Kinetics of absorption of hydrogen sulfide into aqueous Fe(III) solutions

In our recent studies, absorption of H₂S into the aqueous Fe₂(SO₄)₃ and FeCl₃ solutions with various values of ionic strength and pH was investigated in an agitated vessel with a flat interface. The experimental results for both systems revealed that the species which reacts with H₂S is FeOH²⁺. The absorption rates were explained by the theory of gas absorption with an irreversible (l,l)-th order reaction between H₂S and FeOH₂₊. The reaction rate constants were independent of the ionic strength of the solution and correlated as a function of temperature. In this paper, kinetics and mechanism of these absorption reactions are reviewed and the identity for both systems is emphasized.