Nondispersive liquid-liquid extraction of copper and zinc from an aqueous solution by DEHPA and LIX 984 in a hollow fiber membrane module

A liquid-liquid extraction procedure was used to study the amounts of Zn2+ and Cu2+ that could be simultaneously extracted from aqueous solution with di(2-ethylhexyl) phosphoric acid (DEHPA) and LIX 984 diluted with n-heptane at equilibrium. LIX 984 is a 1:1 volume blend of LM 860 (5-dodoecylsalicylaldox.ime) and LM 84 (2-lnydroxy-5-nonylacetophenone oxime). At equilibrium, a 0.3 mom DEHPA-20% (v/v) LIX 984 solution extracted 99% of both the zinc and copper from a solution that had 100 ppm of each metal. A polysulfone hollow-fiber membrane module with 1 mm KD and 5,000-molecular weight cutoff was used to study the amounts of Zn2+ and Cu2+ that could be simultaneously extracted with a mixture of DEHPA and LIX 984. The aqueous and organic streams were operated at 100% recycle. With a 0.6 mol/L DEHPA-10% (v/v) LIX 984 solution, a 90.5 +/- 1.7% (s.d.) extraction of zinc and a 93.70 +/- 0.79% (s.d.) extraction of copper was obtained after 180 min.