Elimination of atrazine through radical/non-radical combined processes by manganese nano-catalysts/PMS and implications to the structure-performance relationship

Abstract

In this study, a series of Mn based catalysts with different oxidative states, crystal structures and morphologies was applied to activate peroxymonosulfate (PMS) for the degradation of atrazine (ATZ). Among them, α-MnO2 nanowires (Mn-1) demonstrated the highest efficiency. The structure-performance relationship study revealed that the generation of Mn(III) along with the transformation of lattice oxygen to surface hydroxyl groups played the dominant role in controlling the efficiency, and Mn-1 are prone to undergo electron transfer to achieve the transition from Mn(IV) to Mn(III) or even Mn(II). Both radical (sulfate radical (SO4•−) and hydroxyl radical (•OH)) and non-radical species (1O2) contributed to ATZ degradation and accordingly inhibit the formation of toxic BrO3− from Br−. Sixteen intermediates were identified in proposed degradation pathways. The toxicity tests, the consistent performance with coexisting anions and humic acid in water matrix, and the satisfying reusability implied the sustainable application of Mn-1/PMS in future.