This project will continue to research of an interdisciplinary team to establish an accurate theoretical model of the electrical double layer at the surface of 2:1 clay minerals suspended in 1-1 and 2-1 electrolyte solutions. The research proposed has become feasible recently because of important, new results obtained by the Principal Investigators and other researchers. The renewal project objectives are: (I) To perform Monte Carlo simulations of the ion distributions in a 1-1 electrolyte near the surface of a 2:1 clay mineral, including fully molecular-scale water-water, water-ion, and ion-ion interactions. (II) To perform statistical mechanical calculations of the interactions ("swelling pressure") between planar charged surfaces immersed in 1-1, 2-1, and 1-2-1 electrolyte solutions. The results obtained will provide a significantly-improved, quantitative foundation for the surface chemistry of 2:1 clay minerals as it occurs typically in mineral weathering and diagenesis.
