Cu (II) Chemisorption on Calcined Substrates made with an Oxidic Refractory Variable Charges Lithological Material

This work presents a complementary study on the nature of copper ions adsorption reaction on calcined substrates with variable charge surfaces prepared with refractory lithological materials obtained from San Juan de Lagunillas, near the city of Mérida, Mérida State, Venezuela. The study was performed on activated and non-activated calcined substrate, prepared with granulometric fraction between 425 mm – 250 mm. The results of the PZC showed that thermal treatment favors the formation of amphoteric oxides with pH0 6 – 7 similar to those reported in the literature. Although the isotherms obtained in previous experiments are L type which indicative of strong affinity of copper ions with the surfaces of the substrates, they do not represent an absolute proof about a chemo-resorption reaction. This kind of adsorption reaction should produce H3O ion that acidifies the solution. The adsorption experiment performed on 2 g of calcined substrates with solutions of 0.001, 0.01 and 0.1 M Cu+2 produced 0.11, 0.27 and 1.19 mmol of protons ions respectively. These data complement the information given by the isotherms about the chemisorption of copper ions with the surface of this calcined substrate, confirming the specific adsorption.