Adsorption and corrosion inhibiting behavior of a new S-triazine derivative

Abstract

The inhibiting effect of 4, 6-bis (5-mercapto-1, 3, 4-thiadiazol-amine)2-phenylamino-1,3,5-triazine BMTDT on the corrosion of mild steel in acidic media has been investigated by weight loss and electrochemical methods. Results obtained reveal that this organic compound is a very good inhibitor. BMTDT is able to reduce the corrosion of steel more effectively in 1M HCl than in 1 M H2SO4. The effect of polarization studies show that the adsorption of BMTDT follows physical adsorption in both acids without changing the mechanism of the hydrogen evolution reaction. Surface analyses were also carried out to establish the mechanism of corrosion inhibition of mild steel in acidic media. The adsorption of this inhibitor on the mild steel surface in obeys the Langmuir absorption isotherm in 1 M HCl and Frumkin adsorption isotherm in 1M H2SO4. The corrosion behavior of mild steel with addition of different concentration of BMTDT was studied in the temperature range 308–333 K. The associated activation parameters and adsorption free energies have been determined and discussed.