Visible light-driven chlorite activation process for enhanced sulfamethoxazole antibiotics degradation, antimicrobial resistance reduction and biotoxicity elimination

In this study, a visible light-driven chlorite activation process, i.e., the combined ClO2-photocatalysis process, was constructed to efficiently produce chlorine dioxide for the enhanced degradation of the sulfamethoxazole antibiotic from aqueous solutions. The superiority of the combined ClO2-photocatalysis process compared to visible light photocatalytic system, and chlorine dioxide oxidation process was systematically investigated. The addition of chlorite in the BiOI-based visible light photocatalytic system achieved 100% removal of sulfamethoxazole within 30 min, surpassing both the photocatalytic system (16%) and chlorine dioxide oxidation process (70%). The degradation constant rate (k) was 0.0771 min−1, which was 2.7 times and 51.4 times higher than the chlorine dioxide oxidation process and photocatalytic system, respectively. Water matrix conditions including pH, inorganic ions, and organic matter had little effect on the degradation efficiency of sulfamethoxazole in the combined ClO2-photocatalysis process. Moreover, antibiotic-resistant bacteria can be effectively inactivated and the production of toxic chlorine-containing intermediates and disinfection byproducts is significantly inhibited. This combined ClO2-photocatalysis process takes advantage of photogenerated radicals to activate chlorite to chlorine dioxide, which not only promotes electron-hole separation, but also exhibits high efficiency, durability, resistance to external environment disturbances, and environmental safety, making it a good candidate for the efficient, green, and sustainable treatment of pharmaceutical wastewater.