Fabrication of superhydrophilic membranes for oil-water separation: A life cycle assessment study

Membrane-based technologies are widely used in oily wastewater treatment. This study selects two superhydrophilic ultrafiltration (UF) membranes (denoted M1 and M2) for oil-in-water emulsion separation and evaluates the environmental impact of membrane fabrication using life cycle assessment (LCA). Although the two membranes have similar separation performance, M1 exhibits ~40% lower environmental impacts than M2 in almost every category owing to its fewer modification steps, lower electricity use, and less solvent consumption. Electricity consumption, reactive-copolymer synthesis, and toxic-solvent use are identified as environmental hotspots in membrane fabrication. A sensitivity analysis of different energy sources reveals that coal-based electricity has the greatest environmental impact, while photovoltaic energy reduces the impact by up to 71%. Considering solvents, dimethylformamide (DMF) shows a slightly lower environmental impact than N-methyl-2-pyrrolidone (NMP).