Removal of cyanide in aqueous solution by oxidation with hydrogen peroxide catalyzed by copper oxide

This work is dedicated to the removal of free cyanide from aqueous solution through oxidation with hydrogen peroxide H₂O₂ catalyzed by copper oxide nanoparticles. Effects of initial molar ratio [H₂O₂]₀/[CN^-]₀, catalyst dose, temperature, pH and the catalyst stability on cyanide removal have been investigated. The use of copper oxide has improved the reaction rate showing catalytic activity. The cyanide removal efficiency was increased from 60% to 94% by increasing in the dose of catalyst from 0.5 g/L to 5.0 g/L. Increasing the temperature from 20 °C to 35 °C promotes cyanide removal and the four successive times re-use of catalyst shows good stability. Kinetics of cyanide removal was found to be of pseudo-first-order with respect to cyanide. The rate constants have been determined.