Antifouling piperazine / polyethyleneimine loose thin film composite nanofiltration membranes for Textile Dye Recovery.

Abstract

The present invention describes a method for synthesizing advanced loose nanofiltration (LNF) membranes using nanocomposite materials through interfacial polymerization. Thin film composite (TFC) nanofiltration membranes were fabricated by reacting polyethylenimine (PEI), a polymeric amine, with piperazine (PIP), a monomeric amine, to form a polyamide layer. This polyamide layer was created through the reaction of trimesoyl chloride (TMC) with a mixture of PEI and PIP. The introduction of a small amount of PIP into the PEI matrix significantly improved the permeation flux while maintaining excellent solute rejection properties. At low PIP / PEI concentration ratios, the resulting membrane exhibited enhanced permeability compared to the LNF-2-0 membranes. By carefully controlling the ratio of PIP to PEI, two-layer polyamide membranes could be synthesized, offering both higher permeation flux and improved salt rejection performance compared to conventional single-layer polyamide membranes. The membranes were extensively characterized, evaluating their chemical composition, surface hydrophilicity, surface charge, and the morphology of the polyamide skin layer. These properties contribute to the membranes' effectiveness in dye recovery and antifouling applications.