Technology Review

The inhibition efficiency of phenolphthalein in controlling corrosion of carbon steel immersed in well water has been evalu-ated by mass loss method both in absence and presence of zinc ion. A synergistic effect exists between phenolphthalein (PN) and Zn2+. The inhibition efficiency (IE) of the PN – Zn2+ system decreases with increase in immersion period. Addition of N-Cetyl-N, N, N-Trimethylammlonium bromide (CTAB) sodium dodecyl sulphate (SDS), sodium sulphite (Na2SO3) does not change the excellent inhibition efficiency of the PN-Zn2+ system. Polarization study suggests that the Pn-Zn2+ system functions as a mixed inhibitor system. AC impedance spectra reveal the presence of a protective film on the metal surface. FTIR spectra indicate that the protective film consists of Fe2+-PN complex and Zn(OH)2