共查询到20条相似文献,搜索用时 15 毫秒
1.
Jun Hu Di Xu Lei Chen Xiangke Wang 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(3):701-708
MX-80 bentonite is considered as one of the best backfill materials for high-level radioactive nuclear waste. Herein, the
bentonite is characterized by using XRD and FTIR techniques. Sorption of radionickel to MX-80 bentonite in the presence/absence
of humic acid (HA) or fulvic acid (FA) as a function of pH is investigated. The results indicate that the presence of HA or
FA decreases the sorption of Ni2+ obviously. The different experimental processes do not affect the sorption of nickel to FA/HA bound bentonite. The sorption
of Ni2+ on FA/HA-bound bentonite decreases with the increasing FA/HA content in the systems. The mechanism of nickel sorption is
also discussed in detail. 相似文献
2.
Lei Chen Bin Gao Songsheng Lu Yunhui Dong 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(3):851-858
Sorption of radionickel on attapulgite is studied as a function of contact time, ionic strength, pH and temperature. The results indicate that the sorption of Ni(II) on attapulgite is strongly ionic strength-dependent at pH <8, and independent of ionic strength at pH >8. Outer-sphere surface complexation or ion exchange contributes to Ni(II) sorption on attapulgite at pH <8, whereas the sorption of Ni(II) is mainly dominated by inner-sphere surface complexation at pH >8. The sorption of Ni(II) on attapulgite increases with increasing temperature, and the thermodynamic parameters (??H 0, ??G 0 and ??S 0) calculated from the temperature dependent sorption isotherms suggest that the sorption of Ni(II) on attapulgite is a spontaneous and endothermic process. The high sorption capacity of attapulgite suggests that attapulgite is a suitable material for the preconcentration and solidification of radionickel from large volumes of aqueous solutions. 相似文献
3.
Xue Wang 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(3):2301-2308
Sequestration of Ni(II) on diatomite as a function of reaction time, pH, ionic strength, foreign ions and temperature were investigated by batch sorption technique. The results indicated that the sorption of Ni(II) on diatomite was quickly in the first contact time of 2 h and then slowly with increasing contact time. The interaction of Ni(II) with diatomite was strongly pH- and ionic strength-dependent at low pH values (i.e., which was dominated by ion exchange or outer-sphere surface complexation), while the pH-dependent and ionic strength-independent sorption at high pH suggested that inner-sphere or multinuclear surface complexation was the main sorption mechanism. With increasing temperature, the sorption of Ni(II) on diatomite increased and the experimental data were well fitted by Langmuir model. The sorption samples at pH 6.8 and 10.0 were also characterized by XPS spectroscopy, and the results suggested that Si atoms also participated in Ni(II) sorption on diatomite. The results are important to evaluate the physicochemical behavior of Ni(II) and other similar radionuclides and heavy metal ions in the environment. 相似文献
4.
Hu Jun Xu Di Chen Lei Wang Xiangke 《Journal of Radioanalytical and Nuclear Chemistry》2020,324(1):447-447
Journal of Radioanalytical and Nuclear Chemistry - The original publication of the article includes mistakes on instrument types of FTIR and XRD characterization in Page 702. The corrected... 相似文献
5.
Xuemei Ren Suowei Wang Shitong Yang Jiaxing Li 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(1):253-259
The sorption of U(VI) from aqueous solution on MX-80 bentonite was studied as a function of contact time, pH, ionic strength,
solid contents, humic acid (HA), fulvic acid (FA) and temperature under ambient conditions using batch technique. The results
indicate that sorption of U(VI) on MX-80 bentonite is strongly dependent on pH and ionic strength. The removal of U(VI) to
MX-80 bentonite is rather quick and the kinetic sorption data is simulated well by a pseudo-second-order rate equation. The
presence of HA enhances the sorption of U(VI) on MX-80 bentonite obviously, but the influence of FA on U(VI) sorption is not
obvious. The thermodynamic parameters (ΔH
0, ΔS
0, and ΔG
0) for the sorption of U(VI) calculated from temperature dependent sorption suggest that the sorption reaction is endothermic
and spontaneous. 相似文献
6.
Songsheng Lu Zhiqiang Guo Caicai Zhang Shouwei Zhang 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(2):621-628
MX-80 bentonite was characterized by XRD and FTIR in detail. The sorption of Th(IV) on MX-80 bentonite was studied as a function
of pH and ionic strength in the presence and absence of humic acid/fulvic acid. The results indicate that the sorption of
Th(IV) on MX-80 bentonite increases from 0 to 95% at pH range of 0–4, and then maintains high level with increasing pH values.
The sorption of Th(IV) on bentonite decreases with increasing ionic strength. The diffusion layer model (DLM) is applied to
simulate the sorption of Th(IV) with the aid of FITEQL 3.1 mode. The species of Th(IV) adsorbed on bare MX-80 bentonite are
consisted of “strong” species
o \textYOHTh4 + \equiv {\text{YOHTh}}^{4 + } at low pH and “weak” species
o \textXOTh(OH)3 \equiv {\text{XOTh(OH)}}_{3} at pH > 4. On HA bound MX-80 bentonite, the species of Th(IV) adsorbed on HA-bentonite hybrids are mainly consisted of
o \textYOThL3 \equiv {\text{YOThL}}_{3} and
o \textXOThL1 \equiv {\text{XOThL}}_{1} at pH < 4, and
o \textXOTh(OH)3 \equiv {\text{XOTh(OH)}}_{3} at pH > 4. Similar species of Th(IV) adsorbed on FA bound MX-80 bentonite are observed as on FA bound MX-80 bentonite. The
sorption isotherm is simulated by Langmuir, Freundlich and Dubinin–Radushkevich (D–R) models, respectively. The sorption mechanism
of Th(IV) on MX-80 bentonite is discussed in detail. 相似文献
7.
The development of nuclear power releases large amounts of radionuclides into the natural environment. Herein, the sorption of radionuclide 63Ni on bentonite from Gaomiaozi county (Inner Mongolia, China) at different experimental conditions such as pH, contact time, ionic strength, foreign cations and anions, and temperatures were investigated by using batch technique. The results indicated that the sorption of 63Ni on the bentonite was quickly at first contact time and then increased slowly with increasing contact time. The sorption of 63Ni was strongly dependent on ionic strength at low pH values and independent of ionic strength at high pH values. The sorption of 63Ni on bentonite was mainly dominated by outer-sphere surface complexation or ion exchange at low pH values, whereas inner-sphere surface complexation was the main sorption mechanism at high pH values. The Langmuir, Freundlich, and D–R models were applied to simulate the sorption isotherms of 63Ni at three different temperatures, and the thermodynamic parameters (i.e., ΔH°, ΔS° and ΔG°) calculated from the temperature-dependent sorption isotherms indicated that the sorption of 63Ni on bentonite was an endothermic and spontaneous process. Experimental results indicate that the bentonite is a suitable material for the preconcentration and solidification of 63Ni from large volume of solutions in radionickel pollution cleanup. 相似文献
8.
Sorption of europium on a MX-80 bentonite sample: experimental and modelling results 总被引:2,自引:0,他引:2
The EDXRF technique offers simultaneous detection and determination of multiple trace elements in F3 generation seed of Cicer arietinum L. plant, developed from irradiated group of 0.05, 0.10, 0.15 kGy and 0.20 kGy using 60Co gamma source (0.12 kGy/h). The accumulations of elements in edible seeds were significantly different (p ≤ 0.05) in different absorbed dose. Out of 14 elementals (S, Cl, K, P, Ca, V, Mn, Fe, Co, Cu, Zn, Rb, Sr and Cd), the accumulations
of K, P, Ca, S, Cu, Zn, Mn, Fe, Cd, Rb, Sr and Cl were increased in seed with in the dose range of 0.15–0.20 kGy, except V
and Co. Also, the yielding potentials of seeds were increased with in the dose range of 0.15–0.20 kGy. 相似文献
9.
Lu Songsheng Xu Hua Wang Mingming Song Xiaoping Liu Qiong 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(2):889-895
The bentonite from Gaomiaozi county (Inner Mongolia, China) (denoted as GMZ bentonite) was characterized by X-ray powder diffraction
and Fourier transform infrared spectroscopy. The effect of pH, contact time, ionic strength, humic acid (HA) and Eu(III) concentrations
on Eu(III) sorption to the GMZ bentonite was studied by batch technique under ambient conditions. The sorption of Eu(III)
on GMZ bentonite was strongly dependent on pH and independent of ionic strength. The sorption of Eu(III) on GMZ bentonite
was mainly dominated by surface complexation rather than by ion exchange. The presence of HA enhanced Eu(III) sorption at
low pH values, but decreased Eu(III) sorption at high pH values. The enhanced sorption of Eu(III) on GMZ bentonite at low
pH was attributed to the strong complexation of Eu(III) with surface adsorbed HA on GMZ bentonite and the reduced sorption
of Eu(III) at high pH was attributed to the formation of soluble HA–Eu complexes in aqueous solution. The strong sorption
of Eu(III) on GMZ bentonite suggested that the GMZ bentonite could be used as the backfill material in nuclear waste disposal. 相似文献
10.
11.
Yunhui Dong Zhengjie Liu Yueyun Li 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(1):257-265
Bentonite has been studied extensively because of its strong sorption and complexation ability. Herein, GMZ bentonite from
Gaomiaozi county (Inner Mongolia, China) was investigated as the candidate of backfill material for the removal of Th(IV)
ions from aqueous solutions. The results indicate that the sorption of Th(IV) is strongly dependent on pH and ionic strength
at pH < 5, and independent of ionic strength at pH > 5. Outer-sphere surface complexation or ion-exchange are the main mechanism
of Th(IV) sorption on GMZ bentonite at low pH values, whereas the sorption of Th(IV) at pH > 5 is mainly dominated by inner-sphere
surface complexation or surface precipitation. Soil fulvic acid (FA) and humic acid (HA) have a positive influence on the
sorption of Th(IV) on bentonite at pH < 5. The different addition sequences of HA and Th(IV) to GMZ bentonite suspensions
have no obvious effect on Th(IV) sorption to HA-bentonite hybrids. The high sorption capacity of Th(IV) on GMZ bentonite suggests
that the GMZ bentonite can remove Th(IV) ions from large volumes of aqueous solutions in real work. 相似文献
12.
13.
Wang Mingming Xie Hongqin Tan Liqiang Qiu Jun Tao Xingquan Wu Cuiping 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(2):763-770
Herein, the sorption properties of Eu(III) on Na-attapulgite were performed by using batch sorption experiments under different
experimental conditions, such as contact time, pH, ionic strength, humic acid and temperatures. The results indicated that
the sorption of Eu(III) on Na-attapulgite was strongly dependent on pH and temperature. At low pH values, the sorption of
Eu(III) was influenced by ionic strength, whereas the sorption was not affected by ionic strength at high pH values. The sorption
of Eu(III) was mainly dominated by ion exchange or outer-sphere surface complexation at low pH values, and by inner-sphere
surface complexation or surface precipitation at high pH values. The sorption of Eu(III) onto Na-attapulgite increased with
increasing temperature. The Langmuir and Freundlich models were applied to simulate the sorption isotherms, and the results
indicated that the Langmuir model simulated the sorption isotherms better than the Freundlich model. The thermodynamic parameters
(∆G
o, ∆S
o, ∆H
o) were calculated from the temperature dependent sorption isotherms at 293, 313 and 333 K, respectively, and the results indicated
that the uptake of Eu(III) on Na-attapulgite was an endothermic and spontaneous process. The results of high Eu(III) sorption
capacity on Na-attapulgite suggest that the attapulgite is a suitable material for the preconcentration and immobilization
of Eu(III) ions from large volumes of aqueous solutions. 相似文献
14.
Mingming Wang Jun Qiu Xinquan Tao Cuiping Wu Weibing Cui Qiong Liu Songsheng Lu 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(3):895-901
Multiwalled carbon nanotubes (MWCNTs) have attracted multidisciplinary study because of their unique physicochemical properties. Herein, the sorption of U(VI) from aqueous solution to oxidized MWCNTs was investigated as a function of contact time, pH and ionic strength. The results indicate that U(VI) sorption on oxidized MWCNTs is strongly dependent on pH and ionic strength. The sorption of U(VI) is mainly dominated by surface complexation and cation exchange. The sorption of U(VI) on oxidized MWCNTs is quickly to achieve the sorption equilibrium. The sorption capacity calculated from sorption isotherms suggests that oxidized MWCNTs are suitable material in the preconcentration and solidification of U(VI) from large volumes of aqueous solutions. 相似文献
15.
Turner SF Clarke SM Rennie AR Thirtle PN Li ZX Thomas RK Langridge S Penfold J 《Langmuir : the ACS journal of surfaces and colloids》2005,21(22):10082-10088
The technique of neutron reflection has been used to investigate the adsorption of alpha-enriched gelatin from aqueous solution onto spun polystyrene substrates. Neutron reflection can provide information about the distribution of material perpendicular to an interface as well as total adsorbed amounts. The adsorbed layers were found to have maximum density at the surface, decaying with distance into solution. The adsorbed amount, layer thickness, and density were all seen to increase with solution concentration. Temperature was found to have little effect on adsorption. Thicker, less dense layers were observed at high pH and thinner, denser layers were observed at low pH, but the total adsorbed amount did not change significantly. The presence of sodium chloride had little effect on the adsorbed layers. The results are discussed in the context of other studies and the known amino acid sequence of alpha-gelatin. 相似文献
16.
Adsorption of La(III) onto GMZ bentonite: effect of contact time,bentonite content,pH value and ionic strength 总被引:3,自引:0,他引:3
Bentonite has been studied extensively because of its strong adsorption capacity. A local Na-bentonite named GMZ bentonite,
collected from Gaomiaozi County (Inner Mongolia, China), was selected as the first choice of buffer/backfill material for
the high-level radioactive waste repository in China. In this research, the adsorption of La (ΙΙΙ) onto GMZ bentonite was
performed as a function of contact time, pH, solid content and metal ion concentrations by using the batch experiments. The
results indicate that the adsorption of La (III) on GMZ bentonite achieves equilibration quickly and the kinetic adsorption
follows the pseudo-second-order model; the adsorption of La (III) on the adsorbent is strongly dependent on pH and solid content,
the adsorption process follows Langmuir isotherm. The equilibrium batch experiment data demonstrate that GMZ bentonite is
effective adsorbent for the removal of La (III) from aqueous solution with the maximum adsorption capacity of 26.8 mg g−1 under the given experimental conditions. 相似文献
17.
18.
Mingming Wang Xingquan Tao Xiaoping Song 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(3):859-865
Oxidized multiwalled carbon nanotubes (MWCNTs) were characterized by SEM and FTIR. The sorption of Th(IV) on MWCNTs was studied as a function of contact time, pH, ionic strength, Th(IV) concentration and temperature. The results indicate that the sorption of Th(IV) on MWCNTs is strongly dependent on pH and weakly dependent on ionic strength. The sorption thermodynamics of Th(IV) on MWCNTs was carried out at 293.15, 313.15 and 333.15 K, respectively, and the thermodynamic parameters (standard free energy changes (??G 0), standard enthalpy change (??H 0) and standard entropy change (??S 0)) were calculated from the temperature dependent sorption isotherms. The sorption of Th(IV) on MWCNTs is a spontaneous and endothermic process. The oxidized MWCNTs may be a promising candidate for the preconcentration and solidification of Th(IV), or its analogue actinides from large volumes of aqueous solutions. 相似文献
19.
P. Chang S. Yu T. Chen A. Ren C. Chen X. Wang 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(1):153-160
Sorption of Th(IV) on Na-rectorite as a function of pH, ionic strength, soil humic acid (HA) and fulvic acid (FA) are studied
under ambient conditions by using a batch technique. The results indicate that the sorption of Th(IV) on Na-rectorite is not
only dependent on medium pH values, but also dependent on medium ionic strength and humic substances. Surface complexation
and cation competition exchange account for Th(IV) sorption on Na-rectorite. The sorption of Th(IV) on Na-rectorite decreases
with the increase on the concentration of NaNO3, Mg(NO3)2 and Ca(NO3)2, and increases with the increasing amount of HA/FA in the suspension/adsorbed on rectorite. Soil HA/FA enhances the sorption
of Th(IV) on rectorite at medium pH<4 drastically, but the presence of FA reduces the sorption of Th(IV) at medium pH>6, and
HA has no effect on Th(IV) sorption at medium pH>6. An interpretation for the results is attempted, considering the occurrence
of different sorption mechanisms. 相似文献