Joint Effect of Ethanol Extract of Orange Peel and halides on the Inhibition of the Corrosion of Aluminum in 0.1 M HCl: An approach to Resource Recovery

Abstract

Richard Alexis Ukpe
Received 08 November 2019/Accepted 12 November 2019

Resource recovery is the science of creating valuable products from waste. Successful resource recovery can reduce the burden of waste disposal. In this study, attempt is made to utilized ethanol extract of orange peel waste as a corrosion inhibitor for mild steel in solution of HCl. Ethanol extract behaved as adsorption inhibitor and the ranged obtained for the inhibition efficiencies of various concentrations of the extract were Calculated inhibition efficiency ranged from 35.03 to 60.08 %, 30.02 to 52.61%, 28.04 to 46.44 % and from 25.98 to 43.34 %. However, in the presence of KBr, KI and KCl, the enhanced range were 40.95 to 71. 02, 40.62 to 71.07 and from 84.22 to 88.12 %. Calculated synergistic parameters were greater than unity indicating that the adsorption of ethanol extract of orange peel waste was enhance by synergistic interaction with halides. Statistical analysis of variance indicated that temperature and
concentration have statistical weight of contributing to the inhibition efficiency of the extract. The prevalence of physical adsorption mechanism was
confirmed through free energy of adsorption deduced from the fitted adsorption isotherms including Langmuir, Freundlich, Temkin, El Awardy et al and Dubinin-Radushkevich isotherms. However, joint adsorption of ethanol extract of orange peel waste did not obey the Temkin and Freundlich isotherm except the Langmuir isotherm, which displayed plots with negative slope (a reversal of what were obtained in the absence of the halides). FTIR of the extract indicated the presence of functional groups that are liken to those that are known good corrosion inhibitors.