Carboxymenthylchitosan as an ecofriendly inhibitor for mild steel in 1 M HCl

The inhibiting influence of Carboxymenthylchitosan (CM-chitosan) on the corrosion of mild steel in 1 M HCl solution was studied by weight loss measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. Polarization measurements show that the CM-chitosan acts essentially as a mixed-type inhibitor. The protection efficiency of this inhibitor increases with the inhibitor concentration to reach 93% at 200 mg/L but decreases slightly with the rise of temperature. The adsorption of used compound on the steel surface obeys modified Langmuir's isotherm. The efficient inhibition is also characterized by a series of greater activation energies of corrosion reaction in the presence of CM-chitosan at various concentrations. (c) 2006 Elsevier B.V. All rights reserved.