Corrosion inhibition and biocidal activity of a cationic surfactant

Abstract

The inhibition efficiency (IE) of CTAB - Zn²⁺ system in controlling corrosion of carbon steel in well water has been evaluated by weight loss method. Enumeration of microorganisms from well water and biocidal efficiency of inhibitor system (CTAB-Zn²⁺) were also determined by serial dilution technique and spread plate method.<b> </b>The formulation consisting of 200 ppm of CTAB and 5 ppm of Zn²⁺ shows an IE of 98%. Potentiodynamic polarization curves indicate that the CTAB – Zn²⁺ system functions as anodic inhibitor. AC impedance spectra reveal that a protective film is formed on the metal surface. FTIR spectra suggest that the protective film consists of Fe²⁺- CTAB complex and Zn(OH)₂. The optimum concentration of CTAB for destroying the bacterias <i>viz</i>. <i>E.coli</i>, <i>Salmonella</i> and <i>Shigella</i> is ³ 25 ppm. At ³ 25 ppm of CTAB, it shows 100% biocidal efficiency in well water containing 5 ppm of Zn²⁺.