Comparative study of the copper inhibition of two [H4L]calixarenic molecules in sulfuric acid medium

• N. M’hanni¹, M. Galai¹, M. Ouakki², M. Ebn Touhami¹, E.H. Rifi³ and Z. Asfari^2,4

¹ Laboratory Materials Engineering and Environment: Modeling and Applications (LMEEMA), Faculty of Sciences, University Ibn Tofail, BP 133, 14000 Kénitra, Morocco
² Laboratory of Materials, Electrochemistry and Environment, Faculty of Science, Ibn Tofail University, BP 133, 14000 Kénitra, Morocco
³ Laboratory of Organic Synthesis and Extraction Processes, Faculty of Science, University Ibn Tofail, BP 133, 14000 Kénitra, Morocco
⁴ Laboratory of Molecular Engineering Applied to the Analysis, IPHC, UMR 7178 CNRS, University of Strasbourg, ECPM, 25 street Becquerel, 67087 Strasbourg Cedex 2, France

Abstract: This is a comparative study of the inhibition and adsorption properties of two Calixarenic organic molecules of the type H4L named Calix1 and Calix2 as good corrosion inhibitors in 0.5 M sulfuric acid by electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The experimental data showed that Calix1 and Calix2 are effective against copper corrosion in 0.5 M H₂SO₄ and the inhibitory efficiency which has been reached at an optimum value is 96.8% for Calix2. The results of EIS measurements have shown that the copper dissolution process occurs under diffusion control. The copper corrosion rates and additive inhibition efficiency were calculated. The results obtained showed that the combination could serve as effective inhibitors of copper corrosion in the sulfuric acid medium. The inhibition mechanisms are estimated from the inhibition efficiency as a function of concentration and immersion time. It is suggested that the molecular and the protonated organic species of both Calix contributed to the observed inhibitory action. In addition, the scanning electron microscope analysis confirmed the inhibitory effect of these two compounds. Furthermore, the SEM images showed that both compounds are adsorbed on the copper surface. Moreover, the increase in immersion time does not significantly affect the inhibitory efficiency values, which confirms the high resistance of the composite.

Keywords: Electrochemical impedance spectroscopy, calixarene, corrosion of copper, potentiodynamic polarization, H2SO4

Int. J. Corros. Scale Inhib., 2020, 9, no. 3, 1037-1048 PDF (623 K)
doi: 10.17675/2305-6894-2020-9-3-16

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