Thermodynamic characterization of metal dissolution and inhibitor adsorption processes in mild steel / 3,5-bis(3,4-dimethoxyphenyl)-4-amino- 1,2,4-triazole / hydrochloric acid system

Abstract

New 3,5-disubstituted-4-amino-1,2,4-triazole derivative, namely 3,5-bis(3,4-dimethoxyphenyl)-4-amino-1,2,4-triazole (3,4MAT) was synthesised and its inhibitive action against the corrosion of mild steel in 1 M HCl solution was investigated at 308 K. The detailed study of 3,4-MAT was been performed using gravimetric measurements and polarisation curves method. Results show that 3,4-MAT is a good inhibitor and its inhibition efficiency reaches 98 % at·10 �3 M. Tafel polarisation study revealed that 3,4-MAT acts as a mixed type inhibitor. The inhibitor adsorption process in mild steel/3,4-MAT /hydrochloric acid system was studied at different temperatures (308-323 K) by means of weight loss measurements. The adsorption of 3,4MAT on steel surface obeyed Langmuir’s adsorption isotherm. The kinetic and thermodynamic parameters for mild steel corrosion and inhibitor adsorption, respectively, were determined and discussed