Evaluation and modelling of dissolved organic matter reactivity toward As(III) and As(V) – implication in environmental arsenic speciation.

摘要: Abstract Many studies have been carried out to identify dissolved organic matter–trace metals interactions, as matter (OM) was demonstrated be a governing parameter of speciation. Concerning arsenic (As), such OM–As are scarce and concluded that, when As binding occurred, it probably through cationic bridges or, in some cases, directly. Yet, analytical proofs remained complex obtain. In this work, with Suwanee River Humic Acid (SRHA), an example matter, studied, considering both III V , at various pH absence/presence Na Ca. Dialysis, fluorescence measurements PHREEQC modelling were performed characterize the mechanisms work for experiments. It observed that on SRHA occurred direct SRHA–As neither nor Ca presence modify mechanism. appeared also bound by interaction, but suffered from competition sites. Oppositely, Ca, overall –SRHA significantly enhanced, acting efficient bridge formation SRHA–Ca–As ternary complex. All obtained data satisfactorily simulated using unique set parameters which can therefore implemented any speciation code better address behaviour environmental conditions.