Sunlight photo-assisted TiO2-based pilot plant scale remediation of (simulated) contaminated aquatic sites

Abstract

A tubular-type solar photoreactor system powered by commercial solar panels and consisting of six 20-tube modules (Pyrex glass) to mimic a pilot plant scale configuration was designed and constructed to examine the remediation of simulated wastewaters contaminated with various classes of organic pollutants such as endocrine disruptors (e.g. bisphenol A), anionic surfactants (sodium butylnaphthalenesulfonate and sodium dodecyl- benzenesulfonate), herbicides (e.g. 2,4-dichlorophenoxyacetic acid) and a commercial dishwasher detergent. Photo-oxidative processes followed fi rst-order kinetics expressed in terms of the total light energy (in kJ) that impinged on the photoreactor. The infl uence of TiO2 loading and circulation fl ow rate of the wastewaters on the dynamics of the photo-oxidation to mineralization (loss of total organic carbon, TOC, or formation of sulfate ions) was investigated. The optimal operational parameters were: TiO2 loading, 2 g L-1; circulation fl ow rate, 7.5 L min-1. On a sunny day, near- quantitative mineralization of the contaminants was achieved after only 4 h of irradiation that corresponded to an accumulated energy of ca 1380 kJ. © 2010 by Japan Oil Chemists' Society.