Removal of Metal Ions from Aqueous Solution Using Trioctyl Phosphine Oxide-Containing Mixed Solvents in Conjunction with a Fibre-Supported Solid Membrane

Abstract

A novel method has been developed for the removal of mercury, arsenic and tin ions using a fibre-supported solid membrane placed between the source phase and the receiving phase which contained trioctyl phosphine oxide (TOPO) in a mixed solvent. The fibre-supported solid membrane was prepared by the esterification of cellulose fibre with tartaric acid at 120 °C. The experimental variables explored were the initial concentration of the metal ion (10-2 to 10-4 M) in the source phase, the type of mixed solvent employed [containing TOPO, TOPO + acetone, TOPO + tetrahydrofuran, TOPO + 1,4-dioxane, TOPO + methanol, TOPO + ethanol or TOPO + 2-propanol (20-80% v/v)], the concentration of HCl (0.25-1 M) in the receiving phase and the stirring speed (50-130 rpm) of the bulk source and the receiving phase. The efficiency of the organic solvent in the mixed solvent followed the order: TOPO + tetrahydrofuran > TOPO + 1,4-dioxane > TOPO + acetone > TOPO + 2-propanol > TOPO + ethanol > TOPO + methanol > TOPO. The separa...