Pervaporation Separation of t‐Butanol‐Water Mixtures by Chitosan Crosslinked <scp>PSSAMA</scp> Membranes Using Diethyl Phthalate as a Plasticizer

ABSTRACT Pervaporation is one of the most efficient membrane technologies, emerging as a key energy‐saving technique for separating azeotropic, close‐boiling, or aqueous organic mixtures. In the present work, we have developed flexible membranes by incorporating different mass% of diethyl phthalate as a plasticizer into polystyrene sulfonic acid‐co‐maleic acid crosslinked chitosan membrane. The resulting membranes were characterized using fourier transform infrared (FTIR), wide‐angle X‐ray diffraction (WXRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and UTM techniques. The effect of diethyl phthalate (DEP) on the membranes was investigated systematically for the separation of water/tert‐butanol mixtures at different temperatures. Among the membranes developed, the membrane containing 1.5 mass% of DEP exhibited the highest separation factor of 6450 with a flux of 7.48 × 10 −2 kg m −2 h −1 at 30°C for 10 mass% of water in the feed. For all the membranes, the total flux and flux of water were found to be overlapping each other, manifesting that the developed membranes could be used effectively to separate water/tert‐butanol mixtures. The activation energy values obtained for the permeation of water ( E pw ) were significantly lower than that of tert‐butanol ( E pTBOH ), indicating that the developed membrane has demonstrated excellent separation performance for the water/tert‐butanol system. The negative ∆H s values of all the membranes were indicating that Langmuir's mode of sorption is predominant.