Study on Desulfovibrio desulfuricans mediated copper corrosion and its inhibition using bio-wax of Colocasia esculenta

Abstract

In the present study, the bio-wax was extracted from Colocasia esculenta and was tested for its corrosion inhibiting property against Desulfovibrio desulfuricans. Inhibition of copper corrosion by bio wax from Colocasia was observed using weight loss method, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Results obtained from the weight loss studies and impedance measurements provided similar trends of inhibition efficiency. Cu coupon coated with bio-wax showed significant reduction in corrosion rate i.e. Rcorr of 0.0011mmpy. This result gives an idea about the protective nature of thick bio-wax coated copper coupons from bacterial adherence and bacterial metabolites. The impedance value in the bio wax coated coupon was found to be from 188.67 to 781.25 ohms at 1 Volt. The wax FTIR analysis in a spectral region of 4000 cm- 1 - 400 cm -1 showed peaks at 2918.75 cm -1 and 2849.73 cm -1 confirming the presence of hydrophobic hydrocarbon. Morphological changes were observed after coating the bio wax as shown from SEM analysis. The incorporation of the hydrophobic property of bio-wax showed sufficient reduction in MIC of copper. Bio-wax acted as a protective covering inhibiting the adherence of corroding bacteria on the surface. Inhibition efficiency results are in good agreement to use Colocasia bio wax as a source of sustainable and renewable surface coating material. This property might be used in future as an ingredient in anti-rust paint used in coating metal surfaces like ship parts, pipelines systems of petroleum industry and other metal made machines etc.