The use of guava (Psidium Guajava) leaf extract as a corrosion inhibitor for iron in acid media.

Corrosion is an interaction of material with its environment that causes material damage. Prevention of corrosion can be conducted using organic inhibitors. One of many organic inhibitors is an extract of guava (psidium guajava) leaves which contains organic substances such as tanin, amino acids, benzoic acid, vitamin, calcium and other substances that act as inhibitor. The aims of this study were to study the efectivenes of guava leaf extract as inhibitor and to calculate the optimum concentration in inhibiting the corrosion of iron in acid medium. Guava leaf extract was grounded and then extracted with ethanol-water (1:2) solvent. The extract obtained was used as a corrosion inhibitor by testing variations in concentration (0-500 ppm) for 7 days and by varying immersion time (2-10 days) at optimum concentration in 3% hydrochloric acid medium. The corrosion rate measurement was done using the weight loss and electrochemical methods. The results showed that the optimum concentration of guava leaf extract was 300 ppm as a corrosion inhibitor of iron plates in hydrochloric acid solution. The corrosion rate in the optimum immersion time test for iron in an acid solution (pH 0.46) with a concentration of 300 ppm on the 8th day was 3,052 mm/year and the inhibitor efficiency was 56-63%. Guava leaf extract can be used as ancorrosion inhibitor and it is effective in inhibiting corrossion of iron in acid medium (hydrochloric acid). [ABSTRACT FROM AUTHOR]