Assessment of biodegradable glycine and glutamic acid based ionic liquids as mild steel corrosion inhibitors in acid solution: an experimental and theoretical approach

Abstract

The current work deals with assessment of amino acid-based ionic liquids (ILs) namely glycine propyl ester lauryl sulfate (GlyC(3)LS) and glutamic acid propyl ester lauryl sulfate (GluC(3)LS) as corrosion inhibitors of Mild steel (MS) in acid media (1M HCl). The ILs were synthesized and their corrosion inhibiting potential have been studied in the test solution for MS by employing gravimetric and electrochemical measurement techniques. The results revealed GluC(3)LS better inhibitor of MS corrosion as compared to GlyC(3)LS, with 99.81% inhibiting effect. Langmuir model of adsorption isotherm was best modeled for the inhibitors under study in order to ascertain their adsorption characteristics. EIS studies indicated the establishment of adsorbed film at the interface of mild steel-electrolytic solution by the molecules of both ILs. The existence of the absorbed ILs' film was affirmed by scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDX). The origination of complex between the ILs-MS surface was affirmed by Fourier transform infrared (FT-IR) spectroscopic experiments. All the outcomes from experimental finding and theoretical calculations (density functional theory (DFT) calculations and Molecular Dynamic (MD) simulation studies) are in line. (C) 2021 Elsevier B.V. All rights reserved.