Degradation Pathways and Efficiencies of Acid Blue 1 by Photocatalytic Reaction with ZnO Nanopowder

The ZnO-mediated photocatalysis process has been successfully applied to degradation of Acid Blue 1 (AB1) dye pollutants. To obtain a better understanding, the mechanistic details of this ZnO-assisted photodegradation of the AB1 dye with low Watt UV irradiation, a large number of the photodegradation intermediates were separated, identified, and characterized by the HPLC−PDA−ESI−MS and GC−MS techniques. The degradation progresses through competitive reactions such as N-de-ethylation, destruction of the conjugated structure, hydroxylation on the benzene ring, hydroxylation on sulfonylated benzene ring, and substitution. The probable photodegradation pathways were proposed and discussed.