Loose Nanofiltration Membranes for the Treatment of Textile Wastewater: A Review

Loose nanofiltration (LNF) membrane separation is the fastest-growing textile wastewater treatment technology, due to its tremendous progress in related material and engineering science. Although LNF membranes outperform traditional treatment in the treatment of textile wastewater, the demand for improved selectivity and specificity in membranes separations is growing as we move our focus to the low-energy recovery of valuable compounds from textile wastewater. In this review, we discuss the separation mechanisms for the treatment of textile wastewater, fabrication of LNF membranes, membrane fouling, and control strategies, as well as recent research on LNF membranes. LNF membranes that can achieve high selectivity for dye/salt mixtures, high water permeance, and excellent antifouling performance—as well as the construction mechanisms involved—are highlighted. We further identify practical needs, knowledge gaps, and technological barriers in both material development and structure design for the high selectivity LNF membrane process. Finally, we discuss research priorities in the context of constructing high-performance LNF membranes.