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- Author or Editor: N. Hafez x
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Abstract
A quantitative study of the interaction of some lanthanide ions with 2,2
-oxybis-[ethyliminodi /acetic/ acid] or 2,2-bis [aminoethyl]ether-tetraacetic acid /BAETA/ was carried out. Stability constants of the lanthanide chelates containing 1
1 ratio of metal to ligand were determined. A discussion of the variation of the metal chelates stability constants in the lanthanide series is given. Radiolysis of the formed chelates has also been investigated both in presence and in absence of oxygen. A radiolytic degradation mechanism is proposed and discussed.
Abstract
Radiolysis of aqueous solutions of di- and trivalent cobalt with 2,2-bis/aminoethyl/ether-tetraacetic acid /BAETA/ was investigated, both in absence and in presence of oxygen. A radiolytic mechanism has been proposed where it has been shown that the degradation of the chelation is due to OH only.
Abstract
Gamma irradiation of di- and trivalent cobalt nitrilotriacetic acid (NTA) chelates was performed both in the presence and absence of oxygen (air). A radiolytic mechanism is proposed where it has been shown that degradation of the cobalt chelates is due to OH radicals formed during radiolysis.
Abstract
Adsorption of some fission product elements on sephadex was attained at pH 5.5±0.2. Individual separation of adsorbed radioactive cerium, uranium and plutonium on sephadex was performed using 25 ml of 10–4M triethylenetetraaminehexaacetic acid (TTHA) at different pH values.
Abstract
A simple, economic and specific radiochemical method for the determination of americium in urine and other biological materials is given. The urine sample is heated in nitric acid to break down any organic complexes of actinides. Insoluble phosphates are precipitated and changed to carbonates. The carbonate solution is passed through a diglycol succinate column and americium is eluted by hydrochloric acid. The eluate is evaporated to prepare a source for counting. The proposed procedure produces high overall yield and the sensitivity of the method is about 0.74 mBq (0.02 pCi). Determination of americium in the presence of other 
-emitters in urine is also given.
Abstract
The effect of γ-rays on acidic and alkaline solutions of ethylenediaminetetraacetatocerium(III) has been studied both in the presence and absence of oxygen. A mechanism is proposed, in which the radiolytic degradation of the complex is due only to OH, while the radiolytic oxidation of Ce(III) EDTA to Ce(IV) by γ-rays occurs via the formation of hydrogen peroxide.
Radiolysis of aqueous solutions of cobalt(II) and cobalt(III)
1:2 bis-carboxymethylaminodiethyl tetraacetate
Abstract
Radiolysis of aqueous solution of di and trivalent cobalt with 1:2 (bis) carboxymethylaminodiethyltetraacetic acid (EGTA) was investigated, both in absence and in presence of oxygen. A radiolytic mechanism has been proposed. It has been shown that the degradation at the ligand of the chelate is due to OH only.
Abstract
The radiolysis of ethylenediaminetetraacetatocobalt (II) and (III) has been studied, both in the presence and absence of oxygen, Radiolytic degradation of the metal chelate was observed. Based on the experimental data, a radiolytic degradation mechanism of the chelates is proposed and discussed.
Abstract
Irradiation of cerium III-triethylenetetraaminehexaacetic acid (TTHA) solutions was done. The degradation of the metal chelate was determined. A radiolytic mechanism has been proposed where it has been showed that the degradation is due to the OH radical, while oxidation of trivalent cerium to tetravalent cerium is due to the hydrogen peroxide molecule.
Abstract
A simple and sensitive spectrophotometric method for the determination of cobalt, nickel and copper with desferrioxamine-B (desferal) is described. The sensitivity of the colour reactions of cobalt, nickel and copper is increased by introducing desferal. The pH range for the formation of Co II, Ni II or Cu II-desferal. Chelates is 4.5–8.5, 5.5–9, and 6.5–9.5, respectively. The molar absorptivities of the chelates are 1.2·105, 5.6·104 and 4.8·104 at 545 nm, 390 nm and 680 nm, respectively. Beer's law is obeyed up to 10 
g/ml of metal ion. The effect of desferal concentration, pH, standing time and interfering ions are discussed. The method was applied to the determination of trace amounts of cobalt, nickel and copper in steel and simulated radioactive wastes.
