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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.
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.
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.
Preparation and Photocatalytic Activity of Magnetic Fe3O4/SiO2/TiO2 Composites  [PDF]
Rijing Wang,Xiaohong Wang,Xiaoguang Xi,Ruanbing Hu,Guohua Jiang
Advances in Materials Science and Engineering , 2012, DOI: 10.1155/2012/409379
Abstract: A simple sol-gel method was used to prepare magnetic Fe3O4/SiO2/TiO2 composites with core-shell structure. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM) have been applied to investigate the structure and morphology of the resultant composites. The obtained composites showed excellent magnetism and higher photodegradation ability than pure TiO2. The photocatalytic mechanism was also discussed. The magnetic composites should be extended to various potential applications, such as photodegradation, catalysis, separation, and purification processes. 1. Introduction Currently, there has been great interest in the preparation of core-shell micro- and nanoparticles for their widespread potential applications in catalysis, chromatography separation, drug delivery, chemical reactors, and protection of environmentally sensitive materials [1–4]. Heterogeneous photocatalysis using semiconducting oxide catalysts is an effective way to purify wastewater or gas. TiO2-based semiconductors have attracted considerable attention due to their high efficiency, good stability, availability, and nontoxicity [5–9]. In recent years, in order to enhance the photocatalytic activity, great efforts have been made to prepare ideal structure of TiO2-based semiconductors [10–12]. Magnetic separation provides a very convenient approach for removing and recycling magnetic composites by applying an added magnetic field. The incorporation of Fe3O4 magnetic particles into TiO2 matrix may block the aggregation of nanoparticles during renewal and can increase the durability of the catalysts [13, 14]. Moreover, such catalysts have a high surface area and well-defined pore size, which enhance their photocatalytic activity [15]. However, magnetic nanoparticles would inescapably encounter an hindrance when applied in practice due to the fact that a photocatalytic reaction is conducted in a suspension. It is not allowed to use magneton to agitate the mixed solutions. Therefore, in the experiment, Ar gas is purged so as to make the magnetic particles suspend in the methylene blue (MB) solution. Many efforts have been made in the development of the design and preparation of magnetic core-shell microspheres. Ye et al. and Yu et al. reported the magnetic material/SiO2/TiO2 composites with core-shell-shell structure [16, 17]. Their methods involve superparamagnetic Fe3O4 and γ-Fe2O3 with an inner layer of SiO2 and outer layer of TiO2 [18, 19]. Their resultant samples exhibit
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.
Photodegradation of bromophenol blue with fluorinated TiO2 composite
L. N. Dlamini,R. W. Krause,G. U. Kulkarni,S. H. Durbach
Applied Water Science , 2011, DOI: 10.1007/s13201-011-0004-3
Abstract: Fluorinated TiO2 composites were prepared by the sol–gel method. The photocatalytic activities of the composites were evaluated with bromophenol blue (BPB). Composites which contained carbon nanotubes showed the highest photodegradation (98%) of BPB at 20 min as compared to pure TiO2. Photodegradation by-products of BPB such as Br and [SO4]2 ions were monitored with ion chromatography. All catalysts were characterized with microscopic techniques, including transmission electron microscopy and scanning electron microscopy which were both equipped with an energy dispersive X-ray spectrophotometer. The polymorph of TiO2 was verified by the use of Raman spectroscopy and powder X-ray diffraction.
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.
Facile method to synthesize magnetic iron oxides/TiO2 hybrid nanoparticles and their photodegradation application of methylene blue  [cached]
Wu Wei,Xiao Xiangheng,Zhang Shaofeng,Ren Feng
Nanoscale Research Letters , 2011,
Abstract: Many methods have been reported to improving the photocatalytic efficiency of organic pollutant and their reliable applications. In this work, we propose a facile pathway to prepare three different types of magnetic iron oxides/TiO2 hybrid nanoparticles (NPs) by seed-mediated method. The hybrid NPs are composed of spindle, hollow, and ultrafine iron oxide NPs as seeds and 3-aminopropyltriethyloxysilane as linker between the magnetic cores and TiO2 layers, respectively. The composite structure and the presence of the iron oxide and titania phase have been confirmed by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectra. The hybrid NPs show good magnetic response, which can get together under an external applied magnetic field and hence they should become promising magnetic recovery catalysts (MRCs). Photocatalytic ability examination of the magnetic hybrid NPs was carried out in methylene blue (MB) solutions illuminated under Hg light in a photochemical reactor. About 50% to 60% of MB was decomposed in 90 min in the presence of magnetic hybrid NPs. The synthesized magnetic hybrid NPs display high photocatalytic efficiency and will find recoverable potential applications in cleaning polluted water with the help of magnetic separation.
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.
M. Zendehdel,Z. Kalateh,H. Alikhani
Iranian Journal of Environmental Health Science & Engineering , 2011,
Abstract: In this study titanium dioxide cluster was incorporated onto NaY zeolite and characterized with X-Ray diffractometer and X-ray spectroscopy. These composites have many advantages such as high stability and high porosity. The adsorption behavior of methylene blue was investigated for NaY zeolite and TiO2/NaY zeolite. The efficiency of time, pH, temperature and initial concentration of methylene blue (MB) on removal effect of methylene blue was investigated by UV-Vis spectroscopy. And, the optimum conditions were determined 8h time, basic pH and high initial concentrations of methylene blue and absorbent. With increasing of temperature, the removal efficiency of NaY zeolite and TiO2/NaY increased. Results showed that 92% and 85% of methylene blue was absorbed by synthesized NaY zeolite and TiO2/zeolite, respectively. Adsorption isotherm as studied by fitting data to Langmuir and Freundlich isotherms models, showed monolayer adsorption and Langmuir equilibrium model to be more relevant.
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