Inhibition of mild steel corrosion by plant extract of Cyperus eragrostis Lam. in 1n Hydrochloric Acid medium
*1Vijila Gnanaselvi G. and 2S. Velrani
1,2Department of Chemistry, Kamaraj College, Thoothukudi-628003 India Affiliated to Manonmaniam Sundaranar University, Abishekapatti, Tirunelveli-627012 India *1E-Mail: vijilagnanaselvi@gmail.com
ABSTRACT
Inhibitory effect of plant extract of Cyperus eragrostis (CE) on mild steel corrosion in 1N HCl medium was investigated. Weight Loss Method, Potentiodynamic Polarization and AC impedance spectroscopy, Langmuir adsorption mechanism, FTIR and SEM were used in this present study. The experiment by Weight Loss Method has shown that the inhibition efficiency(CE) of the inhibitor increases with increase in concentration. Maximum inhibition efficiency is 87.76%. Electrochemical Impedance Spectroscopy results revealed that, the inhibition efficiency increases with increase in concentration of inhibitor and also showed that the increase of transfer resistance with inhibitor concentration. Maximum inhibition efficiency is 94.93%. In Potentiodynamic polarization measurements, Tafel polarization curve reveal that the inhibitor act as a mixed-type inhibitor and also the inhibition efficiency increases with increase in concentration. The maximum inhibition efficiency is 89.03%. Scanning Electron Microscopic analysis has provided the confirmatory evidence of the safeguard of mild steel by the green inhibitor. FTIR spectral analysis revealed that the shift in the absorption frequencies and it supports the interaction between the inhibitor and the metal surface.