Electrospun nanofibrous membranes based on fluorine-free polyimide for swift oil spill cleanup and emulsion separation

The urgent need to mitigate environmental damage caused by oil and organic pollutants in oil production industries and spill accidents necessitates effective removal methods. This study introduces novel nanofibrous membranes composed of fluorine-free polyimide, which was formed by electrospinning of BPADA-TrMPD, produced by polycondensation reaction in one-step and at high temperature using 4,4′-(4,4′-isopropylidenediphenoxy)bis-(phthalic anhydride) (BPADA) and 2,4,6-trimethyl-m-phenylenediamine (TrMPD). The resulting membranes exhibited a hydrophobic nature with a water contact angle of 114° and an oil contact angle of ∼ 0°. The adsorption performance of the nanofibers was explored using Saudi crude oil and non-polar organic solvents (i.e., n-hexane and dodecane). The developed membranes exhibited a crude oil uptake ranging from 35 to 60 g g⁻¹ and demonstrated rapid removal capabilities, reaching equilibrium sorption capacity within a few minutes for crude oil. Moreover, these membranes displayed remarkable flux of 1991, 1508, and 206 L m⁻²h⁻¹ for dodecane, n-hexane, and crude oil, respectively. The capability of the fluorine-free mats designed for oil spill cleanup was validated through its application in treating actual samples. The durability and recyclability of the membranes were showcased by regenerating them through mechanical treatment.