keywords: Corrosion inhibitor, Tannery machines, Langmuir, Temkin and Freundlich isotherm
Most of tannery machines are made of mild steel and these machines are subjected to harsh condition, which includes exposure to moisture, air, acid, base, salt and other environmental components that causes corrosion on machines’ parts. Corrosion is the degradation of the metallic properties of a metal. The aim of this study is to generate measurable and testable data towards the control of corrosion using plant (Sida acuta leaves ethanolic extracts) as inhibitor. This was achieved through the determination of inhibitor’s performance by weight loss techniques, determination of metal-inhibitor interaction mechanism using kinetic parameters and adsorption isotherms (Langmuir, Temkin and Freundlich), the corrosion process through the use of exposure time, phytochemicals of the plant leaves extracts, inhibitor concentration, media concentration, temperature, initial weight of metal and the weight of the metals in every 6 h for a total of 24 h. Mild steel samples were immersed in 0.1 M HCl solution in the absence and presence of varying inhibitor concentrations (blank (0.1 M HCl), 0.2, 0.4 and 0.6 g/dm3) of plant inhibitor (Sida acuta leaves extract). A weight loss technique was adopted and the weights of the mild steel were recorded every 6 h for 24 h. The best inhibition efficiency for the plant extract was 86.667% at 0.6 g/dm3 of the extract at 313 K. The half-life (9.118 h) for the corrosion reaction occurrence for plant inhibitor was high at 0.2 g/dm3 at 313 and at 343 was high at 0.4 g/dm3 (9.290 h). Thus, the plant inhibitor might not be better in its performance than other inhibitors on mild steel when exposed to acidic environment but they are best in aspect of its interaction to the environment due to its ecofriendly, inexpensive and biodegradable properties.