Lignin-Phenylhydrazone as a corrosion inhibitor of API X52 carbon steel in 3.5%NaCl and 0.1 mol/L HCl medium

Abstract

The best alternative to fight against corrosion is the use of an inhibitor, the purpose of this work is the formulation of a new biomass-based molecule against corrosion of carbon steel. Lignin was extracted using the Kraft process and phenylhydrazine molecules have been scratched. The influence of the lignin-phenyl-hydrazone(LP) on the corrosion of carbon steel in salt and the acidic medium was studied by the polarization resistance, the potentiodynamic polarization, and the electrochemical impedance spectroscopy. The results of these tests reveal that the behavior of the inhibitor is a mixed type. The adsorption mechanism of the inhibitor follows the Langmuir isothermal model. Gibbs energy shows that the process of inhibition of carbon steel is spontaneous. The SEM confirms that the inhibitor reduces the corrosion of the steel and stops the corrosion pitting phenomenon. The modified lignin shown as a good corrosion inhibitor in acid medium is highly saline with an efficiency > 96%