Abstract
The chemical dissolution of galena(001) surfaces immersed in acidic and neutral sulfate electrolyte solutions was investigated using Electrochemical Scanning Tunneling Microscopy (ECSTM). The nanometer-scale detail provided by the STM in this investigation provides new mechanistic information regarding surface dissolution processes at the mineral/water interface. In acidic solutions (pH = 2.7), we observe that dissolution occurs by selective removal of step edge species. This process is crystallographically anisotropic, resulting in steps with 〈110〉 orientations. Under neutral pH conditions (pH = 7), the dissolution rate is significantly lower, and no preferential step edge orientation is observed. The anisotropy observed in acidic solutions is attributed to different kinetic rates of dissolution along the 〈110〉 and 〈100〉 directions. Furthermore, we propose that the rate limiting step in the dissolution mechanism is the desorption of hydrosulfide (HS −) from step edges. The origin of the crystallographic anisotropy is discussed in terms of possible atomic structures of the step edges.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
