Donnan Dialysis Assisted by Interpenetrating Polymer Networks for Chromium Ion Transport in Aqueous Media

Abstract

Macroporous polypropylene (MPP) membranes incorporating poly[sodium (styrene sulphonate)], P(SSNa), and poly[(ar-vinylbenzyl) trimethylammonium chloride],P(ClVBTA) were modified via "in situ" radical polymerization. Modified and unmodified MPP were characterized using SEM and charge density properties. Donnan dialysis was used to transport chromium ions. The results show that the degree of modification varied between 2.5% and 4.0%, and the water uptake percentage varied between 15% and 20%. Experimental data for chromium ion transport (Cr(III) and Cr(VI)) were fitted to a mathematical model, and a correlation coefficient very close to 1 was obtained. The main parameters of this mathematical fit are k and a. These parameters report the concentration of chromium ions that converge in the Donnan equilibrium (k) and the response rate of the modified membrane (a).

Activated Polypropylene Membranes With Ion-Exchange Polymers to Transport Chromium Ions in Water

“…Currently, an increasing scientific area involves techniques to remove and recover Cr(III) and Cr(VI) using mainly membrane technologies such as a concentration gradient (Donnan dialysis, diffusion dialysis and dialysis [6,7]), a pressure gradient (ultrafiltration, nanofiltration, and reverse osmosis [8,9]), an electromotive force gradient (electrodialysis [10]), selective transport (liquid, emulsified, and supported membranes [11,12])), ion-exchange [13], precipitation [14] and adsorption [15] methods. However, the problem in using membrane technology appears when ions are of the same charge and are similar in nature or size.…”