Dual-modified PVDF ultrafiltration membranes via semi-interpenetrating polymer network construction and PANI surface polymerization

To enhance the filtration and antifouling properties of polyvinylidene fluoride (PVDF) ultrafiltration membranes, a dual modification strategy was implemented. First, a poly(sodium p-styrene sulfonate) (PSS) polymer was synthesized via free-radical polymerization, and PSS/PVDF membrane with a semi-interpenetrating polymer network (semi-IPN) structure was fabricated via a one-pot strategy combined with the non-solvent induced phase separation (NIPS) method. Subsequently, a polyaniline (PANI) layer was firmly anchored onto the PSS/PVDF membrane surface through two distinct surface polymerization approaches: adsorption followed by polymerization and synchronous polymerization. Under optimal preparation conditions, the resulting PANI-modified PSS/PVDF ultrafiltration membrane demonstrated a high flux of 401.03 L·m⁻²·h⁻¹, a bovine serum albumin (BSA) rejection rate of 99.02%, and an outstanding flux recovery rate (FRR) of 95.59%. Moreover, the PANI-modified PSS/PVDF ultrafiltration membrane exhibited significant antibiofouling efficacy, with inhibition rates against Escherichia coli and Staphylococcus aureus reaching 88.00% and 87.38%, respectively. Additionally, it achieved near-complete removal (99.99%) of both Congo Red (CR) and Methylene Blue (MB). These results indicate that the prepared PANI-modified PSS/PVDF ultrafiltration membrane with a semi-IPN structure holds significant potential for applications in the treatment of protein-containing and dye wastewater.