HIBISCUS ROSA-SINENSIS (JASUD) LEAVES EXTRACTS USED AS CORROSION INHIBITORS FOR MILD STEEL IN HYDROCHLORIC ACID
P. S. Desai*
ABSTRACT
To investigate the efficiency of Jasud extract as a corrosion inhibitor
for mild steel in Hydrochloric acid (HCl) and to assess the effect of
temperature and the inhibition efficiency. The corrosion rates were
determined using the gravimetric (weight loss) and Electrochemical
techniques. The results obtained in the absence and presence of Jasud
extracts were used to calculate the inhibition efficiency (%I), degree
of surface coverage and to propose the mechanism of inhibition and
type of adsorption. Results obtained showed that inhibition efficiency (%I) increased with the
increase in concentration of Jasud extracts and with the increase in temperature. Phenomenon
of chemical adsorption was proposed and inhibitor found to obey Langmuir, Flory-Huggins
and Freundlich adsorption isotherms. The values of Ea, ΔH°, ΔS° and ΔG° obtained revealed
that the adsorption process was spontaneous. Polarization study reveals that the inhibitors
functions as a mixed inhibitor. This paper provides new information on the inhibiting
characteristics of Jasud leaves extract under the specified conditions. This environmentally
friendly inhibitor could find possible applications in metal surface anodising and surface
coatings.
Keywords: Corrosion; Mild Steel; Hydrochloric Acid; Jasud leaves extracts, adsorption.
[Full Text Article]