291930 Comparison of Photocatalytic Activity Under UV and Visible Light Radiation of InVO4-TiO2 and TiO2 Catalysts
Water is a vital natural resource. To develop more sustainable water systems, we must focus efforts on the removal of persistent contaminants. Common aqueous organic contaminants include dyes, pesticides, herbicides, and algal and cyanobacterial metabolites. Oxidation methods, utilizing chlorine, hydrogen peroxide, and potassium permanganate, have been employed with varying levels of efficacy for removal of these and other organic contaminants. Advanced Oxidation Processes, including ozonation and photocatalysis, have greater potential than traditional methods due to their (i) ability to removal pollutant at a considerable rate, (ii) ability to degrade a variety of organic material and (iii) ability to completely mineralize compounds [Crittenden, J., et al., Water treatment : principles and design / MWH, Inc. ; revised by John C. Crittenden ... [et al.]. 2nd ed. ed. 2005, Hoboken, N.J: J. Wiley.].
TiO2 is an effective, inexpensive, and stable photocatalyst used for the decomposition of organics. However, only the ultraviolet portion of the solar irradiation (~4% of the incoming solar energy on the earth’s surface) is absorbed by TiO2 due to its high band gap (3.0-3.2 eV). Several methods have been attempted to move the photo-initiation into the visible spectrum. This project is innovative because it will to use the indium vanadate semiconductor, InVO4, mechanically alloyed to TiO2, to shift photo-initiation into the visible range.
The long term goal of the proposed research is to develop a commercially viable visible range photocatalytic oxidizer (PCO) for the decomposition of organics in aqueous systems. The specific objective of this study was to determine the photocatalytic activity of a coupled indium vanadate – titanium dioxide (InVO4-TiO2) and of a titanium dioxide (TiO2) catalyst for decomposition of methyl orange under ultraviolet and visible spectrum light irradiation.
Photocatalytic reactions were carried out in a 1 liter pyrex reactor at atmospheric pressure and ambient temperature. UV-Vis Spectrometry was utilized to monitor methyl orange concentration (peak absorbance at 460 nm). As the reaction proceeds, the methyl orange absorbance peak decays over time. At these low concentrations, this absorbance is linearly proportional to the decrease in concentration of methyl orange in solution.
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