Simulation of the relationship between calcium carbonate fouling and corrosion of iron surface

Abstract

The heat resistance will increase dramatically with the adhesion of fouling, resulting in the decrease of heat exchange efficiency. To study the relationship between calcium carbonate fouling and corrosion of iron surface, the most stable adsorption site of Ca2+, charge transfer process during adsorption and electronic density of states were analyzed. Additionally, the adsorption of fouling ions on Fe(111) and Fe2O3(001) surface were simulated with methods of first-principles and molecular dynamics, respectively. Results reveal that the most stable adsorption position of Ca2+ on Fe(111) surface is at triple hole site. Ca2+ will get charge from the top Fe atoms and then the Fe atoms become more active and susceptible to be electrochemically corroded. Diffusivity of Ca2+ in CaCO3 aqueous solution on Fe2O3(001) surface is larger than those on Fe(111) surface, which manifests that the fouling ions are prone to adhere to the corroded surface and the process of fouling deposition is accelerated at the same time. The work provides evidence that fouling ions in the aqueous solution are closely related to the corrosion. Thus, the combined role of corrosion resistance and anti-fouling performance should be taken into consideration during the surface optimization.