A new composite membrane based on Keggin polyoxotungstate/poly(vinylidene fluoride) and its application in photocatalysis

Abstract

Polyoxometalate (POM) is a promising candidate as a photocatalyst for the removal of organic pollutants from water, showing striking similarities to TiO₂. However, the drawback of its high solubility in solution makes it difficult to recover and recycle, which impedes its potential applications in wastewater treatment. We have developed a new composite membrane based on Keggin POM and poly(vinylidene fluoride) (PVDF) via combining a doctor-blade method, immersion precipitation and colloid interface techniques. The as-prepared composite membrane was characterized by FTIR, SEM and X-ray EDS, revealing that the Keggin POM could be homogenously intermingled in the composite membrane. The composite membrane not only exhibits good degradability on methyl orange in the presence of H₂O₂ and excellent photocatalytic repeatability by maintaining 97.36% of the initial decolorization efficiency even after 8 cycles, but also can be easily handled and recycled.