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1.
Zhi-Bin Zhang Xiao-Feng Yu Xiao-Hong Cao Rong Hua Min Li Yun-Hai Liu 《Journal of Radioanalytical and Nuclear Chemistry》2014,301(3):821-830
The sulfonated mesoporous carbon (CMK-3-SO3H) prepared by functionalizing mesoporous carbon (CMK-3) via vapor transfer method has been explored for the removal and recovery of uranium from aqueous solutions. The influences of different experimental parameters such as solution pH, initial concentration, contact time and temperature on adsorption were investigated. The results showed that CMK-3-SO3H has the highest uranium sorption capacity at initial pH of 5.0 and contact time of 120 min, and the adsorption process could be better described by the pseudo-second-order model and Langmuir isotherm. Selective adsorption studies showed that the CMK-3-SO3H could selectively remove of U(VI), and the selectivity coefficients of mesoporous carbon in the presence of co-existing ions, Mg(II), Zn(II), Mn(II), Cu(II), Ni(II), Sr(II) and Hg(II) improved after functionalization. 相似文献
2.
D. L. Selin N. P. Tarasova A. V. Malkov G. A. Poskrebyshev 《Reaction Kinetics and Catalysis Letters》1989,39(2):273-278
-radiation of Co60 has been applied to reduce Eu(III) to Eu(II) in aqueous solutions of the mixture of rare earths. The kinetics of the process has been investigated as a function of the absorbed radiation dose and organic additive concentration.
+3 - Co60: Eu(III)Eu(II). .相似文献
3.
The sorption of Cu(II) on olive cake, a biomass by-product of olive oil production, has been investigated by potentiometry
at pH 6, I=0.1 M NaClO4, 25 °C and under atmospheric conditions. Numerical analysis of the experimental data supports the formation of surface complexes
and allows the evaluation of the corresponding formation constant, which is found to amount log β=5.1±0.4. This value is close to corresponding values given in literature for Cu(II)-humate complexes, indicating that the
same type of active sites (e.g. carboxylic and phenolic groups) is responsible for the Cu(II) binding by olive cake. Addition
of a competing metal ion (e.g. Eu(III) ion) in the system leads to replacement of the Cu(II) by Eu(III). Evaluation of the
potentiometric data obtained from competition experiments indicates on a ionexchange mechanism. The formation constant of
the Eu(III) species sorbed on olive cake is found to be log β=5.4±0.9. The results of this study are of particular interest with respect to waste water treatment technologies using biomass
products as adsorbent material and environmental impact assessments regarding disposal of biomass by products in the geosphere. 相似文献
4.
5.
In this work, batch adsorption experiments are carried out for crystal violet dye using mesoporous MCM-41 synthesized at room
temperature and sulfate modified MCM-41 prepared by impregnation method using H2SO4 as sulfatising agent. The surface characteristics, pore structure, bonding behavior and thermal degradation of both the MCM-41
samples are characterized by nitrogen adsorption/desorption isotherms, X-ray diffraction (XRD) patterns, Fourier transform
infrared (FT-IR) spectroscopy and thermo gravimetric analysis (TGA). The adsorption isotherm, kinetics and thermodynamic parameters
are investigated for crystal violet (CV) dye using the calcined and sulfated MCM-41. Results are analysed using Langmuir,
Freundlich and Redlich-Peterson isotherm models. It is found that the Freundlich model is an appropriate model to explain
the adsorption isotherm. The highest adsorption capacity achieved is found to be 3.4×10−4 mol g−1 for the sulfated MCM-41. The percentage removal of crystal violet dye increases with increase in the pH for both the MCM-41
adsorbents. Kinetics of adsorption is found to follow the second-order rate equation. From the thermodynamic investigation,
it is evident that the adsorption is exothermic in nature. 相似文献
6.
Mohamed Ahmed Mahmoud 《Journal of Saudi Chemical Society》2018,22(2):229-238
The adsorption kinetics for removal of uranium (V1) from aqueous solution using silicon dioxide nanopowder (nano-SiO2) was investigated in batch and continuous techniques. Pseudo-first order and pseudo-second order were used to analyze the kinetics of batch experiments. In continuous technique the important parameters (initial concentration, flow rate and bed height) on the breakthrough curves were studied and the adsorption kinetics was analyzed using Thomas and Yoon and Nelson kinetic models. The comparison between the kinetic models was evaluated by the correlation coefficients (r2). The results indicated that the batch experiments fitted well with pseudo second-order kinetic model. The comparison of the experimental breakthrough curve to the breakthrough profile obtained from Thomas and Yoon and Nelson methods showed a satisfactory fit for silicon dioxide nanopowder. 相似文献
7.
R. Yavari Y. D. Huang S. J. Ahmadi 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(2):393-401
Multiwall carbon nanotubes (MWCNTs) were modified by nitric acid solution and then used to study the adsorption of cesium
from aqueous solution using a batch technique under ambient conditions. As produced and oxidized MWCNTs were characterized
by nitrogen adsorption/desorption, Boehm’s titration method and Fourier transform infrared spectroscopy. The physical properties
of MWCNTs such as functional groups, total number of acid sites and specific surface area were greatly improved after oxidation,
and these were responsible for more sorption of cesium from aqueous solution and made them more dispersible in water. The
adsorption of cesium ions as a function of contact time, initial concentration of cesium, pH, ionic strength and oxidized MWCNT concentrations was also investigated. The results showed that cesium adsorption percentage
strongly depended on the pH value, oxidized MWCNT content and on the solution ionic strength. Kinetic data indicated that
the adsorption process achieved equilibrium within 80 min. Equilibrium data for as produced and oxidized MWCNTs was well described
by both Freundlich and Langmuir isotherms. The dominant mechanism of cesium adsorption on oxidized MWCNTs may be mainly attributed
to ion exchange. This study suggests that oxidized MWCNTs can be a promising candidate for the removal of cesium from nuclear
waste solution. 相似文献
8.
Vu D Li Z Zhang H Wang W Wang Z Xu X Dong B Wang C 《Journal of colloid and interface science》2012,367(1):429-435
Anatase mesoporous titanium nanofibers (m-TiO(2) NFs) have been synthesized from calcination of the as-spun TiO(2)/polyvinyl pyrrolidone (PVP)/pluronic123 (P123) composite nanofibers at 450 °C in air for 3h. The structures and the physicochemical properties of m-TiO(2) NFs are characterized by scanning electron microscopy, X-ray diffraction, nitrogen adsorption-desorption isotherm analysis, and determination point of zero charge, respectively. An investigation of Cu(II) adsorption onto m-TiO(2) NFs has been studied in this research. The pH effect, adsorption kinetics, and adsorption isotherms are examined in batch experiments. Experimental data were analyzed using pseudo-first order and pseudo-second order kinetic models. It was found that adsorption kinetics were the best fitting by a pseudo-second order kinetic model. The optimum pH for Cu(II) adsorption was found to be 6.0. The equilibrium data were analyzed by the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm models, which revealed that the Freundlich isotherm is the best-fit isotherm for the adsorption of Cu(II). Compared to the TiO(2) NFs (regular anatase titanium nanofibers) in the same experimental conditions to elucidate the role of the mesoporous structure of m-TiO(2) NFs, experimental results showed that the m-TiO(2) NFs had a better adsorption capacity for Cu(II) due to its higher surface area. 相似文献
9.
Yulia S. Fetisova Oksana A. Dudarko Maja Bauman Aleksandra Lobnik Valeriia V. Sliesarenko 《Journal of Sol-Gel Science and Technology》2018,85(1):66-75
The mesoporous silica samples with different concentrations of phosphonic acid groups on the surface were obtained by direct template synthesis. The block-copolymer Pluronic P123 was used as a template, and sodium meta-silicate with diethylphosphatoethyltriethoxysilane as precursors. According to the SAXS diffractograms, mesoporous silica samples have a p6mm hexagonal symmetry. In addition, we used sol–gel method to synthesize xerogel with the same groups for comparison. All samples possess high values of specific surface area 615–730?m2/g and sorption pore volume. FTIR and potentiometric titration methods were used to investigate the surface layer of these samples. Sorption properties of the samples with phosphonic acid groups were studied in respect to a row of metal cations, among which we focused on lead(II), cadmium(II), and dysprosium(III) cations. 相似文献
10.
11.
A basic investigation on the removal of Cr(III) and Cr(VI) ions from aqueous solution by chitosan beads was conducted in a
batch adsorption system. The chitosan beads were prepared by casting an acidic chitosan solution into an alkaline solution.
The influence of different experimental parameters; pH, agitation period and different concentration of Cr(III) and Cr(VI)
ions was evaluated. A pH 5.0 was found to be an optimum pH for Cr(III) adsorption, and meanwhile pH 3.0 was the optimum pH
for the adsorption of Cr(VI) onto chitosan beads. The Langmuir and Freundlich adsorption isotherm models were applied to describe
the isotherms and isotherm constants for the adsorption of Cr(III) and Cr(VI) onto chitosan beads. Results indicated that
Cr(III) and Cr(VI) uptake could be described by the Langmuir adsorption model. The maximum adsorption capacities of Cr(III)
and Cr(VI) ions onto chitosan beads were 30.03 and 76.92 mg g−1, respectively. Results showed that chitosan beads are favourable adsorbents. The Cr(III) and Cr(VI) ions can be removed from
the chitosan beads by treatment with an aqueous EDTA solution. 相似文献
12.
13.
Juan Tan Yanfei Wang Na Liu Mouwu Liu 《Journal of Radioanalytical and Nuclear Chemistry》2018,315(2):119-126
The adsorption of uranium (VI) using tetraphenylimidodiphosphinate (Htpip) was studied. Factors of affecting sorption efficiency have been investigated and results showed the adsorption of uranium (VI) was equilibrium at pH 4.5, time 20 min, adsorbent dosage 0.005 g and initial concentration 50 mg L?1 reaching 99.86 mg g?1 of adsorption capacity and 99.86% of removal efficiency. Additionally, the interfering ions studies showed that the adsorbent possessed excellent adsorption selectivity of uranium (VI). The surface morphology of Htpip was investigated by SEM. The adsorption process of uranium (VI) onto Htpip fit the pseudo-second-order kinetic model and the Freundlich isotherm model very well. 相似文献
14.
Shahida S. Abbasi Y. A. Ali A. Khan M. I. Shah K. H. Farooq U. Hafeez M. 《Journal of Radioanalytical and Nuclear Chemistry》2020,324(3):1215-1223
Journal of Radioanalytical and Nuclear Chemistry - Solvent extraction of Eu(III) and Nd(III) from aqueous medium was investigated by sulfasalazine in benzoyl alcohol as single extractant and then... 相似文献
15.
以脂肪醇聚氧乙烯醚为模板剂,正硅酸乙酯为Si源,分别以偏钨酸铵,硫酸铝作为W源和Al源进行改性,合成出W-MSU-x以及Al-MSU-x介孔分子筛.并且通过X射线扫描、N_2吸附-脱附、原位红外表征考察W和Al的加入对介孔分子筛的影响.结果得到,W的加入提高了分子筛的有序度,Al的加入使介孔分子筛的孔径减小,比表面积增大. 相似文献
16.
Debasish Das M. K. Sureshkumar K. Radhakrishnan J. Nuwar C. G. S. Pillai 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(1):275-285
Chitosan tripolyphosphate (CTPP) beads were prepared at two different cross-linking densities and adsorption of Cr(III) onto
it were studied as a function of different operational parameters such as solution pH, equilibration time and initial Cr(III)
ion concentration. Higher cross-linked beads were found to have more adsorption capacity at all the experimental pH employed
(pH = 3–5), whereas adsorption capacity is found to increase with increase in pH. Adsorption data were analyzed using Langmuir
and Freundlich isotherm models. Langmuir model is found be more suitable to explain the experimental results with a monolayer
adsorption capacity of 469.5 mg/g. Among the kinetic models used, pseudo-second order kinetic model could best describe the
adsorption process. Competition experiments done in presence of Na(I), Mg(II), Ca(II), Al(III) and Fe(III) revealed that,
except in the case of Al(III), adsorption of Cr(III) is not significantly affected by the presence of foreign cations. NaCl
is found to be a suitable leaching agent for the desorption of adsorbed Cr(III) from CTPP beads. FTIR spectroscopic investigations
confirmed that phosphate groups are the principal binding site responsible for the sorption of Cr(III) onto CTPP beads. 相似文献
17.
18.
1.Eu, a cyclen based Eu(III)-thiol conjugate, was incorporated onto the surface of water-soluble gold nanoparticles to give AuNP-1.Eu. The self-assembly between AuNP-1.Eu and the antenna 2 resulted in the formation of the highly luminescent lanthanide system, AuNP-1.Eu-2, at pH 7.4. The sensing of flavin monophosphate 3 is demonstrated, whereby 3 displaced the antenna 2 in AuNP-1.Eu-2, resulting in the formation of AuNP-1.Eu-3 and quenching of the Eu(III) emission. 相似文献
19.
《Supramolecular Science》1998,5(5-6):523-526
MCM-41 mesoporous molecular sieve materials with nanometer-sized pores show the very strong photoluminescent (PL) effect and the Al-depleted defect sites are responsible for this strong PL effect of the investigated MCM-41 samples. The porous channel structures of molecular sieves are another factor influencing the investigated PL effect. 相似文献
20.
Bao Shidong Li Ye Fei Zhengfu Mei Heng Zhou Yuzhi Wang Xiaoli Liu Dongxue 《Journal of Radioanalytical and Nuclear Chemistry》2020,324(1):385-394
Journal of Radioanalytical and Nuclear Chemistry - Ureido-functionalized ethylene-bridged mesoporous silica (UE-MS) was synthesized by co-condensation method for uranium(VI) uptake. The adsorbents... 相似文献