共查询到20条相似文献,搜索用时 31 毫秒
1.
B. F. Araujo H. T. Matsuda E. I. Carvalho I. C. Araujo 《Journal of Radioanalytical and Nuclear Chemistry》1992,165(4):209-217
A study of Pu recovery at trace level from U solutions by ion exchange technique is presented. Plutonium retention >99.5% onto strong anionic resin, AG-X8, from nitric acid solutions and a 92% recovery using 0.4M HNO3 at 60°C as eluent, were obtained. Uranium interference in Pu sorption from mixed U/Pu nitrate solutions with low U/Pu ratio (25) was not verified. However, for high U/Pu ratio solutions (10000), uranium interference in Pu retention on the resin, decreases to 59%. Selecting the loading conditions and using AG-X4 resin, 99% Pu retention was achieved. The Pu product is still contaminated with U and another purification cycle is recomended. A scheme for U/Pu first cycle separation is proposed. 相似文献
2.
J. N. Mathur M. S. Murali P. R. Natarajan L. P. Badheka A. Banerji K. M. Michael S. C. Kapoor R. K. Dhumwad 《Journal of Radioanalytical and Nuclear Chemistry》1992,165(4):219-227
The tail-end purification of Am from Pu loading effluents in 7.5M HNO3 containing 160 mg l–1 Am and 1.2 mg l–1 Pu has been carried out. With 0.2M CMPO+1.2M TBP in dodecane as the extractant and stripping by 0.04M HNO3+0.05M NaNO2, the Pu level is brought down to 31.2 g l–1. When the acidity was reduced to 4.2M HNO3, one contact with 20% TLA/dodecane and subsequent extraction by a mixture of CMPO and TBP and stripping with 0.04M HNO3+0.05M NaNO2 gave Am samples without any detectable amounts of Pu. The recovery of Am was 90% by the first procedure and 98% by the second one. 相似文献
3.
G. R. Relan A. R. Joshi R. H. Iyer 《Journal of Radioanalytical and Nuclear Chemistry》1985,89(2):379-388
Quantitative determination of uranium in (U, Pu)O2 fuels is usually done by the DAVIES-GRAY method. High concentrations of phosphoric acid in the analytical waste generated by this method make the revocery of plutonium rather complex. Studies on the recovery of plutonium from nitric acid medium containing different concentrations of H3PO4 by conventional anion-exchange procedure reveal that more than 90% of the plutonium can be easily recovered when the phosphoric acid concentration is less than 0.5 M in the solution. A method was developed for the determination of uranium in the presence of plutonium, which involves the reduction of U(VI) to U(IV) by Fe(II) in a medium of 3.5M H3PO4 +4.5M H2SO4 instead of 10–11M H3PO4 so as to have the H3PO4 concentration 0.6M in the waste. A number of determinations of uranium in UO2(NO3)2 working standard solutions and (U, Pu) synthetic solutions with uranium at the 3–7 mg level were carried out by this method. The precision obtained was better than ±0.2% and the accuracy was also within the precision limits. The resulting analytical waste generated was directly subjected to anion exchange separation for the recovery of plutonium which was found to be more than 90%. 相似文献
4.
A method is described for the simultaneous determination of plutonium and uranium in mixed oxides by controlled potential coulometry at a gold working electrode in two stages: first a coulometric oxidation, at 0.73 V vs. a silver/silver chloride electrode, of Pu(III) and U(IV) to Pu(IV) and U(VI) by a combination of a direct electrode reaction and a secondary chemical reaction proceeding concurrently, and secondly, a coulometric reduction at 0.33 V of Pu(IV) to Pu(III), leaving uranium as U(VI). The determination is carried out in a mixture of sulphuric and nitric acids, and Ti(III) is used to reduce plutonium and uranium to Pu(III) and U(IV) before electrolysis. The precision (3sigma) of Pu:U ratio results obtained from mixtures containing about 30% and 2% plutonium was 0.5% and 1-5% respectively. The effect of experimental variables on the time taken to complete the coulometric determination is discussed. 相似文献
5.
Zusammenfassung Dreistofflegierungen in dem Kombinationen {Mo, W}-{Fe, Co, Ni}-B; {V, Nb, Ta, Mo, W}-B-Al werden vornehmlich auf die Existenz von Komplexboriden hin untersucht. Die isotypen Phasen Mo2CoB2, Mo2NiB2, W2FeB2, W2CoB2 und W2NiB2 sind strukturell mit Mo2FeB2 verwandt, aber doch von dieser Phase verschieden. Gefunden werden außerdem die isotypen Phasen MoCoB und WCoB. Das Problem der -Phase wird diskutiert. In manchen Fällen tritt ein Zwischenzustand auf, der vermutlich durch Stapelfehler einer Unterzelle (c/3 in hexagonaler Aufstellung) hervorgerufen wird. Neben dem Auftreten ternärer Phasen bei Nb-B-Al und Ta-B-Al wird eine ausgeprägte Mischphasenbildung: (Nb, Al)B2 und (Ta, Al)B2 beobachtet. Der Dreistoff: Mo-B-Al ist durch die ternäre Phase MoBAl gekennzeichmet, ferner tritt der durch Al stabilisierte CrB-Typ auf (Mo0,45B0,50Al0,05). Die Gleichgewichtsverhältnisse in denT-B-Al-Dreistoffen werden abgeschätzt.
Mit 4 Abbildungen 相似文献
Alloys of the combinations {Mo, W}-{Fe, Co, Ni}-B, {V, Nb, Ta, Mo, W}-B-Al have been examined with respect to the existence of complex borides. The phases of the approximate formula Mo2CoB2, Mo2NiB2, W2FeB2, W2CoB2 and W2NiB2 have been found to be isotypic. They do however not correspond to Mo2FeB2 having U3Si2 structure. Two other complex borides of formula MoCoB and WCoB have been detected having the same crystal structure. The problem of the -phases which partially contain boron will be discussed considering the supposedly occurring stacking faults of a subcell unit (c=c/3 for hexagonal symmetry). Besides formation of ternary compounds for: Nb-B-Al and Ta-B-Al an extended solid solution (Nb, Al)B2 and (Ta, Al)B2 has been observed. The Mo-B-Al-system is characterized by the ternary phase of formula MoBAl. Mo-monoboride having CrB-type has been found to be stabilized by a small amount of Al, thus Mo0,45B0,50Al0,05 being formed. The phase equilibria within the ternary systems have been established for the major part.
Mit 4 Abbildungen 相似文献
6.
N. Gopinath G. A. Rama Rao V. K. Manchanda P. R. Natarajan 《Journal of Radioanalytical and Nuclear Chemistry》1985,96(3):273-280
The potentiometric determination of uranium is widely carried out in phosphoric acid medium to suppress the interferences of plutonium by complexation. Owing to the complexity of the recycling plutonium from the phosphate based waste involving manifold stages of separation, a method has been proposed in the present paper which does not use phosphoric acid. Uranium and plutonium are reduced to U/IV/ and Pu/III/ in 1M H2SO4 by Ti/III/, and NaNO2 is chosen to selectively oxidize Pu/III/ and the excess of Ti/III/. The unreacted NaNO2 is destroyed by sulphamic acid and excess Fe/III/ is added following dilution. The equivalent amount of Fe/II/ thus liberated is titrated against standard K2Cr2O7. R.S.D. obtained for the determination of uranium /1–2 mg/ is 0.3% with plutonium being present upto 4.0 mg. 相似文献
7.
Summary A procedure for the sequential radiochemical determination of plutonium, strontium, uranium and iron nuclides is described. The separation is carried out on a single anion exchange column. Pu(IV), U(VI) and Fe(III) are fixed on Bio Rad AG 1-X4 from 9 mol/l HCl, while the sample effluent is used for the determination of radio-strontium. Fe and U are eluted separately with 7 mol/l HNO3, and Pu(III) is eluted with 1.2 mol/l HCl containing hydrogen peroxide. Subsequently, Pu and U are electrolysed and counted by alpha spectrometry. Radiostrontium is purified by the nitrate method and counted in a low level beta proportional counter. Fe is purified by extraction and cation exchange and 55Fe is counted by X-ray spectrometry with a Si(Li) detector. The sample preparation and the application of the procedure to large samples, namely aerosols from 105 m3 of air, and monthly deposition samples from 0.6 m2 sampling area (10–100 l) are described. Chemical yields are for Pu 70±20, for Sr 80±15, for U 80–90, and for Fe 75±10%. As an example, the maximum airborne radionuclide concentrations determined with that procedure in fortnightly collected samples at Neuherberg after the Chernobyl accident were: 239+240Pu, 2.58; 238Pu, 1.40; 238U, 0.65; 234U, 0.67; 90Sr, 7600; and 55Fe, 990 Bqm–3.With appropriate changes in sample preparation, the procedure is applicable to other kinds of samples. 相似文献
8.
R. M. Sawant M. A. Mahajan N. K. Chaudhuri S. K. Patil 《Journal of Radioanalytical and Nuclear Chemistry》1993,170(1):197-205
Stability constants of the fluoride complexes of Pu(III), Sm(III) and Bi(III) in 1.0M NaClO4/HClO4 medium at 23±1°C have been determined by potentiometry using a fluoride ion-selective electrode. Plutonium was reduced to the trivalent state using quinhydrone with an excess to serve as holding reductant. The log values of concentration stability constants log 1, log 2, and log 3 are 3.58, 6.40 and 12.61 for Pu(III), 3.23, 5.81 and 10.54 for Sm(III) and 3.69, 6.13 and 11.04 for Bi(III), respectively. The log 2 values in all these cases have very large deviation and may be taken only as rough estimates. 相似文献
9.
A controlled potential coulometric method developed earlier for the determination of uranium in the presence of iron or plutonium using platinum working electrode was extended for individual determination of uranium and iron or plutonium in single aliquot. After uranium determination, Fe(III) or Pu(IV) in the aliquot is reduced electrolytically to Fe(II) or Pu(III) and subsequently determined by electrolytic oxidation to Fe(III) or Pu(IV), respectively. Analysis of synthetic solutions indicated that the values for uranium, iron and plutonium obtained by this method are reproducible within±0.2% and are in good agreement with values obtained using conventional redox methods 1, 2. 相似文献
10.
Nan Zhou 《Mikrochimica acta》1992,108(3-6):303-309
In this paper the method of co-precipitating 10 g of Sn(IV) with Be(II) from an ammoniacal medium is made highly selective by incorporating a ternary masking system: (a) NH2OH-NTA-EDTA or (b) H2O2-NTA-EDTA. It serves to preconcentrate Sn(IV) from a number of ionic species, especially from Nb(V), Ta(V) and Ti(IV) in mg or even cg amounts. System (a) is also effective for masking Th(IV) and U(IV), and (b) for Sb(III), Sb(V) and Ge(IV). Hence the two systems are complementary. 相似文献
11.
G. A. Rama Rao V. K. Manchanda P. R. Natarajan 《Journal of Radioanalytical and Nuclear Chemistry》1985,94(2):95-100
Present work summairzes a method for the estimation of uranium in the presence of plutonium involving the reduction of uranium to U/IV/ and plutonium to Pu/III/ by Zn/Hg/ followed by the selective oxidation of Pu/III/to Pu/IV/with HNO3 catalyzed by molybdate in the presence of large sulphate concenration [5M H2SO4+1.5M /NH4/2SO4]. The oxidation of U/IV/ by K2Cr2O7 is then carried out in the presence of excess of Fe/III/ and Al/NO3/3 to a sharp potentiometric end point. R.S.D. obtained for 20 determinations of uranium /3–6 mg/ was 0.3% in the presence of 0.35 mg of plutonium. Larger quantity for plutonium was found to interfere. 相似文献
12.
A. M. Maitra 《Journal of Thermal Analysis and Calorimetry》1990,36(2):657-675
Relative basicities of the rare earth oxides (M2O3) were determined from the measurement by TG - DTA of decomposition temperatures of the carbonates of Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er and Yb. From the comparison of this data with that published by Head and Holley, a sequence of basicity has been proposed for the entire range of rare earth oxides. This sequence in decreasing basicities is: La > Pr ~ Nd > Sm > Gd ~ Eu > Tb ~ Ho ~ Er > Dy Tm Yb Lu > Ce. Basicity of rare earth oxides, therefore, does not decrease progressively with an increase in atomic number.
This research forms part of a larger nationally coordinated program on natural gas conversion conducted in collaboration with the Divisions of Materials Science & Technology and Fuel Technology, and with BHP Melbourne Research Laboratories.
The author is grateful to Dr E. Patsalides of Sydney University for his generous donation of eight rare-earth oxides. The author wishes to thank the colleagues for their contribution to this work: Mr K. Riley and Mr W. Godbeer (chemical analysis), Dr P. F. Nelson and Mr R. Quezada (FTIR analysis), Mr A. Home (XRD analysis), Mr S. P. Chatfield (thermal analysis) and the project leader, Mr R. J. Tyler for his constant encouragement and valuable suggestions. 相似文献
Zusammenfassung Die relative Basizität der Seltenerdenoxide (M2O3) wurde mittels der durch TG-DTA-Untersuchungen festgestellten Zersetzungstemperaturen der Karbonate folgender Metalle bestimmt: Ce, Pr, Sm,Eu, Gd, Tb, Dy, Ho, Er und Yb. Aufgrund eines Vergleiches der hier ermittelten Daten mit denen von Head und Holley wird für die Basizität der Seltenerdenoxide folgende Reihenfolge aufgestellt: La > Pr Nd > Sm > Gd Eu > Tb Ho Er > Dy Tm Yb Lu > Ce. Wie ersichtlich nimmt die Basizität der Seltenerdenoxide mit ansteigender Ordnungszahl nicht progressiv ab.
This research forms part of a larger nationally coordinated program on natural gas conversion conducted in collaboration with the Divisions of Materials Science & Technology and Fuel Technology, and with BHP Melbourne Research Laboratories.
The author is grateful to Dr E. Patsalides of Sydney University for his generous donation of eight rare-earth oxides. The author wishes to thank the colleagues for their contribution to this work: Mr K. Riley and Mr W. Godbeer (chemical analysis), Dr P. F. Nelson and Mr R. Quezada (FTIR analysis), Mr A. Home (XRD analysis), Mr S. P. Chatfield (thermal analysis) and the project leader, Mr R. J. Tyler for his constant encouragement and valuable suggestions. 相似文献
13.
D. R. Ghadse D. M. Noronha I. C. Pius M. M. Charyulu A. R. Joshi C. K. Sivaramakrishnan 《Journal of Radioanalytical and Nuclear Chemistry》1996,213(3):225-232
Sorption of Pu(IV) from hydrochloric acid-oxalic acid solutions has been investigated using different anion exchangers, viz., Dowex-1X4, Amberlite XE-270 (MP) and Amberlyst A-26 (MP) for the recovery of plutonium from plutonium oxalate solutions. Distribution ratios of Pu(IV) for its sorption on these anion exchangers have been determined. The sorption of Pu(IV) from hydrochloric acid solutions decreases drastically in the presence of oxalic acid. However, addition of aluminium chloride enhances the sorption of plutonium in the presence of oxalic acid, indicating the feasibility of recovery of plutonium. Pu(IV) breakthrough capacities have been determined with a 10 ml resin bed of each of these anion exchangers at a flow rate of 60 ml per hour using a solution of Pu(IV) with the composition: 6M HCl+0.05M HNO3+0.1M H2C2O4+0.5M AlCl3+100 mg.l–1 Pu(IV). The 10% Pu(IV) breakthrough capacities for Dowex-1X4, Amberlite XE-270 (MP) and Amberlyst A-26 (MP) are 15.0, 8.9 and 6.2 g of Pu(IV) l–1 of resin respectively. 相似文献
14.
J. T. Coates R. A. Fjeld A. Paulenova T. DeVol 《Journal of Radioanalytical and Nuclear Chemistry》2001,248(2):501-506
A system using an ion chromatograph coupled to a flow-cell scintillation detector for rapidly measuring the oxidation states of actinides at low concentrations (<10–6M) in aqueous solutions was evaluated. The key components of the system are a cation–anion separation column (Dionex, CS5) and a flow cell detector with scintillating cerium activated glass beads. The typical procedure was to introduce a 0.5 ml aliquot of sample spiked with actinides in the +III to +VI oxidation states into a 5 ml sample loop followed by 4 ml of synthetic groundwater simulant. Separation was achieved at a flow rate of 1 ml/min using an isocratic elution with oxalic, diglycolic, and nitric acids followed by distilled water. Tests were first conducted to determine elution times and recoveries for an acidic solution (pH 2) and a ground water simulant (pH 8) containing Am(III), Pu(IV), Th(IV), Pu(V), and U(VI). Then, an analysis was performed using a mixture of Pu(IV), Pu(V), and Pu(VI) in the ground water simulant and compared to results using the DBM extraction technique. Approximate elution times were the same for both the acidic solution and the ground water simulant. These were as follows: Pu(V) at 10 min, Am(III) at 15 min, Pu(IV) at 25 min, Th (IV) at 28 min and U(VI) at 36 min. Recoveries for the acidic solution were quantitative for U(VI) and Th(IV) and exceeded 80% for Am(III). Recoveries for the ground water simulant were quantitative for U(VI), but they were generally not quantitative for Th(IV), Pu(IV), and Am(III). For Th(IV) and Pu(IV), less than quantitative recoveries were attributed to the formation of neutral hydroxides and colloids; for Am(III) they were attributed to insoluble carbonates and/or hydroxycarbonates. When applied to the measurement of plutonium in the ground water simulant, the technique provided showed good agreement with the dibenzoylmethane (DBM) extraction technique, but it could not distinguish between Pu(V) and Pu(VI). This was likely due to the reduction of Pu(VI) to Pu(V) in the sample by the oxalic acid eluent. However, in spite of this limitation, the technique can be used to distinguish between Pu(IV) and Pu(V) in aqueous environmental samples within a pH range of 4 to 8 and an E
H range of -0.2 to 0.6 V, the predominance region for Pu(III), (IV), and (V). In addition, this technique can be used to corroborate oxidation state analysis from the dibenzoylmethane (DBM) extraction method for environmental samples. 相似文献
15.
K. Juodkazis J. Juodkazytė B. Šebeka G. Stalnionis A. Lukinskas 《Russian Journal of Electrochemistry》2003,39(9):954-959
Regularities of formation of a palladium oxide layer and its cathodic reduction in 0.5 M H2SO4 at 0.5–1.3 V (SHE) are studied by cyclic voltammetry, x-ray photoelectron spectroscopy, and electrochemical quartz crystal microbalance. A pure Pd plate and a 0.5-m-thick Pd coating on gold-sputtered quartz crystal is used for electrochemical and microgravimetric studies. It is shown that a Pd electrode dissolves electrochemically in 0.5 M H2SO4 when its potential is cycled between 0.5 and 1.3 V. In the case of 0.5-m-thick Pd coating on the gold substrate, the decrease in the electrode weight during one anodic–cathodic cycle is 1.0–1.5 g/cm2. It is suggested that anodic process at 0.5–1.3 V (SHE) represents electrochemical oxidation of palladium, yielding a surface layer of poorly soluble Pd(OH)2 and/or PdO phases, as expressed by the equation Pd + 2H2O (Pd(OH)2/PdO)s + 2H+ + 2e. This surface layer, (Pd(OH)2/PdO)s, undergoes reduction during the cathodic process. About 5% of the total amount of ionized palladium dissolve in electrolyte. 相似文献
16.
H. S. Sharma R. B. Manolkar J. V. Kamat S. G. Marathe 《Fresenius' Journal of Analytical Chemistry》1993,347(12):486-490
Summary Graphite has been employed as a working electrode in the controlled potential coulometric determination of uranium and plutonium. The couples U(VI)/U(IV) and Pu(IV)/Pu(III) employed for analysis have diverse redox potentials and commonly the working electrodes employed are mercury and platinum. A graphite electrode in the shape of a beaker showed satisfactory performance for the quantitative reduction of U(VI) to U(IV) and Pu(IV) to Pu(III) and also for quantitative oxidation of Pu(III) to Pu(IV). Studies on the levels of the background current, blank values and their reproducible behaviour in acid media have been carried out with a view to achieve good precision and accuracy. A software-based predictive evaluation technique of end-point charge has been investigated. The results have shown that the graphite electrode can be used for the determination of both uranium and plutonium in the presence of each other with a precision and accuracy of better than ±0.5%. 相似文献
17.
P. V. Achuthan B. L. Jangida M. Sundaresan 《Journal of Radioanalytical and Nuclear Chemistry》1990,141(1):171-178
Distribution ratios of europium(III), thorium(IV), uranium(VI) and plutonium(IV) ions on Amberlyst A-15, a macroreticular polystyrene sulfonate resin, after extraction in HTTA-TBP-Shell Sol-T and HTTA-TOPO-benzene solutions have been determined as a function of the aqueous acidity. The affinity orders were EuPu>Th>U and Eu>Th>Pu>U in the former and the latter solutions, respectively. Separation factors were computed from the observed Kd values. A procedure for the separation of a mixture of Eu(III), Th(IV), and U(VI) ions in HTTA-TOPO-benzene solution in an ion-exchange column is described. 相似文献
18.
The mechanisms of the electrocyclic reactions of oxetene (I), 2H-pyran (II), 2-amino-2H-pyran (III), 2H-thiopyran (IV), and chromene (V) in the ground, first singlet, and tripletexcited stateswere studiedby means of the MINDO/3 method. The enthalpies of excitation are 125 (I, So), 32 (I, S1), 113 (I, T1), 188 (II, So), 109 (III, So), 150 (IV, So), and 239 kJ/mole (V, So). The number of isomers of the open form in So is determined by the nature of the substituent attached to the final carbon atom. It was observed that donors stabilize both the transoid isomer and the cisoid isomer, which is twisted 20 ° with respect to the formally single - carbon-carbon bond. Bulky substituents cause 105 ° rotation about the same bond.See [1] for Communication 12.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1028–1036, August, 1982. 相似文献
19.
Zhixian Zhou Yuzhong Wang Jingchao Tao Yaoting Fan Yangjie Wu 《Journal of inclusion phenomena and macrocyclic chemistry》1998,32(1):69-80
A novel anion-selective electrode has been prepared by usingtetraazaporphyrinogen as the electroactive component and o-nitrophenyloctylether as the plasticizer. The electrode exhibits almost Nernstian responsecharacteristics for Pic-, ReO
4
-
,SCN-, ClO
4
-
and TPB-. The linearresponse ranges towards the above-mentioned anions are 10-6 10-2, 10-5 10-2,10-5 10-2, 10-5 10-1, and 10-5 10-2mol/Land the corresponding slopes are -56.8, -57.1, -56.3, -56.1, and -59.9mV/decade with correlation coefficients of -0.99978, -0.99987, -0.99999,-0.99998, and -0.99998, respectively. The electrode shows an anti-Hofmeisterselectivity sequence: Pic- > SCN- >ReO
4
-
> ClO
4
-
> I- >Br- > BF
4
-
> Sal->NO
3
-
> Cl-. The unusual responsemechanism of the novel anion-selective electrode was investigated byexperimental observations and calculation with the MNDO method. Theelectrode was used as a TPB- and a Pic-sensitiveelectrode, respectively, and applied to the assay of levamisolehydrochloride tablets by potentiometric titration and Gran's methods. Theresults obtained are in excellent agreement with that determined by thestandard pharmacopoeia method based on nonaqueous titration. 相似文献
20.
M. A. Abuzwida A. G. Maslennikov V. F. Peretrukhin 《Journal of Radioanalytical and Nuclear Chemistry》1991,147(1):41-50
The simultaneous determination of U(VI), Pu(VI), Pu(V) in 0.5–4.0 M NaOH has been elaborated by means of classical and differential pulse voltamperometry. U(VI) is determined with a dropping mercury electrode (DME) at the half-wave potential of E1/2=–0.89 V vs. Ag/AgCl reference electrode due to reduction to U(V). The limiting current or peak heights are proportional to uranium(VI) concentration in the range of 1.3.10–7–3·10–4 M U(VI). Deviation from proportionality is observed for higher concentrations due to polymerization of uranates. Pu(VI) and Pu(V) are determined with a platinum rotating electrode at E1/2=–0.02 V due to the reaction Pu(VI)+e–»Pu(V) and with DME at E1/2=–1.1 V due to the reduction to Pu(III). The limiting currents of both Pu(VI) and Pu(V) are proportional to their concentrations in the range of 4·10–6–1.2·10–3 M Pu. The determination of U(VI), Pu(VI), Pu(V) is not interfered by the presence of the following salts: 2M NaNO3, 2M NaNO2, 1.5M NaAlO2, 0.5M NaF and ions of Mo(VI), W(VI), V(V), Cu(II). The presence of CrO
4
2–
and FeO
2
–
ions disturbs the determination of U(VI) in 1–4M NaOH, however, contribution of the reaction Fe(III)+e–»Fe(II) to uranium reduction peak can be calculated from the height of the second peak Fe(II)+2 e–»Fe(0). 相似文献