ZnO-Ti3C2TX composites supported on polyacrylic acid/chitosan hydrogels as high-efficiency and recyclable photocatalysts for norfloxacin degradation

Abstract

Photocatalysts immobilized on hydrogels is a win-win mode, which not only improves photocatalysis but also successfully prevents catalyst loss, making it easy to separate and reuse during catalytic process. Here, ZnO-Ti₃C₂T_X photocatalysts are loaded into the chitosan/polyacrylic acid hydrogel networks, realizing the efficiently photocatalytic degradation of norfloxacin. The chitosan-based composite hydrogel features rich functional groups and a dense pore structure, which is beneficial to antibiotic enrichment and photocatalytic degradation. The effects of different catalyst ratios, dosage, initial concentrations and pH on the degradation efficiency are investigated. The norfloxacin degradation rate constant is 0.012 min⁻¹ and its degradation efficiency reaches up to 90 % after 240 min. Importantly, the photocatalytic composite hydrogel still retains 85 % degradation efficiency after 6 cycles. Moreover, e⁻ plays a significant role in the degradation process. This work converts the traditional powder photocatalysts into bulk photocatalysts (photocatalytic hydrogels) to accomplish efficient degradation and rapid recycling for contaminant removal.