Synthesis of novel heterogeneous photocatalysts based on Rose Bengal for effective wastewater disinfection and decontamination

Anionic photosensitizers such as rose Bengal (RB) exhibit low efficiency in the photoinactivation of Gram-negative bacteria. Different strategies have been developed to improve their efficiency being the most effec-tive the addition of the photosensitizer to organic cationic materials. In this context, we have designed the synthesis of a novel heterogeneous photocatalyst based on silica in which the oxidizing properties of singlet oxygen photogenerated by RB have been combined with the chemoattraction of the bacteria to the cationic chains and their biocidal action. Thus, RB and cationic chains have been covalently linked to glass wool to obtain a photocatalyst that showed a highly efficient photodynamic activity against the Gram-positive (Enterococcus faecalis) and Gram-negative (Escherichia coli) bacteria. In addition, the new heterogeneous photocatalyst also resulted to be efficient in the decontamination of drugs such as diclofenac under visible light irradiation.