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Determination of the photocatalytic activity of TiO2 coatings on clay roofing tile substrates methylene blue as model pollutant
Lon?ar Eva S.,Radeka Miroslava M.,Petrovi? Sne?ana B.,Skapin Andrea S.
Acta Periodica Technologica , 2009, DOI: 10.2298/apt0940125l
Abstract: The photocatalytically active mesoporous coatings, based on titanium dioxide sols (Degussa), of the fired clay roofing tiles substrate were prepared by using poly(ethylene glycol) (PEG) M-600 and M-4000, as the structure directing agents. The coatings were deposited using spray technique followed by thermal treatment. Photocatalytic activity of the TiO2 coatings was evaluated by aqueous solution of methylene blue as model dye, deposited on the top of the coatings, after irradiation with UV light. The results were compared with the photocatalytic efficiency of some commercial self-cleaning products (clay roofing tiles, glass). The newly design coatings showed an interesting decolourisation performance (over 30 % after 24 h). It appeared that the procedure of photocatalytic activity determination, in the case of porous substrates, should be renewed by a preadsorption process.

金属学报(英文版) , 2005,
Abstract: A novel TiO2-ZnFe2O4 coating is prepared by plasma spraying. The effects of spra ying parameters and the composition of powders on the microstructure, surface mo rphology and photo-absorption of plasma sprayed coatings are studied. The photoc atalytic efficiency of the as-sprayed coatings is evaluated through the photo mi neralization of methylene blue. It was found that TiO2 coatings can decompose me thylene blue under the illumination of ultraviolet rays, and the degrading effic iency is improved with an increase in the content of FeTiO3 in the coatings. How ever, the presence of large amount of ZnFe2O4 compound will substantially lower the photocatalytic efficiency of the TiO2-ZnFe2O4 coatings for the unfavorable p hoto-excited electron-hole transfer process.
Dispersion and Stabilization of Photocatalytic TiO2 Nanoparticles in Aqueous Suspension for Coatings Applications
Siti Hajar Othman,Suraya Abdul Rashid,Tinia Idaty Mohd Ghazi,Norhafizah Abdullah
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/718214
Abstract: To produce titanium dioxide (TiO2) nanoparticle coatings, it is desirable that the nanoparticles are dispersed into a liquid solution and remain stable for a certain period of time. Controlling the dispersion and aggregation of the nanoparticles is crucial to exploit the advantages of the nanometer-sized TiO2 particles. In this work, TiO2 nanoparticles were dispersed and stabilized in aqueous suspensions using two common dispersants which were polyacrylic acid (PAA) and ammonium polymethacrylate (Darvan C). The effect of parameters such as ultrasonication amplitude and type and amount of dispersants on the dispersibility and stability of the TiO2 aqueous suspensions were examined. Rupture followed by erosion was determined to be the main break up mechanisms when ultrasonication was employed. The addition of dispersant was found to produce more dispersed and more stabilized aqueous suspension. 3 wt.% of PAA with average molecular weight () of 2000 g/mol (PAA 2000) was determined to produce the best and most stable dispersion. The suspensions were then coated on quartz glass, whereby the photocatalytic activity of the coatings was studied via the degradation of formaldehyde gas under UV light. The coatings were demonstrated to be photocatalytically active.
Photocatalytic degradation of Chromium (VI) from wastewater using nanomaterials like TiO2, ZnO, and CdS
K. M. Joshi,V. S. Shrivastava
Applied Nanoscience , 2011, DOI: 10.1007/s13204-011-0023-2
Abstract: The photocatalytic degradation of Cr(VI) from wastewater by using nanomaterials TiO2, ZnO, and CdS. All the experiments were carried out in the batch process. The wastewater obtained from various industries. The amount of chromium was removed using photocatalyst with UV light and in the dark at different pH range. The maximum removal of Cr(VI) was observed at pH 2; out of these photocatalyst TiO2 showed highest capacity for Cr(VI) removal than TiO2 thin film. The removal of chromium has been studied by considering influent concentration, loading of photocatalyst, pH, and contact time as operating variables. The degradation was characterized by FTIR, XRD, SEM, and EDX analysis before and after application of photocatalysts.
Photocatalytic activities of wet oxidation synthesized ZnO and ZnO–TiO2 thick porous films
Ruiqun Chen,Jie Han,Xiaodong Yan,Chongwen Zou,Jiming Bian,Ahmed Alyamani,Wei Gao
Applied Nanoscience , 2011, DOI: 10.1007/s13204-011-0005-4
Abstract: Highly porous zinc oxide (ZnO) film was produced by using reactive magnetron sputtering zinc target followed by wet oxidation. Titanium dioxide (TiO2) was mixed to the porous films by using either TiO2 target magnetron sputter deposition or sol-spin method. The film thickness could reach 50 μm with uniform porosity. On the sputtering prepared ZnO–TiO2 film surface, fine nanorods with small anatase TiO2 nano-clusters on the tips were observed by SEM and TEM, and the titanium (Ti) composition was determined by XPS as 0.37%. The sol-spin treatment could increase the Ti composition to 4.9%, with reduced pore size compared to the untreated ZnO porous film. Photoluminescence measurements showed that the Ti containing porous film has strong ultraviolet-visible light emission. In the photo-catalysis testing, ZnO and ZnO–TiO2 have similar photo-catalysis activity under 365 nm UV irradiation, but under visible light, the photocatalysis activities of ZnO–TiO2 films were twice higher than that of ZnO porous film, implying promising applications of this porous oxide composite for industrial and dairy farm wastewater treatment.
Photocatalytic Properties of Microwave-Synthesized TiO2 and ZnO Nanoparticles Using Malachite Green Dye  [PDF]
A. K. Singh,Umesh T. Nakate
Journal of Nanoparticles , 2013, DOI: 10.1155/2013/310809
Abstract: TiO2 and ZnO nanoparticles (NPs) were synthesized using microwave-assisted method. Synthesized NPs were characterized for their structure, morphology, and elemental composition using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The crystallite size of synthesized NPs of TiO2 and ZnO was about 12.3 and 18.7?nm as obtained from the Scherrer formula from the most intense XRD peak. The synthesized NPs have been found to be in stoichiometric ratio having anatase and hexagonal wurtzite structure for TiO2 and ZnO, respectively, and are spherical in shape. Surface area of TiO2 and ZnO NPs was found to be about 43.52?m2/g and 7.7?m2/g. Photocatalytic (PC) properties of synthesized NPs were studied for malachite green (MG) dye under UV light. TiO2 NPs were found to be highly photocatalytically active among the two, having efficiency and apparent photodegradation rate of 49.35% and , respectively. 1. Introduction Nowadays, organic pollutants like dyes are becoming a serious health problem, which are being discharged by many industries and houses through wastewater in the environment. The discharged wastes containing dyes are toxic to microorganisms and aquatic life [1]. Malachite green (MG) dye is an extensively used biocide in the global aquaculture industry. It is also used as a food colouring agent, food additive, medical disinfectant, and anthelmintic as well as in silk, wool, jute, leather, cotton, paper, and acrylic industries. However, MG has now become a highly controversial compound due to the risks it poses to the consumers of treated fish, including its effects on the immune system and reproductive system and its genotoxic and carcinogenic properties [2]. In the light of the basic and applied researches reviewed, PC oxidation method appears to be a promising route for the treatment of wastewater contaminated with phenols and dyes. In recent years, there has been a wide research interest in developing semiconductor photocatalysts having high PC activities for environmental applications such as water disinfection, hazardous waste remediation, and water purification [3–5]. It is reported that nanosize semiconductors act as an efficient PC agent resulting from either an extremely large-surface-area-to-volume ratio or quantum confinement effects of charge carriers for the degradation of organic pollutants in water under UV irradiation [6–10]. PC function is similar to the chlorophyll in the photosynthesis. In a PC system, photo-induced molecular transformation or reaction takes place at the surface of
Study on preparation and photocatalytic activity of micro/nano-structured ZnO/ S-doped TiO2 composite

张延霖 谢楚如 蔡文娟 吴宏海
- , 2016, DOI: 10.6054/j.jscnun.2015.08.021
Abstract: 采用水热法制备了ZnO纳米线与硫掺杂TiO2(ZnO/S-TiO2)微/纳复合光催化剂,通过SEM、XRD、XPS对复合光催化剂进行表征,探讨了硫掺杂量和煅烧温度对该复合催化剂光催化性能的影响。结果表明,ZnO微米线表面形成了粒径较为均一的纳米S-TiO2颗粒,硫掺杂TiO2中形成了Ti-O-S键;当硫掺杂量为0.8mol%并经500℃高温煅烧的复合光催化剂对菲的降解呈现出最好的光催化活性。
: Micro/nano-structured ZnO/S-doped TiO2 composite (ZnO/S-TiO2) has been successfully prepared by hydrothermal method. The structure and morphology of the ZnO/S-TiO2 composite were characterized by SEM, XRD and XPS. The effect of dosage of sulfur doping into titanium dioxide and calcination temperature on photocatalytic activity of ZnO/S-TiO2 composite was discussed. The result indicated that Ti-O-S bond existed and homogeneous S doped TiO2 nanoparticles could be formed on the surface of ZnO. Under the conditions of 0.8 mol% of sulfur doping and the calcination temperature of 500℃, the synthesized photocatalyst exhibited the best photocatalytic activity for degradation of phenanthrene
Nanocompósitos semicondutores ZnO/TiO2: testes fotocatalíticos
Silva, Shirley Santana;Magalh?es, Fabiano;Sansiviero, Maria Terezinha C.;
Química Nova , 2010, DOI: 10.1590/S0100-40422010000100016
Abstract: titanium dioxide is an efficient photocatalist, being possible to improve its efficiency with better charge separation which occurs when it is coupled with other semiconductors. nanometric particles of zno were used to impregnate tio2 p25 in order to optimize its photocatalytic properties. zno/tio2 composites were obtained at different proportions and were characterized by x-ray diffraction (xrd), micro-raman and diffuse reflectance spectroscopies, measurement of surface area (bet) and scanning electron microscopy (sem). raman spectroscopy data revealed a change on the tio2 surface due the presence of zno which was observed by an enlargement of tio2 peaks and a change on the relation rate between anatase and rutile phases of the composites. the photodegradation of azo-dye drimaren red revealed better efficiency for zno/tio2 3% nanocomposite and for zno pure.
Sol-Gel Synthesis of TiO2/SiO2 and ZnO/SiO2 Composite Films and Evaluation of Their Photocatalytic Activity towards Methyl Green  [PDF]
V. L. Chandraboss,B. Karthikeyan,J. Kamalakkannan,S. Prabha,S. Senthilvelan
Journal of Nanoparticles , 2013, DOI: 10.1155/2013/507161
Abstract: The TiO2/SiO2 and ZnO/SiO2 composite films were prepared by sol-gel dip coating method. The surface morphology and crystal structure of thin films were characterized by means of scanning electron microscopy (SEM) with elementary dispersive X-ray analysis (EDX) and X-ray diffractometer (XRD). Optical properties of films have been investigated using ultraviolet and visible spectroscopy (UV-visible spectroscopy). The photocatalytic activity was established by testing the degradation and decolorization of methyl green (MG) from aqueous solution with artificial UV-light. 1. Introduction Nanomaterials may provide solutions to scientific and ecological challenges in the areas of catalysis, medicine, solar energy conversion, and water treatment [1, 2]. This increasing demand must be accompanied by “green” synthesis methods. In the global efforts to decrease generated hazardous waste, “green” chemistry and chemical processes are progressively integrating with contemporary developments in science and industry. Implementation of these sustainable processes should adopt the 12 fundamental principles of green chemistry [3]. These principles are gear to guide in minimizing the use of dangerous products and maximizing the efficiency of chemical processes. Hence, any synthetic route or chemical process should address these principles by using environmentally benign solvents and nontoxic chemicals [4]. From a biological and physiological point of view, the removal of poisonous chemicals from waste water is currently one of the most important subjects in pollution control. MG is a basic triphenylmethane-type dicationic dye, usually used for staining solutions in medicine and biology [5] and as a photochromophore to sensitize gelatinous films [6]. Triphenylmethane dyes are used widely in the textile industry for dyeing of nylon, wool, cotton, and silk as well as for coloring of waxes, varnish, oil, plastics, and fats. The application of illuminated semiconductors has been effectively working for the decomposition of variety of organic contaminants in water [7]. The major organic compounds that constitute the industrial wastewater include dyes, phenols, chlorophenols, aliphatic alcohols, aromatics, polymers, and carboxylic acids. Among these, toluene, salicylic acid, and 4-chlorophenol have been identified as a water pollutant arising from numerous sources including paper milling, textile, and cosmetic industries [8], causing bad odor to the water. Hence, the destruction of organic compounds is of considerable interest. Over the years, a large number of semiconductors have
Photocatalytic degradation of reactive brilliant red K-2BP by La2O3/ZnO/TiO2

Wang Liming,Li Yan,Cheng Gang,Yao Binghua,Tong Panrui,

环境工程学报 , 2008,
Abstract: 采用溶胶-凝胶法制备了La2O3/ZnO/TiO2复合光催化剂,以紫外灯为光源,活性艳红K-2BP为模型降解物,研究了La2O3/ZnO/TiO2的光催化性能。结果表明:当锌和镧的掺杂量w(ZnO)=20%, w(La2O3)=0.5%, 煅烧温度为500℃时,La2O3/ZnO/TiO2复合光催化剂的光催化活性最高;当催化剂投加量4 g/L,通气量800 mL/min,初始pH值3.12时,La2O3/ZnO/TiO2对活性艳红K-2BP的降解效果最好。实验证明,La2O3/ZnO/TiO2对活性艳红K-2BP的降解遵从Langmuir-Hinshelwood动力学模型,测得其反应速率常数k=11.5 mg/(L·min);吸附常数K=2.88×10-2 L/mg。
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