Mutual Influence of Sodium Dodecyl Sulphate and Calcium Propionate in Biocidal Activity and Corrosion Inhibition of Carbon Steel

Abstract

The inhibition and biocidal efficiency of sodium dodecyl sulphate (SDS) and calcium propionate (CP) in controlling corrosion of carbon steel immersed in an aqueous solution has been evaluated by weight loss and biocidal efficiency method in the absence and presence of Zn2+. The formulation consisting of CP and Zn2+ has excellent inhibition efficiency (IE). The biocidal efficiency of this formulation is 46 %. To improve the biocidal efficiency a third substance SDS is added. A synergistic effect is noticed between SDS, Zn2+ and CP. The formulation consisting 50 ppm of calcium propionate, 200 ppm of SDS and 50 ppm of Zn2+ shows 99 % IE and 100 % biocidal efficiency. Addition of SDS enhances the IE of Zn2+ and CP system. Electrochemical studies were carried out to find out the nature of the corrosion inhibitor. The CP–Zn2+–SDS system functions as a mixed inhibitor. The scanning electron micrographs and atomic force micrographs reveal the formation of a protective film on the metal surface.