Regulatory Mechanisms of Carboxylic Ligands with Varying Carboxyl Group Richness in Fe(II)-Catalyzed Ferrihydrite Transformation

This study focuses on how organic molecules with different carboxyl contents control every step of the Fe(II)-catalyzed transformation of ferrihydrite (Fh), thus influencing the transformation kinetics and the phase assemblage of products. Four typical carboxylic ligands representing mono-, di-, and tri-carboxylic types were chosen. By separating individual reaction steps, the study uncovered the specific impacts of these ligands on Fe(II) adsorption on Fh, Fe(II)-Fh interfacial electron transfer, and the repolymerization of labile Fe(III) into secondary minerals.