Phosphotungstic acid loaded mixed matrix membranes of sodium alginate karayagum for dehydration of aqueous-organic mixtures

Abstract

Novel mixed matrix blend membranes of sodium alginate (SA) / karayagum (KG) have been prepared using solution casting method by incorporating 0, 5, 10, and 15 wt. % of Phosphotungstic acid (PWA) particles and crosslinked by glutaraldehyde. These membranes have been characterized by FTIR, DSC, SEM, X-RD and used for pervaporation (PV) dehydration of isopropyl alcohol (IPA) at 30°C. The phosphotungstic acid, with its hydrophilic nature as well as its molecular sieving effect and its favourable interaction with hydrophilic SA and KG, is responsible to enhance the PV dehydration of aqueous isopropanol in terms of selectivity (α), flux (J), and pervaporation separation index (PSI). The pervaporation performance has been evaluated by varying experimental parameters such as feed composition, different polymer compositions and found to be promising membrane for separation of water- isopropanol mixtures. The results pertaining to the 15 wt% PWA loaded blend membrane SA/PW-15% had the highest selectivity 5525 which is attributed to the combined effect of molecular adhesion between PWA and SA-KG blend matrix as well as hydrophilicity. A significant improvement in PV performance is observed for PWA particles loaded membrane compared to pristine blend membrane.