Synergistic Optimization Strategies for SA-PVA Hydrogel Nanofiltration Membrane Performance by MWCNTs and TiO₂

In this study, a novel hydrogel nanofiltration (NF) membrane is developed through the coating-crosslinking method by synergistically utilizing multi-walled carbon nanotubes (MWCNTs) and titanium dioxide (TiO₂) into the hydrogel coatings of sodium alginate (SA) and polyvinyl alcohol (PVA) on a porous polyvinylidene fluoride (PVDF) matrix membrane. The experimental findings demonstrate that the P-MT@SA-PVA-PVDF hydrogel NF membrane displays outstanding separation performance, hydrophilicity, and antifouling properties. When the ratio of MWCNTs to PVP is kept at 1:4, the pure water flux of the prepared hydrogel NF membrane reaches 226.2 L/(m²ˑh). The rejection rates for Coomassie brilliant blue, Congo red, and Methylene blue are 96.3%, 95.8%, and 92.1%, respectively. Moreover, the total fouling rate of the membrane is merely 28.7%, and the flux recovery rate can attain 93.1%. The remarkable hydrophilicity and highly efficient rejection rates for dyes indicate broad application prospects of MWCNTs-modified hydrogel NF membranes in the field of printing and dyeing wastewater treatment.