Preparation and pervaporation characteristics of novel polyelectrolyte complex membranes containing dual anionic groups

Abstract

Novel polyelectrolyte complexes (PECs) based on dual anionic group copolymers were prepared and their homogeneous membranes were subjected to pervaporation dehydration of acidic feed. Dual anionic copolymers containing weakly charged acid groups (COO − ) and strongly charged acid groups (SO 3 − ), poly(sodium acrylate-co-sodium sytyrenesulfonate) (P(AANa-co-SSNa)), with different compositions were synthesized by radical solution polymerization. SPECs (PECs containing SO 3 groups) consisted of negatively charged P(AANa-co-SSNa) and positively charged chitosan (CS) and their homogeneous SPEC membranes (SPECMs) with tunable compositions were prepared. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure and composition of P(AANa-co-SSNa) and its SPECs. Field emission scanning electron microscopy (FESEM) and contact angle (CA) were used to survey surface properties of SPECMs. Effects of pH values and temperatures of feed mixtures on the swelling behavior and pervaporation dehydration performance of SPECMs were examined. It is found that SPECMs containing SO 3 groups are resistant of acidic feed and display very good pervaporation performance even for the low pH feed. For instance, the water concentration in permeate for SPECM−0.30 reaches as high as 99.4 wt%, which is much higher than 60 wt% for PECM for water–isopropanol mixture with pH 1.2, and also maintains operation stability. The SPECMs could find considerable potential application to pervaporation dehydration of acidic feed. ▸ Synthesis of a novel polyelectrolyte complex (SPEC) and its SPECMs using dual anionic copolymers. ▸ SPECMs containing SO 3 groups show better stability compared to PECM in acidic feed. ▸ SPECMs exhibit very good pervaporation performance at the low feed pH.