Photoinduced reduction of divalent mercury by quinones in the presence of formic acid under anaerobic conditions

Abstract

The laser flash photolysis technique (kexc = 355 nm) was used to investigate the mechanism of the HgCl2 reduction mediated by COÅÀ radicals generated from quenching of the triplet states of 1,4-naphthoqui-2 none (NQ) by formic acid. Kinetic simulations of the experimental signals support the proposed reaction mechanism. This system is of potential interest in the development of UV-A photoinduced photolytic procedures for the treatment of Hg(II) contaminated waters. The successful replacement of NQ with a commercial fulvic acid, as a model compound of dissolved organic matter, showed that the method is applicable to organic matter-containing waters without theaddition of quinones.