Adsorption and corrosion inhibition of new synthesized thiophene Schiff base on mild steel X52 in HCl and H2SO4 solutions

• The new synthesized Schiff base L is efficient inhibitor in HCl and H2SO4.
• Inhibition efficiency of L increases with increasing the L concentration.
• The Schiff base L acts by physical and chemical adsorption on mild steel X52.
• The adsorption behavior of L obeys Langmuir adsorption isotherm.

(NE)-N-(thiophen-3-ylmethylidene)-4-({4-[(E)-(thiophen-2-ylmethylidene)amino]phenyl}m-ethyl)aniline (L) was synthesized and its inhibiting action on the corrosion of mild steel X52 in 1 M hydrochloric acid and 1 M sulfuric acid was examined by different corrosion methods, such as weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The experimental results suggest that this compound is an efficient corrosion inhibitor and the inhibition efficiency increases with the increase in inhibitor concentration. Adsorption of this compound on mild steel surface obeys Langmuir’s isotherm. Correlation between quantum chemical calculations and inhibition efficiency of the investigated compound is discussed using the Density Functional Theory method (DFT).