Corrosion inhibition study of bract extract of Musa acuminata inflorescence on mild steel in hydrochloric acid medium

Abstract

Inhibition efficiency of acid extract of dry Musa acuminata bract as corrosion inhibitor for mild steel in 1N hydrochloric acid was investigated in the present study. Experimental methods include weight loss, polarization and surface analysis studies. The inhibition efficiency increased with increase in inhibitor concentration and decreased with temperature suggesting the occurrence of physical adsorption. Potentiodynamic polarization curves reveal that inhibitor perform as a mixed type of inhibitor. The electrochemical impedance study showed a decrease in double layer capacitance as the adsorption of inhibitor lead to structural change at electrode-solution interface thereby controlling the mild steel dissolution by charge transfer mechanism. The mild steel surface in the absence and presence of the inhibitor was analysed by scanning electron microscopy (SEM). Adsorption isotherms were tested and the experimental data fit well with the Langmuir adsorption. Corrosion inhibitor has efficiency as high as 94.93% at 2% v/v inhibitor concentration. Inhibition mechanism can be attributed to the adsorption of phytochemical compounds of the bract extract on the surface of the mild steel.