INVESTIGATION OF AQUEOUS-METHANOL EXTRACT FROM RED MARINE MACROALGAE GRACILARIA VERRUCOSA AS INHIBITOR FOR BIOCORROSION

摘要

Tropical marine environment is highly corrosive to metals of construction material for marine transportation and pipelines to distribute oil and gas. Indonesia's tropical marine macroalgae have high potential and quality to be developed as a biocorrosion inhibitor for metals in tropical marine environment. This study was conducted to determine the bioactivity from Indonesia's tropical marine macroalgae extract Gracilaria verrucosa to inhibit biocorrosion on carbon steel. Aqueous-methanol crude extract was separated by using column chromatography and produced 6 fractions through UV analysis which respectively treated with quantitative test of ability to inhibit biocorrosion with weight loss method of carbon steel coupon in liquid media of bacteria Thiobacillus ferrooxidans. There were 2 active fractions which have the lowest corrossion rate then treated with analysis for determination of corrosion rate in concentration and time variation. Analysis result of SEM-EDS to carbon steel revealed the biocorrosion mechanism and identification of UV spectrum revealed that both active fractions were mixture of phenolic and flavonoid compounds.