Acid and Alkali-Resistant\nElectrospun Porous Silica/Carbon\nNanotubes Nanofibrous Membrane for Oil/Water Separation

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