electron (dimensionless)h+ Hole (dimensionless)C0 Initial Rhodamine B concentration (ppm)

C Concentration of Rhodamine B at any time(ppm)

t Time (min or h)k Reaction rate constant (h−1)

AcronymsAOPs Advance oxidation processesSEM Scanning electron microscopyXRD X-ray diffraction

References

Alfano, O. M., Bahnemann, D., Cassano, A. E., Dillert, R., &Goslich, R. (2000). Photocatalysis in water environmentsusing artificial and solar light. Catalysis Today, 58, 199–230.

Alinsafi, F., Evenou, E. M., Abdulkarim, M. N., Pons, O.,Zahraa, A., Benhammou, A., et al. (2007). Treatment oftextile industry wastewater by supported photocatalysis.Dyes and Pigments, 74, 439–445.

Ang, E. L., Zhao, H., & Obbard, J. P. (2005). Recent advancesin the bioremediation of persistent organic pollutants viabiomolecular engineering. Enzyme and MicrobialTechnology, 37, 487–496.

Bayer, P., Heuer, E., Karl, U., & Finkel, M. (2005). Economical andecological comparison of granular activated carbon (GAC)adsorber refill strategies. Water Research, 39, 1719–1728.

Chen, X., & Mao, S. S. (2007). Titanium dioxide nanomaterials:Synthesis, properties, modifications and applications.Chemical Reviews, 107, 2891–2959.

Daneshvar, N., Khataee, A. R., Salari, D., & Niaei, A. (2006).Photocatalytic degradation of the herbicide erioglaucine inthe presence of nanosized titanium dioxide: Comparison andmodeling of reaction kinetics. Journal of EnvironmentalScience and Health. Part. B, 41, 1273–1290.

Fox, M. A., & Dulay, M. T. (1993). Heterogeneous photocatal-ysis. Chemical Reviews, 93, 341–357.

Fujishima, A., & Zhang, X. (2006). Titanium dioxide photo-catalysis: Present situation and future approaches. ComptesRendus Chimie, 9, 750–760.

Galindo, C., Jacques, P., & Kalt, A. (2001). Photooxidation of thephenylazonaphthol AO20 on TiO2: Kinetic and mechanisticinvestigations. Chemosphere, 45, 997–1005.

Herrmann, J. M. (2005). Heterogeneous photocatalysis: State of theart and present applications. Topics in Catalysis, 34, 49–65.

Hoffmann, M. R., Martin, S. T., Choi, W., & Bahnemann, D.(1995). Environmental applications of semiconductor pho-tocatalysis. Chemical Reviews, 95, 69–96.

Khataee, A. R., Pons, M. N., & Zahraa, O. (2009). Photocatalyticdegradation of three azo dyes using immobilized TiO2 nano-particles on glass plates activated by UV light irradiation:Influence of dye molecular structure. Journal of HazardousMaterials, 168, 451–457.


Kitano, M., Matsuoka, M., Ueshima, M., & Anpo, M. (2007).Recent developments in titanium oxide-based photocata-lysts. Applied Catalysis A: General, 325, 1–14.

Kumar, J., & Bansal, A. (2012). Photocatalytic degradationof amaranth in aqueous solution catalyzed by immobi-lized nanoparticles of titanium dioxide. InternationalJournal of Environmental Science and Technology, 9,479–484.

Linsebigler, L., Lu, G., & Yates, J. T. (1995). Photocatalysis onTiO2 surfaces: Principles, mechanisms and selected results.Chemical Reviews, 95, 735–758.

Litter, M. I. (1999). Heterogeneous photocatalysis: Transitionmetal ions in photocatalytic systems. Applied Catalysis B:Environment, 23, 89–114.

Mills, A., & Hunte, S. L. (1997). An overview of semiconductorphotocatalysis. Journal of Photochemistry and PhotobiologyA: Chemistry, 108, 1–35.

Mishra, S., Meda, V., Dalai, A. K., McMartin, D. W., Headley, J.V., & Peru, K. M. (2010). Photocatalysis of naphthenicacids in water. Journal of Water Resource and Protection,2, 644–650.

Natarajan, T. S., Natarajan, K., Bajaj, H. C., & Tayade, R. J.(2011). Energy efficient UV-LED source and TiO2 nanotubearray-based reactor for photocatalytic application. Industrialand Engineering Chemistry Research, 50, 7753–7762.

Natarajan, T. S., Thomas, M., Natarajan, K., Bajaj, H. C., &Tayade, R. J. (2011). Study on UV-LED/TiO2 process fordegradation of rhodamine B dye. Chemical EngineeringJournal, 169, 126–134.

Noorjahan,M., Reddy, M. P., Kumari, V. D., Lavedrine, B., Boule,P., & Subrahmanyam, M. (2003). Photocatalytic degradationof H-acid over a novel TiO2 thin film fixed bed reactor and inaqueous suspension. Journal of Photochemistry andPhotobiology A: Chemistry, 156, 179–187.

Parra, S., Sarria, V., Malato, S., Peringer, P., & Pulgarin, C.(2000). Photochemical versus coupled photochemical–bio-logical flow system for the treatment of two biorecalcitrant

herbicides: Metobromuron and isoproturon. AppliedCatalysis B: Environmental, 27, 153–168.

Pirkanniemi, K., & Sillanpaa, M. (2002). Heterogeneous waterphase catalysis as an environmental application: A review.Chemosphere, 48, 1047–1060.

Sano, T., Puzenat, E., Guillard, C., Geantet, C., & Matsuzawa, S.(2008). Degradation of C2H2 with modified-TiO2 photocata-lysts under visible light irradiation. Journal of MolecularCatalysis A: Chemical, 284, 127–133.

Slokar, Y. M., & Marechal, A. M. L. (1998). Methods of decolor-ation of textile wastewaters.Dyes and Pigments, 37, 335–356.

So, W. W., Park, S. B., Kim, K. J., Shin, C. H., & Moon, S. J.(2001). The crystalline phase stability of titania particlesprepared at room temperature by sol–gel method. Journalof Material Science, 36, 4299–4305.

Sun, H., Ullah, R., Chong, S., Ang, H. M., Tade, M. O., &Wang, S. (2011). Room-light-induced indoor air purifica-tion using an efficient Pt/N-TiO2 photocatalyst. AppliedCatalysis B: Environmental, 108, 127–133.

Tayade, R. J., Kulkarni, R. G., & Jasra, R. V. (2006).Photocatalytic degradation of aqueous nitrobenzene bynanocrystalline TiO2. Industrial and Engineering ChemistryResearch, 45, 922–927.

Toor, A. P., Verma, A., Jotshi, C. K., Bajpai, P. K., & Singh, V.(2006). Photocatalytic degradation of Direct Yellow 12 dyeusing UV/TiO2 in a shallow pond slurry reactor. Dyes andPigments, 68, 53–60.

Tunay, O., Kabdasli, I., Eremektar, G., & Orhon, D. (1996). Colorremoval from textile waste waters. Water Science andTechnology, 34, 9–16.

Xu, T., Song, C., Liu, Y., & Han, G. (2006). Band structures ofTiO2 doped with N, C and B. Journal of Zhejiang UniversityScience, 7, 299–303.

Yates, T., & Thompson, T. L. (2006). Surface sciencestudies of the photoactivation of TiO2—new photo-chemical processes. Chemical Reviews, 106, 4428–4453.


A Comparative Study of Immobilization Techniques for Photocatalytic Degradation of Rhodamine B using...

Documents

Transcript of A Comparative Study of Immobilization Techniques for Photocatalytic Degradation of Rhodamine B using...