Enhanced dual synergistic mechanism of adsorption and ozone triggering via biochar-derived zero-valent bimetal sites for water purification

Novel zero-valent iron (ZVI) and zero-valent zinc (ZVZ) bimetal-supported biochar (ZF@BC) was developed for heterogeneous catalytic ozonation (HCO), which demonstrated the unique dual synergistic adsorption and catalysis-induced effective O 3 triggering and interfacial decontamination. ZF@BC exhibited impressive catalytic and structure stabilities for 2-methyl-4-chlorophenoxyacetic acid (MCPA) degradation during long-lasting HCO, which can resist interference from a complex water quality background. Abundant electron-rich oxygen-containing functional groups and defects on BC contributed to the adsorption of MCPA and O 3 , respectively, while the introduced ZVZ was anticipated to expedite O 3 decomposition by facilitating single-electron transfer reduction of O 2 and establishing a robust connection with ZVI. Continuous efficacy of bimetal in three stages enhanced the efficiency of O 3 utilization and hydroxyl radicals ( • OH) yield, thereby safely mitigating the associated toxicity of MCPA after treatment. The development of O 3 /ZF@BC introduced a sustainable, long-term decontamination strategy and provided valuable insights for the advancement of HCO.