Nanofiltration membrane from reactive positively charged nanofiber interlayer for recycling lithium from waste batteries

Abstract

With the development of new energy powered vehicles, the shortage of lithium resources has become more urgent. The recovery and extraction of lithium resources from waste lithium iron phosphate batteries can not only achieve the sustainable development of the new energy industry, alleviate the imbalance between supply and demand of lithium resources, but also greatly reduce the environmental pressure brought by the future battery retirement tide. In this work, poly(ethylene vinyl alcohol) nanofiber was incorporated to construct the positive interlayer via co-crosslinked with PEI and sprayed on PES substrate, on which the positive polyamide nanofiltration layer was formed via interfacial polymerization with 1,3,5-benzenetricarbonyl chloride. The abundant interconnected pore among nanofibers provided high water flux, and meanwhile the dual positively charged layer had synergistic effect on cation rejection. The nanofiber interlayer also greatly improved the roughness and effectively enhanced the hydrophilicity of the membrane surface. The optimized nanofiltration membrane exhibited pure water flux of 36.73 L m-2 h-1 and the high Fe3+ rejection of 99.36%, and the Li+/Fe3+ separation factor reached up to 115. The excellent separation performance was maintained at acid condition, revealing the great potential in the application for recycling lithium from waste batteries.