الفهرس 
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Abstract
In the present thesis, some physicochemical and separation studies of some rarer elements have been carried out. The studied elements have been chosen for their significance in nuclear field, as well as in industrial, environmental and biological fields. All studied elements have radioactive isotopes resulting as fission products (except Co which has no fission product isotopes) or from neutron irradiation. Their isolation and separation from large volume liquid solution is an important task in nuclear field, where large volumes of liquid effluents are produced from various nuclear activities.
The chosen elements in the present thesis are arranged according to increasing atomic numbers are: Co, Se, Zr, Nb, Mo, Tc, Te, Eu and Hf. These elements present in different groups in the periodic table of elements, consequently they have different oxidation states. The studies have been carried out on ions of the most stable oxidation state, i.e. Co(II), Eu(III), Se(IV), Te(IV), Zr(IV), Hf(IV), Nb(V), Mo(VI) and Tc(VII).
The separation studies have been carried out on couples of elements, either because of their close chemical similarity since they belong to the same group of the periodic table (e.g. Zr&Hf, Se&Te) or because they are neighbors in the same period, like some transition elements (Zr&Nb, Mo&Tc), in addition to some couples related to each other as mother-daughter radioactive isotopes like 99Mo-99mTc and 95Zr-95Nb. In the case of Co and Eu, they have been studied together from the point of view of the nature of nuclear radiation emitted from some of their radioactive isotopes such as 60Co and 152+154Eu, respectively. These isotopes emit γ-radiation of high energy and intensity in addition to their long half-lives.
Adsorptions on inorganic and organic ion exchangers, solvent extraction with organic extractants and extraction chromatography have been applied in the present study. Adsorption mechanisms on the prepared inorganic ion exchanger and conventional organic resins are compared. It is proved that the prepared inorganic ion exchanger (CeW) can act as an anion exchanger beside its known cation exchange character, i.e. it has amphoteric character. Diffusion coefficient was calculated in some cases. Some important separation alternatives for the studied elements have been achieved using the chosen techniques, as well as concentration of radioisotopes from large volume of aqueous solutions on small columns.