Impact of hydroxyl group on adsorption behavior and corrosion inhibition of Schiff-base derivative on carbon steel in 1 M HCl

• R.K. Ahmed¹, A. Mohammed², M.A.I. Al-Hamid³, A.M. Mustafa⁴, F.F. Sayyid⁴, A.H. Kadhum⁵ and A. Alamiery⁶

¹ Department of Petroleum and Gas Refining Engineering, College of Petroleum Processes Engineering, Tikrit University, Saladin 34001, Iraq
² Department of Electromechanical Engineering, University of Technology, P.O. Box: 10001, Baghdad, Iraq
³ Energy and Renewable Energies Technology Centre, University of Technology, Baghdad 10001, Iraq
⁴ Department of Production Engineering and Metallurgical, University of Technology, Baghdad, 10001, Iraq
⁵ Faculty of Medicine, University of Al-Ameed, P.O. Box: 56001, Karbala, Iraq
⁶ Al-Ayen Scientific Research Center, Al-Ayen Iraqi University, AUIQ, An Nasiriyah, P.O. Box: 64004, Thi Qar, Iraq

Abstract: The study explores the impact of the hydroxyl group on the adsorption and the corrosion inhibition characteristics of 2-((thiazol-2-ylimino)methyl)phenol (TMP), a Schiff-base derivative, on carbon steel in 1 M hydrochloric acid (HCl) medium. Using weight loss methods measurable to ASTM standards, and computational DFT techniques, the research reveals significant insights into the electronic properties and adsorption mechanisms of TMP. Based on their results, it was concluded that TMP acts as a corrosion inhibitor and that the presence of OH group increases TMP adsorption which enhances corrosion inhibition. At 0.5 mM concentration of TMP, an inhibition efficiency of 89.7% was achieved after 5 hours of immersion at 303 K. Their observations showed that there is an increase in efficiency with the time of immersion up to 10 hours. However, around 48 hours there was a slight decrease in efficiency. Studies involving temperature showed improvement in inhibition efficiency at elevated temperatures (303–333 K); also observed inhibition efficiency was aligned with the Langmuir adsorption isotherm. DFT analysis supported the experimental results, identifying TMP as an effective inhibitor for carbon steel corrosion in acidic solutions. The research highlighted the importance of functional groups in designing corrosion inhibitors tailored toward industrial needs.

Keywords: phenol, thiazole, corrosion, DFT, ASTM

Int. J. Corros. Scale Inhib., 2025, 14, no. 2, 854-875
doi: 10.17675/2305-6894-2025-14-2-22

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