Thermodynamics and electrochemical investigation of (4-(2-amino-6-(cyclopropylamino)-9H-purin-9-yl) cyclopent-2-enyl) methanol sulphate as green and effective corrosion inhibitor for mild steel in 1M hydrochloric acid

The inhibition effect of new drug namely Abacavir sulfate ((4-(2-amino-6-(cyclopropylamino)-9H-purin-9-yl) cyclopent-2-enyl) methanol sulphate) on mild steel has been investigated using potentiodynamic polarization, linear polarization (LPR), electrochemical impedance spectroscopy (EIS) and weight loss measurements. The adsorption of the Abacavir was well described by the Langmuir adsorption isotherm and the adsorption isotherm parameters (K_ads, ΔG_ads) were also determined. Effect of temperature on the efficiency of the corrosion inhibition process was studied and the values of activation energy, pre-exponential factor (λ), enthalpy of activation and entropy of activation were also calculated to elaborate the mechanism of corrosion inhibition. Tafel polarization measurements revealed that Abacavir is a mixed-type inhibitor. EIS plots indicated that the addition of Abacavir increases the charge-transfer resistance (R_ct), decreases the double-layer capacitance (C_dl) of the corrosion process. Abacavir showed maximum efficiency 97.7 % at 400 ppm. The LD₅₀ dose for rat is 3200 mg/kg this shows that the drug is non-toxic and environmentally safe.