Verbena officinalis (VO) leaf extract as an anti-corrosion inhibitor for carbon steel in acidic environment.

Autor: Fouda AES; Department of Chemistry, Faculty of Science, Mansoura University, Mansoura, 35516, Egypt. asfouda@mans.edu.eg., Molouk AF; Department of Chemistry, Faculty of Science, Mansoura University, Mansoura, 35516, Egypt., Atia MF; Department of Chemistry, Faculty of Science, Tanta University, Tanta, Egypt., El-Hossiany A; Department of Chemistry, Faculty of Science, Mansoura University, Mansoura, 35516, Egypt.; Delta for Fertilizers and Chemical Industries, Talkha, Egypt., Almahdy MS; Department of Chemistry, Faculty of Science, Mansoura University, Mansoura, 35516, Egypt.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2024 Jul 12; Vol. 14 (1), pp. 16112. Date of Electronic Publication: 2024 Jul 12.
DOI: 10.1038/s41598-024-65266-z
Abstrakt: In the present work, Verbena Officinalis (VO) leaf extract was used as potential corrosion inhibitor for the corrosion of carbon steel (CS) in 0.5 M H 2 SO 4 medium. Further, the corrosion inhibiting nature of VO leaf extract towards the CS was evaluated using mass loss (ML), potentiodynamic polarization (PDP), electrical impedance spectroscopy (EIS) and surface morphological analyses using atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS) techniques. Calculation of activation energy E a ∗ using Arrhenius equation shows the increase in activation energy when adding the VO leaf extract in 0.5 M H 2 SO 4 medium and the maximum activation energy ( E a ∗  = 49.9 kJ mol -1 ) was observed for 1000 mg L -1 VO leaf extract in acid medium. The negative free energy values suggested the spontaneous and the stability of the adsorbed layer of VO leaf extract on the CS surface. Using EIS measurements, high percent inhibitory effectiveness of 91.1% for 1000 ppm solutions was achieved. With an increase in VO leaf extract dose, the double layer capacitance (C dl ) values fall while the values of charge transfer (R ct ) increase. This showed that a protective layer of VO leaf extract on CS surface was formed. The polarization curves showed that the VO leaf extract acts as a mixed-type inhibitor. It is discovered that the adsorption of VO leaf extract molecules adhering to the CS surface followed the Langmuir isotherm. The anti-corrosion action of VO leaf extract is fully demonstrated by some surface techniques.
(© 2024. The Author(s).)
Databáze: MEDLINE
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