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

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  

1. 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.