Molecular Dynamics Study On The Interaction Mechanism Of Inhibitors For The Calcite Crystal Growth

To prevent the formation of water scale, people try to use different traditional methods: either physical methods or chemical methods. In these methods, adding scale inhibitors to prevent the crystallization of hardly dissolved salts is widely used because its convenience and high economic effect. As there are complicate physical and chemical process such as diffusion, adsorption and crystal growth etc, the mechanism of scale inhibitor works is still unclear. Today, the development of new scale inhibitors in the world is still depending on experiments or experience-deduced methods, which causes many wastes in money, time and manpower. So, it deadly needs to develop a guide-theory. In this paper, the mechanism of inhibiting-additives works is studied by molecular dynamics simulation and the theoretical analyses are given out, which are prospected to provide some useful information for new inhibitors development.Referring to the widely used inhibitor of carboxyl-acid polymer nowadays, the interaction of poly Propyl-acrylate (PPA) on calcite surface is simulated using molecular dynamics method. The results indicate that PPA can inhibit the adsorption of Ca 2+, CO32?on calcite surface effectively and the middle chain has a better effect than the end. Furthermore, different polymerized-degree of PPA molecules'(n=1~10) interaction on calcite surface are studied and the result showed that on the whole, the more chain the PPA has, the more effect it has but the n=8 PPA shows a best inhibition effect, the molecular that has a more polymerized-degree distorted more and its inhibition effective descend in some degree.Metallic ions, such as , , and , have a strong influence on the calcite crystal precipitation and growth. At present, the inhibition-effect of is studied most widely, but all the studies used experimental method. In this paper, molecular dynamics method is used to simulate the interaction of and respectively on the two surfaces of calcite in the same condition (the initial position of ions on each surface as well as the temperature is the same). The results indicate that can inhibit the precipitation and growth of calcite effectively. The binding energy of on calcite surface is greater than that of , which may cause a prior adsorption of , so it is easily to form a crystal adulterating with which results in a distortion in the calcite crystal. Mg 2+Ba 2+Mn 2+Sr2+Mg2+Mg 2+Ca2+Mg2+Mg 2+Ca2+Mg 2+CaCO3Mg2+...