Biomass Extraction as Green Corrosion Inhibitor for Low Carbon Steel in Hydrochloric Acid Solution

Abstract Corrosion is a degradation of metals quality caused by a chemical reaction between a metal and its ambient. The use of a green inhibitor is a natural method to control the corrosion rate of the metal. The objective of this research is to count the efficiency of the green inhibitor from biomass of tea and coffee extract, to find which variable that affect the most of corrosion rate of carbon steel, to determine the best concentration of extracts to control the corrosion rate of carbon steel. The extraction methods are the use method with a solvent ratio 1:4 of ethanol : aqua dest. Weight loss method is used to determine the rate of corrosion with 0,5g/L, 1g/L, and 1,5 g/L variance of inhibitor concentrations and 3, 6, 9, and 12 days immersed times. The lowest corrosion rate is 61,27 mpy at 1,5 g/l of tea extract inhibitor solution with 9 days immersed times and the highest efficiency is 79,02% at 1,5 g/l of tea extract inhibitor solution with 12 days of immersed times.