New insights into the depression performance and mechanism of Fe(III) ion on the sulfidation of smithsonite: A DFT perspective

In this work, we have innovatively performed density functional theory (DFT) calculations on surface structures, adsorption structures, and electronic properties of smithsonite surface to study the depression mechanism of Fe(III) ion on the sulfidation of smithsonite. We found that the pre-adsorption of Fe(III) ion greatly reduced the reactivity of the surface of smithsonite, and the adsorption energies for HS on smith-sonite surface with Fe(III) ion pre-adsorption were evidently less exothermic than those without Fe(III) ion pre-adsorption. In addition, we found that the resulting Fe-S bonds on Fe(III) ion pre-adsorbed smithsonite surface were weaker and more unstable compared with the Zn-S bonds on the surface with-out Fe(III) ion pre-adsorption. Moreover, we found that without Fe(III) ion pre-adsorption, the hindrance of the hydration shell on smithsonite surface to HS was relatively small. However, with Fe(III) ion pre -adsorption, the hindrance of the hydration shell on smithsonite surface to HS became stronger. Thus, the sulfidation of smithsonite was depressed by Fe(III). This work uncovers the inhibition performance and mechanism of Fe(III) ion on the sulfidation of smithsonite at the microcosmic scale, which can help understand the depression effect of Fe(III) ion on the sulfidation of smithsonite in more depth.(c) 2022 Elsevier B.V. All rights reserved.