Fabrication and characterization of PVDF-CTFE/SiO2 electrospun nanofibrous membranes with micro and nano-rough structures for efficient oil-water separation

A crucial step in the purification and recycling of industrial waste oil is the separation and removal of trace water from emulsified oil. After optimizing the polymer content, solvent composition, and SiO2 nanoparticle addition amount of the spinning precursor solution, a Polyvinylidene fluoride-co-trifluoroethylene chloride (PVDF-CTFE)/SiO2 nanofibrous membrane with micro and nano-rough structure was prepared by electrospinning. Using scanning electron microscopy, a pore size analyzer, a contact angle tester, a single-fiber strength tester, and a gravity separation experiment, the influence of SiO2 addition on the morphology, pore size distribution, wettability, mechanical, and separation properties of the modified membranes was characterized. The results demonstrated that the water contact angle of the nanofibrous membrane was increased to 151.3° of superhydrophobic when SiO2 was added at a concentration of 2.5 wt%. The nanofibrous membranes exhibited outstanding separation performance (>99%) for water-in-oil mixtures and emulsions, as well as for various oil-water systems. Moreover, the PVDF-CTFE/SiO2 nanofibrous membranes exhibited superior multi-cycle performance and consistent chemical resistance. This research yielded a novel material and a straightforward method for fabricating superhydrophobic nanofibrous membranes, which demonstrated greater application potential in oil-water separation.