The Theoretical Investigations and Molecular Dynamic Stimulation of Isoniazid as a Corrosion Inhibitor

API5L Steel is known as one of the most useful materials on earth which is also subject to corrosion in certain environments. Many methods have been used to minimize its corrosion, but the use of inhibitors is widely accepted. The use of green inhibitors has gained wide usage because of their environmental friendliness. The theoretical investigations of isoniazid as corrosion inhibitor was carried out using Fourier transform infrared spectroscopy (FTIR), whereas theoretically, quantum chemical parameters and molecular dynamic simulations of the inhibitor were studied. The analyses of the experimental results showed that the expired drug (isoniazid) decreased the corrosion rate of API5L steel in a 0.5M H2SO4 medium. The inhibition efficiency decreased with a decrease in inhibitor concentration. FTIR results showed that the inhibition mechanism is physical through the functional groups present in the expired drug. Relying on quantum chemical parameters and molecular dynamic simulations results, the adsorption/binding strength of the concerned inhibitor molecule on API5L steel surface follows a good order. The computed adsorption/binding energy values (Eads) for the various isolated concentrations from the inhibitor indicate the adsorption process to be non-covalent (physiosorption) which is in good agreement with the literature.