Controllable Fabrication Of Superhydrophilic Silica Nanofibrous Membranes For Oil/water Microemulsion Separation

With increasing environmental awareness and tighter regulations, novel strategies to separateoil from industrial wastewaters, polluted oceanic waters, and oil-spill mixtures, especially in thepresence of surfactants, are highly desired. Conventional methods such as oil skimmers, centrifuges,flotation, depth filters, and coalescers are available for separation of immiscible oil/water mixtures,but are not effective for emulsified oil/water mixtures, especially not for surfactant stabilizedmicroemulsions (droplet sizes <20μm). Membrane-based technologies have aroused great attentionfor the separation of emulsions, because they are relatively cost-effective and available for a widerange of industrial effluents. In spite of the advantages, these polymer dominated separationmembranes generally suffer from low flux, high driven pressure, poor thermal stability, as well asserious fouling and plugging because of surfactant adsorption. So we present a robust methodologyfor creating superhydrophilic and underwater superoleophobic silica nanofibrous (SNF) membraneswith a hierarchical porous structure by the combination of nanofibers with in situ polymerization.In this article, we firstly through the electrospinning technic to fabricate inorganic silicananofiber membrane, and then using the synthesis of BA-CHO monomer and a certain content ofsilica nanoparticles to modify silica membranes. After modification of fiber membranes made by insitu solidification and calcining process,we can get the hierarchical porous silica nanofibermembranes. The SNF membranes can effectively separate micro-size surfactant stabilizedoil-in-water emulsions solely driven by gravity, with high separation efficiency. Most importantly,the membranes exhibit the high flux, robust mechanical strength, high thermal stability, and ease ofcycling for long-term use.Datas finally show the research has successesd to fabricate the superwetting hierarchicalporous silica nanofibrous membranes, the amount of BA-CHO and SiO2NPs are the key factorsinfluencing the fiber surface wettability. Datas show that when the content of BA-CHO and SiO2NPs is1and2wt%, the modified hydrophobic fiber membranes’ underwater oil contact angle can be up to161°, andwith a minute sliding angle of4.2°. At the same time achieve the modification ofinorganic fiber membrane mechanical strength is5.06MPa, elongation at break was2.3%, and aftercalcination at600℃the fuonr d3e0r wmaitne,r oil contact angle can reach159°. Significantly, thenovel membranes exhibited a promising separation flux of2237±180Lm-2h-1, which was an orderof magnitude higher than that of pressure driven commercial separation membranes. This work alsoprovided a versatile in situ strategy for further design and development of functional nanofibrousmembranes towards various applications.