Corrosion inhibition of steel in acidic solution using p-bromopiperazinylbenzene: Experimental and DFT calculations

• A.F. Mahmood¹, H.S. Aljobori², H.H. Al-Doori³, F.F. Sayyid⁴, A.M. Mustafa⁴, A.A.H. Kadhum⁵ and A. Alamiery⁶

¹ Oil and Gas Engineering Department/University of Technology, Baghdad, P.O. Box: 10001, Baghdad, Iraq
² College of Engineering, University of Warith Al-Anbiyaa, P.O. Box: 56001, Karbalaa, Iraq
³ Al-Karkh University of Science, P.O. Box: 10001, Baghdad, Iraq
⁴ Production and Metallurgy Engineering Department, University of Technology-Iraq, P.O. Box: 10001, Baghdad, 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: This study investigates the corrosion inhibition efficiency of para-bromopiperazinylbenzene (PBPB) for mild steel in an acidic medium using weight loss methods at various concentrations (0.1 to 0.5 mM) and immersion time of 5 hours. The inhibition efficiency was found to increase with the inhibitor concentration, reaching a maximum efficiency of 91.3% at the highest concentration. The effect of temperature on corrosion inhibition was also studied at 303 K, 313 K, 323 K, and 333 K, showing a slight increase in inhibition efficiency with rising temperature. Potentiodynamic polarization measurements were conducted at 303 K, confirming the trend observed in weight loss studies. Adsorption isotherm analysis revealed that the inhibitor obeys the Langmuir adsorption isotherm, with the free energy of adsorption suggesting a combination of chemisorption and physisorption processes. Density Functional Theory (DFT) calculations were performed to study the quantum chemical parameters such as E_HOMO, E_LUMO, and others, showing good correlation with experimental data. The harmony between experimental and theoretical results underscores the potential of PBPB as an effective corrosion inhibitor for mild steel in acidic environments.

Keywords: corrosion inhibition, para-bromopiperazinylbenzene, mild steel, acidic medium, DFT analysis

Int. J. Corros. Scale Inhib., 2025, 14, no. 2, 706-729
doi: 10.17675/2305-6894-2025-14-2-15

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