2-(4-{[4-Methyl-6-(1-methyl-1H-1,3-benzodiazol-2-yl)-2-propyl-1H-1,3-benzodiazol-1-yl] methyl} phenyl) benzoic acid as green corrosion inhibitor for mild steel in 1 M hydrochloric acid

Present study describes the inhibition property of benzo 1,3-diazol 2-(4-{[4-Methyl-6-(1-methyl-1H-1,3-benzodiazol-2-yl)-2-propyl-1H-1,3-benzodiazol-1-yl] methyl} phenyl) benzoic acid (Telmisartan, Cresar-H) on mild steel corrosion in 1 M HCl using weight loss, electrochemical, and surface measurements. Results showed that the corrosion inhibition efficiency (η%) increases with increasing Telmisartan concentration and attained the maximum value of 97.39% at 125 mg L⁻¹ concentration. Polarization studies revealed that Telmisartan acted as cathodic type inhibitor. Electrochemical impedance spectroscopy (EIS) studies suggested that the Telmisartan inhibits mild steel corrosion by becoming adsorbate at the metallic/electrolyte surfaces. Among the several tested isotherms, adsorption of the Telmisartan on mild steel surface obeyed the Temkin adsorption isotherm. The values of the apparent activation energy (E_a) suggested that Telmisartan inhibited metallic corrosion by creating energy barrier for corrosion process. The adsorption of corrosion inhibition was well supported by SEM/EDX and AFM studies.