Effect of surfactant addition to Guar Gum and protection of mild steel in hydrochloric acid at high temperatures: Experimental and theoretical studies

Abstract

Guar Gum (GG) is an established green inhibitor for mild steel (MS) corrosion in acidic media. The inhibitor action of GG is enhanced by the synergistic interaction with two non-ionic surfactants (Tween -80 and Triton-X). The synergistic pairs were investigated for MS corrosion in 0.5 M HCl using weight loss and electrochemical methods. The synergistic interactions were monitored via theoretical calculations using NBO analysis implemented in Gaussian-09 packages. AFM, SEM, and XPS spectra were carried out to understand the surface events. Computational calculations (DFT and Monte Carlo simulation) were performed to ensure the synergistic action of GG and surfactants. Experimental results revealed that GG:Tween -80 offers 97.13% and GG:Triton-X has 95.50% inhibition efficiency when used in 800: 5 ppm ration at 303 K. The synergistic pairs exhibited remarkable efficiencies at elevated temperatures also.