Comparison of the dehalogenation of dihalomethanes (CH 2XI, where X = Cl, Br, I) following ultraviolet photolysis in aqueous and NaCl saltwater environments

Abstract

The ultraviolet photolysis of low concentrations of CH 2XI (X = Cl, Br, I) were investigated in water and saltwater solutions by photochemistry and picosecond time-resolved resonance Raman spectroscopy. Photolysis in both kinds of solutions formed mostly CH 2(OH) 2 and HI and HX products. However, photolysis of the CH 2XI molecules in saltwater resulted in production of some CH 2XCl products not observed in aqueous solutions without salt present. The appearance of these new products in saltwater solutions is accompanied by a decrease in the amount of CH 2(OH) 2, HI, and HX products compared to photolysis in aqueous solutions without salt present. The possible implications for photolysis of CH 2XI and other polyhalomethanes in seawater and other salt aqueous environments compared to nonsaltwater solvated environments is briefly discussed. © 2005 American Chemical Society.