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

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 (H 2 O 2 ) over a pH range from 5 to 9. The results indicated that the addition of siderite generally accelerated the conversion process of H 2 O 2 to ·OH regardless of initial pH values. However, the conversion ability from H 2 O 2 to ·OH was only enhanced under the acidic condition. Then, X-substituted siderite generally enhanced the conversion rate and inhibited the capacity of H 2 O 2 to ·OH under neutral and alkaline conditions. The Mn, Ca, and Mg-substituted siderite facilitated both conversion rate and capacity of H 2 O 2 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 Fe 2+ and contributes to the H 2 O 2 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 H 2 O 2 to ·OH.