Fabrication of firm, superhydrophobic and antimicrobial PVDF@ZnO@TA@DT electrospun nanofibrous membranes for emulsion separation

Due to its minute droplet size and stability, separation of the emulsion is a non-negligible challenge. In this paper, polyvinylidene fluoride (PVDF) nanofibrous membranes were prepared via the electrospinning method. The nanofibrous membranes were subsequently surface-modified by ZnO nanoparticles, tannic acid (TA), and n-dodecyl mercaptan (DT), in order to reduce the nanofiber membranes' surface energy while increasing their surface roughness. Thus, superhydrophobic and antibacterial nanofibrous membranes have been fabricated for oil-water emulsion separation. The as-fabricated nanofibrous membranes have a water contact angle of 156.5°. The product has a porosity of up to 73.3% due to the high porosity of the electrospinning nanofibrous membranes. In addition, the tensile strength of the PVDF@ZnO@TA@DT nanofibrous membrane is up to 69.25 MPa. Due to these properties, oil droplets can pass through the membrane during the oil-water separation, while the water phase is blocked by the membrane. This results in a good selective permeability of the membrane. As a result, the separation efficiency of the PVDF@ZnO@TA@DT nanofibrous membranes reaches more than 99%, and the flow flux is 1008.88 L·m−2·h−1. At the same time, antimicrobial testing demonstrates that the nanofibrous membranes have a bacteriostatic rate of over 98%. Combined with these properties, PVDF@ZnO@TA@DT electrospun nanofibrous membranes have great potential for efficient emulsion separation and deep purification of wastewater.