Highly efficient eco-friendly drug inhibitors for Q235 steel in 1 M HCl: Experimental & theoretical study

The issue of environmental pollution has received considerable critical attention in recent years. It is necessary to develop the green and efficient corrosion inhibitors. In this paper, the inhibition of doxazosin mesylate (DM) and terazosin hydrochloride (TH), as green corrosion inhibitors, were explored systematically by electrochemical impedance, polarization curves, SEM, AFM and contact angle. The effect of different heterocyclic amounts on the corrosion inhibition efficiency for Q235 steel in 1 M HCl was also discussed. It was found that DM showed the better performance than TH, with the best corrosion inhibition efficiency of 96.4 % at 1 mg/L. The FTIR and XPS analysis of the corroded Q235 steel surface revealed that the two drugs formed adsorption films on the steel surface and the types of adsorption were chemical and physical adsorption. Finally, the mechanism of the two drugs was analyzed in detail by isothermal adsorption simulations, quantum chemical calculations and molecular dynamics simulations.