Regeneratable lignosulfonic acid/PDADMAC polyelectrolyte-microfiltration (MF) membrane for reactive dye removal: Effects of post treatment and interference of microplastic and microfibers

This research aims to develop a lignin-based polyelectrolyte combination (Lignosulfonic acid sodium salt (LSA)/Poly(diallyldimethylammonium chloride), (PDADMAC)) for surface modification of microfiltration (MF) membranes to enhance reactive dye rejection. Effects of different fabrication parameters on the multilayer structure and reactive dye removal efficiency were investigated. This novel membrane was capable of removing >98 % of reactive dye, which is about 8 times higher than that of the original MF membrane, with about 51 times higher salt/dye selectivity. Interferences of microplastics/microfibers on filtration performance were also investigated. Moreover, the feasibility of regeneration and reuse of the spent membrane was demonstrated. • A novel dye/salt separation LSA/PDADMAC membrane is proposed. • The surface of MF membranes was modified using LSA/PDADMAC compounds. • The effect of post-treatment methods on the structure and filtration performance of LSA multilayer was elucidated. • Effects of microplastics/microfibers on filtration performance of the membrane were investigated.