Arsenic sorption onto disordered mackinawite as a control on the mobility of arsenic in the ambient sulphidic environment

Arsenate, As (V), sorption onto synthetic disordered mackinawite (FeS$_{\rm am}$) follows Langmuir-type behaviour. As (V) is not reduced prior to or during sorption. Arsenite, As(III) sorption can be expressed by a Freundlich isotherm. Comparison of the experimental sorption isotherms to field data describing the mobility of arsenic in a Bangladesh aquifer shows that arsenic mobility may be controlled by As(V) sorption onto FeS$_{\rm am}$ in the aquifer sediment