共查询到20条相似文献,搜索用时 46 毫秒
1.
Donglin Zhao Shaojie Feng Han Xuan Yan Chen 《Journal of Radioanalytical and Nuclear Chemistry》2014,300(3):1027-1037
In this study, the sorption of U(VI) from aqueous solution on Mg2Al layered double hydroxide (Mg2Al LDH) was studied as a function of various water quality parameters such as contact time, pH, ionic strength, soil fulvic acid (FA), solid content and temperature by using a batch technique. The sorption of U(VI) on Mg2Al LDH was dependent on pH. The presence of FA increased U(VI) sorption at low pH, whereas decreased U(VI) sorption at high pH. Both kinetics and thermodynamic parameters of the sorption process were evaluated. It was found that the pseudo-second-order model was more suitable for our experiment. The Langmuir model fitted the sorption isotherms of U(VI) better than the Freundlich and D-R model at three different temperatures of 298, 303 and 313 K. The thermodynamic parameters (ΔH°, ΔS°, and ΔG°) were calculated from the temperature dependent sorption isotherms, and the results suggested that U(VI) sorption was a spontaneous and endothermic process. The results demonstrate that Mg2Al LDH is a promising sorbent material for the preconcentration and separation of uranium pollution from large volumes of aqueous solutions. 相似文献
2.
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
3.
Xiaoping Song Yajie Wang Jingjing Cai Songsheng Lu Yunfei Chen 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(1):685-695
The interaction of U(VI) with Na-attapulgite was studied by using batch technique at different experimental conditions. The effect of contact time, solid content, pH, ionic strength and temperature on the sorption of U(VI) onto Na-attapulgite in the presence and absence of humic acid was also investigated. The results showed that the sorption of U(VI) on Na-attapulgite achieved sorption equilibrium quickly. Sorption of U(VI) on Na-attapulgite increased quickly with increasing pH at pH < 6.5, and then decreased with pH increasing at pH > 6.5. The sorption curves were shifted to left in low NaClO4 solutions as compared those in high NaClO4 solutions. The sorption was strongly dependent on pH and ionic strength. The sorption was 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 thermodynamic parameters (i.e., ΔH 0, ΔS 0, and ΔG 0) for the sorption of U(VI) were calculated from the temperature dependent sorption isotherms, and the results suggested that the sorption reaction was an endothermic and spontaneous process. The Na-attapulgite is a suitable material in the removal and preconcentration of U(VI) from large volumes of aqueous solutions in nuclear waste management. 相似文献
4.
You-qun Wang Zhi-yang Zheng Yi-kang Zhao Jian-hui Huang Zhi-bin Zhang Xiao-hong Cao Ying Dai Rong Hua Yun-hai Liu 《Journal of Radioanalytical and Nuclear Chemistry》2018,317(1):69-80
Hydroxy-aluminum pillared Na-montmorillonite(OH–Al-MT) was prepared for studying sorption of U(VI) in the existence of soluble calcium (Ca2+), carbonate ion (CO32?) and humic acid. Various characterizations confirm that hydroxy-aluminum was successfully pillared into Na-montmorillonite (Na-MT). The effects of pH, concentration of Ca2+ and CO32? as well as HA on the sorption capacity of Na-MT and OH–Al-MT for U(VI) has been investigated by batch experiments. Additionally, the kinetics, isotherms and thermodynamics of adsorption of U(VI) were discussed in detailed. The study indicates that OH–Al-MT can be a potentially promising low-cost adsorbent for removal of U(VI) in wastewaters. 相似文献
5.
Dong Lijia Yang Jianxia Mou Yinyan Sheng Guodong Wang Linxia Linghu Wensheng Asiri Abdullah M. Alamry Khalid A. 《Journal of Radioanalytical and Nuclear Chemistry》2017,314(1):377-386
Herein, we used biochar pyrolyzed from rice straw to adsorb uranium (U) from aqueous solutions. The adsorption of U(VI) on biochar was strongly dependent on pH but independent on ionic strength. HA/FA enhanced the sorption at pH <6.8 while inhibited the sorption at pH >6.8. The sorption reached equilibrium within 3 h, which was not mediated by pH. The adsorption process was spontaneous and endothermic, and enhanced at higher temperature. However, the influence of temperature was negligible at low initial U(VI) concentrations. Therefore, biochar derived from rice straw may be a promising adsorbent for the removal of U(VI).
相似文献6.
Liang Gao Ziqian Yang Keliang Shi Xuefeng Wang Zhijun Guo Wangsuo Wu 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(3):519-526
U(VI) sorption on kaolinite was studied as functions of contact time, pH, U(VI) concentration, solid-to-liquid ratio (m/V) by using a batch experimental method. The effects of sulfate and phosphate on U(VI) sorption were also investigated. It
was found that the sorption kinetics of U(VI) can be described by a pseudo-second-order model. Potentiometric titrations at
variable ionic strengths indicated that the titration curves of kaolinite were not sensitive to ionic strength, and that the
pH of the zero net proton charge (pHPZNPC) was at 6.9. The sorption of U(VI) on kaolinite increased with pH up to 6.5 and reached a plateau at pH >6.5. The presence
of phosphate strongly increased U(VI) sorption especially at pH <5.5, which may be due to formation of ternary surface complexes
involving phosphate. In contrast, the presence of sulfate did not cause any apparent effect on U(VI) sorption. A double layer
model was used to interpret both results of potentiometric titrations and U(VI) sorption on kaolinite. 相似文献
7.
Effect of pH,ionic strength and humic substances on the adsorption of Uranium (VI) onto Na-rectorite
Donglin Zhao Shubin Yang Shaohua Chen Zhiqiang Guo Xin Yang 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(2):557-565
In this study, the adsorption of U(VI) from aqueous solution on Na-rectorite was studied as a function of various environmental
conditions such as contact time, pH, ionic strength, soil humic acid (HA)/fulvic acid (FA), solid contents, and temperature
under ambient conditions by using batch technique. The kinetic adsorption is fitted by the pseudo-second-order model very
well. The adsorption of U(VI) on Na-rectorite was strongly dependent on pH and ionic strength. A positive effect of HA/FA
on U(VI) adsorption was found at low pH, whereas a negative effect was observed at high pH. The presence of HA/FA enhanced
the U(VI) adsorption at low pH values, but reduced U(VI) adsorption at high pH. The thermodynamic parameters (ΔH
0, ΔS
0, and ΔG
0) were also calculated from the temperature dependent adsorption isotherms, and the results suggested that the adsorption
of U(VI) on Na-rectorite was a spontaneous and endothermic process. 相似文献
8.
Pengfei Zong Hai Wang Hui Pan Yaolin Zhao Chaohui He 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(3):1969-1979
To better understand the application of NKF-6 zeolite as an adsorbent for the removal of U(VI) from radionuclides and heavy metal ions polluted water, herein, NKF-6 zeolite was employed to remove U(VI) at different experimental conditions. The influence of solid/liquid ratio, contact time, pH, ionic strength, humic substances and temperature on sorption of U(VI) to NKF-6 zeolite was investigated using batch technique under ambient conditions. The experimental results demonstrated that the sorption of U(VI) on NKF-6 zeolite was strongly dependent on pH. The sorption property of U(VI) was influenced by ionic strength at pH < 7.0, whereas was independent of ionic strength at pH > 7.0. The presence of fulvic acid or humic acid promoted the sorption of U(VI) on NKF-6 zeolite at low pH values while restrained the sorption at high pH values. The thermodynamic parameters (i.e., ΔS 0, ΔH 0, and ΔG 0) calculated from the temperature-dependent sorption isotherms demonstrated that the sorption process of U(VI) on NKF-6 zeolite was endothermic and spontaneous. At low pH values, the sorption of U(VI) was dominated by outer-sphere surface complexation and ion exchange with Na+/H+ on NKF-6 zeolite surfaces, while inner-sphere surface complexation was the main sorption mechanism at high pH values. From the experimental results, one can conclude that NKF-6 zeolite can be used as a potential adsorbent for the preconcentration and solidification of U(VI) from large volumes of aqueous solutions. 相似文献
9.
Wubiao Zhu Zhengjie Liu Lei Chen Yunhui Dong 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(3):781-788
Sorption of U(VI) from aqueous solution to Na-attapulgite was investigated at different experimental chemistry conditions
by using batch technique. The attapulgite sample was characterized by FTIR and XRD. Sorption of U(VI) on attapulgite was strongly
dependent on pH and ionic strength. The sorption of U(VI) on attapulgite increased quickly with rising pH at pH < 6, and decreased
with increasing pH at pH > 7. The presence of humic acid (HA) enhanced the sorption of U(VI) on attapulgite obviously at low
pH because of the strong complexation of surface adsorbed HA with U(VI) on attapulgite surface. Sorption of U(VI) on attapulgite
was mainly dominated by ion exchange and/or outer-sphere surface complexation at low pH values, whereas the sorption was attributed
to the inner-sphere surface complexation or precipitation at high pH values. The sorption increased with increasing temperature
and the thermodynamic parameters calculated from the temperature dependent sorption isotherms suggested that the sorption
of U(VI) on attapulgite was a spontaneous and endothermic process. The results indicate that attapulgite is a very suitable
material for the preconcentration of U(VI) ions from large volumes of aqueous solutions. 相似文献
10.
Sorption properties of oxides IX: Effect of anions on the sorption of uranium (VI) on hydrous oxides
Effect of anions such as nitrate, chloride, sulphate and carbonate on the sorption of U(VI), from aqueous solutions on hydrous
oxides of Ti(IV), Ce(IV) Zr(IV) and Th(IV) has been studied. The sorption of U(VI) is markedly reduced in the presence of
anions, like carbonate, whichform strong complexes with UO
2
2
+ in solution. The results are explained in terms of a competition for free UO
2
2
+ between surface hydroxyl groups and ligands (anions) present in solution. The sorption of U(VI) on these hydrous oxides was
also studied from a bicarbonatecarbonate mixture. Sorption was less under conditions when tricarbonate complex of U(VI) was
formed, but increased at higher pH values (>9), presumably due to the formation and sorption of hydroxo complexes of U(VI). 相似文献
11.
The composite ion exchangers were tested for their ability to remove UO2
2+ from aqueous solutions. Polyacrylonitrile (PAN) composites having natural zeolite, clinoptilolite, and synthetic zeolite, zeolite X, were used as an adsorbents. The influences of pH, U(VI) concentration, temperature and contact time on the sorption behavior of U(VI) were investigated in order to gain a macroscopic understanding of the sorption mechanism. The optimum adsorption conditions were determined for two composites. The sorption behaviors of uranium on both composites from aqueous systems have been studied by batch technique. Parameters on desorption were also investigated to recover the adsorbed uranium. 相似文献
12.
Yalan Liu Liyong Yuan Yali Yuan Jianhui Lan Zijie Li Yixiao Feng Yuliang Zhao Zhifang Chai Weiqun Shi 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(2):803-810
Uranium is one of the most hazardous heavy metal due to its long half-life radioactivity, high toxicity and mobility as aqueous
uranyl ion (UO2
2+) under ordinary environmental conditions. Herein, amino functionalized SBA-15 (APSS) was developed as a rapid and efficient
sorbent for removal of U(VI) from the environment. The APSS sample was synthesized by grafting method and was characterized
by SEM, NMR, SAXS, and N2 sorption/desorption isothermal experiments. The sorption of U(VI) by APSS was investigated under different conditions of
pH, contact time, initial U(VI) concentration, ionic strength and solid–liquid ratio. The results show that the sorption of
U(VI) by APSS is strongly dependent on pH but independent of ionic strength and solid–liquid ratios (m/V). The sorption is ultrafast with an equilibrium time of less than 30 min, and the sorption capacity is as large as 409 mg/g
at pH 5.3 ± 0.1. Besides, the U(VI) sorption by APSS from extremely diluted solution and the desorption of U(VI) from APSS
were also studied. It is found that 100 mg of APSS can almost completely remove the U(VI) ions from 4 L aqueous solution with
the U(VI) concentration as low as 4.2 ppb and the sorbed U(VI) can be completely desorbed by 0.1 mol/L nitric acid. The results
strongly reveal the high performance of the APSS material in the removal and preconcentration of U(VI) from the aqueous solution. 相似文献
13.
Yaling Chi Yuantao Chen Xia Liu Zhijun Guo Linsen Cai 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(3):1349-1355
The sorption of UO2 2+ from aqueous solution on attapulgite was investigated as a function of contact time, solid content, pH, ionic strength, foreign ions, humic acid (HA), and fulvic acid (FA) under ambient conditions by using batch technique. The attapulgite sample was characterized by XRD and FTIR in detail. The results indicated that the sorption of UO2 2+ was strongly dependent on pH and ionic strength. The sorption of UO2 2+ on attapulgite increased quickly with rising pH at pH < 6.5, and decreased with increasing pH at pH > 6.5. The presence of HA or FA enhanced the sorption of UO2 2+ on attapulgite obviously at low pH because of the strong complexation of surface adsorbed HA/FA with UO2 2+ on attapulgite surface. Sorption of UO2 2+ on attapulgite was mainly dominated by ion-exchange or outer-sphere surface complexation at low pH values, but by inner-sphere surface complexation at high pH values. The results indicate that attapulgite is a very suitable adsorbent for the preconcentration and solidification of UO2 2+ from large volumes of aqueous solutions because of its negative surface charge and large surface areas. 相似文献
14.
Du Jinzhou Dong Wenming Wang Xiangke Tao Zuyi 《Journal of Radioanalytical and Nuclear Chemistry》1996,203(1):31-36
The effect of different solid components of calcareous soil on the retention of Sr was investigated by using batch technique and selective extraction method. The sorption and desorption isotherms of Sr on the untreated calcareous soil and the three treated soils were determined at 20°C, pH 7.8±0.2 and in the presence of 0.001 M CaCl2. It was found that all isotherms are linear and that the sorption of Sr on the calcareous soil can be described by a reversible sorption process and the sorption mechanism is mainly ion exchange. 相似文献
15.
Influence of pH,soil humic acid,ionic strength and temperature on sorption of U(VI) onto attapulgite
Liqiang Tan Xiaoli Tan Xuemei Ren Huiyang Mei Xiangke Wang 《Journal of Radioanalytical and Nuclear Chemistry》2018,316(3):981-991
The surface property of attapulgite was investigated by N2-BET surface area and zeta potential analysis in this paper. Solution pH had a remarkable effect on the sorption process, indicated an inner-sphere complexation. Humic acid (HA) in the solution enhanced U(VI) sorption significantly at pH?<?5.0, while decreased U(VI) sorption obviously at pH?>?9.0. The characteristic fluorescence changes of HA indicated that a strong chemical reaction occurred between the functional groups in HA and UO22+. The sorption was a spontaneous and endothermic process with increased entropy, and the increase in temperature would benefit the sorption. 相似文献
16.
Lijuan Song Yulong Wang Lu Zhu Bolong Guo Suwen Chen Wangsuo Wu 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(3):1589-1595
Polyoxometalates K7[α-PW11O39]·14H2O (PW11) modified mesoporous silica (MCM-48) with cubic structure, was prepared by impregnation and calcination methods. The modified mesoporous silica sorbent (PW11/MCM-48) was studied as a potential adsorbent for U(VI) from aqueous solutions. MCM-48 and PW11/MCM-48 were confirmed by X-ray diffraction and nitrogen physisorption techniques. The results indicate the original keggin structure of PW11 and mesoporous structure of MCM-48 are maintained after supporting PW11 on mesoporous silica MCM-48. The effects of contact time, solid-to-liquid ratio (m/V), solution pH and ionic strength on U(VI) sorption behaviors of the pure and modified mesoporous silicas were also studied. Typical sorption isotherms such as Langmuir and Freundlich isotherms were determined for sorption process. The results suggest that the sorption of U(VI) on MCM-48 or PW11/MCM-48 are strongly dependent on pH values but independent of ionic strength. The sorption capacity of PW11/MCM-48 for U(VI) is about ten times more than that of MCM-48. 相似文献
17.
Wenlu Guo Changming Nie Lin Wang Zijie Li Lin Zhu Liuzheng Zhu Zhentai Zhu Weiqun Shi Liyong Yuan 《中国科学:化学(英文版)》2016,59(5):629-636
Functionalized magnetic Fe_3O_4@SiO_2 composite nanoparticles were prepared by simply embedding iron oxide nanoparticles into MCM-41 through one-step synthesis process, followed by aminopropyls grafting on the mesopore channels, aiming to efficiently and conveniently uptake U(VI) from aqueous solution. The resultant material possesses highly ordered mesoporous structure with large surface area, uniform pore size, excellent thermal stability, quick magnetic response, and desirable acids resistance, confirmed by Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), N_2 adsorption/desorption experiments, powder X-ray diffraction(PXRD), and thermogravimetric analysis(TGA). Detailed U(VI) sorption test indicated that this material is indeed an effective U(VI) sorbent with fast sorption kinetics of less than 2 h, large sorption capacity of 160 mg/g at p H 5.0±0.1, and desirable selectivity towards U(VI) ions over a range of competing metal ions. The absorbed U(VI) can be easily desorbed by 0.01 mol/L or more concentrated HNO_3 solution, and the reclaimed sorbent can be reused with no obvious decrease of sorption capacity even after 4 sorption-desorption cycles. The present results suggest the vast opportunities of this kind of magnetic composite on the solid-phase extraction of U(VI). 相似文献
18.
Adsorption of U(VI) by Bacillus mucilaginosus 总被引:1,自引:0,他引:1
19.
Su-Wen Chen Bo-Long Guo Yu-Long Wang Yuan Li Li-Juan Song 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(2):1435-1442
The mesoporous silicas (MCM-41 and MCM-48) are synthesized by hydrothermal method, which are characterized by XRD and BET techniques. The application of mesoporous silicas for the sorption of U(VI) from aqueous solution are studied by using batch technique under ambient condition. The effects of contact time, solid-to-liquid ratio (m/V), solution pH, ionic strength and temperature are determined, and the results indicate that the sorption of U(VI) to MCM-41 or MCM-48 are strongly dependent on pH values but independent of ionic strength. Compared with Langmuir model, the sorption isotherms can be simulated by Freundlich model well according to the high relative coefficients. The parameters for Langmuir and Freundlich sorption isotherms are calculated from the temperature at 298, 318 and 338 K, respectively, and the results suggest that the sorption of U(VI) on MCM-41 or MCM-48 is a spontaneous and exothermic process. In contrast to its sorption capacity for U(VI), MCM-48 is a suitable material for the preconcentration of U(VI) from large volumes of aqueous solutions. 相似文献
20.
Yan Huang Liang Chen Hualin Wang 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(3):777-785
Herein, hydroxyapatite (HAP) was prepared by aqueous precipitation technique and was characterized by using FT-IR and XRD
to determine its chemical functional groups and micro-structure. The removal of cobalt from aqueous solution to HAP was studied
by batch technique as a function of various environmental parameters such as contact time, pH, ionic strength, foreign ions,
fulvic acid (FA), and temperature under ambient conditions. The results indicated that the sorption of Co(II) on HAP was strongly
dependent on pH and ionic strength. The presence of FA enhanced the sorption of Co(II) on HAP at low pH, whereas reduced Co(II)
sorption on HAP at high pH. The Langmuir, Freundlich and D-R models were used to simulate the sorption isotherms at three
different temperatures of 303.15, 323.15 and 343.15 K. The thermodynamic parameters (ΔH°, ΔS° and ΔG°) calculated from the temperature dependent sorption isotherms indicated that the sorption process of Co(II) on HAP was spontaneous
and endothermic. The sorption of Co(II) was dominated by outer-sphere surface complexation and ion exchange at low pH, whereas
inner-sphere surface complexation or surface precipitation was the main sorption mechanism at high pH values. The results
suggest that the HAP is a suitable material in the preconcentration and solidification of Co(II) from large volumes of aqueous
solutions. 相似文献