Improved pervaporation dehydration performance of alginate composite membranes by embedding organo-montmorillonite

•Sodium- or organo-montmorillonite (O-MMT) was embedded into alginate membrane.•Incorporating O-MMT improved the membrane property and separation efficiency.•The hybrid membrane had stable performance at wide operating condition. In this work, two different montmorillonite (MMT) nanoclays were incorporated in sodium alginate (Alg) solution for fabrication of hybrid membrane for pervaporative separation of aqueous isopropanol solution. Sodium-MMT (Na-MMT) was modified to organo-montmorillonite (O-MMT) using cationic surfactant dialkyldimethyl ammonium chloride (DDAC). The influence of incorporating MMTs on the membrane properties and separation performance was investigated. Intercalating of DDA+ on Na-MMT tailored the chemical structure and morphology of the MMTs. Integrating of MMTs modified the physicochemical properties of the membranes. The membrane morphology shows the homogeneous dispersion of MMTs in athe Alg matrix. Positron annihilation lifetime spectroscopy analysis revealed a tuned microstructure of the membranes. Swelling measurements showed better compatibility of O-MMT than the Na-MMT with the Alg matrix. As a result, AlgO-MMT had better separation performance than the AlgNa-MMT with permeation flux of 4764 g∙m−2∙h−1 and water concentration in permeate of 99.99 wt% on dehydrating 70 wt% IPA/water aqueous solution at 25 °C. Owing to the favorable compatibility between the polymer and filler, AlgO-MMT membrane demonstrated stability at different pervaporation operating conditions and long-term use. Our results demonstrated that the properties and separation performance of Alg membrane can be enhanced through incorporation of O-MMTs.