Abstract: Multi-channel structured nanocomposite membrane materials with different mass fractions of silica is prepared by using polymer PVDF as the main raw material. The performance of the prepared material in oil-water separation of aquaculture wastewater is evaluated through SEM morphology, oil retention, oil droplet contact angle, and roughness testing. The results showed that an increase in the mass fraction of silica first improved the SEM morphology and compatibility of the nanofiber membrane, but exceeding 28% would lead to membrane drying and cracking; the nano film S05 containing 28% silica performed the best in oil-water separation, with the highest oil retention rate of 98%; its high oil retention rate is attributed to its hydrophilicity, oleophobicity, and optimized pore structure; and as the mass fraction of silica increases, the contact angle of oil droplets first increases and then decreases. When the mass fraction of silica in the membrane material is within the range of 12% to 20%, the contact angle of oil droplets gradually increases. However, as the mass fraction of silica in the membrane material further increases to 24% to 28%, the contact angle of oil droplets shows a decreasing trend, indicating that an appropriate amount of silica improves the oil-water separation performance. The surface roughness of nanofiber membranes increases with the increase of silica mass fraction, and moderate roughness is beneficial for improving oil-water separation performance.

Key words: nanocomposite membrane materials, farming wastewater, water etching, oil water separation, silicon dioxide