Chemistry of Superoxide Ion-Radical (O2(-)) in Seawater. I. pKasw (HOO) andUncatalyzed Dismutation Kinetics Studied by Pulse Radiolysis

摘要

Experimental data establish that uncatalyzed O2(-) dismutation in chelatedseawater behaves qualitatively and quantitatively much as it does in freshwater. The data also reveal that in some waters other processes are more important; whether and when uncatalyzed dismutation controls O2(-) chemistry in ocean environment remains to be resolved. This issue, rather than the 2.5-4-fold difference in second-order behavior between Millero's estimates and our data, is most likely to exert the major control on rates and reactions of O2(-) in coastal and even oligotrophic systems. If only trace species with low formation fluxes capable of reacting irreversibly with O2(-) are present (X or Y reactants), there may be a progression from irreversible redox reactions of O2(-) consuming these X and Y species in the morning, followed by transition to dismutation-dominated