Uptake of iodide by a mixture of metallic copper and cupric compounds

Ability of copper/cupric compound mixtures to remove iodide from solution w as investigated to predict sorption of radioactive iodine in the environmen t and to assess their use in a nuclear reprocessing method. Thermodynamic c alculations were performed to study the stability of such mixtures in solut ion and to obtain equilibrium constants of Cu(0)/Cu(II)/I- and Cu(0)/Cu(II) /Cl- systems. Both calculations and experimental results showed that a Cu(0 )/ Cu-3(OH)(2)(CO3)(2)(azurite) mixture selectively uptakes iodide ions(ini tial:concentrations: 10(-2) and 10(-1) M) in the presence of 10(-1) M chlor ide ions. Reaction of iodide with copper powder and azurite crystal or copp er plate and azurite powder have also been investigated, leading to precipi tation of Cut onto massive copper phase. The different solids were separate ly analyzed by XPS and MEB-EDX, giving some insight in the uptake mechanism . It is proposed that soluble copper released by the cupric compound is red uced at the surface of metallic copper, leading to a preferential precipita tion of Gut on copper surface.