Application of Bulk Liquid Membrane Technique for Cadmium Extraction from Aqueous Solution

摘要

The extraction of cadmium from aqueous solution using kerosene as a bulk liquid membrane (BLM) with Tri- n -butyl phosphate (TBP) as a carrier was experimentally investigated under various operating conditions. The effects of feed and strip pH, feed initial concentration, TBP concentration, and strip to feed volume ratio on the cadmium ions transport efficiency were investigated. A stripping agent EDTA was used to enhance the transport efficiency of the cadmium ions. Flax and sesame oils were also considered as green liquid membrane alternatives to kerosene. They were evaluated in terms of extraction and separation efficiency. Cadmium extraction and stripping efficiencies of 89 and 94% were, respectively, obtained under specific conditions (100 ppm initial concentration of cadmium ions, 10% (v/v) TBP concentration, (1:2) strip to feed volume ratio, feed phase pH of 3, and strip phase pH of 11). The kinetics of $$hbox {Cd}^{2+}$$ Cd 2 + transport across BLM was investigated using kinetic model derived from the kinetic law of two consecutive irreversible first-order model. Both flax and sesame oils were found less efficient than kerosene in cadmium extraction and stripping rates.