Mechanistic insight into developing a novel loose nanofiltration membrane for effective dye/salt separation by epigallocatechin gallate

•A novel LNF membrane was fabricated by polyphenol-based EGCG via IP process.•The PE layer possessed a loose, smooth, hydrophilic, and negative-charged surface.•The structure of the PE layer can be tailored by adjusting the EGCG diffusion rate.•The LNF-4 showed a water flux of 41.7 LMH·bar−1, and rejection of CR with 98.5 % and NaCl with 7.4 %.•The LNF-4 had long-term stability, superior antifouling and antibacterial properties.