Corrosion inhibitive properties and adsorption behaviour of ethanol extract of Piper guinensis as a green corrosion inhibitor for mild steel in H2SO4

Abstract

The corrosion inhibition of mild steel by ethanol extract of Piper guinensis (EEPG) has been studied using
gravimetric, gasometric and thermometric methods. The results of the study reveals that the different
concentrations of ethanol extract of Piper guinensis (EEPG) inhibit mild steel corrosion. Inhibition efficiency of
the extract is found to vary with concentration, temperature and period of immersion. Values of activation energy
of the inhibited corrosion reaction of mild steel are greater than the value obtained for the blank. Thermodynamic
consideration reveals that adsorption of P. guinensis extract (EEPG) on mild steel surface is spontaneous and
occurs according to Langmuir adsorption isotherm. Physical adsorption mechanism has been proposed for the
adsorption of the inhibitor from the trend of the inhibition efficiency with temperature and the values of some
kinetic and thermodynamic parameters obtained.