Comparative evaluation of anticorrosion properties of HENNA leaves powder on Tin in acidic and alkaline media
Keywords:Corrosion, Tin, Henna leaves powder, HCl, NaOH
The corrosion inhibition behavior of Tin in 1.0 M HCl and 1.0 M NaOH solutions using weight loss technique was investigated at temperature ranges, 25-50 0C. The inhibition efficiency of tin in each media by using the leaves of Lawsonia inermis, L powder was found to be 93.10% at 50 0C and 95.45% at 30 0C and at optimum inhibitor concentration (0.5%) in which the overall results obtained showed that the extract have good performance and could be used to prevent the corrosion of the metal in the tested media. The leaves extract of Lawsonia inermis is the most effective in alkaline solution. At lower concentration of 0.1%, the inhibition efficiency was found to be 31.03% at 50 0C and 50% at 30 0C. This revealed that the inhibition efficiency decreased with increased in temperature but increased with increasing inhibitor concentrations. The research also include determination of activation energy, Gibbs free energy whose values are 28.131, 29.589 kJmol-1; -3.280, -3.245 kJmol-1 in acidic and alkaline media respectively, in addition to calculation of the degree of surface coverage whose data was used in the investigation or approximation of the inhibitor adsorption characteristics and its relation with the different adsorption isotherms. The adsorption was found to obey Freundlich isotherm with linear coefficient (R2) and equilibrium parameter (Kads) to be 0.972, 0.957; 0.06, 0.05 for both systems in acidic and alkaline media respectively. Physical adsorption mechanism is proposed from the trend of DGads. The negative values of DGads show the spontaneity of the inhibition process. The increase in the activation energy of the inhibition processes with values less than the threshold value of 80kJ/mol support the mechanism of physical adsorption process.
How to Cite
Copyright (c) 2020 Authors
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.