Quantum Chemistry Study on Scale and Corrosion Inhibition Performance of Polyaspartic Acid

Abstract

Abstract The corrosion and scale inhibitions performance of polyaspartic acid (PASP) was invesgated based on the quantum chemistry calculation method of semi-empirical method by using the software of GaussView 6 and Gaussian 16.The calculation results show that, for scale inhibition, as the nitrogen atoms of PASP molecules and the oxygen atoms in carboxyl group were electronegative, which caused the electrostatic interaction to happen easily between the oxygen ions of carboxyl and the calciumions on the calcite surface, in addition, the space between the two nitrogen, oxygen ions in PASP molecule was exactly matched the space between the calcium ions on the calcite surface, the adsorption effect of the scale inhibitor to the calcite surface was obviously improved, thereby, the aim that inhibiting CaCO3 scale was achieved, the calculation results were in accordance with the test results. For corrosion inhibition performance, the HOMO energy, the LUMO energy and the difference of the two values was gotten through the calculation. The results were coincident with the mechanism description, and the calculation results were consistent with the test results.