E. A. Saad

Spectrophotometric determination of germanium by phenylfluorone

Abstract Spectrophotometric studies on the reaction between germanium ions and phenylfluorone were discussed including the reaction condition to develop a spectrophotometric method for the determination of germanium. The absorbance was measured at 525 nm after 20 min from the moment of adding the reagent. Beers Law is obeyed, the relative standard deviation is 2%, the senstivity of the method is 2.55 × 10 −3 mg/cm 3 , and the molar absorbtivity based on germanium is 1.75 × 10 3 .

Synthesis and surface protection of nano zerovalent iron (NZVI) with 3-aminopropyltrimethoxysilane for water remediation of cobalt and zinc and their radioactive isotopes

A method is described to synthesize a novel magnetic nano-sorbent via surface modification and protection of nano-zerovalent iron (NZVI) with 3-aminopropyl trimethoxysilane for the formation of NZVI-NH2. The produced magnetic nanomaterial was characterized by FT-IR, SEM, TEM, TGA, surface area analysis (BET) and zeta potential. Based on the TEM analysis, the particle size of the NZVI-NH2 sorbent was identified in the range 45–46 nm. The NZVI-NH2 sorbent was examined to evaluate its adsorption characteristics towards cobalt(II), zinc(II) and their radioactive isotopes in aqueous solutions and water samples using the batch equilibrium and microcolumn techniques. The metal capacity values of Co(II) and Zn(II) were optimized in the presence of different physico-chemical parameters such as pH, contact time, sorbent dose, metal ion concentration and interfering ions on the adsorption process. We also aimed to explore, investigate and evaluate using the microcolumn technique the potential applications of the NZVI-NH2 adsorbent for remediation of cobalt(II), zinc(II) and their radioactive isotopes from radioactive wastewater samples.

Thermodynamics of the extraction of Europium (III) radiotracer by benzyl-phosphonic acid monoester

The extraction of Eu3+ from perchloric acid by ethyl hydrogen benzyl phosphonate (HEBP) dissolved in a series of organic diluents, has been studied at different temperatures. From the variation of the distribution ratio with temperature, the thermodynamic functions ΔH, ΔS and ΔG have been determined. The meaning of the experimentally obtained thermodynamic quantities is discussed.

The composition and stability of the Germanium phenylfluoronate complex

SummaryGermanium phenylfluoronate is formed in solution as an orange coloured complex at pH 2.5–3.4. Its composition has been studied by continuous variation, slope ratio and mole ratio methods. The results indicate that the complex formed is of the 1∶2 type, and its stability constant is 6.80×102. The solid complex was prepared and examined by various methods including chemical analysis, infrared spectroscopy and differential thermal analysis. It conforms to the formula (C19H11O5)2Ge·4H2O and the bonding to the metal was found to be at the C=O and OH groups.ZusammenfassungGermaniumphenylfluoronat entsteht als orange gefärbter Komplex in Lösung bei pH 2,5–3,4. Seine Zusammensetzung wurde durch verschiedene Methoden untersucht, wobei sich ein Verhältnis von 1∶2 und eine Stabilitätskonstante von 6,80·102 ergaben. Der Komplex wurde in festem Zustand hergestellt und auf verschiedene Weise (chemisch-analytisch, IR-spektroskopisch, differential-thermoanalytisch) untersucht. Dabei ergab sich die Formel (C19H11O5)2Ge·4H2O. Das Metall ist an die C=O- und an die OH-Gruppe gebunden.

Efficient set-up for determination of elemental content in liquid samples using neutron activation analysis

A simple, sensitive and fast procedure for analysis of liquid samples called flowing sample neutron activation analysis has been established based on measurement of short-lived radionuclides. This newly developed method involves continuous flowing of sample between an irradiation cell and measurement station. This arrangement makes it easy to analyze a large volume of sample and thus preconcentration steps can be avoided. Moreover, flowing sample technique feeds detector with fresh irradiated material, which maintains constant dead time during whole time of measurement; hence improves accuracy of the method. The method was tested for its repeatability, detection limits and sensitivity. Obtained limits of detection are favorably comparable with those already published in literature.

Kinetic studies of the extraction of 115Cd(II) by a mixture of diphenylcarbazone and 1,10-phenanthroline in benzene

Abstract The rate of extraction of 115 Cd(II) from an aqueous phase at constant ionic strength of 0.1 M (H + , NaClO 4 ) and pH=8.5, t =25°C by a mixture of diphenylcarbazone (DPC) and 1,10-phenthroline (phen) in benzene has been studied using a stirred Lewis cell. The obtained first order rate constants showed that the rate of extraction increases with the increase in [DPC] and [phen], while it decreases with the increase in [H + ]. A plot of K obs vs. 1/[H + ] yielded a straight line, from the slope and intercept of this line the values of the rate constants K HLS and K LS were calculated and found to be equal: K HLS =1.71±1.02×10 4 M −1 min −1 and K LS =2.40±0.07×10 6 M −1 min −1 for the extraction of 115 Cd(II) by a mixture of (DPC) and (phen). The suggested mechanism indicates that the mixed complex is formed by replacing the water molecule in the metal coordination sphere by the synergistic ligand. Activation parameters E *, Δ H *, and Δ S * are calculated and the result confirmed our suggested mechanism.

The synergistic effect of 2-benzoyl- and 2-anilinopyridine on the extraction of certain europium phosphonate complexes

Extraction of Eu(III) ethylbenzylphosphonate or Eu(III) ethylbenzoylphosphonate complex in n-hexane solvent is found to be greatly enhanced in the presence of 2-benzoylpyridine as a synergist. Also, the extraction of Eu(III) ions is enhanced to a smaller extent by a mixture of ethylhydrogenbenzylphosphonate and 2-anilinopyridine. An antagonistic effect is observed in the extraction of europium by the ethylhydrogenbenzoyl-phosphonate and 2-anilinopyridine mixed system. The stoichiometry of the formed complexes is found to be dependent upon the type of synergist employed. This can probably be attributed to the difference in basicity of the two reagents. The equilibrium and formation constants of the extracted complexes as well as the synergistic factors are also reported.

Extraction of praseodymium (III), europium (III), and erbium (III) from nitrate solution by ethyl hydrogen benzyl phosphonate

Abstract The extraction of Pr 3+ , Eu 3+ , and Er 3+ from aqueous nitrate solutions by ethyl hydrogen benzyl phosphonate (HEBP) dissolved in six different organic solvents was studied. The extradant, hydrogen ion, and nitrate dependencies were found to be 2.0, 2.0, and 1.0 power, respectively, HEBP was found to be a good extradant for separation of these three lanthanide ions by varying the pH.

Evaluation of sorptive flotation technique for enhanced removal of radioactive Eu(III) from aqueous solutions

Abstract The present study aims at the removal of Eu(III) from aqueous solutions by sorptive flotation process. This process involves adsorption of Eu(III) onto bentonite and kaolinite clays followed by floatation using sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) collectors. The effect of adsorption parameters (pH, contact time, clay weight, Eu(III) concentration, ionic strength) as well as flotation parameters (collector and frother concentrations, bubbling time, concentrations of foreign cations and anions) on the removal efficiency of Eu(III) were studied. The obtained results show that Eu(III) ions are removed efficiently (R% ~ 95%) at pH=4 after 1 h shaking with clay and 15 min floatation. The adsorption kinetics of Eu(III) onto the employed clays followed the pseudo-second-order model and the equilibrium data fitted well to the Freundlich isotherm model.

Removal of radiocobalt from aqueous solutions by adsorption onto low-cost adsorbents

Four clays (bentonite, montmorillonite, diatomite and sepiolite) were used as low-cost adsorbents for removal of Co(II) radionuclides. The effect of the solution pH was studied in the range 1.5–10. The kinetic data were analyzed by the pseudo-first-order, the pseudo-second-order and intraparticle diffusion models. The equilibrium isotherms of Co(II) were analyzed by Langmuir and Freundlich models. The thermodynamic parameters (ΔGo, ΔHo and ΔSo) were calculated and the results showed that the present adsorption processes are feasible, spontaneous and endothermic in nature. Desorption experiments of Co(II)-loaded clays suggested that adsorption of Co(II) was governed by physical adsorption and surface complexation.