The solid-state thermal reactions of 2,6-diamino-4-chloropyrimidine, 3,3-dimethoxybenzidine and of thiosemicarbazide with
each of 2-hydroxy-1-naphthaldehyde and 2,4-dihydroxybenzaldehyde in a mole ratio of 1∶1 produced (1+1) condensation products
(‘half units’). These solid state reactions have been studied by means of differential thermal analysis (DTA). The products
of the reactions were identified using elemental analysis and IR spectroscopy. Some kinetic parameters such as orders and
activation energies of the reactions were evaluated form the DTA curves.
Many studies have shown that water hyacinth (Eichhornia crassipes) roots can be used to accumulate high concentrations of organic as well as inorganic pollutants. They are currently used to remediate aquatic environments and aqueous solutions. In the present study, sorption of uranium from aqueous solutions by using dried roots of water hyacinth has been investigated. The sorption of uranium was examined as a function of initial concentration, pH, weight of roots and contact time. Five different concentrations 20, 40, 60, 80, and 100 μg . ml-1 were used. Sorption proves to be very rapid and depend on pH, weight of roots and concentration of uranium. Maximum sorption capacity of water hyacinth roots was 64,000 U6+ μg/g. The sorption of uranium by water hyacinth roots follows a Langmuir isotherm.
Authors:H. Aly, M. El-Dessouky, M. Raieh and S. Mohamed
Synergic extraction of trivalent iron and cobalt with thenoyltriflouroacetone (HTTA) and the synergic bases (B) benzylamine
(BA), dibenzylamine (DBA) and tribenzylamine (TBA) was studied. The extracted adducts proved to have the general formula M(TTA)3·B for all the amines investigated. The formation constants of the mixed-ligand complexes decrease in the order DBA>TBA>BA.
While equilibrium constant β3,1 for the Co(TTA)3·DBA complex is higher than the corresponding iron adduct, β3,1 for the iron adducts with BA and TBA are higher than those for cobalt.
Authors:H. Aly, M. Raieh, S. Mohamed and A. Abdel-Rassoul
The effect of ten pure diluents and different mixtures of nitrobenzene and toluene on the synergic extraction of Co2+ by the thenoyltrifluoroacetone (HTTA)-tribenzylamine (TBA) mixture is studied. The logarithm of the extraction constant of
Co(TTA)2 increases with increasing dielectric constant of the diluent, whereas the logarithm of the formation constant of the extracted
adduct Co(TTA)2TBA decreases with increasing dielectric constant of the diluent. This behaviour is explained by changes in the hydrophobic
character of the extracted species. The theory of regular solutions is successfully applied to the extracted adduct. Consideration
of the self-association of the amine salt is necessary in the treatment of the equilibria involved.
Authors:H. Dessouky, M. Abdel-Badei, S. Khalifa and H. Aly
Chromatographic column investigations were performed for the recovery of uranium from aqueous medium of pH 1.0 and ionic strength of 0.6M/NaNO3/, which is comparable /in its chemical activity/ to certain high active waste solutions. Six different active beds were tested and compared in terms of their capacity for uranium, height equivalent to theoretical plate and their numbers. The main uranium species present in the medium were elucidated.
Authors:H. Aly, S. Khalifa, R. Mahfooz and M. Sherif
The effect of temperature on the extraction of Co2+, Zn2+, Cd1+ and Hg2+ by salicylaldoxime diluted with carbon tetrachloride was investigated radiometrically. It is found that the extraction constants
at 25°C increase linearly with l/r, where r is the effective coordination radius of the metal cation. The thermodynamic data
calculated from the effect of temperature on the extraction showed that, 1) the extraction process is endothermic, 2) the
dehydration of the metal cation in the extraction process is the predominating factor in determining the enthalpy variation
and 3) the entropy variation is a contribution of the degree of order caused by the hydration of the proton and the highly
ordered chelate structure of the extracted species.
Authors:H. Aly, M. Raieh, S. Mohamed and A. Abdel-Rassoul
The solvent extraction of divalent iron, cobalt, copper and zinc from perchlorate medium of constant ionic strength (0.1 H+, NaClO4) into a mixture of thenoyltrifluoroacetone (HTTA) and dibenzylamine (DBA) in chloroform has been studied. The extraction
of the different cations were found to increase by more than 103 order of magnitude in presence of DBA. Slope analysis of the extraction results assumed a general formula of M(TTA)2·DBA for the extractable adduct. A stability order of Fe(TTA)2·DBA>Co(TTA)2 ·DBA>Zn(TTA)2·DBA>Cu(TTA)2·DBA has been decumented.
Authors:A. I. El-Said, A. A. M. Aly and A. S. A. Zidan
The thermal decompositions of nine mixed ligand complexes of Mn(II) containing picrate and mono- or bidentate nitrogen ligands were studied by thermogravimetry. The kinetics of decomposition were examined by using the Coats-Redfern and Horowitz-Metzger equations; the decomposition was in all cases of the first order. The activation energies and other kinetic parameters were computed. The decomposition mechanisms exhibited a similar character for all the studied compounds. It was observed from the TG curves that the complexes decomposed to give six-coordinate intermediates, formed from substitution of the picrate into the inner coordination sphere. These intermediates decomposed to Mn(II) picrate and finally to Mn2O3.
Authors:A. A. M. Aly, A. S. A. Zidan and A. I. El-Said
The reactions of bis(2-mercaptobenzothiazolato)nickel(H) with some azoles and morpholine afforded the corresponding mixed ligand complexes. The studied azoles were 2-aminothiazole, benzothiazole, benzoxazole, 2-methylbenzoxazole and 2-mercapto-benzoxazole. The formation of new compounds was confirmed from the spectral data. The thermal decompositions of the compounds together with some related compounds reported in the literature, for comparison, were studied. The activation energies and other kinetic parameters were calculated from the Coats-Redfern and Horowitz-Metzger equations.
Authors:A. A. Helal, Aly A. Helal, N. Z. Salim and S. M. Khalifa
A humin sample, isolated from organic soil (peat) was used to investigate its interaction with different kinds of radioelements
in batch systems. The sorption of the radionuclides 110mAg, 60Co and 65Zn by peat humin was studied under different conditions. The results indicated that humin has high ability to sorb the investigated
nuclides with the sequence Co2+> Zn2+> Ag+, and can retained up to 1.04 mmol/g of Ag+, 1.63 mmol/g of Zn2+and 1.73 mmol/g of Co2+. The sorption process was time dependent and the percentage of uptake increased with pH to reach a maximum at pH~7.5, which
corresponds to the pKavalue of the humin.