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1.
Dishun Zhao Jialei Wang Zhigang Zhang Juan Zhang 《Frontiers of Chemical Engineering in China》2009,3(2):206-210
The degradation of omethoate was conducted using H2O2 as oxidant, TiO2 supported on NaY zeolite as photocatalyst and a 300W lamp as light source. The effect of the calcination temperature of the
photocatalyst, the amount of TiO2 loaded on NaY zeolite, the photocatalyst amount, the pH value and the radiation time on the degradation ratio of omethoate
were investigated. The results show that TiO2/NaY zeolite photocatalyst prepared by sol-gel method had good photocatalysis. The photocatalytic optimum oxidation conditions
of omethoate are as follows: the calcination temperature of the photocatalyst is 550°C,the amount of TiO2 loaded on NaY zeolite is 35.2 wt-%, the amount of photocatalyst is 5 g/L, pH = 8 and the radiation time is 180 min. Under
these conditions, the removal ratio of omethoate is up to 93%. 相似文献
2.
A solution-based processing method has been used to synthesize nanocrystalline TiO2 powders by controlling the hydrolysis of TiCl4 in an aqueous solution in both anatase and rutile phases. The primary particle sizes of the powders were in the range of 5-15 nm. To determine the crystal phase composition and size of the prepared photocatalysts, X-ray diffraction (XRD) measurements were used. We also studied the photocatalytic removal of the herbicide, Bentazon, from contaminated water in the presence of synthesized nanocrystalline TiO2 powders under UV light illumination (30 W). The removal efficiency of Bentazon was 16% when the photolysis was carried out in the absence of TiO2 and it was negligible in the absence of UV light. We have studied the influence of the basic operational parameters such as the different kinds of TiO2, amount of TiO2, irradiation time and initial concentration of Bentazon on the photocatalytic removal efficiency of Bentazon. Our results indicated that 99% removal of the herbicide from the solution containing 15 ppm of Bentazon after selecting desired operational parameters could be achieved in a relatively short time, about 90 min. A kinetic model was successfully established for the prediction of removal of Bentazon by the UV/TiO2 system with any concentration of the herbicide. In this work, we also compared the photocatalytic activity between the commercial TiO2 and synthesized nanocrystalline TiO2 powders. The photocatalytic activities of different photocatalysts were tested using the herbicide solution. 相似文献
3.
Optimization of photocatalytic degradation of phenazopyridine (PhP) under UV light irradiation using immobilized TiO2 nanoparticles was studied. The effect of operational parameters was investigated using response surface methodology (RSM). Maximum removal efficiency was achieved at the optimum conditions: initial drug concentration of 10 mg/L, UV light intensity of 47 W/m2, flow rate of 200 mL/min, and reaction time of 150 min. The residence time distribution (RTD) analysis was studied to find the effect of flow rate on the drug removal efficiency. The tracer (PhP) pulse injection response was studied with UV–vis measurements and was used to prepare RTD curves. 相似文献
4.
Henry Heroe Mungondori Lilian Tichagwa David Meredith Katwire Ochieng Aoyi 《Iranian Polymer Journal》2016,25(2):135-144
Nitrogen-doped titanium dioxide (N–TiO2) was prepared and supported on a novel copolymer grafted membrane matrix to avoid the problems associated with the removal of spent photocatalyst from treated water. Membranes of poly (methacrylic acid) grafted onto poly (vinylidene difluoride) and blended with poly (acrylonitrile) (PMAA-g-PVDF/PAN) were prepared through a dry–wet phase inversion technique. Methacrylic acid side chains were grafted onto an activated PVDF backbone by the method of reversible addition fragmentation chain transfer polymerization and then the novel photocatalytic asymmetric membranes of N–TiO2–PMAA-g-PVDF/PAN were prepared. The casting solutions were blended with 1–5 % N–TiO2 before immersion into the coagulation bath. PVDF and PAN offer several advantages which include: mechanical strength and toughness, chemical resistance, unaffected by long-term exposure to UV radiation, low weight, and thermal stability. N–TiO2 was prepared through sol-gel synthesis. The photocatalytic membranes were evaluated by degradation process of herbicide bentazon in water. Photodegradation studies revealed that the optimum photocatalyst loading was 3 % N–TiO2 and the optimum pH was 7 for the degradation of bentazon in water. UV–Vis, TOC and LC–MS analyses confirmed the successful photodegradation of bentazon. A bentazon removal efficiency of 90.1 % was achieved at pH 7. N–TiO2–PMAA-g-PVDF/PAN membranes were successfully prepared and characterized. These photocatalytic membranes showed great potential as a technology for the effective removal of pesticides from water. According to literature, N–TiO2–PMAA-g-PVDF/PAN asymmetric photocatalytic membranes have not been prepared before for the purpose of treating agricultural wastewater. 相似文献
5.
Yichuan Liao Changsheng Xie Yuan Liu Hao Chen Huayao Li Jun Wu 《Ceramics International》2012,38(6):4437-4444
In order to compare the photocatalytic properties of TiO2, ZnO and their composite in the gas phase pollutant environment, nanocomposite with different mole ratios of TiO2/ZnO were designed to degrade gaseous formaldehyde. The results showed that the rate constant of TiO2 for formaldehyde degradation was 0.05 min?1 which was two orders of magnitude larger than that of ZnO in our experiment. Through comprehensive analysis of UV–vis diffuse reflectance (UV–vis) spectra, photoluminescence spectra (PL) and energy band diagram, it was found that the differences of photocatalytic properties between ZnO and TiO2 may mainly originate from the increased recombination of photoinduced charges in ZnO. The photocatalytic properties of TiO2/ZnO composite for formaldehyde degradation were much worse than those of TiO2, while better than those of ZnO. The addition of a small amount of ZnO weakened the photocatalytic properties of TiO2. It may be attributed to that the recombination action of photoinduced electron–hole pairs in ZnO. 相似文献
6.
Satyen Gautam Sanjay P Kamble Sudhir B Sawant Vishwas G Pangarkar 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2006,81(3):359-364
The photocatalytic degradation of 3‐nitrobenzenesulfonic acid in the presence of solar radiation and artificial UV radiation with suspended TiO2 was studied in a batch and continuous annular reactor, respectively. The effects of catalyst loading, pH, presence of anions and cations and initial concentration on the rate of photocatalytic degradation were investigated. Concentration–time data were correlated with the rate equation d[Ct=0]/dt = krK[Ct=0]/(1 + K[Ct=0]). Studies were carried out to compare the photolytic, photochemical and photocatalytic methods of degradation. Copyright © 2005 Society of Chemical Industry 相似文献
7.
Joon-Chul?Lee Moon-Sun?Kim Chul?Kyung?Kim Chan-Hwa?Chung Sung?M.?Cho Gui?Young?Han Ki?June?Yoon Byung-Woo?Kim
Experiments were performed to investigate the effect of operating parameters on the photodegradation efficiency of paraquat
in a TiO2-suspended photoreactor with immersed UV lamps. TiO2 particles were prepared by a hydrothermal method. The removal rate of paraquat in the reactor was 0.54 mg/l/h with only air-sparging.
The removal rate in 24 h with both the UV radiation and air-sparging was 50% higher than that with only the UV radiation.
Variations of the paraquat concentration at the UV intensities of 4 and 8 W/m2 decreased slowly with time, but that at 12 W/m2 decreased more rapidly. The removal efficiency at the air-sparging flow rate of 1 //min increased as a UV light intensity
increased. pH value in the reactor at the UV intensity of 12 W/m2 decreased with time until 12 h and then increased with time over 12 h. 相似文献
8.
Pure TiO2 and carbon quantum dots (CQDs)-doped TiO2 nanocomposite (CQDs/TiO2 nanocomposite) were prepared by a sol-gel approach for photocatalytic removal of Rhodamine B and cefradine. Analyses by Transmission electronmicroscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), UV–visible spectroscopy and X-ray powder diffraction (XRD) confirmed the successful formation of CQDs/TiO2 heterostructure. The as-prepared TiO2 and CQDs/TiO2 composite possessed small particles, spherical-like shape, and anatase crystal form. Meanwhile, Rhodamine B and cefradine were chosen to evaluate the photocatalytic activity of TiO2 and CQDs/TiO2 composite. Results revealed that with the facile decoration of CQDs, the absorption of photocatalyst was extended into visible light region and photocatalytic activity was improved in comparison with pure TiO2. Furthermore, the mechanism for the improvement of the photocatalytic performance of the composites was discussed on the basis of the results. CQDs play an important role in the photocatalytic process, due to their superior ability to extend the visible absorption and produce more electrons and electron–hole pairs for the degradation of pollutants. In all, the paper offers further insights into the development of CQDs/TiO2 nanocomposite as photocatalyst for the degradation of antibiotics. 相似文献
9.
Won-Chun Oh Feng-Jun Zhang Ming-Liang Chen 《Journal of Industrial and Engineering Chemistry》2010,16(2):321-326
Multi-walled carbon nanotubes (MWCNTs), titanium(IV) isopropoxide (TIP) and potassium hexachloroplatinate(IV) (K2PtCl6) were used for the preparation of Pt/MWCNT/TiO2 composites. The composites were comprehensively characterized by Brauer–Emett–Teller surface area, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy dispersive X-ray and UV–vis absorption spectroscopy. The photoactivity of the prepared materials under UV irradiation was tested using the conversion of methylene blue (MB) in aqueous solution. According to the results of MB removal experiment, it can be considered that the MB removal effect of the Pt/MWCNT/TiO2 composites is affected by two kinds of effects: adsorption effect by MWCNTs and photocatalytic effect by TiO2. Finally, the photocatalytic effect increases due to photo-induced-electron absorption effect by MWCNTs and electron trap effect by Pt metal. 相似文献
10.
Preparation and characterisation of silver‐ or copper‐doped TiO2 catalysts and their catalytic activity in dye degradation
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Oleksandr Lozovskyi Gönül Gündüz Meral Dükkancı Roman Prihod'ko 《Coloration Technology》2015,131(3):245-254
In this study, silver‐ or copper‐doped TiO2–Ce‐, TiO2–La‐, and commercial TiO2 (P25)‐supported catalysts were prepared. The catalysts and supports were characterised by powder X‐ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and nitrogen adsorption studies. UV‐light‐assisted heterogeneous Fenton‐like oxidation of two different‐structure dyes (anionic azo dye Orange II, CI Acid Orange 7 and cationic triphenylmethane dye Crystal Violet, CI Basic Violet 3) was investigated over the catalysts. Higher catalytic activity was observed in the oxidation of Orange II than in the oxidation of Crystal Violet. For both dyes, the TiO2–Ce and TiO2–La‐supported catalysts, which were in the form of anatase only, gave higher photocatalytic activity than the P25‐supported catalysts, which were in the form of anatase and rutile. Complete colour removal was observed during oxidation of Orange II over Cu/TiO2–Ce and Cu/TiO2–La catalysts, whereas the highest degree of decolorisation, 89.3%, was achieved by oxidation of Crystal Violet over Ag/TiO2–Ce. The pH of the solution affected the surface state of the TiO2, thus affecting the photocatalytic degradation of the dyes. The surface area of the catalysts is also a key parameter that influences their photocatalytic activity. It was observed that catalysts having higher surface areas brought about greater dye degradation. 相似文献
11.
Jae-Hong Park 《Desalination》2009,249(2):480-1354
Photochemical degradation and relative toxicity reduction of agricultural wastewater contaminated with methyl 1-[(butylamino)carbonyl]-1H-benzimidazol-2-ylcarbamate (benomyl) by the sonophotocatalytic system was compared with that of the photocatalytic system. Under the optimal conditions, i.e., initial benomyl concentration was 3.2 mg/L, the concentration of TiO2 was 2 g/L and H2O2 concentration was 1.5 mM, the degradation rates with a sonication/UV/TiO2 system was about 1.5 times higher than with a UV/TiO2 system and sonication/UV/TiO2/H2O2 system was about 1.3 times higher than with a UV/TiO2/H2O2 system, respectively. Furthermore, the relative toxicity with a sonophotocatalysis was about 18% lower than with a photocatalysis within a reaction time of 120 min. 相似文献
12.
Abdurrahman Akyol Mahmut Bayramoglu 《Chemical Engineering and Processing: Process Intensification》2008,47(12):2150-2156
The photocatalytic degradation of a commercial azo-reactive textile dye, Remazol Red F-3B, has been investigated in a batch slurry reactor using semiconductor catalysts like, ZnO and TiO2, and two UV sources emitting mainly at 254 and 365 nm. Non-irradiated catalysts and non-catalyzed UV irradiation have negligible effect on the dye degradation. Initial pH, dye concentration, light power and catalyst loading as well as the catalyst type and UV wavelength are considered as process variables. The results showed that decolorization and TOC removal efficiencies of ZnO are higher under 365 nm UV. On the other hand, when two photocatalysts are compared, the decolorization performance of ZnO is higher than TiO2 under 365 nm UV, while TiO2 performs better under 254 nm UV. Furthermore, from the TOC removal point, TiO2 performs better than ZnO irrespective of the UV wavelength. TiO2 irradiated under 254 nm UV degrades successfully both benzene and naphthalene derivatives. 相似文献
13.
《Applied catalysis. B, Environmental》2009,85(3-4):524-532
The photocatalytic transformation of imazamox, a herbicide of imidazolinone family, is investigated in aqueous solution containing titanium dioxide, hydrogen peroxide or the combination of TiO2/H2O2 under simulated sunlight irradiation. The effect of parameters such as the amount of catalysts, the concentration of herbicide, and the pH were investigated by measurement of the rate constant of degradation. Experimental data obtained under different conditions describe the dependency of degradation rate on the above mentioned parameters. Consequently, kinetic parameters were experimentally determined and a pseudo-first-order kinetic was observed. Mulliken charge distributions calculated by the DFT method B3LYP/6–31+G(d) level of theory for key cationic, anionic and neutral structures of imazamox give interpretation for the dependency of photodegradation rate constant on pH. The degradation rate constants were always higher for the heterogeneous catalysis in reactions (TiO2/UV, TiO2/UV/H2O2) compared to the homogeneous systems (UV alone, H2O2/UV). In parallel, five photoproducts could be tentatively identified using Electrospray ionization Fourier transform ion cyclotron resonance mass spectroscopy based on precise chemical formula assignments. 相似文献
14.
Microbial cellulose as a support for photocatalytic oxidation of toluene using TiO2 nanoparticles
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The aim of this study was to investigate the feasibility of toluene degradation using impregnated microbial cellulose (MC) with titanium dioxide (TiO2) nanoparticles (MC/TiO2). The effects of the initial toluene concentration and ultraviolet (UV) source on the degradation efficiency of toluene have been evaluated. The experimental results showed that the rate of toluene degradation decreased with an increasing of the inlet toluene concentration. After 40 min reaction time, the decomposition rate (%) of toluene decreased from 72.3% to 36.02% for experiments conducted at 100 and 500 ppm, respectively. The degradation efficiency of toluene decreased with application of UVA source instead of UVC source. The toluene degradation efficiency (%) reached to 87.79% and 76.87% for UVC and UVA irradiation, respectively. At initial toluene concentration of 100 mg/L, toluene degradation efficiency for photocatalysis and photolysis processes were 70.2% and 10.65%, respectively; indicating that the photocatalytic degradation efficiency is significantly higher than that of photolytic degradation efficiency. Furthermore, photocatalytic degradation kinetics of toluene was studied and the rates of degradation were found to conform to pseudo‐second‐order kinetic. As shown in the present study, impregnation of TiO2 nanoparticles on MC/TiO2 significantly increases toluene removal for short exposure time. It can be concluded that the MC acted as a local toluene concentrator by adsorbing pollutants from the air stream, and thereby diffusing them to the TiO2 nanoparticles for photodegradation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43051. 相似文献
15.
《Ceramics International》2016,42(6):7192-7202
In this paper, a series of CdS/TiO2 NTs have been synthesized by SILAR method. The as-prepared CdS/TiO2 NTs have been analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectrometer (EDS), and ultraviolet–visible (UV–vis). And their photocatalytic activities have been investigated on the degradation of methylene blue under simulated solar light irradiation. XRD results indicate that TiO2 NTs were anatase phase, CdS nanoparticles were hexagonal phase. FESEM results indicate that low deposition concentration can keep the nanotubular structures. UV–vis results indicate that CdS can be used to improve the absorbing capability of TiO2 NTs for visible light, and the content of CdS affects the band gap. Photocatalytic results indicate that CdS nanoparticles are conducive to improve the photocatalytic efficiency of TiO2 NTs, and the highest degradation rate can reach 93.8%. And the photocatalytic mechanism of CdS/TiO2 NTs to methylene blue is also described. 相似文献
16.
Photocatalytic Degradation of Two Commercial Reactive Dyes in Aqueous Phase Using Nanophotocatalysts
This study involves the photocatalytic degradation of Reactive Black 5 (RB5) and Reactive Orange 4 (RO4) dyes, employing heterogeneous
photocatalytic process. Photocatalytic activity of different semiconductors such as titanium dioxide (TiO2) and zinc oxide (ZnO) has been investigated. An attempt has been made to study the effect of process parameters through amount
of catalyst, concentration of dye, and pH on photocatalytic degradation of RB5 and RO4. The experiments were carried out by
varying pH (3–11), amount of catalyst (0.25–1.5 g/L), and initial concentration of dye (10–100 mg/L). The optimum catalyst
dose was found to be 1.25 and 1 g/L for RB5 and RO4, respectively. In the case of RB5, maximum rate of decolorization was
observed in acidic medium at pH 4, whereas the decolorization of RO4 reached maximum in basic region at pH 11. The performance
of photocatalytic system employing ZnO/UV light was observed to be better than TiO2/UV system. The complete decolorization of RB5 was observed after 7 min with ZnO, whereas with TiO2, only 75% dye degraded in 7 min. In the case of RO4, 92 and 62% decolorization was noticed in the same duration. 相似文献
17.
Forough Gashtasbi Reza Jalilzadeh Yengejeh Ali Akbar Babaei 《Korean Journal of Chemical Engineering》2018,35(8):1726-1734
The simultaneous presence of antibiotics and bacteria in aqueous media has been recognized as an environmental threat, due to the enhancement of antibiotic resistance of bacteria. We synthesized an activated carbon impregnated magnetite composite (PAC/Fe3O4) and used it for removal of cephalexin (CEX) from aqueous solution via UV system. A series of batch experiments was carried out under various experimental conditions such as pH of solution (3–11), contact time (0–120 min), catalyst dosages (0.1–2 g/L) and initial CEX concentrations (10, 25, 50 and 100 mg/L). Some common isotherm models were used for study of CEX adsorption and finding the best model. In addition, kinetic studies of CEX photocatalytic removal were performed by fitting the experimental data on first-order and second-order models. Results of comparative studies showed that UV+PAC/Fe3O4 and UV+TiO2 systems, compared to UV/Fe3O4, naked Fe3O4, PAC/Fe3O4 and UV only, had more capability of removing CEX from aqueous solution, indicating PAC/Fe3O4 is effectively catalyzed by UV light. Furthermore, increasing catalyst dosages and decreasing initial CEX concentrations led to the enhancing photocatalytic removal of CEX from solution. The obtained results of kinetic studies also represent that among the studied models, second-order model with significant coefficient of correlation (R2) had higher ability than first-order model to fit the data of CEX removal. Finally, the findings of reusability tests, showed that the applied catalyst would be applicable for CEX removal, even after five consecutive cycles. 相似文献
18.
The photocatalytic degradation of phorate in aqueous suspensions was examined with the use of titanium dioxide (TiO2) as a photocatalyst. About 99% of phorate was degraded after UV irradiation for 60 min. The photodegradation of phorate followed pseudo-first-order kinetics and parameters such as pH of the system, TiO2 dosage, and presence of anions were found to influence the reaction rate. To obtain a better understanding of the mechanistic details of this TiO2-assisted photodegradation of phorate with UV irradiation, the intermediates of the processes were separated, identified, and characterized by the solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) techniques. The probable photodegradation pathways were proposed and discussed. To the best of our knowledge, this is the first study that reports the degradation pathways of phorate. The electrical energy consumption per order of magnitude for photocatalytic degradation of phorate was also calculated and showed that a moderated efficiency (EEO = 96 kWh/(m3 order)) was obtained in TiO2/UV process. 相似文献
19.
《Journal of Industrial and Engineering Chemistry》2014,20(5):3150-3156
A rectangular recycling photo-bioreactor using glucose oxidase (GOx) immobilized on TiO2/polyurethane (PU) was developed as a novel coupling of photodegradation and enzymatic process. This method was tested for removal of Acid Orange 7 (AO7), as a model pollutant. High efficiency of decolorization (>99%) was achieved after 22 min using the GOx/TiO2/PU photo-biocatalyst. Roles of various processes including photodegradation (TiO2/PU), enzymatic process (GOx/PU) and a coupling of photocatalytic–enzymatic (GOx/TiO2/PU) process were investigated in the presence and absence of UV light. All the experiments were performed in a circulation photoreactor equipped with a 6 W UV lamp with rate of 5 mL/min. 相似文献
20.
Ji-Won Yoon Mi-Hwa Baek Ji-Sook Hong Chang-Yong Lee Jeong-Kwon Suh 《Korean Journal of Chemical Engineering》2012,29(12):1722-1729
TiO2 supported on spherical activated carbon (TiO2/SAC) was prepared through an ion-exchange method followed by a heat-treatment process. The adsorption characteristic of TiO2/SAC was evaluated using azo dye methyl orange (MO) as a target substance, and the photocatalytic degradation of MO under UV irradiation was also discussed. A synergistic effect of both the adsorption capacity of activated carbon and the photoactivity of TiO2 on the removal of MO from aqueous solution was observed. Experimental results revealed that the photocatalytic degradation of MO improved with increasing photocatalyst dosage and followed a pseudo-first order kinetic. After five-cycle runs, TiO2/SAC still exhibited relatively high photocatalytic characteristic for the degradation of MO. Besides, the prepared TiO2/SAC can be helpful in the easy separation of photocatalyst from solution after photocatalysis of MO. Furthermore, the use of liquid chromatography/mass spectrometry (LC/MS) technique, identified three intermediates as degradation products during the photocatalytic reaction of MO with TiO2/SAC. 相似文献