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0 photocatalytic activity
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CONFERENCE-ARTICLE 5 Reads 0 Citations Synthesis of Copper Porphyrin into SBA-16 Walls as Catalyst for Oxidation Reacti Published: 04 November 2012
Metalloporphyrins are the most widely studied catalysts for homogeneous selective oxidation alkenes. An important area of research into their catalytic properties is associated with immobilization of the porphyrin onto a solid support, in order to make the catalyst easier to handle and to separate from the reaction medium, as well as possibly stabilize and/or modify the catalytic performance.Among the mesoporoussilicas, SBA-16 is characterized with unique pore size, high hydrothermal and chemical stability. SBA-16 has a body-centered-cubic structure (Im3m symmetry) of nearly spherical cages, in which each cage is connected with 8 neighboring cages through small openings, which facilitates diffusion and transport of various species, for these reasons they are promising candidates to be used as support for functionalization of porphyrins. The SBA-16 was synthesized in acidic medium by F127 as directing agent and Tetraethylorthosilicate as silica source, respectively and then modified by aminopropyltriethoxysilane (APTES) .The synthesis of tetrakis(4-chlorophenyl)porphyrin (TClPP) immobilized into SBA-16 ([email protected]) was performed by using ship-in-a-bottle. The characterization of synthesized materials were identified by FT-IR, UV-vis spectroscopy, XRD, nitrogen adsorption-desorption and SEM.in oxidation of cyclohexene. Oxidation of cyclohexene with tertiary butyl-hydroperoxide (TBHP) as oxidantefficientlywas catalyzed to epoxide, ketone and alcohol in presenceacetonitrile as solvent under reflax condition. The obtained products were characterized by using gas chromatography (GC). In addition, leaching and recycling experiments revealed that the catalyst can be repeatedly applied for cyclohexene oxidation for three successive cycles.
CONFERENCE-ARTICLE 4 Reads 0 Citations Application of N, S-Codoped TiO<sub>2</sub> Photocatalyst for Degradation of Methylene Blue Published: 01 November 2012
In this study, N, S- codoped titania photocatalyst was synthesized through an efficient and straight forward method using a single source, ammonium sulfate, as modification agent of titanium isopropoxide (TTIP) precursor. The catalyst was characterized by X-ray powder diffractometer (XRD), element Analysis of carbon, hydrogen, nitrogen (CHN), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), energy dispersive X-ray spectroscopy (EDX) and IR spectroscopy. Visible light photocatalytic studies were carried out using methylene blue pollutant. The photodegradation efficiency of methylene blue using N, S-codoped TiO2 were 98%. Also the degradation of methylene blue was tested using P25 photocatalyst for comparison. The result of photocatalytic degradation of methylene blue indicated that photocatalytic activity of N, S-codoped TiO2 (98%) was better than P25 (82%) photocatalyst, because the band gap of N, S-codoped TiO2 is lower than of P25 photocatalyst.
CONFERENCE-ARTICLE 4 Reads 0 Citations Degradation of Rhodamine B Using Cr-doped TiO<sub>2</sub> under Visible Light Irradiation Published: 01 November 2012
Dye pollutants produced from the textile industries are becoming a major source of environmental contamination. Traditional methods such as flocculation, carbon adsorption, reverse osmosis and activated sludge process have difficulties in the complete destruction of dye pollutants for the treatment of dye-containing. In the past decades, scientists and engineers are all interested in developing the semiconductor photocatalytic reactions. TiO2 has widely been investigated for photocatalyzed degradation of organic dyes because of its strong photoactive ability, stability, non-toxic and low cost. TiO2 photocatalyst is well known to generate various active oxygen species such as hydroxyl radicals, hydrogen peroxide, superoxide radical anions, etc. by redox reactions under UV irradiation. Anatase-type of TiO2 has highly photocatalytic activity for decomposition of various environmental pollutants in both gas and liquid phases. However, TiO2 can only utilize a small part (less than 5%) of the solar light energy for photocatalytic oxidation and the artificial UV light sources are unstable and expensive. In order to achieve photooxidation of pollutants with efficient utilization by titania particles under visible light irradiation, i.e., the band gaps must be smaller than 3.2 eV, the development of photocatalysts with high activity under visible light irradiation has been required. In attempt to devise the photocatalysts that can be operated at lower energies, the methods of modified TiO2 are ion implantation using Cr or V ions, various synthesis techniques and substitutional doping of non-metals such as N. In this study, Cr-doped TiO2 powder was prepared by sol–gel method with the aim of extending the light absorption spectrum toward the visible light region. The photocatalytic activity under visible light irradiation was evaluated using rhodamine B as a model organic compound and was carried out in a recycle fluidized bed reactor. The effects of initial acid dye concentration, particle size and loading amounts of photocatalyst were investigated.