Evaluation of polyphenol composition and anti-corrosion properties of Cryptostegia grandiflora plant extract on mild steel in acidic medium

The total phenolic and flavonoid compounds present in Cryptostegia grandiflora leaf extract were analyzed. The results confirmed that the extract contains the Myricetin 3582.22(mu g/g) and Rutin 45.62(mu g/g) as major components. C. grandiflora extract was evaluated for its anti-corrosion property on mild steel in 1 M H2SO4. A maximum inhibition efficiency of 87.54% was achieved by using 500 ppm of the inhibitor. Polarization studies indicate that the extract acts as a mixed inhibitor. The formation of productive layer on mild steel by inhibitor was confirmed by SEM-EDS and AFM. The extract is adsorbed on the mild steel according to Temkin adsorption isotherm. (C) 2016 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.