Enhanced anti-fouling performance of PVDF hollow fiber ultrafiltration membranes for shale gas wastewater treatment using PVDF-g-PEGMA

Developing high-performance anti-fouling ultrafiltration membranes is essential for treating shale gas wastewater (SGW), addressing its severe membrane fouling issues. This study reports the fabrication of polyvinylidene fluoride (PVDF)/PVDF-graft-poly(ethylene glycol) methyl ether methacrylate (PVDF-g-PEGMA) blended hollow fiber membranes via non-solvent induced phase separation for direct treatment of SGW. The influences of the copolymer doping ratio on microstructure, chemical composition, and hydrophilicity were systematically investigated. The addition of PVDF-g-PEGMA contributed to a favorable membrane morphology and significantly improved hydrophilicity. The 20 wt% PVDF-g-PEGMA modified membrane achieved a 64.4% increase in pure water flux while retaining over 95.9% rejection for both humic acid and bovine serum albumin. More importantly, in long-term filtration of SGW, the modified membrane demonstrated a stable permeation flux of ~30.4 L·m −2 ·h −1 , surpassing the performance of the unmodified membrane by 300% and reducing the cost of water treatment for unit flux by 17.6%. Analysis based on the extended Dragun-Landau-Verwey-Overbeek theory indicated that the incorporation of PVDF-g-PEGMA effectively reduced the attractive interaction energy between the membrane and pollutants. These results demonstrate that the PVDF-g-PEGMA blending modification not only significantly enhanced membrane permeability and anti-fouling performance under challenging real wastewater conditions but also achieved sustained flux and superior anti-fouling behavior during lab-scale SGW operation, thereby enabling water reuse with reduced maintenance demand.