Computational and Electrochemical Study of Pyrantel as Alternative Green Corrosion Inhibitor of S275JR Mild Steel and 1100-H14 Aluminum Alloys in H2SO4 Acidic Environment

Abstract

Abstract The study on Recycling and application of Pyrantel as alternative corrosion inhibitor of S275JR mild steel and 1100-H14 aluminum alloys in 1 M H2SO4 acid environment was investigated adopting different experimental methods including weight loss, hydrogen evolution (gasometric), electrochemical impedance spectroscopic, potentiodynamic polarization and computational (quantum chemical calculations and molecular dynamic simulation) methods It was observed that pyrantel was a good inhibitor for both metals but with more inhibition on the 1100-H14 – type aluminum. Inhibition efficiency was recorded between 42.5% and 95.2% for aluminum at concentrations of 500 ppm and 1500 ppm respectively while 30.0% and 72.5% was recorded for S275JR mild steel at same concentrations as aluminum. This high inhibition efficient was attributed to the strong adsorption of the molecules on both metal surfaces. This result was in agreement with those of gasometric experiment. Electrochemical impedance showed higher and increasing values of charge transfer resistance and decreasing values for the double layer capacitance which indicated a better inhibition. From quantum calculations, the EHOMO values was higher than that of the ELUMO while the energy gap was calculated to be 1.9 with binding energy of 132.9. An indication that absorption was very strong and pyrantel is a good inhibitor. The data were in agreement with Langmuir adsorption isotherm as the correlation coefficient values were approximately unity indicating a physical adsorption and hence adsorption consists entirely of a monolayer at the surface.