PANIALA (FLACOURTIA JANGOMAS) PLANT EXTRACT AS ECO FRIENDLY INHIBITOR ON THE CORROSION OF MILD STEEL IN ACIDIC MEDIA

摘要

The inhibition of corrosion of mild steel using Paniala (Flacourtia jangomas) extract in 1M HCl and 0.5 H2SO4 solutions was investigated by weight loss method at 30?C. The result showed that corrosion rate was significantly decreased in presence of the extract and inhibition efficiency increased with increasing the concentration of extract. In case of HCl maximum inhibition efficiency (98%) was noticed at 5% v/v inhibitor concentration and no considerable change in inhibition efficiency was observed after this concentration and in 0.5M H2SO4, it was found 95% efficiency at the same concentration of inhibitor. At lower concentration of inhibitor, better inhibition was observed in HCl medium as compared to H2SO4. The decreased corrosion rate was due to adsorption of plant extract which was discussed on the basis of Langmuir and Freundlich adsorption isotherm. Adsorption of Flacourtia jangomas depends on its chemical composition which showed the presence of various compounds like flavonoids, steroids, tannins and phenolic compounds etc. which has oxygen atoms with lone pair electrons for co-ordinate bonding with metal.