Although membrane technology has attracted considerable attention for oily wastewater treatment, the plastic waste generated from discarded membranes presents an immediate challenge for achieving eco-friendly separation. We designed on-demand biodegradable superhydrophilic membranes composed of polylactic acid nanofibers in conjunction with polyethylene oxide hydrogels using electrospinning technology for ultrafast purification of oily water. Our results showed that the use of the polyethylene oxide hydrogels increased the number of hydrogen bonds formed between the membrane surface and water molecules by 357.6%. This converted hydrophobic membranes into superhydrophilic ones, which prevented membrane fouling and accelerated emulsion penetration through the membranes. The oil-in-water emulsion permeance of our newly designed nanofiber membranes increased by 61.9 times (2.1 × 104 liters per square meter per hour per bar) with separation efficiency >99.6%, which was superior to state-of-the-art membranes. Moreover, the formation of hydrogen bonds was found to accelerate polylactic acid biodegradation into lactic acid by over 30%, offering a promising approach for waste membrane treatment.