L. Touafri  , A. Kadri  , A. Khelifa  , N. Aimeur  , N. Benbrahim  , 
    The Inhibition and Adsorption Processes of L-Cysteine Against the Corrosion of XC 18 Carbon Steel in 2N H<SUB>2</SUB>SO<SUB>4</SUB>,
    Journal of Engineering and Applied Sciences,
    Volume 3,Issue 9,
    2008,
    Pages 688-696,
    ISSN 1816-949x,
    jeasci.2008.688.696,
    (https://makhillpublications.co/view-article.php?doi=jeasci.2008.688.696)
    Abstract: The inhibition effect of L-cysteine as environmentally friendly corrosion inhibitor for XC 18 carbon steel in stirred 2 N sulphuric acid has been investigated by electrochemical techniques. The impedance measurements showed that the inhibition efficiency increased with the increase of inhibitor concentration to reach more than 84% at 500 mg L<SUP>-1</SUP> and indicated that the amino acid act as mixed type inhibitor, while the adsorption followed the Langmuir isotherm. Effect of temperature is also studied in the 30-60°C range. The values of adsorption free energy ( G<SUP>0</SUP><SUB>ads</SUB>) and activation energies (E<SUB>a</SUB>) reveal a physical adsorption of the inhibitor on the steel surface.
    Keywords: L-cysteine;ac impedance;corrosion inhibition;carbon steel;sulphuric acid