Dehydration of 1,4-dioxane by pervaporation using modified blend membranes of chitosan and nylon 66

Abstract

The pervaporation separation of 1,4-dioxane/water mixtures was carried out using crosslinked blend membranes of chitosan (CS) and nylon 66 (NYL). These membranes were characterized by FTIR, TGA, XRD, and tensile strength to assess intermolecular interactions, thermal stability, crystallinity and mechanical strength, respectively. Sorption studies were carried out in pure liquids and binary mixtures of different compositions to evaluate polymer–liquid interactions. The effects of CS/NYL ratio, membrane thickness, feed concentration on the transmembrane permeation rate and separation factor were investigated. Optimum CS/NYL ratio was determined as 90/10 (w/w) for 4.3 wt% feed water concentration at 40 °C. Increasing barrier from 30 to 120 μm improved the separation factor from 767 to 1123 at the cost of flux, which lowered from 0.118 to 0.028 kg/m 2 h. The membrane performance was also investigated for the separation of various feed compositions of 1,4-dioxane–water mixtures and permeate pressures. The azeotrope formed at 82-wt% dioxane was easily broken with a selectivity of 865 and water flux of 0.089 kg/m 2 h.