A stable underwater superoleophobic membrane constructed by CuO oriented rods and PAA water-adsorbent resin for fast and high efficient oil–water separation

The practical   application of filter membranes for oil–water separation requires high efficient, large flux and excellent stability. Hydrogel membrane with superhydrophilicity and underwater superoleophobicity has been considered as an ideal material for efficient separation of oil–water mixture. However, hydrogel materials are generally fragile and easy to dehydrate. In this work, inorganic CuO oriented-rods framework was used to support water-adsorbent polyacrylic acid (PAA) resin for constructing superhydrophilic-superoleophobic composite hydrogel membrane. The as-prepared composite membrane displayed stable underwater superoleophobicity during swelling-drying cycles and abrasion test. In “bottom-injection” filter apparatus, the CuO@PAA membrane exhibited high separation efficiencies, above 99.90%, for kerosene-water, hexadecane-water, soybean oil–water and rapeseed oil–water mixtures with water penetration fluxes larger than 5700 L•m −2 •h −1 . The excellent separation efficiency and flux were capable of maintaining for 200 separation processes. This work paved the way for designing and constructing economical and practical oil–water separation equipment for industrial application.