Visible light photosensitised cross-flow microfiltration membrane reactors for managing microplastic-contaminated bio-effluents

The demand for advanced water treatment solutions necessitates the development of multifunctional, photodynamically active membranes. Phthalocyanines (Pcs), a class of organic photosensitizers, offer significant potential for enhancing treatment efficacy through photodynamic activity. This study reports the development of Pc-modified polymeric microfiltration membranes as visible-light-responsive, multifunctional membrane reactors with enhanced photodynamic and filtration properties. Cobalt phthalocyanine (CoPc), zinc phthalocyanine (ZnPc), tetra-amino zinc phthalocyanine (TAZnPc), and tetra-sulfonated aluminum phthalocyanine (TSAlPc) were integrated into the membranes, imparting notable changes in morphology, surface wettability, and chemical functionality. Characterization revealed improvements in optical responsiveness and surface properties that contributed to robust photodynamic and filtration performance. Static photodynamic evaluations demonstrated high efficacy, with ZnPc mixed matrix membrane (MMM) achieving superior dye degradation and TSAlPc grafted membrane (GM) yielding significant bacterial inactivation. Filtration trials confirmed ZnPc MMM's biofouling resistance and permeance stability, reaching 99.97 % rejection of bio-fouled microplastics (MPs) and a 45 % permeance enhancement under irradiation. Virus filtration results demonstrated TSAlPc MMM's viral retention efficacy, achieving a 2.05-log reduction against Influenza A virus. These findings underscore the potential of Pc-functionalized membranes as promising candidates for advanced water treatment applications, offering robust contaminant rejection, biofouling control, and broad-spectrum antimicrobial efficacy in a single, multifunctional platform.