Assessment of caffeine adsorption onto mild steel surface as an eco-friendly corrosion inhibitor
The adsorption and corrosion-inhibition properties of caffeine as an eco-friendly corrosion inhibitor for mild steel in acid medium were investigated by electrochemical and spectroscopic techniques. Polarization experiments indicated that caffeine behaves as a cathodic-type inhibitor. Impedance data showed that surface coverage increased with caffeine concentration in the range of 1.0 to 10.0 mmol L-1. The maximum inhibition efficiency obtained was 92.4%. The adsorption of the corrosion inhibitor was consistent with the Frumkin adsorption isotherm with a free energy of adsorption of -66.1 kJ mol-1. Contact angle measurements revealed the formation of a hydrophobic protective film, while scanning electron microscopy, energy dispersive spectroscopy and fluorescence experiments clearly verified the presence of caffeine on the surface.
| Main Authors: | , , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Sociedade Brasileira de Química
2014
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| Online Access: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532014000100010 |
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