Oil-Water Separation Performance and Thermoregeneration of a Nanofibrous SiO2 Membrane Prepared by Sol-Electrospinning

Graphical An efficient and durable hydrophilic SiO 2 fiber membrane was designed by a template-free strategy combined with electrostatic spinning technology. The material can perform separation of oily wastewater under gravity-only conditions and has demonstrated high separation performance for effective separation of oil-water mixtures and oil-in-water (O/W) emulsions. The discharge of oily wastewater seriously affects human health and the sustainable development of the ecological environment. Therefore, developing oil-water separation materials capable of removing organic pollutants is imperative. In this study, we report the preparation of a SiO 2 nanofiber membrane based on tetraethyl orthosilicate (TEOS) using a template-free strategy combined with electrostatic spinning technology. The prepared SiO 2 nanofiber membrane was characterized using SEM, EDX, FT-IR, AFM, XRD, CA, and TG techniques. The prepared SiO 2 nanofiber membranes exhibit excellent hydrophilicity (WCA=0°) in air and oleophobicity (UWOCA=136°) underwater, with excellent anti-pollution properties for gravity-driven oil-water separation. The SiO 2 nanofiber membrane can effectively separate different kinds of oil-water mixtures with high water flux (4420 L m −2 h −1 ) and excellent separation efficiency (99.1 %), with a flux loss of 5.65 % after ten cycles, indicating excellent cycling stability. In addition, it can also be used to separate various oil-in-water emulsions stabilized by surfactants with a separation flux higher than 2079 L m −2 h −1 and a separation efficiency maintained at more than 97 %. During the separation of 150 mL lotion, the membrane was seriously scaled due to long-term pollution. Simple water washing could not restore the membrane flux, and the irreversible scaling rate was 50.74 %, which seriously affected the continuous separation. However, due to the excellent thermal stability of SiO 2 nanofiber membranes, oil contaminated membranes can be heated and regenerated, resulting in a flux recovery rate of nearly 100 %. Overall, this material has a wide range of potential applications in environmental protection, especially in the treatment of oily wastewater, due to its simple fabrication method, high flux, and superb oil resistance and recyclability.