Separation of silver(I) and copper(II) by polymer inclusion membranes with aza[18]crown-6 derivatives as ion carriers

In the presented work, we analyzed transport properties of novel polymer inclusion membranes (PIMs) containing a cellulose triacetate polymer matrix, o-nitrophenyloctyl ether as plasticizer and macrocyclic exchangers N-(diethylthiophosphoryl)-aza[18] crown-6 and N-(diethyloxophosphoryl)-aza[18] crown-6 as specific carriers toward silver(I) ions. The study was specifically focused on the transport properties of Ag(I) at conditions simulating industrial wastewaters. We analyzed the impact of several parameters on Ag(I) transport process such as: the carrier content in the PIM and strip phases composition. We concluded that efficient transport processes occur through a PIM containing 0.25 M of crown ethers. The process was very fast and efficient for solutions of initial silver concentration smaller than 10-3 mol L-1, for which nearly all of silver was removed within 6 h. The performed experiments proved that Ag(I) transport through the membrane was a facilitated counter-transport process. Additionally, it possessed an excellent long-term integrity and a high selectivity for Ag(I) from Cu(II) ions.