The effect of isomorphic substitution on siderite activation of hydrogen peroxide: The decomposition of H2O2 and the yield of ·OH

Abstract To investigate the effect of isomorphic substitution on siderite activation of hydrogen peroxide, different X-substituted siderite (X = Mn, Co, Ca, and Mg) was artificially synthesized and utilized to activate hydrogen peroxide (H2O2) over a pH range from 5 to 9. The results indicated that the addition of siderite generally accelerated the conversion process of H2O2 to ·OH regardless of initial pH values. However, the conversion ability from H2O2 to ·OH was only enhanced under the acidic condition. Then, X-substituted siderite generally enhanced the conversion rate and inhibited the capacity of H2O2 to ·OH under neutral and alkaline conditions. The Mn, Ca, and Mg-substituted siderite facilitated both conversion rate and capacity of H2O2 to ·OH under weakly acidic conditions, while Co-substituted siderite inhibited both compared to the raw siderite. The element substitution mainly affected the stability of siderite, which resulted in the dissolution of siderite to generate Fe2+ and contributes to the H2O2 decomposition and the ·OH generation. Findings from this research suggested that the isomorphic substitution of siderite had a non-negligible impact on the transformation of H2O2 to ·OH.