Coating of Akaganeite on Sand

Abstract

The study of sand coating with the iron oxide akaganeite (Ak) was conducted to find the optimal coating conditions for the best attachment of the Ak mineral to the sand. The mineral growth on the surface of sand can dictate the reactivity of the redox reaction between iron ion and redox-active contaminants. Aiming to increase the environmental relevance, this study added this form of iron oxide to sand as could be found in groundwater aquifers. The parameters used for sand coating include pH value, the ratio of the sand to Ak, the method of coating using either the dry or suspended particles, ionic strength, and length of exposure for coating. This study found that the conditions for the best Ak attachment to sand include the usage of Ak in suspension instead of dry Ak, at a pH of 5, using an acid for pH adjustment which does not contain chlorine ions. This project provided a reproducible procedure for coating Ak onto sand, which will be used to study iron oxides reactivity in model environmental systems.