Facilitated transport of lead(II) and cadmium(II) through novel activated composite membranes containing di-(2-ethyl-hexyl)phosphoric acid as carrier

This paper describes an approach to the chemical characterisation of the fa cilitated transport of lead(II) and cadmium(II) by an activated composite m embrane (ACM) containing immobilised di-(2-ethyl-hexyl)phosphoric acid (DEH PA). Such membranes were prepared, by interfacial polymerisation and charac terised physically and chemically. The ACMs were used to experimentally determine their transport behaviour fo r Pb(II) and Cd(II). So, the influence of some chemical parameters (i.e. DE HPA concentration on the ACM, the feed solution composition, the concentrat ion of nitric acid in the stripping solution, and the ionic strength of the feed and stripping aqueous solutions) was assayed for each metal ion. A correlation of the chemical behaviour of those ACM systems with the physi cal characterisation of those membranes, prior to and after their use, is r eported. The optimum chemical conditions for Pb(II) and Cd(II) transport en hance the lifetime of the ACMs, giving higher DEHPA immobilisation on the p olymeric phase of the composite membrane. (C) 2000 Elsevier Science B.V. Al l rights reserved.