Acta Physico-Chimica Sinica

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

Ya Guo1,2, Piao Jin1, Minhua Shao3, Shigang Dong4, Ronggui Du1, Changjian Lin1   

  1. 1 Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian Province, P. R. China;
    2 Department of Metallurgy and Chemical Engineering, Gansu Vocational & Technical College of Nonferrous Metallurgy, Jinchang 737100, Gansu Province, P. R. China;
    3 Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Klwloon, Hong Kong, P. R. China;
    4 College of Energy, Xiamen University. Xiamen 361102, Fujian Province, P. R. China
  • Received:2020-03-14 Revised:2020-04-23 Accepted:2020-05-12 Published:2020-05-18
  • Supported by:
    The project was supported by the National Natural Science Foundation of China (51731008, 21573182, 21073151, 21203158).

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.

Key words: Reinforcing steel, Chloride, Localized corrosion, Corrosion inhibitor, Simulated concrete pore solution


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