Corrosion Inhibition by Green Synthesized Inhibitor: 4,4′-(1,4Phenylene)bis(6-amino-3-methyl-2,4dihydropyrano[2,3-c]pyrazole-5 carbonitrile) for Mild Steel in 0.5 M H₂SO₄ Solution

The corrosion inhibition performance of the synthesized green compound namely: 4,4′-(1,4phenylene)bis(6-amino-3-methyl-2,4 dihydropyrano[2,3-c]pyrazole-5-carbonitrile) (BPP) has been tested for mild steel (MS) in 0.5 M H₂SO₄. Two techniques (gravimetric and electrochemical) have been utilized to evaluate the corrosion inhibition performance of BPP. The experimental results indicate that BPP shows excellent inhibition efficiency, i.e. 98% at 150 mg L^{− 1}. Langmuir adsorption isotherm was fitted well for the adsorption of BPP molecules on MS surface. The electrochemical technique such as electrochemical impedance spectroscopy results revealed increase in charge transfer resistance in presence of BPP and polarization study indicates mixed type of inhibitor action. The surface morphology for MS with and without BPP was studied by scanning electron microscopy and atomic force microscopy which suggested corrosion retardation in the presence of BPP.