Evaluation of the effectiveness of gabapentin as a corrosion inhibitor for mild steel in a 1 M hydrochloric acid environment using theoretical and experimental methods

Gabapentin (Neurontin) is an anticonvulsant drug primarily used to treat neuropathic pain and partial seizures. The anti-corrosion property of Gabapentin on mild steel in 1 M HCl was reported for the first time, and the inhibition properties of this drug material were characterized by gravimetric analysis, thermodynamic analysis, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), atomic force microscopy (AFM) and contact angle measurements. The obtained results show that Gabapentin is an excellent anti-corrosion inhibitor (90.3% at 400 ppm) at 303 K. Gabapentin is adsorbed onto a metal surface by a physical and chemical adsorption mechanism, as shown by the Langmuir adsorption isotherms. Electrochemical analyses show that Gabapentin acts as a mixed-type inhibitor. The electrochemical impedance spectroscopy data indicate that the charge transfer process suppresses the corrosion reaction. SEM-EDX tests of the inhibited steel sample show that the inhibitor significantly improved the surface morphology. AFM and Contact angle measurements indicated the surface roughness reduces in the presence of inhibitor. The data is overwhelming in favour of using and applying Gabapentin as a non-toxic green inhibitor for mild steel.