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Chevalier M.,Laboratoire Materiaux et Molecules en Milieux Amazonien | Roos C.,Laboratoire Materiaux et Molecules en Milieux Amazonien | Tomi F.,CNRS Environmental Sciences | Sutour S.,Laboratoire Materiaux et Molecules en Milieux Amazonien | Lebrini M.,Laboratoire Materiaux et Molecules en Milieux Amazonien
ECS Transactions | Year: 2015

The use of Xylopia frutescens extract as a C38 steel corrosion inhibitor in 1 M HCl solution was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. Potentiodynamic polarization curves indicated that Xylopia frutescens extract behaves as mixed-type inhibitor. Graphical methods are illustrated by synthetic data to determine the parameter of CPE (α Q). The adsorption of the extract constituents was further discussed in view of angmuir adsorption isotherm. The effect of temperature on the inhibition efficiency was investigated using EIS and potentiodynamic polarization. SEM and EDX observations confirmed the existence of protective inhibitor film on metal surface. © The Electrochemical Society.


Chevalier M.,Laboratoire Materiaux et Molecules en Milieux Amazonien | Robert F.,Laboratoire Materiaux et Molecules en Milieux Amazonien | Amusant N.,Laboratoire Materiaux et Molecules en Milieux Amazonien | Traisnel M.,Ecole Nationale Superieure de Chimie de Lille | And 2 more authors.
Electrochimica Acta | Year: 2014

The present report continues to focus on the broadening application of plant extracts for metallic corrosion control and reports on the inhibiting effect of the Aniba rosaeodora alkaloidic extract on the corrosion of C38 steel in 1 M hydrochloric acid. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were applied to study the metal corrosion behavior in the absence and presence of inhibitor. Studies on the phytochemical constituents were established to determine the active(s) molecule(s). XPS was also carried out to establish the mechanism of corrosion inhibition of the active molecule of C38 steel in acid solution. The inhibitor extract acted as an efficient corrosion inhibitor in 1 M HCl. The experimental data obtained from EIS method show a frequency distribution and therefore a modelling element with frequency dispersion behaviour, a constant phase element (CPEα, Q) has been used. Graphical methods are illustrated by synthetic data to determine the parameter of CPE (α, Q). Polarization studies showed that the Aniba rosaeodora alkaloidic extract was a mixed-type inhibitor and its inhibition efficiency increased with the inhibitor concentration. Studies on the phytochemical constituents of the total alkaloids extract shows that it contains the anibine as the major alkaloid. The results obtained from the electrochemical study have clearly showed that the inhibition efficiency of the total extract was due to the presence of anibine. The XPS studies showed the formation of inhibitor layer containing the Aniba rosaeodora alkaloidic extract and the anibine molecules. © 2014 Elsevier Ltd. All rights reserved.


Suedile F.,Laboratoire Materiaux et Molecules en Milieux Amazonien | Robert F.,Laboratoire Materiaux et Molecules en Milieux Amazonien | Roos C.,Laboratoire Materiaux et Molecules en Milieux Amazonien | Lebrini M.,Laboratoire Materiaux et Molecules en Milieux Amazonien
Electrochimica Acta | Year: 2014

Ethanol extract of Mansoa alliacea was tested as corrosion inhibitor for zinc in NaCl 3% media using polarization and electrochemical impedance spectroscopy (EIS). Potentiodynamic polarization curves indicated that the plant extract behaves as mixed-type inhibitor. Impedance measurements showed that there are two phenomena in the process of inhibition. The results obtained show that this plant extract could serve as an effective inhibitor for the corrosion of zinc in NaCl 3% media. The extract obtained give inhibition around 90%. The experimental data obtained from EIS method show a frequency distribution and therefore a modelling element with frequency dispersion behaviour, a constant phase element (CPEα,Q) has been used. Graphical methods are illustrated by synthetic data to determine the parameter of CPE (α, Q). Polarization curves show that Mansoa alliacea extract affects the anodic and cathodic reactions and the corrosion potential values were shifted to the positive potentials in the presence of the crude extract. Studies on the phytochemical constituents of the total extract were also established. Electrochemical studies, on the chemical families present in the crude extract, were also carried out to find the main constituents responsible for corrosion inhibition properties of the plant extract. © 2014 Elsevier Ltd.


Faustin M.,Laboratoire Materiaux et Molecules en Milieux Amazonien | Maciuk A.,University Paris - Sud | Salvin P.,Laboratoire Materiaux et Molecules en Milieux Amazonien | Roos C.,Laboratoire Materiaux et Molecules en Milieux Amazonien | Lebrini M.,Laboratoire Materiaux et Molecules en Milieux Amazonien
Corrosion Science | Year: 2015

Corrosion inhibition by alkaloids extract (AE) from Geissospermum laeve on C38 steel in 1. M HCl is investigated with electrochemical studies. Inhibition efficiency of 92% is reached with 100. mg/L of AE at 25. °C. Potentiodynamic polarization showed that the extract behaves as mixed-type inhibitors. The Nyquist plots showed that increasing AE concentration, charge-transfer resistance increased and double-layer capacitance decreased, involving increased inhibition efficiency. Adsorption of the inhibitor molecules corresponds to Langmuir adsorption isotherm. Immersion time and temperature effects were investigated using EIS and potentiodynamic polarization. SEM and EDX supported the adsorption conclusions. The active compound responsible for the corrosion inhibition is geissospermine. © 2014 Elsevier Ltd.

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