In-situ preparation of CMPs based electrospun nanofibrous composite membranes for effective air filtration and oil–water separation

Abstract

The development of multifunctional filtration materials is a major tool for air purification. Herein, two electrospun nanofibrous composite conjugated microporous polymer membranes (ENC-CMPs-M) with multilayered porous structures were synthesized by selecting different monomers via Sonogashira-Hagihara cross-coupling using PVDF/PMMA as a substrate for the separation of water-in-oil emulsions and effective filtration of PM in high humidity environments. As measured by a Karl Fischer hydrometer, the separation efficiencies of ENC-CMPs-M for gasoline and kerosene derived water-in-oil emulsions were found to be 99.99 % and 99.67 % by a gravity-driven oil–water separation process, respectively. Its permeation fluxes could reach up to 953.46 L m^-2h⁻¹. The particulate matter (PM) adsorption performance of ENC-CMPs-M was investigated by simulating the PM adsorption in air with a lighted cigarette. The ENC-CMPs-M−2 membrane showed excellent removal efficiency, i.e., the removal efficiencies were measured to be PM_0.3 ≥ 99.5 % PM_0.5 ≥ 99. 7 %, PM_1.0 ≥ 99.6 %, PM_2.5 ≥ 99.9 %, PM_5.0 ≥ 99.9 %, and PM₁₀ ≥ 99.9 %, respectively. Thanks its ultra-hydrophobicity as well as unique multilayered porous structure, even in the high humidity environment (RH: 95 ± 3 %), the efficiency of ENC-CMPs-M−2 for PM_0.3, PM_0.5, and PM_1.0 reaches up to 99.92 %, 99.95 %, and 99.97 %, respectively, with an excellent the removal efficiency of higher than 99.99 % for PM_2.5, PM_5.0 and PM₁₀. For a practical measurement by filtration of PM particles generated from vehicle exhaust gas, the removal efficiency of ENC-CMPs-M−1 and ENC-CMPs-M−2 for PM_2.5-10 was calculated to be over 96 %, showing great potential for eliminating inhaled particulate matter and separation of oil/water emulsion as a kind of new advanced membrane material in complex environments by taking advantages of its simple fabrication, excellent chemical stability, and desired mechanical properties.