Self-cleaning PDA/ZIF-67@PP membrane for dye wastewater remediation with peroxymonosulfate and visible light activation

Abstract

Introducing catalytic oxidation into membrane technology offers a promising prospect to overcome the fouling obstacle. Herein, a biomimetic poly-dopamine and zeolitic imidazolate framework-67 decorated polypropylene (PDA/ZIF-67@PP) membrane was fabricated via in-situ self-assembly approach, which was further employed for dye wastewater remediation with concurrent visible light and peroxymonosulfate (PMS) activation. The uniform PDA and ZIF-67 endowed the membrane with permeability 2.5 times higher than that before modification. The newly-designed membrane exhibited excellent properties in the presence of PMS and visible light, such as physical filtration, photocatalysis, PMS catalysis, recyclability, anti-fouling and self-cleaning. Mechanism insight proposed that filtration could accelerate the mass transfer efficiency of foulants onto membrane surface and pore walls, benefiting for dye degradation with synergistic effects of PMS and visible light catalysis. Quenching tests found that •SO4− and •O2− made significant contributions to dye degradation. The presented performance of visible-light PDA/ZIF-67@PP/PMS system provided a novel strategy for purification of aquatic environment.