This document summarizes research on the effect of dye type on a Pr-doped TiO2-montmorillonite composite photocatalyst. Two dyes, Basic Yellow 28 and Basic Blue 41, were tested for degradation efficiency under UV light irradiation. Higher adsorption and overall degradation efficiencies were observed for Basic Blue 41 compared to Basic Yellow 28. Kinetic analysis showed pseudo-first order degradation for both dyes. FTIR analysis confirmed degradation of characteristic dye functional groups over time. The composite photocatalyst effectively degraded both dyes within regulatory limits for chemical oxygen demand.
#scichallenge2017 Photocatalytic Degradation of Synthetic Wastewaters Contain...Seher Elif Mekik
#scichallenge2017
In our project, it was aimed to purify wastewaters containing methylene blue component and harmful to environment from methylene blue. For this purpose, synthetic methylene blue waste water was formed and chemically treated by photocatalysis.
Abstract— 2, 4-dinitrophenol and 2, 4, 6- trinitrophenol were successfully photodegraded using visible light active monoclinic BiVO4 as photocatalyst. 10ppm of dinitrophenol is photodegraded using 50mg BiVO4 under irradiation for 3h. 10ppm trinitrophenol is photodegraded using 100mg BiVO4 under irradiation for 3h. Ease of photodegradation of DNP and TNP varied in the order DNP > TNP for the same amount of photocatalyst. Photoluminescence studies confirmed the formation of •OH free radicals due to irradiation. Synergetic effect is noticed between BiVO4 and H2O2.
Nitrogen-doped graphene-supported copper complex: a novel photocatalyst for C...Pawan Kumar
A copper(II) complex grafted to nitrogen-doped graphene (GrN700–CuC) was synthesized and then
demonstrated as an efficient photocatalyst for CO2 reduction into methanol under visible light irradiation
using a DMF/water mixture. The chemical and microstructural features of GrN700–CuC nanosheets were
studied by FTIR, XPS, XRD and HRTEM analyses. Owing to its truly heterogeneous nature, GrN700–CuC
could be easily recovered after the photocatalytic reaction and showed efficient recyclability for
subsequent runs.
adsorption of methylene blue onto xanthogenated modified chitosan microbeadsSiti Nadzifah Ghazali
Methylene Blue (MB) is thiazine dyes that widely use to color product in many industry such as textile, printing, leather, cosmetic and paper. Xanthogenated-Modified Chitosan Microbeads (XMCM) is use to observe the new alternative adsorbent in removing MB from water body through adsorption process. The interactions between MB and functional group in XMCM were confirmed by Fourier Transform Infrared (FT-IR) spectra. Several parameters that influence adsorption ability such as the effect of adsorbent dosage of XMCM and the effect of initial pH of MB aqueous solution were studied. This study were done at optimum condition which is at pH 4 of initial pH of MB solution, 0.01 g of initial XMCM dosage, 6 hours stirring time and temperature of (30 ± 2 ℃). The adsorption data fit well Langmuir model more than Freundlich model. Based on Langmuir model, the maximum monolayer adsorption capacity of MB was 21.62 mg g-1 which indicated that XMCM can be a new alternative adsorbent for removing MB.
Visible Light Induced Selective Photocatalytic Oxidation of Benzyl Amine to N...IJERA Editor
Irradiated semiconductor catalysis in the presence of molecular oxygen can be considered as an innovative and sustainable technique for organic transformations. The present work reports the preparation ofGraphene oxide/TiO2composite by improved Hummer’s method followed by hydrothermal technique. The prepared system was characterized by various physico-chemical techniques such as X-Ray diffraction, IR-Spectroscopy, UV-DRS, XPS, SEM and TEM Analysis.On reaction, benzylamine in CH3CN yieldedN-benzylidene-1-phenylmethanamine as the sole product. The reaction was monitored by GC-MS Analysis.
#scichallenge2017 Photocatalytic Degradation of Synthetic Wastewaters Contain...Seher Elif Mekik
#scichallenge2017
In our project, it was aimed to purify wastewaters containing methylene blue component and harmful to environment from methylene blue. For this purpose, synthetic methylene blue waste water was formed and chemically treated by photocatalysis.
Abstract— 2, 4-dinitrophenol and 2, 4, 6- trinitrophenol were successfully photodegraded using visible light active monoclinic BiVO4 as photocatalyst. 10ppm of dinitrophenol is photodegraded using 50mg BiVO4 under irradiation for 3h. 10ppm trinitrophenol is photodegraded using 100mg BiVO4 under irradiation for 3h. Ease of photodegradation of DNP and TNP varied in the order DNP > TNP for the same amount of photocatalyst. Photoluminescence studies confirmed the formation of •OH free radicals due to irradiation. Synergetic effect is noticed between BiVO4 and H2O2.
Nitrogen-doped graphene-supported copper complex: a novel photocatalyst for C...Pawan Kumar
A copper(II) complex grafted to nitrogen-doped graphene (GrN700–CuC) was synthesized and then
demonstrated as an efficient photocatalyst for CO2 reduction into methanol under visible light irradiation
using a DMF/water mixture. The chemical and microstructural features of GrN700–CuC nanosheets were
studied by FTIR, XPS, XRD and HRTEM analyses. Owing to its truly heterogeneous nature, GrN700–CuC
could be easily recovered after the photocatalytic reaction and showed efficient recyclability for
subsequent runs.
adsorption of methylene blue onto xanthogenated modified chitosan microbeadsSiti Nadzifah Ghazali
Methylene Blue (MB) is thiazine dyes that widely use to color product in many industry such as textile, printing, leather, cosmetic and paper. Xanthogenated-Modified Chitosan Microbeads (XMCM) is use to observe the new alternative adsorbent in removing MB from water body through adsorption process. The interactions between MB and functional group in XMCM were confirmed by Fourier Transform Infrared (FT-IR) spectra. Several parameters that influence adsorption ability such as the effect of adsorbent dosage of XMCM and the effect of initial pH of MB aqueous solution were studied. This study were done at optimum condition which is at pH 4 of initial pH of MB solution, 0.01 g of initial XMCM dosage, 6 hours stirring time and temperature of (30 ± 2 ℃). The adsorption data fit well Langmuir model more than Freundlich model. Based on Langmuir model, the maximum monolayer adsorption capacity of MB was 21.62 mg g-1 which indicated that XMCM can be a new alternative adsorbent for removing MB.
Visible Light Induced Selective Photocatalytic Oxidation of Benzyl Amine to N...IJERA Editor
Irradiated semiconductor catalysis in the presence of molecular oxygen can be considered as an innovative and sustainable technique for organic transformations. The present work reports the preparation ofGraphene oxide/TiO2composite by improved Hummer’s method followed by hydrothermal technique. The prepared system was characterized by various physico-chemical techniques such as X-Ray diffraction, IR-Spectroscopy, UV-DRS, XPS, SEM and TEM Analysis.On reaction, benzylamine in CH3CN yieldedN-benzylidene-1-phenylmethanamine as the sole product. The reaction was monitored by GC-MS Analysis.
Preparation, characterization and application of sonochemically doped fe3+ in...eSAT Journals
Abstract In this present study, mechanistic investigation of ultrasound–assisted dye decolorization/degradation was investigated using sonochemically prepared Fe3+ doped ZnO. Fe3+ doped ZnO nanoparticle was prepared under ultrasound (20 kHz) irradiation using a doping concentration of 2 wt% of Fe(III). To investigate the catalytic activity of Fe3+ doped ZnO, Acid Red 14 (azo dye) was chosen for decolorization/degradation using sonolysis, photocatalysis and sono–photocatalysis processes. To study the influence of dopant onto structure, crystallinity, and optical properties, different analytical analyses were performed such as X–ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Zeta potential, Delsa Nano Particle Size Analyzer (PSA), Vibrating Sample Magnetometer analysis (VSM) and Field Emission Scanning Electron Microscopy (FE–SEM) etc. For photocatalytic experiments, a blended high pressure mercury UV lamp with maximum peak emission at 365 nm was used. The decolorization/degradation of dye with modified photocatalyst showed faster reaction kinetics under sono–photocatalytic process. Ultrasound showed an additive effect for degradation/decolorization process. The maximum decolorization of AR14 was achieved (~ 82%) under sono–photocatlytic process with an initial dye concentration of 20 ppm. The sono–photocatalysis process showed 1.4 – 1.6 higher reaction rates with Fe–doped ZnO than pure ZnO. Index Terms: ZnO, Fe–ZnO, Fe-doped ZnO, Sonocatalytic, Photocatalytic, Advanced Oxidation Process, AOP
Synthesis Of Cobalt Doped Titania Nano Materials Assisted By Anionic Heteroge...IJERA Editor
: This paper presents about the synthesis of (0.25-1.0) wt.% cobalt doped titania nanomaterials
without surfactants: pure Co2+/TiO2 and in presence of 1,4-Butane sultone and 1,3-Propane sultone Anionic
Gemini surfactants and CTAB (Heterogemini surfactant)-0.5wt.%Co2+/TiO2-HgS(1&2).The synthesized nano
photocatalysts have been characterized by using various advanced techniques like X-Ray Diffraction (XRD),
Ultraviolet-visible Diffuse Reflection Spectroscopy (UV-Vis DRS), X-ray Photoelectron Spectroscopy (XPS),
Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS), Fourier Transform Infrared
Spectroscopic Studies (FT-IR), Transmission Electron Microscopy (TEM). From the characterization studies all
the catalysts synthesized were reported in anatase phase. TEM indicates the particles size of prepared catalysts
reported with 7-10 nm and 15 nm for pure Co2+/ TiO2 catalyst. From XPS studies Cobalt was found to be in +2
oxidation state. From BET results the surface area was reported to be-89.51 and 77.93 (m2
/g) for Co2+/TiO2-
HgS(1)& Co2+/TiO2-HgS(2). From UV-DRS studies absorbance band shifted more towards visible region (red
shift). In order to find out the efficiency of the synthesized photocatalyst the photocatalytic activity studies were
carried out by degradation of Acid Red as a model azo dye pollutant in presence of the visible light irradiation.
The antibacterial activity of the synthesized catalysts against Escherichia coli was also studied. Thus from the
results 0.5wt.% Co2+/TiO2-HgS(1) exhibited highest photocatalytic activity for the degradation of azo dye Acid
Red as well as proved to be an excellent antibacterial agent
Photochemistry Mediated Synthesis and Characterization of Thyroxine Capped Si...priyanka raviraj
Objective:
Silver nanoparticles (AgNPs) are one of the noble metal nanoparticles studied due to their amenability of synthesis, functionalization and ease of detection. Synthesis of silver nanoparticles using thyroxine as a reducing and capping agent through the one step photochemical method
Characterization of synthesized silver nanoparticles (Thy-AgNPs)
1. UV-Spectroscopy Analysis
2. Fourier Transforms-Infra Red Spectroscopy (FT-IR)
3. High Resolution Transmission Electron Microscopy(HR-TEM)
4. Field Emission Scanning Electron Microscopy(FE-SEM)
5. Dynamic Light Scattering (DLS)
6. Zeta potential
Uses:
*AgNPs have unique optical, electrical, and thermal properties
*Exhibit high plasmon efficiency
*More sensitive towards localized surface plasmon resonance
*Less time consuming, economic and more ecofriendly
*It is used in electronics, food industry, cosmetics, photochemical, biomedicine and chemistry.
Photocatalytic degradation of some organic dyes under solar light irradiation...Iranian Chemical Society
Nanoparticles of the ZnO and TiO2 were synthesized and the physicochemical properties of the compounds were characterized by IR, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD patterns of the ZnO and TiO2 nanoparticles could be indexed to hexagonal and rutile phase, respectively. Aggregated nanoparticles of ZnO and TiO2 with spherical-like shapes were observed with particle diameter in the range of 80-100 nm. These nanoparticles were used for photocatalytic degradation of various dyes, Rhodamine B (RhB), Methylene blue (MB) and Acridine orange (AO) under solar light irradiation at room temperature. Effect of the amount of catalyst on the rate of photodegradation was investigated. In general, because ZnO is unstable, due to incongruous dissolution to yield Zn(OH)2 on the ZnO particle surfaces and thus leading to catalyst inactivation,the catalytic activity of the system for photodegradation of dyes decreased dramatically when TiO2 was replaced by ZnO.
Engineering Research Publication
Best International Journals, High Impact Journals,
International Journal of Engineering & Technical Research
ISSN : 2321-0869 (O) 2454-4698 (P)
www.erpublication.org
Photo-electrocatalytic activity of TiO2 nanotubes prepared with two-step anod...Iranian Chemical Society
To improve the photo-catalytic degradation of salicylic acid, we reported the fabrication of ordered TiO2 nanotube arrays by a simple and effective two-step anodization method and then these TiO2 nanotubes treated in a methanol solution under UV light irradiation. The TiO2 nanotubes prepared in the two-step anodization process showed better photo-catalytic activity than TiO2 nanotubes prepared in one-step anodization process. Also, compared with TiO2 nanotubes without the UV pretreatment, the TiO2 nanotubes pretreated in a methanol solution under UV light irradiation exhibited significant enhancements in both photocurrent and activity. The treated TiO2 nanotubes exhibited a 5-fold enhancement in photocurrent and a 2.5-fold increase in the photo-catalytic degradation of salicylic acid. Also the effect of addition of persulfate and periodate on the photo-catalytic degradation of salicylic acid were investigated. The results showed that the degradation efficiency of salicylic acid increased with increasing persulfate and periodate concentrations. These treated TiO2 nanotubes are promising candidates for practical photochemical reactors.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IOSR Journal of Applied Chemistry (IOSR-JAC) is an open access international journal that provides rapid publication (within a month) of articles in all areas of applied chemistry and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Chemical Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Preparation, characterization and application of sonochemically doped fe3+ in...eSAT Journals
Abstract In this present study, mechanistic investigation of ultrasound–assisted dye decolorization/degradation was investigated using sonochemically prepared Fe3+ doped ZnO. Fe3+ doped ZnO nanoparticle was prepared under ultrasound (20 kHz) irradiation using a doping concentration of 2 wt% of Fe(III). To investigate the catalytic activity of Fe3+ doped ZnO, Acid Red 14 (azo dye) was chosen for decolorization/degradation using sonolysis, photocatalysis and sono–photocatalysis processes. To study the influence of dopant onto structure, crystallinity, and optical properties, different analytical analyses were performed such as X–ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Zeta potential, Delsa Nano Particle Size Analyzer (PSA), Vibrating Sample Magnetometer analysis (VSM) and Field Emission Scanning Electron Microscopy (FE–SEM) etc. For photocatalytic experiments, a blended high pressure mercury UV lamp with maximum peak emission at 365 nm was used. The decolorization/degradation of dye with modified photocatalyst showed faster reaction kinetics under sono–photocatalytic process. Ultrasound showed an additive effect for degradation/decolorization process. The maximum decolorization of AR14 was achieved (~ 82%) under sono–photocatlytic process with an initial dye concentration of 20 ppm. The sono–photocatalysis process showed 1.4 – 1.6 higher reaction rates with Fe–doped ZnO than pure ZnO. Index Terms: ZnO, Fe–ZnO, Fe-doped ZnO, Sonocatalytic, Photocatalytic, Advanced Oxidation Process, AOP
Synthesis Of Cobalt Doped Titania Nano Materials Assisted By Anionic Heteroge...IJERA Editor
: This paper presents about the synthesis of (0.25-1.0) wt.% cobalt doped titania nanomaterials
without surfactants: pure Co2+/TiO2 and in presence of 1,4-Butane sultone and 1,3-Propane sultone Anionic
Gemini surfactants and CTAB (Heterogemini surfactant)-0.5wt.%Co2+/TiO2-HgS(1&2).The synthesized nano
photocatalysts have been characterized by using various advanced techniques like X-Ray Diffraction (XRD),
Ultraviolet-visible Diffuse Reflection Spectroscopy (UV-Vis DRS), X-ray Photoelectron Spectroscopy (XPS),
Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS), Fourier Transform Infrared
Spectroscopic Studies (FT-IR), Transmission Electron Microscopy (TEM). From the characterization studies all
the catalysts synthesized were reported in anatase phase. TEM indicates the particles size of prepared catalysts
reported with 7-10 nm and 15 nm for pure Co2+/ TiO2 catalyst. From XPS studies Cobalt was found to be in +2
oxidation state. From BET results the surface area was reported to be-89.51 and 77.93 (m2
/g) for Co2+/TiO2-
HgS(1)& Co2+/TiO2-HgS(2). From UV-DRS studies absorbance band shifted more towards visible region (red
shift). In order to find out the efficiency of the synthesized photocatalyst the photocatalytic activity studies were
carried out by degradation of Acid Red as a model azo dye pollutant in presence of the visible light irradiation.
The antibacterial activity of the synthesized catalysts against Escherichia coli was also studied. Thus from the
results 0.5wt.% Co2+/TiO2-HgS(1) exhibited highest photocatalytic activity for the degradation of azo dye Acid
Red as well as proved to be an excellent antibacterial agent
Photochemistry Mediated Synthesis and Characterization of Thyroxine Capped Si...priyanka raviraj
Objective:
Silver nanoparticles (AgNPs) are one of the noble metal nanoparticles studied due to their amenability of synthesis, functionalization and ease of detection. Synthesis of silver nanoparticles using thyroxine as a reducing and capping agent through the one step photochemical method
Characterization of synthesized silver nanoparticles (Thy-AgNPs)
1. UV-Spectroscopy Analysis
2. Fourier Transforms-Infra Red Spectroscopy (FT-IR)
3. High Resolution Transmission Electron Microscopy(HR-TEM)
4. Field Emission Scanning Electron Microscopy(FE-SEM)
5. Dynamic Light Scattering (DLS)
6. Zeta potential
Uses:
*AgNPs have unique optical, electrical, and thermal properties
*Exhibit high plasmon efficiency
*More sensitive towards localized surface plasmon resonance
*Less time consuming, economic and more ecofriendly
*It is used in electronics, food industry, cosmetics, photochemical, biomedicine and chemistry.
Photocatalytic degradation of some organic dyes under solar light irradiation...Iranian Chemical Society
Nanoparticles of the ZnO and TiO2 were synthesized and the physicochemical properties of the compounds were characterized by IR, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD patterns of the ZnO and TiO2 nanoparticles could be indexed to hexagonal and rutile phase, respectively. Aggregated nanoparticles of ZnO and TiO2 with spherical-like shapes were observed with particle diameter in the range of 80-100 nm. These nanoparticles were used for photocatalytic degradation of various dyes, Rhodamine B (RhB), Methylene blue (MB) and Acridine orange (AO) under solar light irradiation at room temperature. Effect of the amount of catalyst on the rate of photodegradation was investigated. In general, because ZnO is unstable, due to incongruous dissolution to yield Zn(OH)2 on the ZnO particle surfaces and thus leading to catalyst inactivation,the catalytic activity of the system for photodegradation of dyes decreased dramatically when TiO2 was replaced by ZnO.
Engineering Research Publication
Best International Journals, High Impact Journals,
International Journal of Engineering & Technical Research
ISSN : 2321-0869 (O) 2454-4698 (P)
www.erpublication.org
Photo-electrocatalytic activity of TiO2 nanotubes prepared with two-step anod...Iranian Chemical Society
To improve the photo-catalytic degradation of salicylic acid, we reported the fabrication of ordered TiO2 nanotube arrays by a simple and effective two-step anodization method and then these TiO2 nanotubes treated in a methanol solution under UV light irradiation. The TiO2 nanotubes prepared in the two-step anodization process showed better photo-catalytic activity than TiO2 nanotubes prepared in one-step anodization process. Also, compared with TiO2 nanotubes without the UV pretreatment, the TiO2 nanotubes pretreated in a methanol solution under UV light irradiation exhibited significant enhancements in both photocurrent and activity. The treated TiO2 nanotubes exhibited a 5-fold enhancement in photocurrent and a 2.5-fold increase in the photo-catalytic degradation of salicylic acid. Also the effect of addition of persulfate and periodate on the photo-catalytic degradation of salicylic acid were investigated. The results showed that the degradation efficiency of salicylic acid increased with increasing persulfate and periodate concentrations. These treated TiO2 nanotubes are promising candidates for practical photochemical reactors.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IOSR Journal of Applied Chemistry (IOSR-JAC) is an open access international journal that provides rapid publication (within a month) of articles in all areas of applied chemistry and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Chemical Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Optical Control of Selectivity of High Rate CO2 Photoreduction Via Interband-...Pawan Kumar
Photonic crystals consisting of TiO2 nanotube arrays (PMTiNTs) with periodically modulated diameters were fabricated using a precise charge-controlled pulsed anodization technique. The PMTiNTs were decorated with gold nanoparticles (Au NPs) to form plasmonic photonic crystal photocatalysts (Au-PMTiNTs). A systematic study of CO2 photoreduction performance on as-prepared samples was conducted using different wavelengths and illumination sequences. A remarkable selectivity of the mechanism of CO2 photoreduction could be engineered by merely varying the spectral composition of the illumination sequence. Under AM1.5 G simulated sunlight (pathway#1), the Au-PMTiNTs produced methane (302 µmol h-1) from CO2 with high selectivity (89.3%). When also illuminated by a UV-poor white lamp (pathway#2), the Au-PMTiNTs produced formaldehyde (420 µmol h-1) and carbon monoxide (323 µmol h-1) with almost no methane evolved. We confirmed the photoreduction results by 13C isotope labeling experiments using GC-MS. These results point to optical control of the selectivity of high-rate CO2 photoreduction through selection of one of two different mechanistic pathways. Pathway#1 implicates electron-hole pairs generated through interband transitions in TiO2 and Au as the primary active species responsible for reducing CO2 to methane. Pathway#2 involves excitation of both TiO2 and surface plasmons in Au. Hot electrons produced by plasmon damping and photogenerated holes in TiO2 proceed to reduce CO2 to HCHO and CO through a plasmonic Z-scheme.
Octahedral rhenium K4[Re6S8(CN)6] and Cu(OH)2cluster modifiedTiO2for the phot...Pawan Kumar
tOctahedral hexacyano rhenium K4[Re6S8(CN)6] cluster complexes were grafted onto photoactive Cu(OH)2cluster modified TiO2{Cu(OH)2/TiO2} support. The rhenium and copper cluster modified TiO2photocata-lyst combines the advantages of heterogeneous catalyst (facile recovery, recycling ability of the catalyst)with the reactivity, selectivity of the soluble molecular catalyst. The synthesized heterogeneous cata-lyst was found to be highly efficient photoredox catalyst for the reduction of CO2under visible lightirradiation. Methanol was found to be the major liquid product with the formation of hydrogen as a byproduct as determined with GC-FID and GC-TCD, respectively. The methanol yield after 24 h irradiationwas found to be 149 mol/0.1 g cat. for Re-cluster@Cu(OH)2/TiO2photocatalyst that is much higher than35 mol/0.1 g cat. for Cu(OH)2/TiO2and 75 mol/0.1 g cat. for equimolar rhenium cluster in the presenceof triethanolamine (TEOA) as a sacrificial donor. The quantum yields (MeOH) of Re-cluster@Cu(OH)2/TiO2and Cu(OH)2/TiO2were found to be 0.018 and 0.004 mol einstein−1, respectively. These values are muchhigher than those reported for other heterogeneous catalysts for six electron transfer reaction
Equilibrium and Kinetics Adsorption of Cadmium and Lead Ions from Aqueous Sol...theijes
Sourcing cheap adsorbents for the treatment of waste water is imperative for local environments. The adsorption of cadmium (Cd) and lead (Pb) from aqueous solution onto bamboo activated carbon prepared by chemical activation with ZnCl2 was investigated. The unwashed chemical activated bamboo carbon (UCABC) achieved up to 87.81% and 96.45% removal of Cd and Pb at pH-5 and 11, respectively. Removal equilibrium was attained within 1hr and 2.5hrs for Cd and Pb, respectively. The Cd and Pb adsorption increased with adsorbent dosage decrease while removal rate (%) increased with Cd and Pb concentration. Adsorption isotherm of Cd and Pb onto UCABC was determined and correlated with four isotherm models (Langmuir, Freundlich, Temkin and Hills). The equilibrium data fitted into Freundlich Cd (R2 = 0.9873, SSE = 0.045), Pb (R2 =0.9903, SSE = 0.051); Temkin Cd (R2 =0.9730, SSE = 0.052), Pb (R2 = 0.9079, SSE = 0.056); Hills Cd (R2 = 0.9961, SSE = 0.048), Pb (R2.= 0.9183, SSE = 0.053) and Langmuir Cd (R2 = 0.9653, SSE = 0.302), Pb (R2 = 0.9899, SSE = 0.136) isotherms. The Freundlich fitting showed isotherm adsorption capacity constants Kf = 7.843 and 5.098 (mg/g) for Cd and Pb, respectively. Furthermore, their adsorption kinetics correlated with the Pseudo-first order, Pseudo-second order and Intra-particle diffusion models and could be best described by the Pseudo-second order equation, suggesting chemisorptions as the limiting process. This study demonstrated that the UCABC can remove Cd2+ and Pb+ ions from aqueous solution to avert expensive commercial adsorbents
PHOTOCATALYTIC DEGRADATION OF RB21 DYE BY TIO2 AND ZNO UNDER NATURAL SUNLIGHT...IAEME Publication
The present work aims to degrade the RB21 dye from synthetic wastewater using
semiconductors TiO2 and ZnO. The activity of photocatalytic degradation process of dye was
carried out using different light sources of 900 W/m
2
intensity in natural sunlight from 02:00 to
04:00 pm with 48°C temperature in Ahmedabad city in the month of May, 600 Watt microwave
oven and high pressure UV-light photocatalytic reactor of wavelength 200-450 nm. All the
experiments were performed with dye concentration 50 mg/L, catalyst dosage 0.8 g, pH 7, room
temperature, irradiation time 240 min followed by 30 min in dark. All the samples were collected at
different time intervals of 30, 60, 90, 120, 150, 180, 210, 240 min for the analysis of COD
degradation and color removal. The best performances was achieved using high pressure UVphotocatalytic
reactor using TiO2. The successful result obtained using TiO2is 80% COD
degradation and 99% color removal followed by 75% COD and 99% color removal with ZnO.
Chemical kinetics was found to follow first order mechanism. The formation of intermediate
compounds and identification of the final products were carried out using LCMS/MS analysis and
FT-IR techniques.
Mater of Engineering Thesis at Vishwakarma government engineering college affiliated to Gujarat Technological University.
Ahmedabad, Gujarat
The title of the work is "Microwave solution combustion synthesis of visible light-responsive photocatalyst for degradation of reactive turquoise blue (RB21) dye
This work is based on originality based but some publications are going through with this work.
Thank you for publication
Keep watching.
DISINFECTION OF WATER CONTAINING E. COLI BY PHOTOCATALYTIC ROUTE USING TIO2/...Michael George
Disinfection of water containing E. coli is a major concern. The objective of this research is to disinfect the water containing E. coli by photocatalytic route using TiO2 and Carbon doped TiO2 and comparison of the two. The photocatalytic disinfection was tested under UV light and visible light irradiation. The experiments were carried out using different culture concentrations and different catalyst concentrations. It was examined that 99.94% disinfection occurs at 0.2 grams C-doped TiO2 concentration per 200 ml of solution.
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after 24 h irradiation was 9934 μmol g−1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride 145 μmol g−1cat under identical conditions. The presence of triethylamine was found to be vital for the higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for subsequent six runs without significant loss in photo activity.
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used
for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after
24 h irradiation was 9934 mmol g1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a
sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride
145 mmol g1cat under identical conditions. The presence of triethylamine was found to be vital for the
higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for
subsequent six runs without significant loss in photo activity.
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used
for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after
24 h irradiation was 9934 mmol g1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a
sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride
145 mmol g1cat under identical conditions. The presence of triethylamine was found to be vital for the
higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for
subsequent six runs without significant loss in photo activity.
Visible Light Assisted Degradation of Eosin Yellow using Heteroatom Functiona...IJERA Editor
10 ppm EY dye were successfully photodegraded using visible light active 0.75wt% Ba & 0.25wt% Zr codoped
TiO2 nanomaterial that were synthesized by Sol-gel method as nanomaterials under irradiation for 20
minutes and characterized by various advanced instrumental techniques. The X-ray Diffraction Spectroscopic
showed that the prepared nanomaterial were in the anatase phase with 2θ at 25.3º. UV-visible Diffuse
Reflectance Spectra analysis explained that the dopants found in the TiO2, imparts a significance absorption
shift towards visible region and their exisistance were confirmed by X-ray Photoelectron Spectral data.
Quantitatively the formation of hydroxyl radical by the nanomaterial in aqueous solution under visible
light irradiation was investigated by the photoluminiscent technique. Finally the effects of different parameters
in the photocatalytic degradation of EY were established in aqueous solution
Photocatalytic Degradation of Azo Dye (Methyl Red) In Water under Visible Lig...IJEAB
Commercial TiO2 (P25) co-doped with bimetallic silver and nickel nanoparticles (Ag-Ni/TiO2) was prepared by g-irradiation method. The properties of Ag-Ni/TiO2 were characterized by X-Ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), energy dispersive X-ray spectroscopy techniques (EDX) and surface area measurement by Brunauer-Emmett-Teller (BET) method. The size of silver and nickel nanoparticles was determined by TEM to be of 1-2 nm.The photo-catalytic degradation of azo dye methyl red in the aqueous suspensions of TiO2 and Ag-Ni/TiO2 under visible light was carried out to evaluate the photo-catalytic activity. Results showed that Ag-Ni/TiO2 was found to enhance photo-degradation efficiency of azo dye metyl red compared to commercial TiO2. The results showed that Ag 3% (w/w) and Ni 1.5% (w/w) co-doped TiO2 had the highest photoactivity among all studied samples under visible light. Thus, g-irradiation method can be suitably applied to prepare photo-catalyst of Ag-Ni/TiO2with highly photocatalytic activity.
Reduced graphene oxide–CuO nanocomposites for photocatalyticconversion of CO2...Pawan Kumar
Reduced graphene oxide (rGO)–copper oxide nanocomposites are prepared by covalent grafting of CuOnanorods on the rGO skeleton. Chemical and structural features of rGO–CuO nanocomposites are probedby FTIR, XPS, XRD and HRTEM analyses. Photocatalytic potential of rGO–CuO nanocomposites is exploredfor reduction of CO2into the methanol under the visible light irradiation. The breadth of CuO nanorods andthe oxidation state of Cu in the rGO–CuO/Cu2O nanocomposites are systematically varied to investigatetheir photocatalytic activities. The pristine CuO nanorods exhibited very low photocatalytic activity owingto fast recombination of charge carriers and yielded 175 mol g−1methanol, whereas rGO–Cu2O andrGO–CuO exhibited significantly improved photocatalytic activities and yielded five (862 mol g−1) andseven (1228 mol g−1) folds methanol, respectively. The superior photocatalytic activity of CuO in therGO–CuO nanocomposites was attributed to slow recombination of charge carriers and efficient transferof photo-generated electrons through the rGO skeleton. This study further excludes the use of scavengingdonor.
Reduced graphene oxide–CuO nanocomposites for photocatalyticconversion of CO2...Pawan Kumar
tReduced graphene oxide (rGO)–copper oxide nanocomposites are prepared by covalent grafting of CuOnanorods on the rGO skeleton. Chemical and structural features of rGO–CuO nanocomposites are probedby FTIR, XPS, XRD and HRTEM analyses. Photocatalytic potential of rGO–CuO nanocomposites is exploredfor reduction of CO2into the methanol under the visible light irradiation. The breadth of CuO nanorods andthe oxidation state of Cu in the rGO–CuO/Cu2O nanocomposites are systematically varied to investigatetheir photocatalytic activities. The pristine CuO nanorods exhibited very low photocatalytic activity owingto fast recombination of charge carriers and yielded 175 mol g−1methanol, whereas rGO–Cu2O andrGO–CuO exhibited significantly improved photocatalytic activities and yielded five (862 mol g−1) andseven (1228 mol g−1) folds methanol, respectively. The superior photocatalytic activity of CuO in therGO–CuO nanocomposites was attributed to slow recombination of charge carriers and efficient transferof photo-generated electrons through the rGO skeleton. This study further excludes the use of scavengingdonor.
Sunlight induced removal of Rhodamine B from water through Semiconductor Pho...Hariprasad Narayanan
Application of Advanced Oxidation Processes (AOP) for the removal of toxic pollutants from water has been receiving increasing
attention in recent times. Photocatalysis using semiconductor oxides is one such AOP which is being investigated extensively for
the degradation of dyes in effluent water. This paper reports our findings on the sunlight induced photocatalytic removal of the
hazardous xanthene dye Rhodamine B from water, mediated by TiO2 and ‘platinum deposited TiO2’ (Pt/TiO2).Unlike in the case of
photocatalytic degradation of many organic pollutants which are driven by UV light, Rhodamine B can be removed in presence of
TiO2 even by visible light. Pt/TiO2 is ~5 times more active than TiO2 alone for the solar photocatalytic degradation of the dye,
which is attributed to extension of the absorption of light to the visible range and retardation of the recombination of
photogenerated electrons and holes. The dye itself can absorb visible light and act as a photo sensitizer to activate TiO2. The
effects of various parameters such as catalyst loading, concentration of the dye, pH, Pt concentration in Pt/TiO2, externallyadded
H2O2 etc on the adsorption and /or degradation of the dye are evaluated. The degradation of the dye proceeds through
intermediates and complete removal of Total Organic Carbon (TOC) is achieved many hours after the decolorisation of the dye.
The rate of degradation decreases beyond a critical concentration of the dye, possibly due to reduction in the path length of
photons in deeply colored solution. The higher degradation in alkaline pH is explained in terms of the ionization state of the
catalyst surface and the enhanced adsorption facilitated by the electrostatic attraction between the negatively charged catalyst
surface and the zwitter ionic form of the dye. H2O2, upto a critical concentration, accelerates the degradation. The observations are
critically analysed and suitable mechanism for the photocatalytic mineralisation of RhB is proposed.
Similar to Effect of Dye Type on MMT-Supported Pr-Doped TiO2 Composite Photocatalyst (20)
Sunlight induced removal of Rhodamine B from water through Semiconductor Pho...
Effect of Dye Type on MMT-Supported Pr-Doped TiO2 Composite Photocatalyst
1. Vol. 130 (2016) ACTA PHYSICA POLONICA A No. 1
Special issue of the 2nd International Conference on Computational and Experimental Science and Engineering (ICCESEN 2015)
Effect of Dye Type on Montmorillonite-Supported
Pr-Doped TiO2 Composite Photocatalsyt
B. Otsukarci and Y. Kalpakli∗
Yildiz Technical University, Department of Chemical Engineering, 34210, Istanbul, Turkey
Scarcity of water in today’s world has led to scientific researches for finding smarter ways of discharging and
re-using water located in the seas and lakes. That is how advanced oxidation technologies have emerged as one of
the new discharging techniques to keep water sources clean. In our method we have synthesized praseodymium (Pr)
doped TiO2-Montmorillonite composite photocatalyst by using acid sol-gel method. Pr, in the group of rare earth
metals, is known for its ability to form Lewis bases in order to break down aldehydes, amines, etc., by decreasing
the crystal size and consequently increasing the surface area. We have used the mineral form of the bentonite clay
(montmorillonite) to increase the surface area of our composite photocatalyst. Two types of azo dyes which are
commercially known as Basic Yellow 28 (BY 28) and Basic Blue 41 (BB 41) were used in experimants. These dyes
are composed of different chemical structures: BY 28 is known as azomethine dye (–CH=N–), whereas BB 41 has
one azo bond (–N=N–). The initial model dye concentrations were 100 ppm. Amount of 1.0 g/l of photocatalyst
was used throughout the experiments. In order to evaluate degradation efficiency results, the dissolved organic
carbon analyzer was used. We have found the optimum dark adsorption time to be under 15 minutes. By stirring
under 15 minutes in the dark we have achieved efficiency of 52.50% for BY 28 and 66.74% for BB 41. On the other
hand, by stirring under UV-A light irradiation for two hours we have achieved the overall degradation efficiency
of 86.30% for BY 28 and 92.39% for BB 41. Our results show that higher adsorption and overall efficiencies were
observed in BB 41 than in BY 28. Moreover, according to Water Pollution Control Regulations, the chemical oxygen
demand limitations for textile industry are between 200–400 mg/l. To evaluate the degradation characteristics of
Pr-doped TiO2-Montmorillonite composite, the change of chemical oxygen demand values with time for 100 mg/l
of BY 28 and BB 41 were investigated. The obtained chemical oxygen demand values were 60.5 and 34.8 mg O2/l
after 2 hours of oxidation processes for BY 28 and BB 41. As it can be seen from the results, obtained values are
below the limitations.
DOI: 10.12693/APhysPolA.130.198
PACS/topics: 81.16.Hc, 87.64.K, 87.64.km
1. Introduction
Recently, heterogeneous photocatalysis of TiO2 doped
with rare earth elements has attracted extensive atten-
tion due to broadening of the oxidation activity of TiO2
into the visible region of spectrum, which decreases the
cost of degradation and makes the process feasible for in-
dustrial usage. Even though TiO2 has a large band gap
(3.2 eV in the anatase form) and strong oxidation po-
tential of the photogenerated holes (∼ 2.9 V vs NHE at
pH 0), its efficiency is limited under the visible light [1].
Photocatalytic reaction has several steps: (a) produc-
tion of electron-hole pairs (e−
/h+
) by generating the re-
quired over-band-gap energy on the photocatalyst sur-
face, (b) separation of e−
/h+
pairs by electron scavengers
or traps on TiO2 surface, (c) a redox process between
the separated e−
and h+
and the pollutants located in
the solution, (d) desorption of the products from the
surface [2].
One of the ways to extend the visible light sensitiv-
ity spectrum of TiO2 from UV area is to prolong the
e−
/h+
separation in order to have effective redox pro-
cesses. Here is where the incorporation with rare earth
∗corresponding author; e-mail: kalpakli@yildiz.edu.tr
elements becomes useful. Praseodymium, which is an el-
ement belonging to rare earth elements group, was used
in this study as a doping agent. According to Xiuqin
et al. doping of the photocatalyst with the appropriate
amounts of rare earths improves the photocatalytic ac-
tivity of the photocatalyst by increasing the formation
rate of e−
/h+
pairs and thus increasing the amount of
hydroxyl radicals (·OH) [3]. Su et al. have stated that
doping with Pr induces the photocatalytic activity in vis-
ible range of spectrum [4].
In this study our aim was to prepare TiO2-
Montmorillonite (MMT) doped with Pr, using acid sol-
gel method, in order to compare the degradation and de-
coloration results for two model pollutants. As the model
pollutants, two colorants, Basic Yellow 28 (BY 28) and
Basic Blue 41 (BB 41), were used. MMT, which is a min-
eral form of bentonite clay, widely found in Turkey, was
used as the supporting material for TiO2. Both, BY 28
and BB 41 are basic, cationic dyes soluble in water due
to their sulfonate groups (SO−
3 ) [5]. BY 28 is also known
as the azomethine dye (-CH=N-) or the hydrazone dye
(=N-N(H,R)-) [6]. BB 41 is a mono azo dye, due to pres-
ence in its structure of one azo group (-N=N-) [7]. BY 28
is used in acrylic, wool, and nylon dyeing [8]. BB 41 is
suitable for acrylic, wool, and cotton dyeing [9].
(198)
2. Effect of Dye Type on Montmorillonite-Supported Pr-Doped TiO2 Composite Photocatalsyt 199
2. Experimental
BY 28 and BB 41 were purchased from Alptekim Dye
and Chemicals Incorporated Company. The commercial
name of BY 28 is Acryla Golden Yellow GL and the com-
mercial name of BB 41 is Acryla Blue GRL. Pr-doped
TiO2-MMT has been synthesized using analytical grade
precursors. These precursors were tetra-tert-buthyl-
orthotitanate (Merck), absolute ethanol (Merck), nitric
acid (Merck) and sodium bentonite (Esan Eczacıbaşı
Industrial Raw Materials Incorporated Company, Kü-
tahya). Praseodymium (III) nitrate hexahydrate 99.9%
with a chemical formula of Pr(NO3)3 · 6H2O was pur-
chased from Sigma-Aldrich. Distilled water has been
used in all experiments.
2.1. Equipment
All adsorption and photocatalytic oxidation experi-
ments were conducted using Luzchem photoreactor. This
reactor was equipped with eight UV-A black fluorescent
8 W lamps. Lamps were turned off during the adsorption
experiments. WiseShake branded stirrer was used in the
synthesis step. Dissolved organic carbon was analyzed
using Hach-Lange IL 550 TOC-TN analyzer. In order to
determine the effect of photocatalyst on the color prop-
erties of water, absorbance values after each experiment
were measured using Perkin Elmer branded Lambda 35
UV/VIS spectrometer at λ = 415 nm for BY 28 and at
λ = 617 nm for BB 41.
2.2. Experimental procedure
For the experiments we have employed solutions of
25 ml of BY 28 and BB 41 in a 100 ml beaker. Concentra-
tion was kept at 100 ppm throughout the experiments for
both dyes. Optimum adsorption and degradation data
was obtained step by step.
2.3. Adsorption process
As known from the previous experiments and literature
findings, photocatalytic reactions take place collabora-
tively in two stages: adsorption and degradation. In the
adsorption stage we have determined the optimum stir-
ring conditions in the dark, when the UV lights were
turned off, by trying stirring of BY 28 for 15, 25, 35, and
45 minutes.
2.4. Photocatalytic reactions
Degradation process was studied when we have deter-
mined our optimum adsorption time. Our aim was to
obtain the lowest adsorption percentage and the highest
oxidation potential. Our optimum adsorption time for
BY 28 was 15 min. After that we have tried out dif-
ferent photocatalyst amounts of 1.0, 1.5, 2.0, 2.5, and
3.0 g/l under UV-A irradiation time of 35, 45, 60, 90,
and 120 min. We have obtained the highest oxidation
of BY 28, which had settled at around 120 min, using
1.0 g/l of photocatalyst. Later we have compared our re-
sults with those obtained for BB 41. In the experiments
with BB 41 the degradation stage had lasted 30, 60, 90,
and 120 min.
3. Results and discussion
3.1. Photocatalytic degradation experiments
Adsorption is an important step in the studied pro-
cess, which increases the amount of compounds to be de-
graded under the UV-A irradiation. We have determined
adsorption efficiencies for both dyes. After 15 min of ab-
sorption, the adsorption efficiency was 52.50% for BY 28
and 66.74% for BB 41. BB 41 had a higher adsorption ca-
pacity compared to BY 28. The highest overall efficiency
(adsorption% + oxidation%, after 120 min of UV-A ir-
radiation) was 86.30% for BY 28, which is less than that
for BB 41, with a value of 92.39%.
When the UV-A irradiation time was increased from
30 to 120 min, the surface attacking rate for both dyes
had decreased and finally had stabilized around the same
value, as shown in Fig. 1. However, the initial attacking
rate of BB 41 to the surface of the photocatalyst was
higher. According to Bouafia et al. [10], who have applied
the photo-Fenton process, the rate of oxidation of BB 41
was also higher than that of BY 28, which is coherent
with our findings.
Fig. 1. Surface attack rate for BY 28 and BB 41 as
function of UV-A irradiation time, after 15 min of dark
adsorption. Concentration of the model compounds was
100 ppm. Amount of the photocatalyst used was 1.0g/l.
Kinetic results obtained by varying the irradiation time
have shown that the 1st order Langmuir-Hinshelwood ki-
netics is applicable under these steady conditions. In this
manner, values of the kapparent and t1/2 for BY 28 were
were 0.0094 min−1
and 101.9 min, as shown in Table I.
Even though photocatalyst attacked BB 41 faster due
to higher adsorption yield reaction proceeded slower to
reach its half-life value compared to BY 28.
Giwa et al. found apparent rate constant for 100 ppm
of BB 41 as 0.005 l/mol min using only TiO2 Degussa
P-25 as a photocatalyst after 60 min of irradiation [11].
Our results are in a good agreement with the literature
result.
3. 200 B. Otsukarci, Y. Kalpakli
TABLE I
Calculated apparent rate constant and half life values for
BY 28 and BB 41 dyes.
kapparent [min−1
] kapparent [l/mol min] t1/2 [min]
BY 28 0.0068 0.0085 73.4
BB 41 0.0094 0.0055 101.9
After the degradation period, decolorization efficiency
of dyes was observed as a function of time using a spec-
trophotometer.
3.2. UV-Vis spectroscopy
Degradation study of BY 28 and BB 41 was followed
by a study using UV-Vis spectroscopy. The results are
depicted in Fig. 2. Discoloration efficiency (%) for the
BB 41 was lower than that of BY 28 at the end of 2 h
of irradiation. However, at the end of 90 min period of
irradiation BB 41 had reached its highest discoloration
efficiency. Therefore, the highest discoloration efficiencies
calculated at the end of 2 h for BY 28 and 90 min for
BB 41 were 84.05% and 80.94%, respectively. This is due
to the different chemical structures of the dyes.
As the overall efficiency had increased, the absorbance
values for discoloration of the dyes had eventually de-
creased after 120 min of illumination, as shown in Fig. 2.
In Fig. 2a TOC removal efficiency has a sigmoidal shape,
indicating the formation of by-products that slow down
the degradation efficiency and the degradation rate cal-
culated in Table I for BY 28 [12].
Fig. 2. Comparison of the change of the TOC removal
(blue) and the remaining dye absorbance value (red)
with the irradiation time, for two model dyes (a) BY 28
and (b) BB 41.
3.3. FTIR
At the end of the study, the characteristic peaks of
BY 28 and BB 41 were investigated using FTIR analysis.
For BY 28 these characteristic peaks were found at 1638,
1604, 1552, 1328, 1178, 935, 829, 786, and 642 cm−1
, as
shown in Fig. 3. In an orderly fashion peak at 1638 cm−1
is related to stretching of the C=N group, due to hy-
drazine form of the dye [13], peak at 1604 cm−1
is re-
lated to vibration of the C=N group [14], 1552 cm−1
is
related to combined vibration of NH–N=C group’s N–H
bending and –N=C stress [15], peaks from the range of
1550–1300 cm−1
, 1463, and 1330 cm−1
belong to the
alkanes and alkenes [16], 1247 cm−1
from the range of
1300–1000 cm−1
belongs to the ethers [16], 1178, 1120,
and 1034 cm−1
peaks belong to the S=O stress due to
RO–SO−
3 [16], 935 and 829c m−1
peaks belong to the
C–H bending vibrations, located in the range of 950–
780 cm−1
[17, 18].
Fig. 3. Comparision of FTIR results for BY 28. (a)
BY 28 dye powder, (b) 15 min adsorption, (c) 15 min ad-
sorption + oxidation (d) 1% Pr, 25% TiO2-MMT com-
posite photocatalyst.
Range 1300–900 cm−1
in the spectrum belongs to the
aromatics group in the composition of the dye, which is
removed from the solution with the sequential adsorp-
tion and degradation reactions. In addition, peaks at
935 and 642 cm−1
also disappear. A characteristic peak
at 1604 cm−1
was also cleared away at the end of redox
reactions.
Peak at 3610 cm−1
, which is the characteristic peak of
the photocatalyst, due to OH stretching reduced BY 28
dye powder’s 3610 cm−1
peak represented by the C–H
bending.
Characteristic peaks of mono azo dye BB 41 were also
analyzed. For BB 41 these characteristic peaks are lo-
cated at 1610, 1547, 1483, 1426, 1402, 1372, 1328, 1268,
1110, 984, 860, 829, and 732 cm−1
, as shown in Fig. 4.
Peak at 1610 cm−1
belongs to the amines and amides
represented by the range of 1650–1550 cm−1
[16], peaks
at 1547, 1483, 1426, and 1402 cm−1
are related with
the N=N vibration, represented by the 1500–1400 cm−1
range [19], peaks at 1372, 1328, and 1268 cm−1
are due
to symmetric C–O stretching [14], 1114 cm−1
is related
to stretching of S=O, due to RO–SO−
3 group [16], peak
at 987 cm−1
belongs to the alkenes and aromatics in the
4. Effect of Dye Type on Montmorillonite-Supported Pr-Doped TiO2 Composite Photocatalsyt 201
range of 1000–650 cm−1
[16], peaks at 860 and 829 cm−1
from the range of 950–780 cm−1
are related with the C–H
bending [19] and to the range of 800–400 cm−1
, due to
aromatic compounds [16].
Fig. 4. Comparision of FTIR results for BB 41. (a)
BB 41 dye powder, (b) 15 min adsorption, (c) 15 min ad-
sorption + oxidation (d) 1% Pr, 25% TiO2-MMT com-
posite photocatalyst.
When 1300–950 cm−1
range is investigated, it is seen
that, due to sequential reactions of adsorption and ox-
idation, the aromatic compounds, peaks of which are
located in this area, are removed. Therefore, peaks at
1166, 1114, and 987 cm−1
are reduced at the end of re-
actions. In the range of 1700–1270 cm−1
peaks at 1483,
1402, and 1372 cm−1
, resulted from C=N bond due to
aromatic compounds, amines, alkanes, and alkenes, are
also degraded. Peaks at 860, 829, 732, 619 cm−1
are
also removed by the sequential adsorption and oxidation
reactions.
4. Conclusions
In this study degradation and decoloration of two basic
cationic azo dyes were investigated as a function of irra-
diation time. This work demonstrates for the first time
that MMT-supported Pr-doped TiO2 composite photo-
catalyst has a high efficiency for both degradation and
decoloration. The degradation and decoloration rates
of the dyes and their efficiencies were influenced by the
time the dyes were exposed to the UV-A light. High-
est TOC removal achieved for BY 28 and BB 41 were
86.30% and 92.39% at 120 min respectively. Whereas
the most discoloration efficiency was achieved at the end
of 2 h with 84.05% for BY 28, the highest discoloration
rate for BB 41 was achieved at the end of 90 min with
80.94%. Even though, production of by-products in the
degradation reaction of BY 28 is observed, the system
is fast enough to overcome inhibition of oxidation and
continues the photocatalytic reaction.
FTIR analysis helped us to determine the character-
istic peaks of BY 28 and BB 41 and had shown that
most of the dye removal is achieved only after 2 h of ir-
radiation. FTIR analysis results supported the results of
TOC and UV-Vis analysis. The most important part of
this report is the conduction of the experiments without
using oxidation agents. In the further experiments oxi-
dation agents will be used to improve degradation and
discoloration efficiencies in a shorter irradiation time.
Acknowledgments
The authors would like to thank Yıldız Technical Uni-
versity BAPK project no. 2014-07-01-YL05 for financial
support of this work.
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