Sheep bone powder modified PVDF membrane for highlyefficient oil-in-water emulsion separation

Background: The wetting properties and roughness modification of membrane surfaces are crucial for their application in emulsion separation. However, traditional membrane modification methods suffer from high cost, complex preparation, and secondary pollution. Methods: In this study, a novel, simple, and economical interfacial engineering method was developed using tannic acid (TA), sodium alginate (SA), and sheep bone powder (BP) as raw materials. Through vacuum filtration, these materials were deposited onto polyvinylidene fluoride (PVDF) membrane to fabricate superhydrophilic/underwater superoleophobic filtration membrane (PDBS). BP induced surface roughness and wetting properties to the membrane, while preserving the porous structure of the substrate membrane. The complex formed by TA and SA encapsulated BP onto the surface of PVDF microfiltration membrane, enhancing its mechanical properties. Significant Findings: The prepared membrane exhibited a membrane flux of 347 Lm(-2)h(-1) bar(-1) and a separation efficiency of 99.9 % for emulsified oil. Furthermore, after soaking in NaCl solution for 30 h, the membrane still showed excellent stability. Therefore, this study developed a new membrane surface modification strategy with promising application prospects in oily wastewater treatment.