Multi-functional composite membrane with strong photocatalysis to effectively separate emulsified-oil/dyes from complex oily sewage

Multi-functional filtration membranes, with effective purification capacity against diverse emulsified-oils, high adsorption ability for soluble organic dyes in aquatic system, good physical/chemical stability, and strong Photocatalysis induced anti oil/dye fouling functions, are highly desirable for the complex oily sewage purification, but still a challenge to be realized. Herein, a ternary beta-iron oxyhydroxide (β-FeOOH)/halloysite-nanotubes (HNTs)/polyvinylidene fluoride (PVDF) porous membrane has been designed to address this challenge. The resultant membrane exhibits effective separation efficiency towards various oil-water emulsions and high soluble pollutants adsorption by filtration during the rapid oily wastewater purification. Interestingly, it also displays high flux (~6500 L∙m−2∙h−1), good cycling stability (after 5 cycles the flux recovery rate is still closed to 100%), and strong chemical/physical stability. Given the robust photo-Fenton catalytic activity of β-FeOOH, the permeation flux and adsorption capacity of the fouled membrane could be quickly restored (recovery: higher than 99%) within 10 min under visible light irradiation. Our results open an alternative and effective route to solve the oil/dye fouling issue for complex wastewater remedy.