Investigation Of Separability Of DMC/Methanol Azeotropic Mixtures By Chitosan Hybrid Membrane

Abstract

Dimethyl carbonate (DMC) is a green solvent, environment friendly fuel additive. It is produced by carbonylation of methanol The production cost of DMC is very high by conventional process. Because DMC and methanol forms azeotrope and can not separated by distillation. Its separation can be made by pervaporation (PV) economically. Pervaporation (PV) is an environment friendly membrane process also in which liquid-liquid mixtures are separated under vacuum with high selectivity. Pervaporation selectivity is dependent to sorption selectivity and diffusion selectivity. Membrane used in pervaporation process is a semi-permeable barrier and provides selective separation and transport. In PV development of an appropriate membrane material is important for obtaining pure substances. Hydrophilic membrane can separate methanol that is a polar component. Chitosan is a harmless, biosoluble, natural polymer and has hydrophilic property. But it does not resist to aqueous conditions. Therefore it should be modified by crosslinking. Tetraethoxysilan (TEOS) and tungstophosphoric acid (TPA) can be used as crosslinking agent and additive blending component in membrane production for increasing chemical and mechanical stability. In this study, sorption tests were carried out to determine the usability of chitosan-tetraethoxysilan (TEOS) and chitosan-Tungstophosphoric acid (TPA) hybrid membranes in separation of DMC-Methanol mixture with PV.