Supported TiO2solar photocatalysis at semi-pilot scale: degradation of pesticides found in citrus processing industry wastewater, reactivity and influence of photogenerated species

Abstract

BACKGROUND Thiabendazole, imazalil and acetamiprid, pesticides found in wastewater in the citrus fruit processing industry, are recalcitrant to biological treatments. This study deals with the preparation of TiO2 supported on glass beads and its use as a photocatalyst in a compound parabolic collector (CPC) solar reactor for the elimination of a mixture of these pesticides (100 µg L−1 each) in different water matrices. RESULTS The TiO2 supported catalyst prepared exhibited good mechanical stability and photocatalytic activity with acetaminophen as the test compound, even in complex matrices. Imazalil degradation was complete, regardless of the type of water, but strong influence of the matrix was oberved in the photocatalytic degradation of thiabendazol and acetamiprid. CONCLUSIONS The TiO2-coated glass spheres showed good performance after five cycles in a real municipal wastewater treatment plant (MWWTP) secondary effluent. Both the type of water and the nature of the pollutant play an important role in photocatalytic degradation efficiency. The main photogenerated species involved in the photocatalytic degradation of each pesticide in distilled water were identified. © 2013 Society of Chemical Industry