Abstract
The inhibition of aluminium metal corrosion in 1.85 M hydrochloric acid solution using extract of Carica papaya leaf was studied using gasometric technique. Aluminium coupons were immersed in test solutions of un-inhibited 1.85 M HCl and those containing extract concentrations of 10 %, 20 %, 30 %, 40 % and 50 % (v/v) at room temperature. The volume of hydrogen gas evolved as a result of the rate of reaction between aluminium coupons and the acid extracts was recorded. The inhibition efficiency of the extract was determined and the adsorption isotherm of the process was estimated using Temkin, Freundlich, Frumkin and Langmuir adsorption theories. The microstructure examination was also determined. The result of the investigation induced that the Carica papaya leaf extract retarded the acid induced corrosion of aluminium with a reduction in the volume of hydrogen gas evolved per increasing extract concentrations. The adsorption studies revealed Langmuir isotherm as the best model for the adsorption of Carica papaya extract (R2 =1) on aluminium surface. The adsorption result with the microstructure of the coupons implied an involvement of chemisorption process in the interaction of the extract with aluminium metal.
Highlights
The deterioration of materials due to their chemical or electrochemical interactions with the surrounding environment is generally understood as corrosion
The present study aims at investigating the inhibitive, adsorptive characteristics of Carica papaya leaf extract and the surface morphology of the extract inhibition on aluminium specimen in 1.85 M HCl solution using gasometric technique
The free corrosion of the aluminium metal in 1.85 M HCl was characterized by rapid effervescence resulting from hydrogen evolution in the presence of the blank solution (0% extract) and the various extract concentrations (10% - 50%) for the Carica papaya leaf extract
Summary
The deterioration of materials due to their chemical or electrochemical interactions with the surrounding environment is generally understood as corrosion. There has been an increasing awareness on the use of environment friendly substances as corrosion inhibitors in place of the harmful synthetic chemicals. This has orchestrated the drive on the development of green corrosion inhibitors from plant extracts. Each weighed specimen was dropped into the mylius cell containing 50 cm of the blank solution, 1.85 M HCl, as the control and in the presence of the various extract concentrations (10% - 50%) for Carica papaya extract at room temperature, the principle of which hydrogen gas is given off as a result of aluminium reacting with HCl. The volume of hydrogen gas evolved per minute interval was recorded in each volume/volume dilutions.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
