Spectroscopic methods used for analyzing protective film formed by L-Histidine on carbon steel

S.Sivakumar; A.Sahaya Raja; J.Sathiyabama; V.Prathipa

Authors

S.Sivakumar PG and Research Department of Chemistry, GTN Arts College, Dindigul – 624005, Tamil Nadu, India
A.Sahaya Raja PG and Research Department of Chemistry, GTN Arts College, Dindigul – 624005, Tamil Nadu, India
J.Sathiyabama PG and Research Department of Chemistry, GTN Arts College, Dindigul – 624005, Tamil Nadu, India
V.Prathipa Department of Chemistry, P.S.N.A. College of Engineering &Technology, Dindigul, Tamil Nadu, India

Keywords:

L-Histidine, Synergistic effect, FTIR, SEM,EDAX

Abstract

The corrosion inhibition of carbon steel (CS) using the “green” inhibitor, L-Histidine (L-His) was investigated. This study
was conducted at pH 7.8. The effect caused by Zn2+ additive also was investigated. The study was done over a range of concentrations. Gravimetric method and electrochemical methods were applied. It was found that the L-Histidine acts as a good inhibitor at pH 7.8. The inhibition efficiency increases with increasing L-His concentration. The addition of Zn2+ to L-Histidine significantly increased the inhibition efficiency. Tafel results indicated that decrease the corrosion current (Icorr) value. The influence of biocide SDS on the inhibition efficiency of L-Histidine – Zn2+ system has been investigated. Also it is evident that at minimum concentration of biocides added to the inhibitor system, 100 % biocidal efficiency is noticed. The protective film formed on the metal surface has been analyzed by FT-IR, SEM and EDAX spectra. It is found that the protective film consists of Fe2+ - L-Histidine complex and Zn(OH)2.