Biogenic α-Mn2O3 excels in areas where commercial α-Mn2O3 performs poorly: Native and advanced oxidation degradation of atrazine

In organic degradation, a prevalent perspective that biogenic manganese oxides possess enhanced catalytic ability compared to their chemical counterparts remains experimentally unvalidated. In this study, biogenic α-Mn 2 O 3 was proven to be superior to its chemogenic counterpart in atrazine degradation. In native degradation, biogenic α-Mn 2 O 3 achieved a 35.39–65.09 % degradation efficiency, while commercial α-Mn 2 O 3 showed no such ability. This is because biogenic α-Mn 2 O 3 generated greater amounts of reactive oxygen species than commercial α-Mn 2 O 3 (the contribution order for atrazine degradation was 1 O 2 > • OH >> O 2 •−) . In advanced oxidation, only periodate was efficiently activated by biogenic α-Mn 2 O 3 , achieving a 79.79 % degradation efficiency. Comparatively, the corresponding efficiency for commercial α-Mn 2 O 3 was 18.58 %. This discrepancy is due to the significantly higher levels of • OH and O 2 •− generation in the biogenic α-Mn 2 O 3 /periodate system (the contribution order was • OH > O 2 •− ). Importantly, the (332 ) and (222) crystal planes of biogenic α-Mn 2 O 3 exhibited a higher catalytic ability than the (211) plane in activating periodate to produce • OH and O 2 •− . The N(8)-C(10), C(17)-C(23), and N(9)-C(17) bonds in atrazine were susceptible to attack by • OH, while the C(3)-Cl(7) bond was liable to be attacked by O 2 •− , ultimately resulting in the formation of seven intermediates.