Inhibitory effect of a new isoniazid derivative as an effective inhibitor for mild steel corrosion in 1.0 M HCl: combined experimental and computational study

Controlling corrosion of metals such as mild steel (MS), which is extensively employed in various industrial fields, is a topic of great interest for researchers and scientists. At the same time, designing highly effective and environmentally friendly corrosion inhibitors is most desired yet still challenging. In this context, this study focuses on the use of a new corrosion inhibitor namely (E)-N′-(4-(2-(methyl(pyridin-2-yl)amino)ethoxy)benzylidene) isonicotinohydrazide (INH) as efficient, sustainable inhibitors for MS corrosion in acidic medium (1.0 M HCl). Different chemical, electrochemical and theoretical approaches were used to study and give new insights into the mechanism of corrosion protection of MS by the synthesized isonicotinohydrazide derivative. Experimental results disclosed that this compound could effectively control and reduce the corrosion of MS through physicochemical adsorption, which follows the Langmuir isotherm model. Potentiodynamic polarization technique (PDP) showed that the studied inhibitor affects both anodic and cathodic reactions; thus, it demonstrated that it is a mixed-type inhibitor. Moreover, surface characterization of metal by scanning electron microscope confirms that our inhibitor is subject to strong adsorption over the iron surface. Besides experimental techniques, theoretical approaches like DFT calculations, molecular dynamics simulation and radial distribution function were used to give precise information about the mechanism of corrosion inhibition and unveiled factors controlling the performance of the investigated inhibitor.