Superhydrophobic SiO2 micro/nanofibrous membranes with porous surface prepared by freeze electrospinning for oil adsorption

Superhydrophobic polymer fibrous membranes have advantages in oil-water separation and oil spill treatment but are not resistant to high temperature and chemical corrosion resistance. Superhydrophobic SiO2 micro/nanofibrous membranes are one of the research hotspots because of the high temperature stability, corrosion resistance, and low cost of SiO2. In this study, camphene was dispersed into the SiO2 spinning solution for freeze electrospinning. SiO2 micro/nanofibrous membranes with porous surface were obtained by camphene sublimation through freeze drying and calcining. The effects of polystyrene and camphene contents on the surface pore structure of SiO2 micro/nanofibrous membranes were investigated. The specific surface area of the porous fibrous membrane was approximately five times as high as that of the conventional electrospun SiO2 micro/nanofibrous membrane. Furthermore, superhydrophobic property was obtained after hexamethyl-disilazane modification. The contact angle of porous fibrous membrane was more than 150 degrees and the sliding angle was just 2.1 degrees. The maximum absorption capacity of the modified SiO2 micro/nanofibrous membrane with porous surface for three kinds of oils can reach 43.7 g/g. In addition, the absorption capacity of the porous membrane for methyl silicone oil was still higher than 34 g/g after repeated use for five times. Hence, porous SiO2 micro/nanofibrous membranes exhibit application prospect in oil/water separation and oil pollution adsorption.