Development of multifunctional and freestanding PVDF/SMA/CuS membranes with antibacterial, oil-water separation and dye degradation for wastewater treatment

Industrial wastewater is characterized by the complex coexistence of multiphase contaminants, including waste oil, persistent organic dyes, and other refractory pollutants. The efficient separation and degradation of such wastewater have become the key challenges that urgently need to be broken through in the field of environmental functional materials. In response to this demand, Polyvinylidene fluoride (PVDF)/Styrene-co-maleic anhydride (SMA)/Copper sulfide (CuS) composite membranes, integrating antibacterial activity, oil-water separation, and dye degradation functionalities, were fabricated via novel non-solvent induced phase inversion and in-situ deposition techniques. The PVDF/SMA/CuS membranes exhibited a bacteriostatic efficiency of 99%. For oil-water separation, their efficiency for typical oil-in-water emulsions exceeded 98.4%, remaining above 90% after five consecutive recycling cycles, demonstrating excellent operational stability. Under visible light irradiation, the PVDF/SMA/CuS membrane achieved complete degradation of Rhodamine B (RhB) and Methyl Orange (MO) solutions within 9 minutes, and Cochineal (Ponceau 4R) solution within 6 minutes, via a photo-Fenton-like reaction. Notably, the membrane retained a dye degradation efficiency above 94% after five cyclic runs, confirming its long-term catalytic durability. As a result, this membrane can treat dye wastewater and oily wastewater efficiently and quickly. This study presents a readily implementable wastewater treatment technology with excellent anti-fouling performance and high efficiency, highlighting its substantial practical application prospects in environmental remediation.