Tristaniopsis merguensis Griff. Extract as Inhibitor for Corrosion of Stainless Steel

Green inhibitors are inhibitors that utilize secondary metabolites of plant to reduce the rate of corrosion. Secondary metabolites with heteroatom content phosphate, nitrogen, oxygen and sulfur function as ligands and adsorption centers to bind metals. These metabolites compounds include alkaloids, flavonoids, and tannins. Tristaniopsis merguensis Griff. is a local plant of Bangka Belitung which contains alkaloid, flavonoids and tannins. The focus of this research is to analyze the effect of T. merguensis leaf extract on corrosion rate of stainless steel. T. merguensis extract was obtained by maceration for 3 x 24 hours using ethanol solvent. Determination of corrosion rate using the mass reduction method. Then, functional group analysis contained in extract uses the Fourier Transform Infrared (FT-IR) at wavenumber region 4000–400 cm⁻1. The results obtained that at the highest concentration of 1000 mg/L the extract of T. merguensis was able to inhibit the corrosion rate of stainless steel until the corrosion rate was 0.3826 mmpy equal to inhibition efficiency 85.27%. This inhibiting ability is more likely because T. merguensis leaf extract containing phenolic compounds. Therefor T. merguensis extract can be used as a green inhibitor. (paper)