Pervaporation characteristics of polyelectrolyte complex gel membranes based on two anionic polysaccharides having a chelating structure

Polyelectrolyte complex (PEC) membranes, based on two anionic polysaccharides, composed of sodium alginate (SA) and carrageenan (CG), were prepared by interaction with divalent calcium ions. By using FT-IR, XRD, and DSC, their structural characteristics were analyzed, suggesting a morphological deformation with a chelate formation between them. As a result, it can be considered that the chelation of calcium ions would interfere in the intermolecular hydrogen bonding interaction between SA and CG. Moreover, to investigate the permeation properties related to their structural characteristics, pervaporation separation for an 85/15 wt% ethanol/water mixture was carried out. These membranes showed approximately the following pervaporation performance: permeation flux of 94–253 g/m2 h and ethanol concentration in the permeate of 0.26–0.52 wt% at 40 °C.