共查询到20条相似文献,搜索用时 15 毫秒
1.
Kwang-Pill Lee Hyung-Gik Kim Keung-Shik Park Duck-Won Kang Eun-Hee Kim 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(1):137-140
The adsorption characteristics of carbon on a strong base anion and cation exchange mixed resin, Amberlite IRN-150 in OH+ and H− (1∶1) used in nuclear power plant, were investigated at 6, 30 and 50 °C at a concentration of carbon up to 0.02M. The expression
for the adsorption of carbon was well fitted to the Freundlich equation and the constants,k andn in the equation were deduced. Furthermore, we could explain that the adsorption capacity on the mixed resin increases with
temperature. 相似文献
2.
Ho LN Ishihara T Ueshima S Nishiguchi H Takita Y 《Journal of colloid and interface science》2004,272(2):399-403
In our previous study, we found that Ti(OH)(4) exhibited fluoride ion exchange properties. In order to improve the ion exchange capacity, mesoporous Ti oxohydroxide (TiOx(OH)y) had been prepared by using dodecylamine as template. Zirconia and silica had been introduced into the mesoporous Ti oxohydroxide to enhance the ion exchange capacity. The mesoporous structure and the morphology of the mesoporous materials obtained were confirmed using XRD and SEM, respectively. A fluoride ion exchange study was done on each sample. Results showed that mesoporous Ti oxohydroxide containing zirconia exhibited the highest fluoride ion exchange capacity, as it has the smallest particle size, with high uniformity among the mesoporous materials prepared. 相似文献
3.
J. Inczédy 《Journal of Thermal Analysis and Calorimetry》1978,13(2):257-261
The water uptakes of completely swollen and air dried anion exchange resins were investigated by traditional and also by thermoanalytical measurements. In investigations on the air dried resin samples of HSO4, H2PO4, SO4, HPO4 and PO4 forms, two types of water (strongly and loosely bound) were found. The sequence of water uptake on the resins investigated was compared to the opposite order of the adsorption strengths of the anions and to the entropies of the hydrated anions. A conclusion was made regarding the role of the hydration of the anions in the selectivity sequence of anion exchange.
Zusammenfassung Die Wasseraufnahme vollständig angequollener und lufttrockener Anionenaustauscherharze wurde mittels herkömmlicher sowie auch thermoanalytischer Messungen untersucht. Bei den Prüfungen der lufttrockenen Harzproben in den HSO4-, H2PO4-, SO4-, HPO4-, und PO4-Formen wurden zwei Arten von Wasser gefunden: stark und schwach gebundenes. Die Reihenfolge der Wasseraufnahme wurde mit der umgekehrten Reihenfolge der Adsorptionsstärke der Anionen und mit der Entropie der hydratisierten Anionen verglichen. Schlüsse bezüglich der Rolle der Hydratisierung der Anionen bei der Selektvititätsreihenfolge des Anionenaustausch wurden gezogen.
Résumé On a étudié par des mesures traditionnelles et par analyse thermique l'absorption d'eau par des résines échangeuses anioniques totalement gonflées et séchées à l'air. Lors de l'étude des échantillons de résines séchées à l'air, de formes HSO4, H2PO4, SO4, HPO4 et PO4, on a trouvé deux types d'eau: de l'eau fortement liée et de l'eau faiblement liée. On a comparé l'ordre de l'absorption d'eau des résines étudiées à l'ordre inverse des forces d'adsorption des anions et à l'entropie des anions hydratés. On en tire des conclusions sur le rôle de l'hydratation des anions sur la sélectivité de l'échange anionique.
- , . - HSO4-, H2PO4-, SO4-, HPO4-, PO4- : . . .相似文献
4.
V. A. Pulhani S. Dafauti A. G. Hegde 《Journal of Radioanalytical and Nuclear Chemistry》2012,294(2):299-302
Uranium determination in environmental samples is faced with problems due to presence of iron and other major elements. Iron is also used many a times for pre-concentration of uranium and actinides. Separation of milligram quantity of Fe from microgram quantity of uranium becomes essential during the estimation step. A simple two step procedure has been standardized for separating uranium and iron using anion exchange in 0.025 M H2SO4. Quantitative recovery of uranium was obtained as well as good separation from iron. This method was applied for estimation of uranium in water samples. 相似文献
5.
Warren T. Ford Glenn H. Beasley Berni P. Chong James W. Neely 《Journal of polymer science. Part A, Polymer chemistry》1982,20(5):1213-1229
Carbonaceous adsorbents are obtained by thermolysis of sulfonated macroreticular polystyrene ion exchange resins at 300-500°C. The hard, spherical, carbonaceous particles react exothermally with elemental chlorine to form products containing up to 38% Cl. The chlorinated particles react readily with polyamines to form anion exchange resins with capacities of up to 2.2 meq/g dry resin. Less than 60% of the nitrogen atoms in the particles are utilized as ion exchange sites. The carbonaceous particles can also be chloromethylated with chloromethyl methyl ether or chlorinated with sulfuryl chloride and then aminated with polyamines to form anion exchange resins, sulfonated with sulfuric acid or chlorosulfonic acid to form strongly acidic cation exchange resins, or chlorosulfonated and then aminated with polyamines to form anion exchange resins. Model structures of the thermolyzed resins containing polycyclic aromatic hydrocarbon fragments are proposed to explain their chemical reactivities. 相似文献
6.
Weihua Zhang Kurt Ungar Ian Hoffman Ryan Lawrie 《Journal of Radioanalytical and Nuclear Chemistry》2009,282(3):761-765
To support interpretation of observed atmospheric krypton radioisotopes, a database of krypton radioisotope in the primary
coolant of CANDU reactors has been established. This database is comprised of 40,000 records of high-quality 89Kr, 87Kr, 88Kr and 85mKr analyses. Records from the database were retrieved by a specifically designed data-mining module and subjected to further
analysis. Results from the analysis were subsequently used to study isotopic ratios of observed krypton radioisotopes in the
CANDU reactor primary coolant. These studies provided practical information on the characterization of CANDU reactor krypton
radioisotope, which can potentially be used to discriminate between reactor effluent and fuel reprocessing for nuclear safeguard
85Kr monitoring applications (Kalinowski et al., J Environ Radioact 73:203, 2004). The study also has some potential application
to Fissile material cut-off treaty. 相似文献
7.
Phenol removal from aqueous solution by adsorption and ion exchange mechanisms onto polymeric resins 总被引:1,自引:0,他引:1
Michelle Caetano Csar Valderrama Adriana Farran Jos Luis Cortina 《Journal of colloid and interface science》2009,338(2):402-409
The removal of phenol from aqueous solution was evaluated by using a nonfunctionalized hyper-cross-linked polymer Macronet MN200 and two ion exchange resins, Dowex XZ (strong anion exchange resin) and AuRIX 100 (weak anion exchange). Equilibrium experimental data were fitted to the Langmuir and Freundlich isotherms at different pHs. The Langmuir model describes successfully the phenol removal onto the three resins. The extent of the phenol adsorption was affected by the pH of the solution; thus, the nonfunctionalized resin reported the maximum loading adsorption under acidic conditions, where the molecular phenol form predominates. In contrast both ion exchange resins reported the maximum removal under alkaline conditions where the phenolate may be removed by a combined effect of both adsorption and ion exchange mechanisms. A theoretical model proposed in the literature was used to fit the experimental data and a double contribution was observed from the parameters obtained by the model. Kinetic experiments under different initial phenol concentrations and under the best pH conditions observed in the equilibrium experiments were performed. Two different models were used to define the controlling mechanism of the overall adsorption process: the homogeneous particle diffusion model and the shell progressive model fit the kinetic experimental data and determined the resin phase mechanism as the rate-limiting diffusion for the phenol removal. Resins charged after the kinetic experiments were further eluted by different methods. Desorption of nonfunctionalized resin was achieved by using the solution (50% v/v) of methanol/water with a recovery close to 90%. In the case of the ion exchange resins the desorption process was performed at different pHs and considering the effect of the competitive ion Cl−. The desorption processes were controlled by the ion exchange mechanism for Dowex XZ and AuRIX 100 resins; thus, no significant effect for the addition of Cl− under acidic conditions was observed, while under alkaline conditions the total recovery increased, specially for Dowex XZ resin. 相似文献
8.
9.
Some complex analytical problems which are connected with the operation of nuclear power plants cooled with gas and moderated
with heavy water can be solved by combination of the high separation efficiency of gas chromatography with the sensitive and
selective detection of radioactive radiation. The main fields of application of these methods are the control of the coolant,
of gaseous wastes, and the control of the isotopic purity of heavy water. A review of papers dealing with these problems is
given describing the procedures, methods, and the results achieved. 相似文献
10.
11.
离子交换树脂催化酯化生物油的试验研究 总被引:1,自引:0,他引:1
生物油黏稠、稳定性差、热值低、腐蚀性强,需要进行改质与品位提升,将生物油中的有机酸通过酯化的方法转化为中性的酯类可以改善生物油的性能。实验利用模型反应,筛选出了适合于生物油体系的732型和NKC-9型两种树脂作为酯化改质的催化剂。生物油和甲醇在间歇釜内以732和NKC-9为催化剂进行改质以后,酸值分别降低了88.54%和85.95%,表明生物油中的有机酸极大地转化为中性酯类。此外,热值分别提高了32.26%和31.64%,水分分别降低了27.74%和30.87%,密度均降低了21.77%,黏度降低均接近97%。732树脂固定床催化酯化生物油后,酸值降低了92.61%。加速陈化实验和铝片腐蚀性实验结果分别表明,改质生物油的稳定性和腐蚀性能得到了改善。 相似文献
12.
W. Zhang K. Ungar I. Hoffman R. Lawrie 《Journal of Radioanalytical and Nuclear Chemistry》2009,280(1):121-128
To support interpretation of observed atmospheric 135Xe, 133Xe, 133mXe and 131mXe, a database of xenon radioisotope in the primary coolant of CANDU reactors has been established. This database is comprised
of 40000 records of high-quality xenon radioisotope analyses. Records from the database were retrieved by a specifically designed
data-mining module and subjected to further analysis. Results from the analysis were subsequently used to study isotopic ratios
of observed xenon radioisotopes in the CANDU reactor primary coolant. These studies provided novel and practical information
on the characterization of CANDU reactor xenon radioisotope releases, which can be used to discriminate between reactor effluence
and underground nuclear test releases. 相似文献
13.
Protonation and ion exchange equilibria of weak base anion-exchange resins, in which tertiary amine moieties were introduced as a functional group, were investigated by applying NMR spectroscopy to species adsorbed into the resins. 31P NMR signals of the phosphinate ion in the resin phases shifted to a lower field due to the influence of protonation of the tertiary amine groups of the resins in the pH range of 4-10. Protonation constants of the tertiary amine groups in styrene-divinylbenzene (DVB)-based resins were estimated to be KH = 106.4 for Amberlite IRA96 and 106.5 for DIAION WA30 by the 31P NMR method using the phosphinate ion as a probe species. In addition to the low field shift caused by the protonation of the tertiary amine moieties, another low field shift was observed for the phosphinate ion in acrylic acid-DVB-based resins at a rather high pH. This shift should be due to an unexpected deprotonation in the acrylic resin: a tautomerism accompanying the proton release from the amide form to the imide one in the functional group, thus, the resin could exhibit a cation exchange property at the high pH. Protonation constants of the tertiary amine moieties in the acrylic resins were estimated to be 108.8 for DIAION WA10, 109.0 for Amberlite IRA67 and 109.3 for Bio-Rad AG 4-X4 on the basis of the Henderson-Hasselbalch equation using the resin phase pH estimated by the 133Cs and 1H NMR signal intensities. 相似文献
14.
C. -C. Chan P. -C. Liu P. -S. Weng 《Journal of Radioanalytical and Nuclear Chemistry》1985,95(2):81-91
This paper deals with a rapid method to determine radionuclides in reactor coolant by anion, cation, and anion-cation exchange membranes. A high pressure filtration device was established to simulate the THOR cooling water sampling system by means of several membranes mentioned above. The experimental results indicate that the adsorption efficiency of each membrane for several radionuclides is /1/ >95% with cation exchange membrane for Zn, Co, Na, Mn, Cu, Cs, Ba, La, W etc., /2/ >98% with anion exchange membrane for I, and /3/ <98% with anion-cation exchange membranes for Fe and Cr. The results are obtained using cooling water of Tsing Hua Open-Pool Reactor and the following radionuclides were identified:99mTc,140Ba,140La,51Cr,131I,58Co,60Co,54Mn,46Sc,59Fe,24Na, etc. 相似文献
15.
A new method for the determination of ion exchange equilibrium constants is developed. A technique based in the application of potentiometric titrations is used in the study of non selective strong acidic resins. Potentiometric titrations are carried out without constant ionic strength, so a mathematical treatment is developed in order to take into account the estimation of the activity coefficients and the liquid junction potentials. The ion exchange thermodynamic equilibrium constants for two resins, Dowex CM-15 and Dowex C650, between the proton form and the alkaline metals at 25 degrees C are given. 相似文献
16.
S. Sarri P. Misaelides F. Noli L. Papadopoulou D. Zamboulis 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(1):399-403
The iodide removal from aqueous solutions (initial I?-concentration: 300–5,000 mg/L) by a low and a high molecular weight polyethylenimine-epichlorohydrin resin was investigated both in absence and presence of background electrolytes (NaCl and Na2SO4, ionic strength due to background electrolyte 0.1 M) using a batch technique, 131I as radioactive tracer and high-resolution γ-ray spectrometry. The experiments in absence of background electrolyte were performed using solutions of initial pH 3 and 7, whereas those in presence using solutions of initial pH 3. The results, which demonstrated the high iodide-removal efficiency of both resins, were modeled using the Langmuir and Freundlich isotherm equations. The experimental data were better reproduced using the Langmuir equation. Using this equation maximum sorption capacity values (Q max) of 638.8 and 603.3 mg/g were obtained for the high molecular weight resin from solutions of initial pH 3 and 7 respectively, whereas the corresponding values for the low molecular weight one were slightly lower (552.4 and 507.5 mg/g respectively). The iodide uptake by the resins strongly depended on the presence of competing anions and especially of sulfates. The examination of sections of the I-loaded resins grains by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) revealed that iodine was evenly distributed throughout the bulk of the resins and not only bound to their surface. 相似文献
17.
18.
The preparation of ammonium molybdophosphate (AMP) precipitated directly into the IRA-900 resinous structure and their application to the determination of cesium-137 in waters are described. The sample of water is passed through the resin, which retains the cesium. After the removal of strontium-90 and potassium-40 with 0.1M ammonium nitrate solution, the cesium is eluted with 1M sodium hydroxide solution. The AMP dissolved in the alkaline solution is used to precipitate the cesium by acidifying the solution. 相似文献
19.
Measurements of actinide nuclides in water samples from the primary circuit of a nuclear power plant
G. Rosner 《Journal of Radioanalytical and Nuclear Chemistry》1981,64(1-2):55-64
Weekly, consecutive primary coolant samples from a boiling water reactor have been analyzed for239, 240Pu,238Pu+241Am,242Cm and244Cm for about two years, and for238Pu,241Pu and241Am for one year. Concentration ranges are reported. Samples were prepared for counting either directly by evaporation or by
chemical separation on BioRad AG 1×4 resin and subsequent electrolysis, and were counted in 20 cm dia Frish grid ionization
chambers. Procedures are described. For most actinide nuclides, activity ratios in primary coolant were found to be different
from those in worldwide fallout, thus allowing an identification of origin in the case, that actinides should be detected
in the vicinity of a nuclear power station. 相似文献
20.
Navarrete-Casas R Navarrete-Guijosa A Valenzuela-Calahorro C López-González JD García-Rodríguez A 《Journal of colloid and interface science》2007,306(2):345-353
We examined the exchange of univalent cations (Na+ and H+) retained on two commercially available synthetic zeolites with Li+ ions present in aqueous solutions in contact with the solids with a view to preparing effective controlled-release pharmaceutical forms. The studied zeolites were manufactured by Merck and featured channel diameters of 0.5 (Zeolite 5A, Ref. 1.05705.250, designated Z-05 in this work) and 1.0 nm (Zeolite 13X, Ref. 1.05703.250, designated Z-10 here). The XRD technique revealed that Z-05 possesses an LTA structure derived from that of sodalite and Z-10 a faujasite-type structure. Their exchange capacities were found to be 2.72 and 3.54 meq/g. The Z-Na + Li(+) / Z-Li + Na(+) and Z-H + Li(+) / Z-Li + H(+) ion-exchange processes were found to be reversible and their kinetic laws to obey the equation (-dC/dt) = k(a) x C(n) x (1-theta) - (k(d) x theta), with n = 1 for Z-10 and n = 2 for Z-05. Based on the equilibrium results, the overall processes involve one (with Z-05) or two single ion-exchange processes (with Z-10). In both cases, the equations that govern equilibrium are direct results of the kinetic laws. Thus, the first process-the one with only Z-05-involves the retention of Li+ cations at anionic sites on the outer surface of the solid and their access to the larger pores; the second process-which occurs with Z-10 only-involves the retention of lithium(I) cations within the zeolite channels. In both systems, the exchange with Li+ (from the aqueous solution) is easier than that with H+; this is consistent with our kinetic, equilibrium, and thermodynamic results. 相似文献