Impurities Incorporation Nano-minerals associated to AMD: Structural Effects and in Arsenate Adsorption Mechanism

The release of Fe and Al from weathering of sulfide-bearing ores deposits and their host rocks leads to the formation of metastable nano-crystalline mineral phases such as schwertmannite and basaluminite. Both have been described as scavenger of potentially toxic elements (i.e., As and Cu) in solution, due to their high and charger surface area. However, this surface properties can be affected by impurity incorporation during precipitation processes. Recent titration and HEXD experiments showed that a limited Al incorporation in schwertmannite structure, strongly affected the surface coordination in sorbed arsenate. Here we propose a HEXD experiment where synthetic schwertmannite and basaluminite will be co-precipitated with Al and Si, respectively, at several pH. In addition, we aim to perform differential d-PDF analysis of arsenate adsorbed on pure and impure phases to probe the effect of impurities in the nano-mineral structure and its surface properties.