Stable and Flexible Polyurethane Membranes with WO₃/Bi₂MoO₆ Nanoparticles for the Photocatalytic Degradation of 2,4-Dichlorophenol

The objective of this work is to develop a microsomal composite catalytic membrane that exhibits efficient catalytic capabilities and robust stability, thereby addressing the challenge of recycling and reusing powdered photocatalytic materials. Specifically, Bi2MoO6 and WO3 nanoparticles were incorporated onto polyurethane (PU) substrates using a hybrid in situ growth method. By forming Bi2MoO6/WO3 heterojunctions, the photocatalytic activity of the membrane was enhanced without compromising its structural integrity. The flexibility and porosity of PUs play a crucial role in facilitating the adsorption of 2,4-dichlorophenol (DCP) molecules on the membrane's surface, leading to the efficient degradation of contaminants through the cleavage of C–Cl bonds triggered by the migration of electron pairs generated by the photocatalysts. A 5 × 5 cm composite membrane was tested for degradation in 20 mg/L 2,4-DCP solutions with neutral pH, achieving a degradation rate of 78.8% within 120 min. The composite membrane exhibited stability after undergoing six cycles of testing, affirming the effectiveness of its composition. Furthermore, a detailed analysis was conducted on the photocatalytic reaction mechanism of 2,4-DCP on the WO3/Bi2MoO6/PU membrane surface, highlighting the potential of porous composite membranes for wastewater treatment.