Radical-/non-radical-mediated catalyst activation of peroxymonosulfate for efficient atrazine degradation.

Efficient degradation technologies are urgent to be developed to avoid the ecological and healthy hazards brought from atrazine (ATZ). LaCoO/peroxymonosulfate (PMS) system was proved to have strong degradation capabilities to contaminants. In this work, we intended to investigate the effect of the synthesis method on LaCoO. However, the hydrothermal method yielded a new material (H-Co) with better catalytic performance than LaCoO, which showed stable catalytic ability at pH 3.0-9.0 and 5 consecutive cycles. The coexistence of inorganic Cl, SO, NO, HPO, HCO and organic humic acids exerted little influences on the H-Co/PMS system. In addition, the actual livestock and poultry breeding wastewater could be well degraded and mineralized by the H-Co/PMS system. Free radical burst experiments and EPR characterization were performed to verify the synergistic effects of free radicals and non-free radicals during ATZ degradation. Based on SEM, XRD, O-TPD, FTIR, XPS, and electrochemistry characterizations, the efficient catalytic ability of H-Co could be attributed to the abundant oxygen vacancies, surface hydroxyl groups, zero-valent cobalt sites and high electronic conductivity. The degradation pathways were proposed based on the detection of degradation intermediates of ATZ by UPLC-MS. Moreover, the toxic of ATZ during the oxidation was evaluated by TEXT and E. coli inhibition assay. This work comprehensively analyzed the catalytic reaction mechanism of the H-Co/PMS system and provided a feasible pathway for the treatment of the actual livestock and poultry breeding wastewater.