A facile surface modification of a PVDF membrane via CaCO3 mineralization for efficient oil/water emulsion separation

In order to solve urgent environmental problems caused by oil spills, it is meaningful and necessary to develop novel materials or techniques for efficient oil/water separation. Here, a new polyvinylidene fluoride (PVDF)-based composite membrane was successfully fabricated via a layer-by-layer self-assembly process, where the active sites were provided by pDA for the CaCO3 growth. Importantly, the CaCO3 structure could be regulated by the concentration of the precursor solution, showing the high flexibility of preparation. The as-prepared PVDF@pDA@CaCO3 membrane possessed superhydrophilic/underwater superoleophobic property and superior anti-fouling ability. In addition, the optimal PVDF@pDA@CaCO3-2 membrane showed a high permeation flux only under gravity, and the separation efficiency was as high as 99%. With the merits of low-cost and great separation performance, the as-prepared PVDF@pDA@CaCO3 membrane exhibited great potential in practical industrial applications for highly efficient oil/water emulsion separation.