South African Journal of Chemical Engineering (Apr 2022)
Understanding the divergence of agro waste extracts on the microstructure, mechanical, and corrosion performance of steel alloy
Abstract
The toxic nature and low-inhibition potency of some conventional organic molecules in corrosion inhibition of engineering materials against the acid-containing solutions requires further investigation. Subsequently, the use of nontoxic, durable and environmental friendly palm kernel shell-derived extracts for the development of biodegradable inhibitor in stainless steel corrosion management is the purpose of this study. The anticorrosive property of the extract was evaluated by gravimetric and electrochemical tests. The hardness, yield strength, ultimate tensile strength, and microstructure were also examined. The scanning electron microscopy examination was used to verify the protection performance of the inhibitor while X-ray diffraction was used to confirm the crystallinity of the inhibitor. The results obtained show that the palm kernel shell can suppress acid corrosion in all ranges of concentrations. Microscopic analysis revealed a lower population density and degree of pitting corrosion on the inhibited samples as compared to the uninhibited sample, which was covered with various dimensions of pits. Electrochemical results reflected that the palm kernel shell complex could retard corrosion of stainless steel by 93% inhibition efficiency via mixed anodic and cathodic inhibition mechanisms. The mechanical property of the inhibited samples was improved compared to the uninhibited samples. The extract adsorption on stainless steel surface was found to conform the Langmuir adsorption isotherms. Therefore, palm kernel waste extract on the metal surface enhances the mass and charge barrier resulting in the reduction of the corrosion rate. However, this study provides new opportunity for the synthesis and design of effective corrosion inhibitors based on waste materials .
