Inhibition of Copper Corrosion in H2SO4, NaCl and NaOH Solutions by Citrullus colocynthis Fruits Extract

Abstract

The inhibitive effect of extract of Citrullus colocynthis fruits on copper corrosion in H₂SO₄, NaCl and NaOH solutions were studied using conventional weight loss and electrochemical polarization methods. Results obtained showed that extract functioned as effective and excellent inhibitors in the acidic, salt and alkaline media. Potentiodynamic polarization curves indicated that the plants extracts behave as mixed-type inhibitors. The fruit extract of Citrullus colocynthis demonstrated better inhibition efficiency in the acidic medium than in the alkaline and salt medium. The experimental data complied with the Langmuir adsorption isotherm and the value and sign of the Gibb’s free energy of adsorption obtained suggested that inhibitor molecules have been spontaneously adsorbed onto the copper surface through a physical adsorption mechanism.

Keywords: Copper inhibition, kinetics, plant ex, Corrosion tract, Langmuir, weight loss, and thermodynamics.