Chemical studies on the synthesis and characterization of some ion- exchange materials and its use in the treatment of hazardous wastes

Now inorganic ion exchange materials play an important role in analytical chemistry, based originally on their thermal and radiation resistance as well as their stability to chemical attack.Vanadate salts are one of the main categories of inorganic ion exchange materials widely used in separation and preconcentration of some toxic and hazardous elements from different waste media. Attempts in this study are focused on the preparation of two inorganic ion exchange materials ,Tin Vanadate (SnV) and Titanium Potassium Vanadate(TiKV) for treatment of hazardous waste.These material were characterized using X-ray spectra (XRD and XRF), IR, TGA-DTA and total elemental analysis studies. On the basis of distribution studies, the materials have been found that they are highly selective for Pb(II) and Cs(I)ions. Thermodynamic parameters (i.e. ΔG, ΔS and ΔH) have also been calculated for the adsorption of Pb²⁺, Cs⁺, Fe³⁺, Cd²⁺, Cu⁺², Zn²⁺and Co²⁺ ions on Tin Vanadate (SnV) and Titanium Potassium Vanadate(TiKV) showing that the overall adsorption process is spontaneous and endothermic. The mechanism of diffusion of Fe³⁺, Co²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Cs⁺and Pb²⁺ ions for Tin Vanadate (SnV) and Titanium Potassium Vanadate(TiKV) as cation exchangers were studied as a function of particle size, concentration of the exchanging ions, reaction temperatures and drying temperatures. The exchange rate was controlled by a particle diffusion mechanism as a limited batch technique and is confirmed from straight lines of B versus 1/r² plots. The values of diffusion coefficients, activation energies and entropies of activation were calculated and their significance was discussed. The data obtained have been compared with that reported for other inorganic exchangers. Exchange isotherms for Cs⁺ ,Co²⁺and Cd²⁺ions were determined at 25, 45 and 65±1 degree C. These isotherms showed that Cs⁺ ,Co²⁺and Cd²⁺ are physically adsorbed. Finally, separations of the above mentioned cations on Tin Vanadate (SnV) and Titanium Potassium Vanadate(TiKV) in columns were performed .