Inhibition of corrosion of mild steel in acidic medium using ethanol extract of Aloe vera

Purpose The purpose of this paper is to study the effect of concentration of H 2 SO 4 on the corrosion of mild steel and to investigate the inhibitive properties of Aloe vera for mild steel corrosion. The study also seeks to investigate the possibility of using Aloe vera as a green corrosion inhibitor for mild steel. Design/methodology/approach Gasometric (Hydrogen evolution) and thermometric methods of corrosion monitoring have been adopted for the study. The study was conducted at 303 and 333 K and the concentrations of inhibitor used were 0.1, 0.2, 0.3 and 0.4 g/L. The inhibitor was prepared by using alcohol extract of moisture free samples of Aloe vera . The functional groups present in the extract have been determined using infra red spectrophotometer. Thermodynamic and adsorption theories have been used to interpret the data. Findings Ethanol extract of Aloe vera is a good inhibitor for mild steel corrosion at 303 and 333 K. The inhibitor acts by chemical adsorption isotherm. Functional groups identified in the extract are found to played dominant role in the adsorptive and inhibitive potentials of this extract. Values of inhibition efficiency obtained from gasometric and thermometric analysis were comparable. Research limitations/implications Further study on synergism with the view of enhancing the inhibition efficiency of Aloe vera extract and the used of other analytical methods may reveals a wealth of information on the possibilities of transforming this research for field application. Originality/value The paper provides information on the use of Aloe vera as a green corrosion inhibitor. It has not been published elsewhere.