Pyrite (FeS2) is the most abundant sulfide mineral, exerting significant influence on the environment. In natural waters, pyrite oxidation contributes to acid mine drainage by producing sulfuric acid and iron oxyhydroxides. Reactivity at the pyrite-water interface has been the subject of many computational and experimental studies. However, the structure of the pristine pyrite surface, and the changes that occur with oxidation, have not been determined in situ. In this work, X-ray crystal truncation rod (CTR) analysis was used to evaluate the atomic-scale structure of the pyrite surface. To better understand the influence of electrochemistry on environmentally relevant reactions at this interface, CTR measurements were conducted at varying potential and electrolyte solutions using a newly developed in-situ electrochemical cell.<br/>The results of this work show the structural changes at the pyrite-electrolyte interface under applied potential, and investigate the influence of electrochemistry on the adsorption of aqueous metal ions. These experiments highlight a relatively new development in synchrotron-based methods for studying mineral-water interfaces, expanding the range of CTR sample environments to include in-situ electrochemical analysis.

Electrochemical studies of the pyrite-electrolyte interface structure

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.