Effect of an Environmentally Friendly Diisooctyl Sebacate-based Mixed Corrosion Inhibitor on Reinforcing Steel

Abstract

Corrosion protection of reinforcing steel in concrete is an urgent task in modern society. Use of corrosion inhibitors in concrete is an effective, simple, and economical method for protecting reinforcing steel from corrosion. Mixed corrosion inhibitors usually perform better than a single inhibitor in actual reinforced concrete systems because of their synergistic inhibition effects. In recent years, environmentally friendly corrosion inhibitors have attracted increasing attention from corrosion researchers. Diisooctyl sebacate and sodium D-gluconate are environmentally friendly organic corrosion inhibitors, and ZnSO4 is an inorganic cathodic inhibitor, they may form an innovative, nontoxic, and pollution-free mixed corrosion inhibitor to control reinforcing steel corrosion. Additionally, diisooctyl sebacate and sodium D-gluconate serve as absorption-type inhibitors, and ZnSO4 acts as a precipitation-type inhibitor. We hypothesized that their combination might show a good synergistic corrosion inhibition effect on reinforcing steel. In this study, we developed a diisooctyl sebacate-based mixed corrosion inhibitor that includes D-gluconate and ZnSO4 and investigated its synergistic inhibition effects on reinforcing steel (Q235 steel) corrosion in a simulated polluted concrete pore solution. The reinforcing steel corrosion behavior and the properties of the mixed corrosion inhibitor were studied by polarization curve measurements, electrochemical impedance spectroscopy tests, and surface analysis methods (scanning electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy). The results indicated that the reinforcing steel in the simulated polluted concrete pore solution (pH 11.00, 0.5 mol•L −1 NaCl) was in an active dissolving state and that localized corrosion took place. The mixed corrosion inhibitor, consisting of diisooctyl sebacate (59 mmol•L −1 ), sodium D-gluconate (0.5 mmol•L −1 ), and ZnSO4 (1.5 mmol•L −1 ), had an obvious and powerful inhibition effect. Its inhibition efficiency reached 96.8% and 90.0% in the simulated polluted concrete pore solution and the cement mortar, respectively. The mixture of diisooctyl sebacate with sodium D-gluconate and ZnSO4 acted as a mixed-type inhibitor and effectively controlled both anodic and cathodic reactions of the steel corrosion.

The inhibitor effect of migrating corrosion inhibitors on Q235 steel in high alkaline environment under cathodic polarization

“…The oxide film formed mainly consisted of Fe 3 O 4 , Fe 2 O 3 and FeOOH (Zhao et al. , 2019; Guo et al. , 2022).…”

“…Fe 2p 3/2 was divided into 706.8 for Fe 0 , 709.7 for Fe(II), 710.8 for Fe(III) and 712.1 for FeOOH (Zhao et al. , 2019; Guo et al. , 2022).…”

“…When the cathodic polarization potential was À0.8 V, the rate of oxygen consumption at the electrode/solution interface was higher than the rate of diffusion, indicating that the Q235 steel was in the stage of oxygen diffusion control. The oxide film formed mainly consisted of Fe 3 O 4 , Fe 2 O 3 and FeOOH (Zhao et al, 2019;Guo et al, 2022).…”

PickT: A Decision-Making Tool for the Optimal Pickling Process Operation

“…At the same time SEM and/or Raman spectroscopy measurements are carried out for the characterization of the surface, both before and after the corrosion experiment. These methods are shown and explained in the works of Guo et al [ 38 ] and Hossain et al [ 39 ]. However, industrial processes require fast, cheap, and easy enough to understand methods of evaluation on site.…”