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Hybrid TiO2-C composites for the photodegradation of methylene blue under visible light  [PDF]
J. Matos
Boletin del Grupo Espa?ol del Carbon , 2013,
Abstract: Photodegradation of methylene blue (MB) on TiO2 in presence of activated carbons (AC) was studied. Two different lamps were employed and results were compared against those obtained on a commercial TiO2. Apparent first order rate constant for the degradation of MB was higher in presence of any AC in comparison of TiO2 alone but much higher under visible light irradiation. It can be concluded that TiO2 enhances its photoactivity by a factor up to 8.7 in the degradation of MB in presence of AC and this increase was associated with the surface properties of AC.
Optimization of preparation conditions of ZnO–SiO2 xerogel by sol–gel technique for photodegradation of methylene blue dye
R. M. Mohamed,E. S. Baeissa,I. A. Mkhalid,M. A. Al-Rayyani
Applied Nanoscience , 2013, DOI: 10.1007/s13204-012-0074-z
Abstract: The ZnO–SiO2 xerogel photocatalyst was prepared via the sol–gel technique and applied for photodegradation of methylene blue (MB) dye. The optimum conditions for preparation of ZnO–SiO2 gel is 30:70 ZnO:SiO2 molar ratio and TEOS:C2H5OH:H2O:HNO3 is 1:16:12:0.04 molar ratios at 30°C for 30 min, at these conditions the photoactivity of ZnO–SiO2 xerogel was 99% at a surface area of 500 m2/g after 60 min. The optimum loading of ZnO–SiO2 photocatalyst was 0.050 wt% that gives 99% MB dye removal efficiency after 40 min. The overall kinetics of photodegradation of MB dye using ZnO–SiO2 photocatalyst was found to be of the first order.
Preparation, characterization and photodegradation of methylene blue based on TiO2 microparticles modified with thiophene substituents
Pei Liu,Peng Zhang,DongLiang Cao,WenTing Xue
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-012-5447-x
Abstract: The new microparticles, 2-formylthiophene (FT)/TiO2 and (E)-1,2-bis(5-formyl-2-thienyl) ethylene (EBFTE)/TiO2 were synthesized with a silane coupling agent. The prepared TiO2 composites were characterized using Ultraviolet-Vis absorption (UV-Vis), X-ray diffraction (XRD), scanning electron microscope (SEM) and thermogravimetric analyzer (TGA). Methylene blue was used as a model material to examine the photocatalytic activities of the prepared catalysts under both Ultraviolet-Vis (UV) and visible (Vis) light. The enhanced photocatalytic activities were observed in the presence of (FT)/TiO2 and EBFTE/TiO2 under Vis light. It suggests that FT or EBFTE plays a block or active role in the photodegradation mechanisms under UV and Vis light irradiation, respectively.
Synthesis and highly visible-induced photocatalytic activity of CNT-CdSe composite for methylene blue solution  [cached]
Chen Ming-Liang,Oh Won-Chun
Nanoscale Research Letters , 2011,
Abstract: Carbon nanotube-cadmium selenide (CNT-CdSe) composite was synthesized by a facile hydrothermal method derived from multi-walled carbon nanotubes as a stating material. The as-prepared products were characterized by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis, transmission electron microscopy (TEM), and UV-vis diffuse reflectance spectrophotometer. The as-synthesized CNT-CdSe composite efficiently catalyzed the photodegradation of methylene blue in aqueous solutions under visible-light irradiation, exhibiting higher photocatalytic activity.
Photodegradation of Methylene Blue in a Batch Fixed Bed Photoreactor Using Activated Carbon Fibers Supported TiO2 Photocatalyst
FU Ping-feng,ZHAO Zhuo,PENG Peng,DAI Xue-gang,

过程工程学报 , 2008,
Abstract: A batch fixed bed photoreactor, using felt-form activated carbon fibers (ACF) supported TiO2 photocatalyst(TiO2/ACF), was developed to carry out photocatalytic degradation of methylene blue (MB) solution. The effects of TiO2 particle size, loaded TiO2 amount, initial MB concentration, airflow rate and successive run on the decomposition rate were investigated. The results showed that photodegradation process followed a pseudo-first-order reaction kinetic law. The apparent first-order reaction constant kapp was larger than 0.047 min-1 with half reaction time t1/2 shorter than 15 min, which was comparable to reported data using suspended Degussa P-25 TiO2 particles. The high degradation rate was mainly attributed to adsorption of MB molecules onto the surface of TiO2/ACF. The photocatalytic efficiency still remained nearly 90% after 12 successive runs, showing that successive usage of the designed photoreactor was possible. The synergic enhancement effect in combination of adsorption with ACF and photodegradation with TiO2 was proved by comparing MB removal rates in the successive degradation and adsorption runs, respectively.
Synthesis of Carbon Nanomaterials-CdSe Composites and Their Photocatalytic Activity for Degradation of Methylene Blue
Ming-Liang Chen,Ze-Da Meng,Lei Zhu,Chong-Yeon Park,Jong-Geun Choi,Trisha Ghosh,Kwang-Youn Cho,Won-Chun Oh
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/964872
Abstract: We use multi-walled carbon nanotube (MWCNT) and graphene as carbon nanomaterials to obtain carbon nanomaterilas-CdSe composites using a facile hydrothermal method. The intrinsic characteristics of resulting composites were studied by X-ray diffraction (XRD), Scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM) and UV-vis diffuse reflectance spectrophotometer. The as-prepared carbon nanomaterilas-CdSe composites possessed great adsorptivity of dyes, extended light absorption range, and efficient charge separation properties simultaneously. Hence, in the photodegradation of methylene blue, a significant enhancement in the reaction rate was observed with carbon nanomaterilas-CdSe composites, compared to the CdSe compound.
Photocatalytic Activity and Characterization of Carbon-Modified Titania for Visible-Light-Active Photodegradation of Nitrogen Oxides
Chun-Hung Huang,Yu-Ming Lin,I-Kai Wang,Chun-Mei Lu
International Journal of Photoenergy , 2012, DOI: 10.1155/2012/548647
Abstract: A variety of carbon-modified titania powders were prepared by impregnation method using a commercial available titania powder, Hombikat UV100, as matrix material while a range of alcohols from propanol to hexanol were used as precursors of carbon sources. Rising the carbon number of alcoholic precursor molecule, the modified titania showed increasing visible activities of NO photodegradation. The catalyst modified with cyclohexanol exhibited the best activities of 62%, 62%, 59%, and 54% for the total NO removal under UV, blue, green, and red light irradiation, respectively. The high activity with long wavelength irradiation suggested a good capability of photocatalysis in full visible light spectrum. Analysis of UV-visible spectrum indicated that carbon modification promoted visible light absorption and red shift in band gap. XPS spectroscopic analysis identified the existence of carbonate species (C=O), which increased with the increasing carbon number of precursor molecule. Photoluminescence spectra demonstrated that the carbonate species suppressed the recombination rate of electron-hole pair. As a result, a mechanism of visible-light-active photocatalyst was proposed according to the formation of carbonate species on carbon-modified TiO2.
Influence of H-Type and L-Type Activated Carbon in the Photodegradation of Methylene Blue and Phenol under UV and Visible Light Irradiated TiO2  [PDF]
Juan Matos, Karina Quintana, Andreina García
Modern Research in Catalysis (MRC) , 2012, DOI: 10.4236/mrc.2012.11001
Abstract: Photodegradation of methylene blue (MB) and phenol (Ph) on TiO2 in presence of H-type and L-type activated carbons (AC) was studied. Photodegradation of MB and Ph were studied under two different lamps and results were compared against those obtained on a commercial TiO2. Apparent first order rate constant for the degradation of MB was higher in presence of any AC in comparison of TiO2 alone while only in presence of ACco2-800phenol was photodegradated in shorter irradiation time than that required by TiO2. It can be concluded that TiO2 enhances its photoactivity by a factor up to 8.7 in the degradation of MB in presence of AC and this effect is associated to the specific surface properties of AC.
Effects of bismuth vandate and anthraquinone dye on the photodegradation of polycarbonate
Saron, Clodoaldo;Felisberti, Maria Isabel;Zulli, Fabio;Giordano, Marco;
Journal of the Brazilian Chemical Society , 2007, DOI: 10.1590/S0103-50532007000500005
Abstract: both inorganic and organic compounds, such as oxides or salts of metals and polycyclic and azo compounds, are frequently used as colorants in polymeric systems. bismuth vanadate pigment has been used as an environmentally friendly alternative for cadmium containing pigments and anthraquinone dyes represent a polycyclic colorant class of wide use in polymers. besides their coloring properties, both bismuth vanadate and anthraquinone present photocatalytic activity or photochemical properties that can influence the mechanism and the kinetics of the photodegradation of the polymer into which they are incorporated. in this paper the influence of bismuth vanadate pigment and anthraquinone dye on the photodegradation of polycarbonate was evaluated. for this purpose, samples of polycarbonate containing the colorants were submitted to photochemical aging following the recommendations of astm g53. bismuth vanadate accelerates the photodegradation of polycarbonate, causing a faster drop in the mechanical properties and an increase in the hydroperoxide concentration during the aging process. the coloring ability of the pigment is also affected. the photodegradation behavior of polycarbonate in presence of bismuth vanadate may be caused by a possible direct chemical reaction between pigment and polymer, promoted by uv radiation. on the other hand, the presence of anthraquinone dye seems to stabilize the polycarbonate against photodegradation through a deactivation mechanism of the excited state.
A Facile and Generic Strategy to Synthesize Large-Scale Carbon Nanotubes
Yong Hu,Ting Mei,Libo Wang,Haisheng Qian
Journal of Nanomaterials , 2010, DOI: 10.1155/2010/415940
Abstract: An easy method to prepare carbon nanotubes (CNTs) has been demonstrated using a two-step refluxing and calcination process. First, a readily available inorganic salt, Ni(NO3)2?6H2O, used as the catalyst precursor was dissolved in the high-boiling-point organic solvents (alcohols or polyhydric alcohol) by refluxing at 190°C for 3 hours. After refluxing, NiO nanoparticles obtained in the solution act as the catalyst, and the organic refluxing solvents are used as the carbon source for the growth of CNTs. Second, CNTs are prepared by calcining the refluxed solution at 800°C in an N2 atmosphere for 3 hours. Results show that CNT growth possibly originates from carbon rings, with the nanotube walls growing perpendicular to these rings and forming a closed tube at the end.
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