Solvent extraction of mercury(II) from nitric and hydrochloric acid solutions by dihexyl sulfide

The solvent extraction of mercury(II) from nitric acid and hydrochloric aci d solutions by dihexyl sulphide (DHS, R2S) in benzene has been investigated under different conditions. The organic extracts were examined by infrared and Raman spectroscopies. As a result, the following equilibrium equations are proposed for the extraction of mercury (II) by DHS: from nitric acid s olutions, Hg(NO3)(2)(a) + mHNO(3)(a) + 2R(2)S(o) reversible arrow (R2S)(2)H g(NO3)(2)(HNO3) (m)(o). where m = 0 and 1 are satisfied at [HNO3] < 4 mol d m(-3) and <greater than or equal to> 4 mol dm(-3), respectively, in which ( a) and (o) represent the aqueous and organic phases, respectively. The equi librium equation, Hg (NO3)(2)(a) + mHNO(3)(a) + R2S(o) reversible arrow R2S . Hg(NO3)(2)(HNO3) (m)(o), is expected at a higher loading of mercury; fro m hydrochloric acid solutions, HgCl2(a) + 2R(2)S(o) reversible arrow (R2S)( 2)HgCl2(o), and when mercury loading increases, HgCl2(a) + R2S(o) reversibl e arrow R2S(o) reversible arrow R2S . HgCl2(o).