Preparation of highly selective PSf/ZnO/PEG400 tight ultrafiltration membrane for dyes removal

Tight ultrafiltration (UF) has increasingly been developed to overcome the low selectivity of conventional UF membranes towards soluble contaminants. In this work, a tight structure of polysulfone-based (PSf) UF membrane was prepared by blending PSf with polyethylene glycol (PEG400), ZnO nanoparticle (ZnO-Np), and acetone (Ac) in dimethylacetamide (DMAc). The influences of Ac/DMAc ratio (1: 15 to 1:25) and PEG400 concentration (0–25 wt%) on the binodal curve of the polymer solution, characteristics, and performances of the UF membrane were studied. The membrane performances were investigated by observing the permeate flux and dye rejection during real textile wastewater treatment. The binodal curves are close to the polymer line, which means that rapid demixing occurred after the casted solution was immersed in the coagulation bath. Based on FTIR analysis, PEG400 and ZnO-Np were partially entrapped in the UF membrane structure. Over 90% of color removal at a permeate flux of 72 L.m 2.h 1 could be achieved when the Ac/DMAC ratio was 1:12. The tight-UF membrane removed TDS and Naphthol AS by 74.5% and 92.8%, respectively. Since the experimental result showed a high contaminants removal, the tight-UF could be used as clean technology to produce clean water for water reuse purposes at low energy requirements