Comprehensive review of nanofiltration membranes for efficient resource recovery from textile wastewater

• The crucial role of NF membranes in dye wastewater resource recovery is discussed. • The NF membrane treatment flowchart for textile wastewater is presented. • Applications of NF membranes and integrated technologies are reviewed. • NF membrane fabrication methods and their impacts are analyzed. • Challenges and future directions for NF membrane technology are identified. With the advancement of sustainable development goals, the potential for resource recovery from textile wastewater streams, such as the recovery of acids, alkalis, salts, dyes, and water, has become a prominent research topic in both industrial and environmental fields. Nanofiltration (NF) membranes utilize mechanisms such as size exclusion and charge repulsion to effectively recover dyes, salts (e.g., NaCl, Na 2 SO 4 ), and heavy metals, which have shown exceptional effectiveness, making them a promising technology for resource recovery in textile wastewater treatment. This review offers a comprehensive analysis of the potential applications of NF membranes for this purpose. It begins by examining the characteristics of wastewater quality and treatment requirements, emphasizing the essential role of NF membranes in resource recovery. A review of the overall process flow diagram for textile wastewater treatment provides a broad understanding of designing NF membranes and selecting appropriate upstream and downstream processes. The review then explores various types of NF membranes suited to specific recovery applications. Loose nanofiltration membranes are particularly suitable for dye recovery, while dense NF membranes excel at the selective separation of NaCl and Na 2 SO 4 and heavy metal ion recovery. Additionally, the integration of NF membranes with other technologies is analyzed, demonstrating how these combined approaches can enhance recovery efficiency and broaden the range of resources that can be recovered. This review also summarizes different fabrication methods for NF membranes, focusing on how these modifications regulate membrane structure to improve resource recovery performance from textile wastewater. Finally, future research directions are proposed. These efforts aim to highlight the broader application potential of NF membranes in textile wastewater resource recovery.