Synthesis and Characterization of Biopolymeric Blend Membranes Based on Sodium Alginate for the Pervaporation Dehydration of Isopropanol/Water Mixtures

Synthesized graft copolymers of hydroxyethylcellulose and acrylamide (HEC‐g‐AAm) were prepared by solution polymerization method. The grafting reaction was confirmed by Fourier transform infrared spectroscopy and differential scanning calorimetry. The graft copolymers were blended in different ratios with sodium alginate (NaAlg), and the membranes were prepared by the solution casting method. The resulted membranes were then crosslinked with glutaraldehyde (GA) in acetone‐water medium. Swelling experiments were performed on the blend membranes in water‐isopropanol mixtures at 30°C. Pervaporation experiments were performed at 30°C for the feed mixtures ranging from 10–50 wt.% of water in water‐isopropanol mixtures. Flux and selectivity of the membranes increased with an increasing amount of HEC‐g‐AAm copolymers in the blend membrane. The membrane NaAlg/HEC‐g‐AAm‐30 appears to have a good potential for dehydrating 10 wt.% water with a high selectivity of 2036 and a substantial water flux of 1.036 kg/m2 · h. Flux increased with increasing amount of water in the feed, but selectivity decreased considerably.