Egg Shell Powders-Coated Membrane for Surfactant-Stabilized Crude Oil-in-Water Emulsions Efficient Separation

Low-cost, environmentally friendly superwetting materials are urgently desired in industrial oily wastewater situations. In our work, egg shell powders (ESP)-coated polyvinylidene fluoride (PVDF) membranes were fabricated by vacuum pumping ESP and sodium alginate suspensions onto a PDVF membrane. The ESP-coated PVDF membrane exhibited superamphilicity in air and showed superior underwater superoleophobicity with the contact angle above 156°. This membrane can efficiently separate low viscosity oil-in-water emulsions, which exhibit a high separation efficiency of more than 99.6%. What's more, it also successfully separated high viscosity crude oil-in-water emulsions. In addition, the ESP-coated PVDF membrane still demonstrated an efficient separation efficiency after 10 times. Hence, we believe that this environmentally friendly material combined with a simple and economical method will be a better choice for the Tween-80-stabilized crude oil-in-water emulsions separation.