Adsorptive and Anticorrosive Studies of Guar Gum and Halides with Mild Steel in Acidic Medium

The inhibitory effect of guar gum (GG) as a green inhibitor has been studied using a variety of methodologies, including weight loss, thermometric studies at 30-60 ºC. The potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron micrographs have been found to the good inhibitor for mild steel corrosion in H2SO4 (pH = 1) medium. Guar gum fits to the Langmuir adsorption isotherm when it adsorbs to metal surfaces. It has also been investigated how adding halides (KCl, KBr and KI) will affect the process. The findings demonstrated that guar gum concentration increased with inhibition efficiency (I%). All of the concentrations of guar gum are shown to be promoted by the inhibitive impact of guar gum in addition to halide ions. The trend Cl– < Br– < I– has been seen to improve inhibition efficiency (I%) and the extent of surface coverage (θ), which suggests that the electronegativity and radii of the halide ions play a significant role in the adsorption process. According to polarization curves, guar gum functions as a mixed-type inhibitor. The outcomes of gravimetric studies and electrochemical procedures were in good agreement. Based on thermodynamic characteristics and a comparison of the FT-IR spectra of pure and metal surface product, a thorough adsorption of the inhibitor molecules on the mild steel surface was proposed. When the synergism parameter (SI) was analyzed, it is found to be greater than unity, indicating that synergism alone is responsible for the increased inhibitory efficiency caused by the addition of halides.