Title: Degradation of phenolic wastewaters by solar/TiO₂ and solar/TiO₂/H₂O₂ processes

Authors: S. Adishkumar; S Kanmani

Addresses: Department of Civil Engineering, Centre for Environmental Studies, Anna University, Chennai 600025, India. ' Department of Civil Engineering, Centre for Environmental Studies, Anna University, Chennai 600025, India.

Abstract: The application of Advanced Oxidation Processes (AOPs) (solar/TiO2 and solar/TiO2/H2O2) to treat phenol, o-cresol, m-cresol, and p-cresol wastewaters was investigated. The experiments were performed in batch solar reactor using TiO₂ as catalyst. The effect of the hydrogen peroxide concentration on the degradation kinetics was evaluated in the range of 0.15–1.5 g/L. It was observed that the degradation rate increased as the hydrogen peroxide increased, but excessive H₂O₂ concentration was detrimental. The rate of degradation is two to three times faster in solar/TiO₂/H₂O₂ process when compared with solar/TiO₂ process. In the presence of inorganic salts, the phenol removal was 19% and 90% in solar/TiO₂ and solar/TiO₂/H₂O₂ process, respectively. For untreated samples of 100 mg/L the BOD/COD ratio is 0, while solar photocatalytic treatment of 1 h permits its enhancement up to values near 0.66 and 0.57 for m-cresol and o-cresol; for phenol and p-cresol the values were nearer to 0.53 and 0.65 after 2 h and 3 h phototreatment respectively, which represent considerable biodegradability of wastewaters.

Keywords: solar photocatalysis; TiO2; titanium dioxide; advanced oxidation process; hydroxyl radicals; phenol wastewaters; H2O2; hydrogen peroxide; inorganic salts; biodegradability; wastewater treatment; batch solar reactors.

DOI: 10.1504/IJEWM.2012.044167

International Journal of Environment and Waste Management, 2012 Vol.9 No.1/2, pp.169 - 180

Published online: 13 Dec 2014 *

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