INHIBITORY POTENTIALS OF Bryophyllum pinnatum LEAVES EXTRACT ON SULPHATE REDUCING BACTERIA INDUCED ANAEROBIC CORROSION OF OIL PIPELINE STEEL

Abstract

In the present study sulphate reducing bacteria (SRB) were cultured from crude water sample collected from underground water very close to rusted oil pipeline steel. Effect of Bryophyllum pinnatum leaves extract on the cultured test organism induced corrosion of oil pipeline steel was examined using media absorbance comparison, scanning electron microscope surface morphology and gravimetric techniques. The corrosion test results from the media absorbance comparison and scanning electron microscope surface morphology show inhibition activity by the test extract (Bryophyllum pinnatum leaves) on the test organism (sulphate reducing bacterial). Gravimetric analysis results confirmed, test organism induced corrosion inhibition by the test extract and the corrosion inhibition was more pronounced as the concentration of the plant extract increased. Inhibition was attributed to adsorption of the extract molecules on the pipeline steel coupons. The adsorption fitted best into Langmuir adsorption isotherm, and the trend in calculated free energy of adsorption values suggests physisorption mechanism.