Experimental and Computational Chemistry Investigations of Tartaric acid as a Green Corrosion Inhibitor for API 5L X 52 Carbon Steel in 0.5 M HCl

Abstract

Uduak Bassey Essien, Magdalene E. Ikpi and Alexander I Ikeuba and Nsikak Bassey Essien

Investigation of suitable corrosion inhibitor for API 5L X 52 carbon steel in 0.5 M HCl, is of significant industrial importance because of the role of the metal in several sectors. Tartaric acid was tested as a corrosion inhibitor for the metals using weight loss, potentiodynaic polarization and electrochemical impedance methods. The tested compound displayed maximum inhibition efficiency of 85%, which showed a strong dependency on concentration, temperature and time. Spontaneous and exothermic physical adsorption of the inhibitor on the metal surface was ascertained as the mechanism of inhibition. Isotherms established by the Langmuir and Freundlich assumptions fitted the adsorption process Information from computational chemistry calculations indicated significant roles of the frontier molecular orbitals towards the inhibition of the metal corrosion. Also, the sites for electrophilic, nucleophilic and radical attacks were observed to be within the carboxyl functional groups.