Acid and Alkali-Resistant Electrospun Porous Silica/Carbon Nanotubes Nanofibrous Membrane for Oil/Water Separation

Managing oily wastewater remains a challenging issue in terms of technology. The technology of membrane separation can provide both high separation efficiency and low operating cost, so the exploitation of highly effective oil/water separation membranes has become a research hotspot. In the present work, we prepared porous silica (SiO₂)/carbon nanotubes (CNTs) nanofibrous membrane (PSCM) by comixing hydrophilic CNTs and carbon nanospheres (CNSs) with SiO₂ precursor liquid, followed by the electrospinning method. The addition of CNTs has enhanced the roughness of the nanofibrous membrane and improved the wettability, making the membrane superhydrophilic. Meanwhile, the strong electrostatic attraction between SiO₂ and CNTs makes the bond between them stronger, which is favorable for withstanding the osmotic pressure from the liquid. The presence of PSCM micro/nanoporous structure creates an infiltration channel for the liquid, and the porous structure gives it excellent porosity, which greatly improves the performance of oil/water separation. The membrane has high separation performance for oil/water mixtures in gravity-based feeding devices with a high separation flux of up to 8340 L m^–2 h^–1 and separation efficiency of up to 99.5%. In addition, we found that PSCM has good resistance to oil pollution and acid and alkali resistances through testing. It still has a flux of 6231 L m^–2 h^–1 and 5512 L m^–2 h^–1 under strong acid and alkali conditions, respectively, and performs well in the cyclic separation test under strong acid and alkali conditions. This work provides perspectives on oily wastewater and water purification remediation.