Solvated calcium ions in charged silica nanopores

摘要: Hydroxyl surface density in porous silica drops down to nearly zero when the pH of confined aqueous solution is greater than 10.5. To study such extreme conditions, we developed a model slit nanopores where all hydrogen atoms hydroxylated are removed and negative charge resulting oxygen dangling bonds compensated by Ca2+ counterions. We employed grand canonical Monte Carlo molecular dynamics simulations address how counterions affect thermodynamics, structure, water. While most arrange themselves according so-called “Stern layer,” no diffuse layer observed. The presence affects pore filling for strong confinement effects large. At full loading, significant changes observed layering first two adsorbed water layers compared with fully surfaces. However, structure orientati...