Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Article Title: RESOLUTION OF ADSORPTION CHARACTERISATION AMBIGUITY THROUGH THE ADEJO-EKWENCHI ADSORPTION ISOTHERM: A CASE STUDY OF LEAF EXTRACT OF HYPTIS SUAVEOLEN POIT AS GREEN CORROSION INHIBITOR OF CORROSION OF MILD STEEL IN 2 M HCl
by Sylvester O. Adejo, M. M. Ekwenchi, John U. Ahile, Joseph A. Gbertyo and Angela Kaior

Abstract:
The resolution of ambiguity usually associated with the characterisation of adsorption process of the plant extracts as corrosion inhibitors for metal corrosion was achieved through the use of Adejo-Ekwenchi adsorption isotherm using the case of corrosion inhibition of mild steel corrosion in 2 M HCl by ethanol leaf extract of Hyptis suaveolens poit. The study was carried out using the weight loss method at the temperature range of 301 K to 313 K. The inhibition efficiency, %IE, was found to decrease with increase in temperature, suggestive of physical adsorption (physisorption) mechanism. The observed decrease in the value of parameter b of the Adejo-Ekwenchi isotherm is a confirmation of a physisorption for adsorption of this extract onto the metal surface. By the use of R2 and ?Gads this adsorption would be thought to well fit into Langmuir, Freundlich, Temkin and El-Awady. But the adsorption process best fit the Langmuir isotherm, as resolved through the Adejo-Ekwenchi isotherm. Implicitly, this is one clear case of emerging trends for sustainable development and human capacity building as focus is now on plant extracts, away from synthetic inhibitors, as eco-friendly inhibitors for metal corrosion prevention due reasons like cost, strict environmental regulations, renewability and biodegradability. The design and development of new and effective inhibitors will only be possible if adsorption of inhibitor onto the metal surface is clearly understood.

Keywords: adsorption; mild steel; hyptis suaveolens poit; adejo-ekwenchi isotherm; physisorption

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