Abstract
An investigation of the performance of Urena lobata leaves extract as a corrosion inhibitor, on copper in 1M NaOH solution was carried out using Gravimetric, Electrochemical and Surface analytical methods. Adsorption of the extract on the surface of the metal was studied using Langmuir and Freundlich isotherm plots. Phytochemical contents of the extract were determined using Gas Chromatography-Mass Spectrometric (GC-MS) technique. Corrosion inhibition of the extract was monitored at different concentration. The results obtained revealed that the leaves contain good phytochemicals with hetero atoms that are rich in electrons. The corrosion inhibition efficiency of the extract gave a maximum value of 94.8% at 2.5g/L extract concentration. It was observed that the corrosion rate of copper decreased with increase in the extract concentration in the basic solution. The adsorption process reduced as temperature increased, thereby indicating physisorption. The Langmuir isotherms gave the best fit indicating chemisorption. Physical adsorption was confirmed for the leaves extract from observations of inhibition efficiency with temperature, activation energy and enthalpy of adsorption values, indicating that the extract has mixed properties. The inhibition efficiencies (% IE) were attributed to the phytochemical components (alkaloids, saponins, flavonoids, tannins, cynagenic glycosides) present in the extract.
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Copyright (c) 2024 N. J. Maduelosi, Z. K. Barineka,, N. B. Iroha