Potential of aqueous Cupressus macrocarpa extract (CME) as eco-friendly corrosion inhibitor against aluminum in HCl environment

• M.E. Eissa¹, E.E. El Katori^2,3, A. El-Hossainy⁴, E.M. El-Hossainy⁴ and A.S. Fouda⁴

¹ Chemistry Department, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11623, Kingdom of Saudi Arabia
² Chemistry Department, Faculty of Science, New Valley University, El Kharga-72511, Egypt
³ Al-Ayen Iraqi University, Thi-qar, 64001, Iraq
⁴ Chemistry Department, Faculty of Science, Mansoura University, Mansoura-35516, Egypt

Abstract: Cupressus is one of several genera of evergreen conifers within the family Cupressaceae that have the common name cypress. The efficiency of Cupressus macrocarpa extract (CME) as corrosion inhibitor for Al in 1 M HCl medium was carried out using weight loss (WL), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. The results prove that the chemical content of CME can inhibit the corrosion rate of Al and exhibit high inhibition efficiency. Also, the results showed variation in inhibition performance of the extract with varying concentrations, immersion time and temperature. Temkin was tested to describe the adsorption behavior of the extract on the Al surface. Potentiodynamic polarization study clearly revealed that extract acts as a mixed type of inhibitor. According to the EIS study’s findings, the charge transfer resistance (Rct) increased while the double layer capacitance (Cdl) decreased. The extract is adsorbed on the Al surface, covering larger area from the surface of Al and hence, %IE increases. The adsorption of the extract on the Al surface is spontaneous, according to kinetic and thermodynamic characteristics and stable. CME inhibits corrosion on the Al surface through physical and chemical adsorption. According to the findings, CME may be useful as a corrosion inhibitor for Al in 1 M HCl.

Keywords: corrosion inhibition, aluminum, HCl, Cupressus macrocarpa extract, Temkin isotherm

Int. J. Corros. Scale Inhib., 2025, 14, no. 1, 132-154
doi: 10.17675/2305-6894-2025-14-1-8

Download PDF (Total downloads: 55)

Back to this issue content: 2025, Vol. 14, Issue 1 (pp. 1-... (in progress))