Recent progress of organic solvent nanofiltration membranes

Solvent separations present one of the largest opportunities for membrane technologies. Currently, industries use millions of tons of solvents for the manufacture of drugs, oils and chemicals. Multiple separations and purifications must be conducted in order to purify the products from the solvents. However, the existing separation processes are energy-intensive. Organic solvent nanofiltration (OSN) or solvent-resistant nanofiltration has emerged as an energy-efficient alternative to the existing processes. We have summarized the recent advances in the fabrication of state-of-the-art polymeric membranes including integrally skinned asymmetric membranes, thin film composite membranes and nanocomposite membranes in this review. The separation performances of OSN membranes continue to push the boundary in terms of high solvent permeances and rejections to various solutes. The advancements have been achieved through novel membrane materials and innovative fabrication methods. We have also discussed the future outlook of OSN processes and pointed out the potential areas for further research exploration.