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1.
The sorption of Cd(II) on Haro river sand from deionized water is reported. The sorption system obeyed according to the Freundlich and Dubinin–Radushkevich (D-R) isotherms. The Freundlich parameters 1/n = 0.67±0.05 and of A = 1.38±1.14 mmole·g-1 have been ascertained. D-R isotherm yields the values of = -0.003741±0.000321 kJ2·mole-2, X
m = 0.23±0.21 mole·g-1 and of E = 11.6±0.5 kJ·mole-1. The influence of common anions and cations on the sorption was examined. Trivalent Bi enhances the sorption whereas Fe, Cr, Al and chromate ions reduce the sorption significantly. Hf(IV) and Ag(I) indicate substantial sorption (61–98%) whereas Gd(III), Re(VII) and Sc(III) show low sorption (<5%). The elements having low sorption can be separated from elements indicating higher sorption using Haro river sand column. 相似文献
2.
Sorption and thermodynamic behavior of zinc(II)-thiocyanate complexes onto polyurethane foam from acidic solutions 总被引:1,自引:0,他引:1
S. M. Hasany M. M. Saeed M. Ahmed 《Journal of Radioanalytical and Nuclear Chemistry》2002,252(3):477-484
The uptake of Zn(II)-SCN complex onto polyurethane foam (PUF) has been investigated in detail with respect to different composition and variable concentration of electrolyte, zinc, thiocyanate ions and PUF, and equilibration time. The sorption data followed both Langmuir and Dubinin-Radushkevich (D-R) sorption isotherms over the entire concentration range of zinc investigated whereas Freundlich sorption isotherm is obeyed upto 13.6.10-3M concentration. The Langmuir constants Q = 202±7 mmole.g-1 and of b = (1.78±0.31.104 dm3.mole-1 and of D-R paraneter X
m = 493±1 mmole.g-1, b = activity coefficient = -0.028±0.0002 and of sorption energy E = 13.2±0.5 kJ.mole-1 and Freundlich constants 1/n = 0.42±0.03 and c
m = 6.47±1.7 mmole.g-1 were evaluated. The influence of temperature variation on sorption have yielded DH = -77.5±2.9 kJ.mole-1, DS = -5±0.09 J.mole-1.K-1 and DG = -6.67±0.05 kJ.mole-1. The effect of common anions and cations on the sorption has been examined. Sulphate, ascorbate and bromide ions enhances the sorption to some extent whereas nitrite, Pb(II), Fe(III), Al(III), Cu(II) and Co(II) decrease to sorption significantly. A possible mechanism has been envisaged for Zn(II)-SCN sorption onto PUF. 相似文献
3.
Catalin Borcia Karin Popa Claudiu C. Pavel Adina Dascălu Cristina Viţelaru Bogdan A. Apetrăchioaei 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(1):25-30
The sorption of the thallous ion from aqueous acidic solution (pH = 1.5) onto as-synthesized and modified ETS-10 titanosilicates
was studied by using an isotope dilution method and a batch-mode technique. The present results show that the thallium(I)
sorption was effective onto all three considered materials and is enhanced by the porosity and acidity modification of the
ETS-10 titanosilicate. The best uptake performance was achieved by the meso-ETS-10. This behavior is explained based on the
newly created additional mesoporous system and enriching the external surface with silanol groups. Also, the presence of phosphorus
enhanced the inherent porosity allowing thus better internal diffusion properties of crystalline material. However, the chemically
modified surface seems to have a negative contribution to the kinetic uptake of thallous ion as shown by the positive value
of the activation energy E
a, in comparison with the processes more favorable energetically for ETS-10 and meso-ETS-10 materials. 相似文献
4.
Mekawy Zakaria A. Moussa Saber I. Mousa Abeer M. Dakroury Gehan A. Allan Karam F. 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(5):2331-2347
Journal of Radioanalytical and Nuclear Chemistry - Nano ZnO is biosynthesized using Lactobcillus sp. Poly Acrylic acid-co-Acrylonitrile/ZnO, PAACAN/ZnO, and poly Acrylic acid-co-Maleic acid/ZnO,... 相似文献
5.
Liqiang Tan Yeling Jin Jing Chen Xiaochun Cheng Jie Wu Liangdong Feng 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(2):601-610
The sorption of Co(II) on Na-attapulgite as a function of contact time, solid content, pH, ionic strength, foreign ions, fulvic
acid (FA) and temperature under ambient conditions was studied. The kinetic of Co(II) sorption on Na-attapulgite was described
well by pseudo-second-order model. The sorption of Co(II) on Na-attapulgite was strongly dependent on pH and ionic strength.
The sorption of Co(II) was mainly dominated by outer-sphere surface complexation and/or ion exchange at low pH, whereas inner-sphere
surface complexation or surface precipitation was the main sorption mechanism at high pH values. The presence of FA did not
affect Co(II) sorption obviously at pH <7, and a negative effect was observed at pH >7. The Langmuir and Freundlich models
were used to simulate the sorption data at different temperatures, and the results indicated that the Langmuir model simulated
the data better than the Freundlich isotherm model. The thermodynamic parameters (∆G°, ∆S°,
∆H°) calculated from the temperature-dependent sorption isotherms indicated that the sorption of Co(II) on Na-attapulgite was
an endothermic and spontaneous process. The results suggest that the attapulgite sample is a suitable material in the preconcentration
and solidification of radiocobalt from large volumes of aqueous solutions. 相似文献
6.
Amorphous zirconium phosphate (ZP), an inorganic ion exchange material of tetravalent metal acid (tma) salt, is synthesized by the sol-gel method and characterized by elemental analysis (ICP-AES), thermal analysis (TGA, DSC), FT-IR and X-ray diffraction studies. The resistivity of the material to acids, bases and organic solvents is assessed. The sorption behavior of the dyes acriflavin (AF) and brilliant green (BG) toward ZP was studied at 313, 323 and 333 K and the kinetic and thermodynamic parameters evaluated. Adsorption isotherms [Langmuir and Fruendlich], breakthrough capacity and elution behavior of these dyes are also studied. The sorption affinity of dyes towards ZP is BG > AF. 相似文献
7.
A. K. Sagidullin B. S. Smolyakov L. M. Levchenko A. A. Galitskii A. L. Bychkov 《Russian Journal of Applied Chemistry》2013,86(12):1867-1872
Physicochemical properties of nanoporous modified carbon sorbents and sorption of cadmium ions (0.1–20 mg L?1) onto them from nitrate solutions at pH 5–7 were studied. The acid-base nature of functional oxygen-containing groups on the carbon surface of the sorbents was determined. The ability to sorb cadmium ions depends on the kind of chemical modification of the sorbent surface. 相似文献
8.
9.
A. Kitamura T. Yamamoto S. Nishikawa H. Moriyama 《Journal of Radioanalytical and Nuclear Chemistry》1999,239(3):449-453
Sorption behavior of Am(III) onto granite was investigated. The distribution coefficient (K
d
) of Am(III) onto granite was determined in the solution of which pH was ranged from 2.9 to 11.4 and ionic strength was set
at 10−2 and 10−1. TheK
d
values were found to increase with increasing pH and with decreasing ionic strength. The obtained data were successfully
analyzed by applying an electrical double layer model. The optimum parameter values of the double layer electrostatics and
adsorption reactions were obtained, and the selective adsorption behavior of Am(III) onto the granite was discussed. 相似文献
10.
The retention profile of uranium (VI) as uranyl ions (UO(2)(2+)) from the aqueous media onto the solid sorbent date pits has been investigated. The sorption of UO(2)(2+) ions onto the date pits was achieved quantitatively (98+/-3.4%, n=5) after 15 min of shaking at pH 6-7. The sorption of UO(2)(2+) onto the used sorbent was found fast, followed by a first order rate equation with an overall rate constant, k of 4.8+/-0.05 s(-1). The sorption data were explained in a manner consistent with a "solvent extraction" mechanism. The sorption data were also subjected to Freundlich isotherm model over a wide range of equilibrium concentration (1-20 microgmL(-1)) of UO(2)(2+). The results revealed that, a "dual-mode" of sorption mechanism involving absorption related to "solvent extraction" and an added component for "surface adsorption" is most likely operated simultaneously for uranyl ions uptaking the solid sorbent. The thermodynamic parameters (-DeltaH, DeltaS and DeltaG) of the uranyl ions uptake onto the date pits indicated that, the process is endothermic and proceeds spontaneously. The interference of some diverse ions on the sorption UO(2)(2+) from the aqueous media onto the date pits packed column was critically investigated and the data revealed quantitative collection of UO(2)(2+) at 5 mLmin(-1) flow rate. The retained UO(2)(2+) was recovered quantitatively with HCl (3.0 molL(-1)) from the column at 5 mLmin(-1) flow rate. The mode of binding of the date pits with UO(2)(2+) was determined from the IR spectral date bits before and after extraction of uranium (VI). The height equivalent (HETP) and the number (N) of theoretical plates of the date pits packed column were determined from the chromatograms. Complete retention and recovery of UO(2)(2+) spiked to wastewater samples by the date pits packed column was successfully achieved. The capacity of the used sorbent towards retention of uranium (VI) from aqueous solutions was much better than the most common sorbents. 相似文献
11.
Batch experiments aimed at the sorption of Pb(II) onto peat were performed from an aqueous solution in both the absence and
presence of common complexing agents (acetate or citrate). The influence of the initial pH of the solution, metal ion concentration
and contact time on the sorption efficiency of Pb(II) was examined at ambient temperature (18 ± 0.5) °C for each experiment.
The results showed that the presence of acetate improved the efficiency of the sorption process, while the presence of citrate
in the aqueous solution decreased the efficiency of the Pb(II) sorption onto peat. The equilibrium data fitted well with the
Langmuir isotherm model and confirmed the monolayer sorption of uncomplexed and complexed Pb(II) species onto peat. The values
of maximum sorption capacities (q
max) were 135.13 mg g−1 for Pb(II) complexed with acetate, q > 79.36 mg g−1 for uncomplexed Pb, q > 38.46 mg g−1 for Pb(II) complexed with citrate. The kinetics of Pb(II) sorption onto peat, in both the absence and presence of complexing
agents, indicated a pseudosecond order mechanism. Analysis of IR spectra showed that carboxylic and hydroxyl groups had an
important role in the binding process of Pb(II) species onto peat. 相似文献
12.
Modeling adsorption of copper (II) onto fly ash and bentonite complex from aqueous solutions 总被引:1,自引:0,他引:1
Transportation of copper (II) ions from aqueous solutions to a fly ash and bentonite complex amorphous heterogeneous oxides (AHO: CaO-SiO(2)-Al(2)O(3)-MgO-FeO) system was studied. The particles of the fly ash and bentonite complex AHO system were highly porous and composed of platelike grains. They provide the physical basis for establishing a liquid-solid reaction model applicable to mesoporous solids. The main innovation of this model was in simplifying the powder granules to aggregates of close particles, while the particles act in accordance with the model better. The calculated curves from the models were well in line with the experimental results. 相似文献
13.
Yan Li Chunli Wang Zhijun Guo Chunli Liu Wangsuo Wu 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(3):1683-1691
Graphene oxide (GO) is one of the most important carbon nano-materials. In this paper, GO was synthesized from flake graphite and characterized by transmission electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. The sorption of Th(IV) on GO was investigated as a function of contact time, solid-to-liquid ratio, pH, ionic strength, and in the presence of fulvic acid (FA) and humic acid (HA) by batch experiments. The sorption percentage of Th(IV) on GO decreased with increasing ionic strength and decreasing solid-to-liquid ratio. The sorption edge of Th(IV) in the presence of FA/HA is much lower than that in the absence of FA/HA. Furthermore, the sorption processes of Th(IV) can be described by a pseudo-second order rate model. Based on the Langmuir model, the maximum sorption capacities (Csmax) of Th(IV) were about 5.80 × 10?4 mol/L. From thermodynamic investigation, sorption of Th(IV) on GO is spontaneous and endothermic in nature. The rapid sorption rate and high sorption capacity suggest that GO is a promising adsorbent for Th(IV). 相似文献
14.
Removal of Cu(II), Zn(II) and Co(II) ions from aqueous solutions by adsorption onto natural bentonite 总被引:1,自引:0,他引:1
In this study, the removal of Cu(II), Zn(II) and Co(II) ions from aqueous solutions using the adsorption process onto natural
bentonite has been investigated as a function of initial metal concentration, pH and temperature. In order to find out the
effect of temperature on adsorption, the experiments were conducted at 20, 50, 75 and 90 °C. For all the metal cations studied,
the maximum adsorption was observed at 20 °C. The batch method has been employed using initial metal concentrations in solution
ranging from 15 to 70 mg L−1 at pH 3.0, 5.0, 7.0 and 9.0. A flame atomic absorption spectrometer was used for measuring the heavy metal concentrations
before and after adsorption. The percentage adsorption and distribution coefficients (K
d) were determined for the adsorption system as a function of adsorbate concentration. In the ion exchange evaluation part
of the study, it is determined that in every concentration range, adsorption ratios of bentonitic clay-heavy metal cations
match to Langmuir, Freundlich and Dubinin-Kaganer-Radushkevich (DKR) adsorption isotherm data, adding to that every cation
exchange capacity of metals has been calculated. It is shown that the bentonite is sensitive to pH changes, so that the amounts
of heavy metal cations adsorbed increase as pH increase in adsorbent-adsorbate system. It is evident that the adsorption phenomena
depend on the surface charge density of adsorbent and hydrated ion diameter depending upon the solution pH. According to the
adsorption equilibrium studies, the selectivity order can be given as Zn2+>Cu2+>Co2+. These results show that bentonitic clay hold great potential to remove the relevant heavy metal cations from industrial
wastewater. Also, from the results of the thermodynamic analysis, standard free energy ΔG
0, standard enthalpy ΔH
0 and standard entropy ΔS
0 of the adsorption process were calculated. 相似文献
15.
The sorption of uranium(VI) from aqueous solutions was investigated using synthesized magnesium silicate hollow spheres as
a novel adsorbent. Batch experiments were conducted to study the effects of initial pH, amount of adsorbent, contact time
and initial U(VI) concentrations on uranium sorption efficiency. The desorbing of U(VI) and the effect of coexisting ions
were also investigated. Kinetic studies showed that the sorption followed a pseudo-second-order kinetic model. The Langmuir
sorption isotherm model correlates well with the uranium sorption equilibrium data for the concentration range of 25–400 mg/L.
The maximum uranium sorption capacity onto magnesium silicate hollow spheres was estimated to be about 107 mg/g under the
experimental conditions. Desorption of uranium was achieved using inorganic acid as the desorbing agent. The practical utility
of magnesium silicate hollow spheres for U(VI) uptake was investigated with high salt concentration of intercrystalline brine.
This work suggests that magnesium silicate hollow spheres can be used as a highly efficient adsorbent for removal of uranium
from aqueous solutions. 相似文献
16.
Yin Zhuoxin Pan Duoqiang Liu Peng Wu Hanyu Li Zhan Wu Wangsuo 《Journal of Radioanalytical and Nuclear Chemistry》2018,316(1):301-312
Journal of Radioanalytical and Nuclear Chemistry - Activated bentonite was obtained from acid activation and purification of raw bentonite, sorption of Th(IV) onto activated bentonite was studied... 相似文献
17.
《Journal of Saudi Chemical Society》2014,18(6):792-801
Release of heavy metals into water as a result of industrial activities may pose a serious threat to the environment. The objective of this study is to assess the uptake of Cu2+ from aqueous solutions onto multi-walled carbon nanotubes (MWCNT). The potential of the t-MWCNT to remove Cu2+ cations from aqueous solutions was investigated in batch reactor under different experimental conditions. The processing parameters such as initial concentration of Cu2+ ions, temperature, and adsorbent mass were also investigated. Copper uptake was quantitatively evaluated using the Langmuir, Freundlich and Dubinin–Kaganer–Radushkevich (DKR) models. In addition, the adsorption equilibrium was described well by the Langmuir isotherm model with maximum adsorption capacity of 12.34 mg/g of Cu2+ cations on t-MWCNT. Various thermodynamic parameters, such as ΔG0, ΔH0 and ΔS0 were calculated. The thermodynamics of Cu2+ cations adsorption onto t-MWCNT system pointed at spontaneous and endothermic nature of the process. Using the second-order kinetic constants, the activation energy of adsorption (Ea) was determined as 27.187 kJ/mol according to the Arrhenius equation. 相似文献
18.
Miloslav Drtil Juraj T?lgyessy Tibor Braun 《Fresenius' Journal of Analytical Chemistry》1990,338(1):50-53
Summary Iron(III) is sorbed by polyether type open-cell polyurethane foams from HCl solutions of 4 mol/l or higher. The capacity of the foams is around 50 mg·l–1. The iron (III) sorbed can be eluted from the foam with 0.01 mol/l HCl or distilled water. An optimization of the sorption conditions showed that the process can be used for analytical applications. The polyurethane foam sorbents examined did not sorb iron(II). The mechanism of sorption by polyether foams seems to follow a mechanism similar to that of the extraction of iron(III) by etheric solvents. 相似文献
19.
This work presents spectroscopic studies and electrochemical characterization of Cu(II)—dicyandiamide (DCDA) complex formation. The range of conditions leading to the precipitation of the complex is significantly larger than that presented in the literature. In all cases the stoichiometry of the compound is: [Cu(DCDA)2(SO4)(H2O)5). The spectroscopic data suggest that DCDA is a monodentate ligand forming a bond with Cu2+ via the nitryl nitrogen. Electroreduction of this complex is a two-step process occurring through a Cu(I)—DCDA intermediate. 相似文献
20.
R. Donat 《The Journal of chemical thermodynamics》2009,41(7):829-835
The adsorption of uranium (VI) from aqueous solutions onto natural sepiolite has been studied using a batch adsorber. The parameters that affect the uranium (VI) sorption, such as contact time, solution pH, initial uranium(VI) concentration, and temperature, have been investigated and optimized conditions determined. Equilibrium isotherm studies were used to evaluate the maximum sorption capacity of sepiolite and experimental results showed this to be 34.61 mg · g?1. The experimental results were correlated reasonably well by the Langmuir adsorption isotherm and the isotherm parameters (Qo and b) were calculated. Thermodynamic parameters (ΔH° = ?126.64 kJ · mol?1, ΔS° = ?353.84 J · mol?1 · K?1, ΔG° = ?21.14 kJ · mol?1) showed the exothermic heat of adsorption and the feasibility of the process. The results suggested that sepiolite was suitable as sorbent material for recovery and adsorption of uranium (VI) ions from aqueous solutions. 相似文献