Adsorption and Inhibition of Rosin Thiourea Imidazole Quaternary Ammonium Salt on Steel Surface in Hcl Solution

Abstract

Rosin thiourea imidazole quaternary ammonium salt (RTIQAs) was synthesized by connecting rosin and imidazole units via thiourea linker. The inhibitive action of RTIQAs on the corrosion cold rolled steel (CRS) in 1.0 M HCl solution at four experimental temperatures of 20-40 oC. The results demonstrate that RTIQAs is an efficient inhibitor. Furthermore, weight loss method illustrates that the maximum inhibition efficiency can reach 95% with 100 mg L-1 RTIQAs. The adsorption rule on the CRS surface fully complies with Langmuir isotherm with the standard adsorption Gibbs free energy of about -42 kJ mol-1. RTIQAs is considered as a mixed-type inhibitor by significantly enhancing the charge transfer resistance onto steel/solution interface. The efficient inhibition of RTIQAs can also be verified by AFM, SEM and CLSM. The direct adsorption proof of RTIQAs molecules on steel sample in inhibited system can be further presented in EDX and XPS.

Keywords: Rosin, Quaternary ammonium salt, Corrosion inhibitor, Steel, Adsorption, Hydrochloric acid