Title:
Investigating Inhibitory Actions of Expired Omeprazole in Sulphuric Acid as Corrosion Resistance of Mild-steel

Authors:
Okechukwu Dominic Onukwuli, Ifeanyi John Obibuenyi*, Linda Nnodi, Uchenna Luvia Ezeamaku, Joseph Okechukwu Ezeugo, Monday Omotioma, Nigeria

Abstract:

It is proposed to investigate the inhibitory actions of omeprazole in acid environments as corrosion resistance of mild-steel. This omeprazole was characterized for its functional groups and chemical constituents using Fourier transform infra-red spectroscopy and gas chromatography. Experimental techniques and gravimetric methods were also employed. The inhibitory effects of the drug were assessed and efficiencies optimized using response surface methodology RSM, and artificial neural network ANN, models. The predominant functional groups found were C-H, C=H, C=O, C- F, and C=C stretches; C=N and N=O stretching; and N-H deformation, and contains theophylline, n-hexa-decanoic acid, di-n-octyl phthalate and methyl tetra-triacontyl ether. The Gibbs free energy results were negative, indicating the flow of heat from the inhibitor-mild-steel interface at a seemingly higher temperature to the surroundings at a lower temperature. The adsorption of the inhibitor molecules was physical and not chemisorption. The Frumkin isotherm provided the best fit and optimum efficiency of 93.71% was attained. The ANN yielded better optimization results because it had a higher value of R² and lower values of root-mean-square-error RMSE and standard error of prediction SEP. The impedance method displayed a capacitive loop, signifying charge-transfer process-controlled, and polarization measurements showed that the drug was a mixed-type inhibitor. Available studies have not investigated inhibitory actions of Omeprazole in acidic environments. Hence, this study aims to fill this gap and has proved Omeprazole as an excellent inhibitor for controlling mild-steel corrosion in sulphuric acid media.

DOI: http://dx.doi.org/10.51505/ijaemr.2025.1010