Elucidation of corrosion inhibition property of compounds isolated from Butanolic Date Palm Leaves extract for low carbon steel in 15% HCl solution: Experimental and theoretical approaches
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Elsevier
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The present work reports on the corrosion inhibition property of compounds isolated from butanolic
extract of Date Palm leaves for low carbon steel in 15% HCl solution. Six compounds were isolated from
Date Palm leaves and purified using a combination of column chromatography, thin layer chromatography,
and Prep HPLC-MS system. The isolated compounds were characterized using 1H NMR, 13C NMR, and
GC–MS. Their identity was revealed to be a mixture of fatty alkanes, oleanolic acid (OA), vanillyl alcohol
(VA), b-Sitosterol-3-O-b-D-glucoside (b-SSG), sucrose sugar, and carotenoid lutein. As a result of the
amount of the different isolates obtained, only three out of the six compounds namely b-SSG, OA, and
VA were tested for anticorrosion property for low carbon steel in 15% HCl. The corrosion inhibition of
the isolated compounds was performed using weight loss and electrochemical techniques. Surface morphology
analysis of the corroded steel in the absence and presence of the isolated compounds was undertaken
using SEM/EDAX and 3D optical profilometer. Also, DFT calculations was performed in order to
indicate the reactivities and bonding sites of the isolated molecules as well as Monte Carlos simulations
(MCS) to determine the energy of interaction between the inhibitors and carbon steel surface. Results
obtained show that the values of inhibition efficiency (IE) for the different isolated compounds at the concentration
(35 ppm) studied follow the trend: b-SSG (46.57%) > VAisolated (39.30%) > VAcommercial
(36.81%) > OA (31.94%) at 25 �C. It is also noted that, for the isolated OA, IE increased with increase in
concentration but decreased with increase in temperature. For isolated VA, IE decreased with increase
in temperature. However, for the commercial VA, IE slightly increased with rise in temperature. The
experimental results are in agreement with the theoretical prediction. In both predicted and experimental
results, b-SSG is the best corrosion inhibitor.
Keywords
QD Chemistry