Electrochemical appraisal of the Gemini surfactant as an inhibitor to reduce corrosion: simulation study to relate the inhibition efficiency with the electronic characteristics

• M.J. Meften¹, A.A. Kadhim¹, A.S. Abdulnabi¹ and J.M. Khalaf Al-zyadi²

¹ Department of Chemistry, College of Education-Qurna, University of Basrah, Basra 61001, Iraq
² Department of Physics, College of Education for Pure Sciences, University of Basrah, Basrah 6100, Iraq

Abstract: The current study included testing and evaluating the Gemini surfactant as an inhibitor to impart high resistance to corrosion challenges in installations used for seawater desalination, oil and gas transmission, and protection of down-hole pipelines (N-80 steel). The Gemini surfactant is sodium 2,2′-(18,25-dioxo-17,26-dioxa-20,23-diazadotetracontane-20,23-diyl) diacetate, designated as SDD. The SDD compound was studied as an inhibitor at 50°C (±1) in 1 N HCl as the corrosive environment. The inhibitor was evaluated through electrochemical impedance (EIS) and potentiodynamic polarization curves (PPC). The results showed that SDD acts as a mixed-type inhibitor. The theoretical adsorption characteristics were studied through the Monte Carlo technique, which provided useful information regarding the adsorption behavior of SDD, which adsorbed vertically on the Fe(001) surface through oxygen and nitrogen atoms. The simulation study confirms that the experimental results are associated with the electronic characteristics of the structure. The Gemini surfactant showed excellent results in inhibiting, where the efficiency optimum reached 89.40% and 91.37% as determined by the EIS and PPC techniques, respectively. From the Fermi level, it was noted that the minimum conduction band and the maximal valence band did not overlap, therefore metallic features appeared in the SDD inhibitor. Mulliken showed the electrophilic and nucleophilic sites, where the oxygen and nitrogen heteroatoms were the electrons-rich sites.

Keywords: corrosion inhibitors, electronic characteristics, Tafel plot, Monte Carlo, HOMO, LUMO, SEM, EIS

Int. J. Corros. Scale Inhib., 2025, 14, no. 1, 38-60
doi: 10.17675/2305-6894-2025-14-1-3

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