Liquid–liquid extraction of mercury (II) from hydrochloric acid solutions by Aliquat 336

The liquid–liquid extraction of mercury (II) from hydrochloric acid solutions using Aliquat 336 (tri-octyl methylammonium chloride) as extractant dissolved in commercial kerosene Exxsol D-80 has been investigated in this paper. In the organic phase, 1-octanol (15% v/v) has been added as modifier agent to avoid the formation of a third phase. The study was carried out at room temperature (25 ± 1) °C and aqueous/organic volumetric ratio of unity. The reactive system showed very fast extraction kinetics and mercury was quantitatively extracted within 5 min at pH ≥ 1. The analysis slope method has been used to evaluate the experimental behaviour of chloride ions and extractant concentrations on the mercury extraction with Aliquat 336. An equilibrium model has been proposed for this reactive system and equilibrium coefficients valid for the operational conditions investigated in this study were determined numerically by data fitting. Mercury was stripped out satisfactorily using thiourea as stripping agent.