Advanced Monte Carlo approach to study evolution of quartz surface during the dissolution process

Area of Science:

• Geochemistry
• Computational Science
• Materials Science

Background:

• Mineral dissolution and precipitation are complex surface processes.
• Understanding these reactions is crucial for geochemistry and materials science.
• Existing methods have limitations in simulating mineral-water interfaces.

Purpose of the Study:

• To develop a novel Monte Carlo algorithm for simulating mineral surface reactions.
• To investigate the interplay between dissolution and precipitation.
• To understand the role of surface topography and reactive sites in mineral dissolution.

Main Methods:

• A new time-independent Monte Carlo algorithm was developed.
• The algorithm integrates reactive and configurational-biased Monte Carlo techniques.
• Simulations focused on quartz-water interfaces in neutral pH.

Main Results:

• The direct dissolution mechanism results in unrealistic complete dissolution.
• The stepwise dissolution mechanism accurately reflects experimental steady-state dissolution.
• Least coordinated surface sites (Q(1)) are identified as primary reactive sites for hydrolysis and precipitation.

Conclusions:

• Stepwise dissolution is a more geochemically relevant mechanism for quartz.
• Surface topology significantly influences dissolution and precipitation processes.
• The findings are applicable to various silica polymorphs and protonation conditions.