Metal cationic defect-enriched ZnMnAl-LDHs for photocatalytic ozonation of Bisphenol A under visible light

Bisphenol A (BPA), a persistent organic pollutant, is generally recognized for its significant risks on human health. This study introduces an innovative approach to BPA degradation using layered double hydroxides (LDHs) doped with metal cationic defects, synthesized through a combination of hydrothermal treatment and precise acid etching. These modifications introduced metal cationic defects that increased the availability of active sites. The defects also created a new defect energy level, reducing the band gap from 2.91 eV to 2.67 eV, enhancing visible-light absorption. The altered valence band position to 2.75 eV facilitated the generation of hydroxyl radicals (·OH). This approach achieved rapid decomposition of BPA and over 90 % efficiency in its mineralization under visible-light. The process of photocatalytic ozonation for TOC removal aligns with a second-order kinetic model, which was validated through the experiment. The experimental data was closely fitted the kinetic equation, yielding an activation energy of 12.17 KJ/mol. This development not only advances LDH photocatalysts' design but also extends the applicability of advanced oxidation processes (AOP) in water treatment, providing a robust solution for mitigating the impact of hazardous organic contaminants.