Photocatalysts and Photoreactors for Treatment of Industrial Effluents

Abstract:

Development of photocatalysts and photoreactors for treatment of industrial effluents is considered important to harness solar energy for environmental clean up. The photocatalytic method of decolorization of textile dyes utilizes UV component of sunlight (3-5%) and the only solid phase (TiO₂ catalyst) can be recycled on a technical scale. Moreover, the method does not produce any sludge unlike adsorption and coagulation methods. These attributes of the photocatalytic method are attractive for possible application in industry. Our group is presently working on pilot scale photoreactors and exploring feasibility of industrial application of this technique. We have developed a few TiO₂ based photocatalysts (P-25 TiO₂, ZnO, TiO₂ (bulk) and rare earth metal (In₂O₃, Nd₂O₃, Yb₂O₃ and Sm₂O₃) doped TiO₂), photo catalyst bearing supports (e.g., acrylic sheet) and photoreactors (annular immersion well type, falling film type and shallow slurry photoreactors) for use with UV & sunlight. We have carried out a few tests with Solar Slurry Photoreactor (SSPR) in field using actual textile wastewater with encouraging results. The SSPR developed under this study was capable of decolorizing textile wastewater under specified conditions approximately with a treatment rate of 9.0 Lh^-1. The reactor area exposed to sunlight was approximately 1 m². Thus, a reactor having 18-20 m² exposed area would treat about 1.0 m³ textile wastewater at a rate approximately equal to180 Lh^-1. The present data suggest that it may be possible to apply this technique initially for the color treatment of textile wastewater from small dyeing operations. However, the details of techno-economic feasibility need to be assessed beforehand. The proposed book chapter would present details of all the above-mentioned efforts. It would be targeted to bring out inadequacies associated with the photocatalytic technology for wastewater treatment.

• Periodical: Materials Science Forum (Volume 712)
• Pages: 191-217
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.712.191
• Online since: February 2012
• Authors: Nageswara Rao Neti
• Keywords: Industrial Effluents, Photocatalyst, Photoreactors, Treatment

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