Corrosion inhibition of mild steel in 1 M HCl solution by henna extract: A comparative study of the inhibition by henna and its constituents (Lawsone, Gallic acid, α- d-Glucose and Tannic acid)

• Published in: Corrosion science Vol. 51; no. 9; pp. 1935 - 1949
• Main Authors: Ostovari, A., Hoseinieh, S.M., Peikari, M., Shadizadeh, S.R., Hashemi, S.J.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2009
• Subjects: A. Acid solutions; B. EIS; B. SEM; C. Acid inhibition; C. Pitting corrosion; B. SEM; C. Acid inhibition; C. Pitting corrosion; B. EIS; A. Acid solutions
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2009.05.024

The inhibitive action of henna extract ( Lawsonia inermis) and its main constituents (lawsone, gallic acid, α- d-Glucose and tannic acid) on corrosion of mild steel in 1 M HCl solution was investigated through electrochemical techniques and surface analysis (SEM/EDS). Polarization measurements indicate that all the examined compounds act as a mixed inhibitor and inhibition efficiency increases with inhibitor concentration. Maximum inhibition efficiency (92.06%) is obtained at 1.2 g/l henna extract. Inhibition efficiency increases in the order: lawsone > henna extract > gallic acid > α- d-Glucose > tannic acid. Also, inhibition mechanism and thermodynamic parameters are discussed.