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

• Cryptostegia grandiflora extract inhibited mild steel corrosion in 1 M H2SO4.
• Phenolic and flavonoid compounds were found to be the active ingredients.
• XRD studies clearly revealed the formation of a complex.
• SEM-EDX results indicated the formation of a protective film on the mild steel.

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(μg/g) and Rutin 45.62(μg/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.

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