Evaluation of the selectivity of two anion exchange membranes for selective separation of an organic acid

Abstract

Membrane separation processes present some features that make them attractive for different applications, such as wastewater treatment of several industrial segments. However, there are some restrictions that need to be overcome in order to improve the systems efficiency. In the past years, novel ion-exchange membranes for specific electrodialysis applications have been developed. Among them, it is possible to mention the monovalent-ions selective membranes, the bipolar membranes and the membranes suitable for the transport of organic ions, which are the object of this study. The selective separation of organic ions using specific membranes has been recently studied, but its selectivity performance is not fully understood. This study proposes to investigate the transport of two competing anions (one inorganic and one organic) through an anion exchange membrane suitable for the transfer of medium size organic anions. The objective of the study is to determine quantitatively the conditions that allow higher selectivity for the organic anions and the total separation rate. The results will be compared to an ion-exchange membrane designed for general applications. Tests will be performed in a three-compartment cell, using solutions containing different inorganic:organic ratios. The results will be analyzed in terms of percent extraction, total demineralization ratio and by means of the calculation of the separation factor. (AU)