SPECTROPHOTOMETRIC STUDIES ON THE INHIBITION POTENTIAL OF COSTUS AFER EXTRACT

ABSTRACT

Inhibition effect of Costus afer on mild steel in 1M HCl was studied using Atomic Absorption Spectroscopy at four different temperatures (30^oC, 40^oC, 50^oC, 60^oC). It was found out that Costus afer inhibited the corrosion of mild steel in the acidic environment and that the efficiency of inhibition is favoured at reduced temperature. From the experimental study, it was observed that, an increase in the concentration of the acid resulted in a reduction in inhibition efficiency. A physical observation was that, green pigments coated the surface of the metal which must have been a function of the phytochemicals (saponnins, tannins, steroid and heteroatoms) present in the Costus afer. Thus, the extracts of Costus afer inhibited the corrosion process through physiosorption mechanism.