Solvent and material selection for greener membrane manufacturing

Membrane separation technologies involve energy-efficient processes, which have been rapidly developed and applied in the last few decades. However, the full life cycle of traditional membrane manufacturing has remained unsustainable as nonbiodegradable petroleum-based polymers and hazardous solvents are employed. Therefore bio-based polymers and green solvents must be more utilized in membrane fabrication. To improve the sustainability of membrane systems, in this work, we discuss using green solvents during membrane preparation, utilizing green monomers when making thin-film composite membranes, employing biopolymers instead of conventional petroleum-based polymers, and utilizing recycled materials to accomplish a circular economy. In most cases, the performances of green membranes are comparable to those of conventional petroleum-based membranes, providing viable alternatives for existing technologies. However, a comprehensive sustainability assessment of green membrane systems is required, and quantitative comparisons are necessary for a detailed understanding of the selection of materials and processing routes. Polymer membrane systems with a closed-loop life cycle must be designed by adopting both bioderived and biodegradable materials as well as waste utilization.