Towards Greener Fabrication of Polymeric Membranes: Recycling Membrane Wastewater

It is widely accepted that membrane process is a green and sustainable technology; however, it is not well known that the membrane fabrication process itself is quite far from being green with more than billions of liters of wastewater being generated contaminated with toxic solvents like DMF and NMP. This problem is often overlooked and current research is focused on replacing the toxic solvents with greener alternative. Such generation of wastewater is increasing at a rapid rate with the growing membrane market and it is an urgent challenge to be resolved. In this work, we present a simple and practical method to recycle wastewater generated from membrane fabrication process. Different classes of adsorbent materials including molecularly imprinted polymers, zeolites and graphene have been screened and their isotherm and kinetic behaviors have been fully elucidated for recycling membrane wastewater. It is shown that wastewater can be completely purified and recycled, and the mass intensity for membrane fabrication process can be reduced by more than 99%. In addition, it was validated that the used adsorbent can be easily regenerated more than 10 times, minimizing the generation of solid waste.