Photocatalytic degradation of carbaryl in aqueous solutions containing TiO2 suspensions

The photocatalytic degradation of carbaryl in aqueous TiO2 dispersions irradiated with simulated solar light was investigated. Complete mineralization of the pesticide to CO2 was observed, with the formation of nitrate and ammonium ions as nitrogen-containing end products. Various aromatic intermediates, detected during the process, were identified using HPLC and GC-MS techniques, and their kinetic evolution was also investigated. The formation of the transient compound 1,3-indandione, more persistent than carbaryl, was observed. From obtained analytical and kinetic data, a possible reaction scheme was proposed.