Highly efficient photocatalytic hyperbranched polyethyleneimine/bismuth vanadate membranes for the degradation of triclosan

Worldwide, pharmaceutical and personal care products are increasingly being used and produced and their presence in various water bodies has attracted significant attention amongst the public and scientists. Classified as emerging pollutants, these pharmaceutical and personal care products ultimately accumulate in and contaminate natural water bodies through several pathways. In this study, a photocatalytic membrane consisting of bismuth vanadate nanoparticles and hyperbranched polyethyleneimine, blended in polyethersulphone, was used in the degradation of triclosan. Bismuth vanadate was characterised using X-ray diffraction and Raman spectroscopy. These analyses revealed that there was successful synthesis of the monoclinic phase of bismuth vanadate, as well as a monoclinic-to-tetragonal (M -> T) phase transformation upon the addition of hyperbranched polyethyleneimine to the nanoparticles. The modified membranes showed improved water flux and hydrophilicity (contact angles of between 71 degrees and 56 degrees) as compared to that of the bare polyethersulphone (75 degrees) upon the addition of hyperbranched polyethylene amine and bismuth vanadate. The modified membranes were effective in the photodegradation of triclosan (up to 86%), and the generation of chloride ions was observed.