Novel reusable porous polyimide fibers for hot-oil adsorption.

•The porous polyimide (PI) fibers were fabricated by electrospinning and post-treatment.•PI fibers exhibited a stable morphology and porous structures at 200°C.•The hot motor oil adsorption capacity of porous PI fiber at 200°C was 57.4gg−1.•Adsorption performance remained up to 80% within 10 times cycles.•Thermostability and porous structures of PI fibers were the key factors for the excellent hot oil adsorption performance.