Modelling realistic clay systems with ClayCode

TL;DR

ClayCode is a software tool that enables realistic molecular modeling of clay materials, revealing differences in ionic adsorption patterns compared to idealized models, with applications in nuclear waste management.

Contribution

The paper introduces ClayCode, a new software for modeling realistic clay structures, improving upon idealized models for better accuracy in simulating clay properties.

Findings

Realistic clay models differ significantly from idealized ones in ionic adsorption patterns.

ClayCode effectively simulates competitive adsorption of barium and sodium on various clays.

Application demonstrates relevance to nuclear waste disposal strategies.

Abstract

Clays are a broad class of ubiquitous layered materials. Their specific chemophysical properties are intimately connected to their molecular structure, featuring repeating patterns broken by substitutions. Molecular dynamics simulations can provide insight into the mechanisms leading to the emergent properties of these layered materials, however up to now idealised clay structures have been simulated to make the modelling process tractable. We present ClayCode, software facilitating the modelling of clay systems closely resembling experimentally determined structures. By comparing a realistic model to a commonly used montmorillonite clay model, we demonstrate that idealised models feature noticeably different ionic adsorption patterns. We then present an application of ClayCode to the study the competitive barium and sodium adsorption on Wyoming montmorillonite, Georgia kaolinite, and Montana illite, of interest in the context of nuclear waste disposal.