Preparation of modified polymer- Alumino silicate composite and their application in removal of some radionuclides from aqueous solutions

Ion exchange is one of the most common and effective treatment methods for radioactive liquid waste. This technique is well developed and has been employed for many years in both the nuclear industry and in other industries. In this thesis polyacrylamide- zeolite and polyacrylamide- bentonite composites were prepared and characterized using advanced analytical techniques. The prepared materials were used as composite ion exchangers for removal of Cesium, Cobalt and Strontium ions from simulated waste solution. Effect of ph of the medium on the removal of aforementioned ions was investigated. The sorption kinetic was studied and the data were analyzed by different kinetic models which rivaled that the mechanism of the sorption processes is mainly controlled by pseudo-second order reaction, and particle diffusion might be involved in the sorption processes. The values of diffusion coefficient of the three metal ions were calculated and suggested that chemisorption was the predominated sorption mechanism. Several isotherm models were applied for the sorption, and thermodynamic parameters were determined. The positive values of enthalpy change, δH, for the three metal ions confirmed the endothermic nature of the sorption processes. The results indicated that the prepared materials can be used as efficient ion exchange materials for the removal of cesium, cobalt and strontium ions from simulated waste solution. In the present study, immobilization of polyacrylamide- zeolite and/ or polyacrylamide- bentonite composites loaded with cesium, cobalt and/or strontium radionuclides with Ordinary Portland Cement (OPC) has been carried out. Several factors affecting the characteristics of the final solidified waste product towards safe disposal such as mechanical strength and leaching behavior of the radioisotopes have been studied. The obtained results showed that the presence of polyacrylamide- zeolite and/ or polyacrylamide- bentonite composites in the cemented wastes improve the mechanical characteristics of the solidified cement matrix (mechanical strength) towards the safety requirements and reduce considerably the radionuclides leach rates.