Fabrication and forming mechanism of polychlorotrifluoroethylene membranes with tunable pore architectures for efficient oil-water separation

PCTFE microporous membrane fabricated via sacrificial template method. • Custom-tailored pore sizes (0.31 to 1.28 μm). • Remarkable capability in separating various oil/water mixtures and emulsion. • Excellent creep resistance, mechanical properties and corrosion resistance. The efficient purification and recycling of oily waste rely heavily on membrane separation technology, where fluoropolymer-based membranes hold particular promise. This study demonstrated a sacrificial template strategy to fabricate polychlorotrifluoroethylene (PCTFE) membranes with tunable pore architectures. This approach leveraged a solvent-assisted process to incorporate a fluoroelastomer (FR) template, forming PCTFE/FR sintered films. By controlling FR content, sintered films with co-continuous morphology can be obtained, which subsequently enabled the formation of penetrating pore structure. A key finding was the linear correlation between sintering time and phase size, which provides precision in pore structure control, complemented by the use of smaller PCTFE particles for refining the phase morphology. The optimized membranes integrated strong hydrophobicity/oleophilicity, robust mechanical properties, excellent creep resistance, and efficient oil/water separation performance. They delivered high separation fluxes (15351 L/(m 2 h) for oil/water mixtures; 7649 L/(m 2 h) for emulsions) with superior efficiency (>99%) and oil purity (>99.95 wt%). Moreover, they retained excellent performance after 15 operational cycles or 7-day immersion in various corrosive media (including DMF, DMAc, 1M H 2 SO 4 , 1M NaOH and concentrated HNO 3 ), with no significant performances degradation observed. These findings underscore the great potential of the developed membranes for treating and recycling oily wastes, even under harsh environmental conditions. Download: Download high-res image (464KB) Download: Download full-size image