Experimental, theoretical and mathematical studies of Echium italicum L. extract as a corrosion inhibitor for carbon steel in acidic medium
Abstract
Butanolic extract of Echium italicum L. (BEEI) was investigated as eco-friendly corrosion inhibitor for carbon steel (API 5L-X60) in 1 M hydrochloric acid solution using electrochemical, gravimetric and scanning electron microscopy methods. The effect of rising temperature was inspected and the apparent energies of the dissolution process were discussed. The BEEI behaved as mixed type inhibitor with the highest inhibition at 500 ppm. The adsorption of the inhibitor on the steel surface, follow Freundlich isotherm and its mod was found to be physisorption. The corrosion rate decreased with increase in the inhibitor concentration and rose with temperature. Additionally, quantum chemical parameters such as energy gap, EHOMO and ELUMO were calculated and used to predict the relationship for the adsorption mechanism. The obtained experimental data were in good agreement with those predicated by mathematical regression.
- Publication:
-
Materials Research Express
- Pub Date:
- August 2019
- DOI:
- 10.1088/2053-1591/ab194f
- Bibcode:
- 2019MRE.....6h6546B
- Keywords:
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- Echium italicum L.;
- corrosion inhibitor;
- quantum chemical parameters;
- mathematical regression