Effect of inorganic ions on the photocatalytic treatment of agro-industrial wastewaters containing imazalil

Abstract

In this work we studied the elimination, mineralization and detoxification of wastewaters from banana postharvest industries, contaminated with the fungicide imazalil, by means of heterogeneous advanced oxidation processes. We compared the activity of the commercial photocatalyst Evonik P25 and the lab-made EST-1023t in the degradation of imazalil in deionized water and in industrial wastewater. Results show an important negative water-matrix effect for wastewater treatment at acidic pH values due, mainly, to the presence of ions adsorbed onto the TiO2 photocatalyst surface. At pH 7 only bicarbonate anions and bacteria hindered the degradation and mineralization of imazalil. Mineralization of imazalil was completely inhibited by dissolved aluminium in concentrations as low as 5 mg L−1.