Photocatalytic and photolytic transformation of chloramben in aqueous solutions

The photocatalytic degradation of chloramben (3-amino-2,5-dichlorobenzoic a cid) was investigated in aqueous solutions containing TiO2 suspensions unde r irradiation with simulated solar light. The primary degradation of the he rbicide, the mineralisation of the organic carbon to CO2 and the formation of chloride ion from organic chlorine proved to be relatively fast, whereas the conversion of organic nitrogen into ammonium and nitrate ions took pla ce only at delayed irradiation times. Photolytic degradation processes prov ed also to be active in the examined time interval, but they were far from producing complete mineralisation, leaving considerable amounts of residual organic products. Various aromatic intermediates that originated from chlo ramben during the photocatalytic treatment were detected and identified usi ng GC-MS. Similarly, the main aromatic products arising from photolytic dec omposition were also identified, and, in rum, they proved to undergo comple te mineralisation upon addition of TiO2. (C) 1999 Elsevier Science B.V. All rights reserved.