Evaluation of the Corrosion Behavior of Steel in Sodium Chloride Solution in the Presence of SDS and Pterocarya Fraxinifolia Extract: A Comparison of a Synthetic Inhibitor with a Green Inhibitor

Corrosion inhibitors are widely used in closed systems to reduce corrosion. Green inhibitors have attracted considerable attention in recent years due to their renewability, biocompatibility, lower cost, and reduced environmental impact. In this study, the effects of a synthetic inhibitor (sodium dodecyl sulfate, SDS) and a green inhibitor (Pterocarya fraxinifolia extract) on the corrosion of carbon steel in ۳.۵ wt.% sodium chloride solution were compared. Electrochemical tests, including potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), as well as weight-loss measurements after prolonged immersion in inhibitor-containing solutions, were employed to evaluate the effects of the inhibitors. The optimum concentrations of SDS and Pterocarya fraxinifolia extract for achieving maximum inhibition efficiencies of ۸۶% and ۹۶% were determined to be ۵۰ ppm and ۳۰۰ ppm, respectively. The polarization resistance obtained from EIS increased by approximately ۱.۹ and ۱۳.۷ times upon the addition of the optimum concentrations of SDS and Pterocarya fraxinifolia extract, respectively, compared with the uninhibited solution, demonstrating the significant effectiveness of the green inhibitor in reducing corrosion. It should be noted that increasing or decreasing the inhibitor concentration from its optimum value resulted in a decrease in inhibition efficiency; nevertheless, the corrosion resistance remained higher than that of the uninhibited solution. SEM images of the corroded surfaces after ۴۸ h of immersion showed reduced surface roughness and fewer signs of corrosion in the presence of the inhibitors. The weight-loss results after ۲۱۶ h of immersion further demonstrated that Pterocarya fraxinifolia extract provided better long-term performance than SDS, reducing the corrosion rate from ۰.۷۲ to ۰.۱۸ mm/y and achieving an inhibition efficiency of ۸۱%, compared with ۶۶% for SDS.

کلیدواژه ها:

Green inhibitor ، Sodium dodecyl sulfate ، Pterocarya fraxinifolia extract ، Polarization ، Electrochemical impedance ، بازدارنده سبز ، سدیم دودسیل سولفات ، عصاره گیاه لرگ ، پلاریزاسیون ، امپدانس الکتروشیمیایی