Interactions of Organic Molecules with Calcite and Magnesite Surfaces

Abstract

This paper presents molecular dynamics simulations of methanoic acid and methylamine molecules interacting with various calcite and magnesite surfaces in aqueous conditions. A new set of potentials for the interaction of nitrogen atoms with mineral surfaces is fitted and tested using ab initio methods. The results show that methanoic acid adsorption is stronger than methylamine adsorption onto calcite and magnesite surfaces. The competition between the surface water structure and the adsorbing molecule is shown to be a major component of the adsorption energy and explains why adsorption is stronger at particular surface indices and onto calcite surfaces rather than magnesite surfaces.