Open AccessThermodynamic, chemical and electrochemical investigations of 2-mercapto benzimidazole as corrosion inhibitor for mild steel in hydrochloric acid solutions
Author(s) -
Mohammed Benabdellah,
Abdessamad Tounsi,
K.F. Khaled,
B. Hammouti
Publication year - 2010
Publication title -
arabian journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.789
H-Index - 70
eISSN - 1878-5379
pISSN - 1878-5352
DOI - 10.1016/j.arabjc.2010.06.010
Subject(s) - chemistry , hydrochloric acid , adsorption , dielectric spectroscopy , corrosion , langmuir adsorption model , electrochemistry , corrosion inhibitor , benzimidazole , inorganic chemistry , nuclear chemistry , electrode , organic chemistry
The inhibiting action of 2-mercapto benzimidazole (2MBI) on mild steel in 1.0M hydrochloric acid has been investigated at 308K using weight loss measurements and electrochemical techniques (impedance spectroscopy and potentiodynamic polarisation). Inhibition efficiency increases with 2MBI concentration to attain 98% at 10−3M. Polarisation curves indicate that 2MBI acts as a mixed-type inhibitor. Inhibition efficiency values obtained from various methods were in good agreement. EIS measurements showed an increase of the transfer resistance with the inhibitor concentration. The temperature effect on the corrosion behaviour of steel in 1.0M HCl without and with the 2MBI at various concentrations was studied in the temperature range from 308 to 353K. Thermodynamic parameters such as heat of adsorption (ΔHads∘), entropy of adsorption (ΔSads∘) and adsorption free energy (ΔGads∘) have been calculated. Kinetic parameters for the corrosion reaction at different concentrations of 2MBI were determined. Adsorption of 2MBI on the mild steel surface in 1.0M HCl follows the Langmuir isotherm model
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