الفهرس 
AbstractOnly 14 pages are availabe for public view
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Abstract
The overall work can be summarized as follow. 1In chapter one, a brief review on the recommended methods for the preconcentration, separation and determination of some toxic metals is undertaken. Special attention is given to liquidliquid, liquidsolid separation employing polyurethane foam as a solid sorbent and potentiometric measurements using ionselective membrane electrodes. The literature survey revealed that, few studies have been reported on the preconcentration and determination of uranium (VI) and barium (II) ions employing polyurethane foams and membrane sensor, the survey revealed a need for reliable and rapid methods for removal and determination of uranium (VI) and barium (II) ions in wastewater. 2 Chapter two is concerned with: iDeveloping a simple liquidliquid extraction procedures for the chemical separation of uranium (VI) species in aqueous media and subsequent determination of picric acid in water. The method is based upon the extraction of the ternary complex ionassociate of uranium (VI), crown ether and picric acid at pH <U+2264> 3 in chloroform. The stiochiometry of the formed complex ionassociate was determined. The method was also applied successfully for the analysis of picric acid in water. ii The kinetics of uranium (VI) sorption by the unloaded polyurethane foams and foams loaded with crown ether or trinbutyl phosphate were found fast. The dependence of the uranium (VI) uptake by the reagents loaded foam on pH, salt effect, metal ion concentration, etc., was explained in a manner consistent with a ?solvent extraction? mechanism. The sorption data also followed Langmuir, Freundlich and DubininRadushkevich (DR) type sorption isotherms. Thus, a ?dualmode sorption mechanism? involves both absorption related to solvent extraction and an added component for surface adsorption seems a more likely model. The thermodynamic characteristics of uranium (VI) sorption by the unloaded reagent and TBPloaded foams have been studied. The positive and negative values of <U+2206>H and <U+2206>S may be interpreted as the endothermic and exothermic nature of uranium (VI) sorption onto unloaded and TBP immobilized PUFs, respectively. The sorption and recovery percentages of uranium (VI) from water by the proposed loaded foam columns were achieved quantitatively. The height equivalent (HETP), the number (N) of the theoretical plates , the breakthrough capacity and the critical capacity of uranium (VI) sorption onto the unloaded and loaded foam colums are calculated. 3 Chapter three includes fabrication of a novel selective and precise PVC membrane sensor for the assay of barium (II) species in industrial wastewaters. The developed sensor is based on the incorporation of the complex ionassociate of barium (II)RoseBangal as a neutral carrier in plasticized PVC matrix. The developed sensor is stable and exhibits fast potential response and activity in the tested concentration range of barium (II) ions. It also showed excellent selectivity for barium (II) towards several cations. The plasticizer 0NPOE significantly controls the calibration slope and the life time of the fabricated sensor. The direct potentiometric and standard addition measurements of barium (II) in industrial wastewaters showed an acceptable average of 96.5<U+2013>101.2 %. The accuracy of the determination was verified with the data obtained employing direct spectrophotometry and AAS spectrometry.