Inhibitory Effect of Extracts of Amella radican on Corrosion of Carbon Steel Sheets in HCl Solution

摘要

The measurement of the corrosion inhibiting capacity of the extracts of Acmella radicans was carried out in Hydrochloric acid (HCl) on carbon steel sheets. In the first instance an extraction was conducted in aqueous medium with the Soxhlet equipment. Subsequently, a phytochemical characterization is performed to identify the presence of chemical compounds with anticorrosive potential. It was evidenced the presence of coumarins, flavonoids and tannins. The latter by its OH-group around the aromatic rings, like the carbonyl groups can interact with the cations on the surface of the adsorbed metal which protects it. The tannins were those with the main concentration 2.82 g/L while saponins and triterpenes had practically no presence in this extract and the flavonoids and coumarins had a lower concentration than tannins 0.94 and 0.06 g/L, respectively. The anti-corrosion capacity was measured by weight loss tests and Linear Scanning Voltamperometry (LSV) where 1 Molar (M) solutions of HCl were prepared with inhibitor concentrations based on extracts of Acmella ranging from 2400, 4800 and 7200 parts per million (ppm). The concentrations of 4800 and 7200 ppm were found to have the highest efficacy inhibitor with values above 80%. The Linear Sweep Voltamperometry (LSV) test reveals the mixed character of the inhibitor and a change in the cathodic of the branch.