SCALE INHIBITION OF SODIUM CARBOXYMETHYL CELLULOSE AT DIFFERENT GROWTH STAGES BASED ON MOLECULAR DYNAMICS SIMULATION

Sodium carboxymethyl cellulose (SCMC) effectively inhibits the growth of calcium carbonate (CaCO3) scale. In order to investigate the effect of temperature on the scale inhibition of SCMC, dynamics simulations were carried out for the amorphous calcium carbonate and crystal calcite system based on molecular dynamics simulation. The effect of temperature on the scale inhibition mechanism of SCMC has been revealed. The results show that the mechanism of interaction between CaCO3 and SCMC was mainly composed of electrostatic interactions and hydrogen bond. The scale inhibition efficiency of SCMC in two different growth stages increases with the increasing temperature in the range from 303 K to 323 K. In the solution system of SCMC and amorphous CaCO3, SCMC is easy to react with free calcium ions in solution, which reduces the amount of freedom in the solution and prevents the formation of calcium carbonate. However, in the solution system of SCMC and calcite, the energy of binding between SCMC and calcite plane increases with the increase of temperature, which makes SCMC adsorbed on the surface of calcite crystal and hinders the regular growth of calcite crystal.