Experimental and Theoretical investigation of flavonoid based plants stem and leaves of Dodonaea viscosa Mundulea sericea and Cassia alata on mild steel corrosion in acid media

Abstract

The present research is aimed to evaluate the inhibitive properties of stem and leaves extracts newlineof three flavonoid based plants such as Dodonaea viscosa DV Mundulea sericea MS and Cassia newlinealata CA as corrosion inhibitors for mild steel in 1M HCl and 0 point 5M H2SO4 using potentiodynamic polarization electrochemical impedance spectroscopy and mass loss methods and Surface analytical techniques like UV SEMEDX FTIR XRD 3D Laser Profiler and Quantum chemical studies Mass loss measurements were performed by immersing the mild steel coupons into acid solution 100mL without and with various amounts of inhibitors at different periods of immersion and temperature Electrochemical studies were carried out using Solartron and Biologic interfaced with an IBM computer Analysis of results of the mass loss measurement infer that the inhibition efficiency increases with increasing concentration and time immersion of DVLE DVSE MSLE MSSE CALE and CASE respectively in 1 M HCl and 0 point 5 M H2SO4 solution indicating the enhanced stability of the adsorbed constituents of the extract on mild steel surface All the investigated inhibitors afford a maximum IE in the range of 86 to 94 percent in both acid media Temperature studies reveal the stability of the inhibitors at all investigated temperature The data obtained from the weight loss measurements were fitted into various adsorption isotherms using the statistical package SPSS The activation parameters of the investigated inhibitors for the corrosion process Ea DHa and DSa reflect the kinetic and mechanistic effect of the inhibitors Potentiodynamic polarization results reveal the mixed nature of the inhibitors Surface analytical techniques confirm the formation of insoluble FeComplex on the mild steel surface Quantum chemical studies confirm the probable adsorption centers through which the Fe atom is linked to form Fec newline