Chitosan-based mixed matrix membranes: effect of different fillers on membrane properties and performance in hydrophilic pervaporation

Abstract

Pervaporation is still regarded as an emergent process, with a great potential to be an alternative to classical separation processes, with technical advantages. Chitosan is considered a promising material in next-generation pervaporation membranes, especially hybrid and mixed matrix membranes. This study aimed to evaluate the effect of fillers such as calcium carbonate, kaolinite, graphene, and graphene oxide, added separately at the concentration of 1 wt.%, on the mechanic and physical-chemical properties, microstructure, and hydrophilic pervaporation performance of chitosan membranes cross-linked with glutaraldehyde. The fillers influenced the mechanical and physicochemical properties of the membranes differently. Relative to the hydrophilic pervaporation tests, the presence of calcium carbonate and kaolinite increased membrane efficiency (αW/E of 1,777 and 1,225 against 611 in the control), whereas graphene reduced the permeate flux (0.341 kg·m−2·h−1 against 0.397 kg·m−2·h−1 in the control). The addition of graphene oxide increased the flux and permeability of ethanol (0.089 kg·m−2·h−1 and 8.66·10−14 kg·m−1·s−1·Pa−1 against 0.019 kg·m−2·h−1 and 1.74·10−14 kg·m−1·s−1·Pa−1 in the control), unlike the other fillers, which had no significant influence on this parameter. Thus, the membranes containing the fillers calcium carbonate and kaolinite were more suited for use in hydrophilic pervaporation (PSI of 842 and 561 against 228 in the control). Graphene did not affect membrane properties (αW/E of 398 and PSI of 127). Graphene oxide (αW/E of 174 and PSI of 72) may be considered as an alternative and starting point for the development and research of mixed matrix membranes based on chitosan to be used in target-organophilic pervaporation.