الفهرس 
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Abstract
The aim of this thesis is to prepare and characterize some synthetic humic acids with simpler overall structures but under different preparation conditions. Also, the work is devoted to compare between synthetic and the natural humic acid samples in properties and interactions with the metal ions Cs+, Sr2+, Cd2+, Hg2+, Pb2+, Cr3+, Ce3+, Pr3+, Nd3+, Gd3+, Er3+, Dy3+, Tb3+, Tm3+ and Se4+ in the presence of the radionuclides Eu3+and Co2+. The study involved separation, purification as well as characterization of humic acids (natural and synthetic samples) and determination of the binding constants of europium radionuclide with humic materials as a ligand. The natural humic acid used in this study was separated from the bottom sediments of Ismailia Canal (ICHA). The elemental composition of the investigated humic acids (natural and synthetic) indicates that the major elements are carbon and oxygen. The infrared spectra of the investigated humic acid materials (natural and synthetic humic acids) were found to have a variety of bands that are diagnostic of specific molecular structures, indicating the major constituent of the humic acid samples (aliphatic, aromatic, carboxylic<U+2026>) and the purity of these samples. This increase in the binding constants with pH was ascribed to the additional ionization of the acidic groups of the respective humic acids. The following equations were obtained to relate the binding constant of Eu3+ with different humic acids in terms of pH. The sorption of metal ions was found to increase with increase the contact time till reach equilibrium after 24 hours. The sorption of metals by natural humic acid and synthetic humic acid, after 24 hr increase with increasing pH. The effect of different humic acids concentration on its sorption on clay sample at pH=8.5, the sorption increases as the humic acids concentration increases. The sorption of the humic acid on clay treated by metal ions with different charge was found to follow the order: Se4+ > Cr3+ > Cd2+ > Cs+ . The sequence of sorption of humic acids on clay treated metal ions with the same valency is: Cd2+ > Hg2+ > Sr2+ > Pb2+ . When the clay is saturated with the trivalent lanthanides (Cr3+, Ce3+, Pr3+, Nd3+, Gd3+, Er3+, Dy3+, Tb3+and Tm3+ ), it is found that high coordination of humic acid with the trivalent lanthanides, but no specific reaction is related to the sequence of lanthanides. Preparation of Cobalthumate and its Interaction with different Metal Ion: The cobalthumate precipitates were found to increase with increasing Co2+ concentration at pH=7.5. Preparation of Cobalthumate and its Interaction with different Metal Ion: The cobalthumate precipitates were found to increase with increasing Co2+ concentration at pH=7.5. It is found that by increasing the molar concentration of the metal ions in solution, Co60 was released, in solution, in the presence of Hg2+ and Pb2. This sequence agree with the value of the ionic potential of these cations, except Cd2+. With a growth in the ionic potential, the tendency of cations to form complex increases. The natural humic acid is closely resembled to the synthetic humic acid in structure and trend of the sorption or interaction with metal ions.