Efficient degradation and detoxification of bisphenol analogues through carbon doping and oxygen-vacancy co-modification of BiVO4: risk assessment of BPA alternatives based on toxicity monitoring

The unregulated use and abuse of bisphenol analogues (BPs) have led to a sharp increase in environmental concentrations. Although photocatalytic technology can effectively degrade these compounds, insufficient attention has been paid to the ecological risks posed by both the parent compounds and their degradation products. In this study, BiVO 4 co-modified with oxygen vacancies and carbon (BVO-3) was successfully prepared via molecular intercalation combined with calcination. This material exhibited significantly enhanced photocatalytic degradation performance toward various BPs. Structural characterization and in-situ spectral analysis indicated that oxygen vacancies act as a dynamic “electron reservoir”, working synergistically with carbon doping to promote the separation of photogenerated carriers. Carbon doping not only enhances pollutant adsorption through π–π conjugation but also, together with oxygen vacancies, improves the activation of molecular oxygen. Toxicity assessment revealed that although the parental toxicity order was BPAF > BPF > BPA, the intermediates of BPAF and BPF exhibited a transient toxicity surge exceeding that of their parent compounds during the early photocatalytic stage. This is attributed to the generation of numerous breakdown products that retain the core toxic structure. In contrast, no such effect was observed for BPA. These findings indicate that, contrary to their intended purpose as safer alternatives, BPAF and BPF pose higher ecological risks during environmental transformation due to the formation of highly toxic intermediates. This study not only developed a method for constructing efficient modified photocatalysts but also proposed that “transformation process toxicity evolution” should be included in the comprehensive ecological risk assessment of pollutants and their substitutes.