Copper(II) Removal from Synthetic Wastewater Solutions Using Supported Liquid Membrane and Polymer Inclusion Membrane

Abstract

The application of supported liquid membranes (SLMs) and polymer inclusion membranes (PIMs) for the transport of Cu(II) in a continuous extraction–re-extraction system using di-(2-hethylhexyl) phosphoric acid (D2EHPA) as carrier was examined. The SLM was prepared by soaking a support in D2EHPA-chloroform solution. Furthermore, a PIM was prepared by casting solution containing cellulose triacetate (CTA) as polymer, acetylated kraft lignin as filler, and 40% by weight D2EHPA as carrier and without added plasticizer. Lignin was incorporated into PIMs to enhance the mechanical properties of CTA in acidic media. Transport of Cu(II) ions through SLMs and PIMs was determined. The effect of feed pH, HNO3 concentration in strip phase, and D2EHPA concentration in membrane phase were studied. The optimum conditions to transport more than 68% of Cu(II) are, feed pH=4.5, HNO3 0.5 M in strip phase and 30% (v/v) of D2EHPA concentration in membrane phase. In the same initial conditions, the PIM containing 40% by weight D2EHPA assured the transport of 74% of Cu (II). The transport of Cu(II) through the SLM and PIM was investigated by evaluating the initial fluxes through the membranes, the recovery efficiency of each, and their stability after many cycles. The experiments demonstrated that the prepared PIM has better performance than the SLM, as proved by a better initial flow, better recovery efficiency, and higher stability. We also confirmed that the interdiffusion of Cu(II) through the PIM followed a kinetic law of first order.