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1.
Cui Pang Yunhai Liu Xiaohong Cao Rong Hua Caixia Wang Chunqing Li 《Journal of Radioanalytical and Nuclear Chemistry》2010,286(1):185-193
Chitosan-coated attapulgite beads were prepared by coating chitosan on naturally and abundantly available attapulgite, and
made into spherical beads to adsorb uranium from aqueous solutions. The beads were characterized by SEM, EDS and FT-IR. The
characteristics of beads of adsorbing uranium(VI) from aqueous solutions were studied at different conditions of pH, initial
uranium concentration, contact time, biomass dosage and temperature. The pseudo-second order rate equation was used to describe
the kinetic data, and isotherm data were fitted to Langmuir and Freundlich adsorption models. Thermodynamic parameters (ΔG°, ΔH°, and ΔS°) of the biosorption were also calculated. Thermodynamic parameters of the CAAB, viz., ΔG°(308 K), ΔH°, and ΔS° were determined to be −21.59, 6.29l and 90.51 J/mol K, respectively. The experimental results demonstrate that the beads
of chitosan coated onto attapulgite exhibit considerable potential for application in both adsorption and removal of uranium
from aqueous solutions. 相似文献
2.
G. S. Murthy M. V. Sivaiah S. S. Kumar V. N. Reddy R. M. Krishna S. Lakshminarayana 《Journal of Radioanalytical and Nuclear Chemistry》2004,260(1):109-114
The applicability of zirconium phosphate-ammonium molybdophosphate (ZrP-AMP) for the efficient removal of cesium from aqueous
acidic solutions by adsorption has been investigated. The adsorption data analysis was carried out using the Freundlich, Dubinin-Raduskevich
(D-R) and Langmuir isotherms for the uptake of Cs in the initial concentration range of 3.75.10-5-7.52.10-3 mol.dm-3 on the ZrP-AMP exchanger from nitric acid medium. The mean free energy (E) values for the adsorption of Cs were obtained from the D-R isotherm. Equilibrium adsorption values at different temperatures
have been utilized to evaluate the change in enthalpy, entropy and free energy (ΔH°, ΔS°, ΔG°). The adsorption of cesium on the ZrP-AMP exchanger was found to be endothermic.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
In this paper, the crosslinked polyester resin containing acrylic acid functional groups was used for the adsorption of uranium
ions from aqueous solutions. For this purpose, the crosslinked polyester resin of unsaturated polyester in styrene monomer
(Polipol 353, Poliya) and acrylic acid as weight percentage at 80 and 20%, respectively was synthesized by using methyl ethyl
ketone peroxide (MEKp, Butanox M60, Azo Nobel)-cobalt octoate initiator system. The adsorption of uranium ions on the sample (0.05 g copolymer
and 5 mL of U(VI) solution were mixed) of the crosslinked polyester resin functionalized with acrylic acid was carried out
in a batch reactor. The effects of adsorption parameters of the contact time, temperature, pH of solution and initial uranium(VI)
concentration for U(VI) adsorption on the crosslinked polyester resin functionalized with acrylic acid were investigated.
The adsorption data obtained from experimental results depending on the initial U(VI) concentration were analyzed by the Freundlich,
Langmuir and Dubinin–Radushkevich (D–R) adsorption isotherms. The adsorption capacity and free energy change were determined
by using D–R isotherm. The obtained experimental adsorption data depending on temperature were evaluated to calculate the
thermodynamic parameters of enthalpy (ΔH°), entropy (ΔS°) and free energy change (ΔG°) for the U(VI) adsorption on the crosslinked polyester resin functionalized with acrylic acid from aqueous solutions. The
obtained adsorption data depending on contact time were analyzed by using adsorption models such as the modified Freundlich,
Elovich, pseudo-first order and pseudo-second-order kinetic models. 相似文献
4.
Composites could be more effective adsorbents than inorganic and organic components individually. In the present study, the
red macro marine algae, Jania Rubens and yeast, Saccharomyces cerevisiae immobilized on silica gel were used as a constituent of bi-functionalized biosorbent to remove thorium ions from aqueous
solution. Optimum biosorption conditions were determined as a function of pH, initial Th(IV) concentration, contact time,
temperature, volume/mass ratio and co-ion effect. The morphological analysis of the biocomposite was performed by the scanning
electron microscopy and functional groups in the biosorbent were determined by FT-IR spectroscopy. In order to find the adsorption
characteristics, Langmuir, Freundlich, and Dubinin–Radushkevich adsorption isotherms were applied to the adsorption data.
The data were well described by Langmuir adsorption isotherms while the fit of Freundlich adsorption isotherms and Dubinin–Radushkevich
equation to adsorption data was poor. Using the equilibrium constant value obtained at different temperature, the thermodynamics
properties of the biosorption (ΔG°, ΔH° and ΔS°) were also determined. The results show that biosorption of Th(IV) ions onto biocomposite was exothermic nature, spontaneous
and more favorable at lower temperature under examined conditions. 相似文献
5.
P. Senthil Kumar R. V. Abhinaya K. Gayathri Lashmi V. Arthi R. Pavithra V. Sathyaselvabala S. Dinesh Kirupha S. Sivanesan 《Colloid Journal》2011,73(5):651-661
The adsorption of methylene blue (MB) dye from aqueous solution onto a cashew nut shell (CNS) was investigated as a function
of parameters such as solution pH, CNS dose, contact time, initial MB dye concentration and temperature. The CNS was shown
to be effective for the quantitative removal of MB dye, and the equilibrium was reached in 60 min. The experimental data were
analysed by two-parameter isotherms (Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models) using nonlinear regression
analysis. The characteristic parameters for each isotherm and the related correlation coefficients were determined. Thermodynamic
parameters such as ΔG°, ΔH° and ΔS° were also evaluated, the sorption process was found to be spontaneous and exothermic. Pseudo-first-order, pseudo-second-order
and Elovich kinetic models were used to analyze the adsorption process. The results of the kinetic study suggest that the
adsorption of MB dye matches the pseudo-second-order equation, suggesting that the adsorption process is presumably chemisorption.
The adsorption process was found to be controlled by both surface and pore diffusion. Analysis of adsorption data using a
Boyd kinetic plot confirmed that the external mass transfer is a rate determining step in the sorption process. A single-stage
batch adsorber was designed for different CNS doses to effluent volume ratios using the Freundlich equation. The results indicated
that the CNS could be used effectively to adsorb MB dye from aqueous solutions. 相似文献
6.
R. Donat K. Esen H. Cetisli S. Aytas 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(1):253-261
Ulva sp. and sepiolite were used to prepare composite adsorbent. The adsorption of uranium(VI) from aqueous solutions onto Ulva sp.-sepiolite has been studied by using a batch adsorber. The parameters that affect the uranium(VI) adsorption, such as solution
pH, initial uranium(VI) concentration, and temperature, have been investigated and the optimum conditions determined. The
adsorption patterns of uranium on the composite adsorbent followed the Freundlich and Dubinin-Radushkevich (D-R) isotherms.
The Freundlich, Langmuir, and Dubinin-Radushkevich (D-R) models have been applied and the data correlate well with Freundlich
model. The sorption is physical in nature (sorption energy, E = 4.01 kJ/mol). The thermodynamic parameters such as variation of enthalpy ΔH, variation of entropy ΔS and variation of Gibbs free energy ΔG were calculated from the slope and intercept of lnK
d
vs. 1/T plots. Thermodynamic parameters (ΔH
ads
= −22.17 kJ/mol, ΔS
ads
= −17.47 J/mol·K, ΔG
o
ads
(298.15 K) = −16.96 kJ/mol) show the exothermic heat of adsorption and the feasibility of the process. The results suggested
that the Ulva sp-sepiolite composite adsorbent is suitable as a sorbent material for recovery and biosorption/adsorption of uranium ions from
aqueous solutions. 相似文献
7.
C. -L. Zhang F. Zhao Y. Wang 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(4):653-657
Batch adsorption experiments were carried out for the removal of ofloxacin from aqueous solution using modified coal fly ash
as adsorbent. The effects of various parameters such as contact time, initial solution concentration and temperature on the
adsorption system were investigated. The optimum contact time was found to be 150 min. The adsorption isotherm data fit well
with the Langmuir model, and the kinetic data fit well with the pseudo-second order and the intra-particle diffusion model.
Intra-particle diffusion analysis demonstrates that ofloxacin diffuses quickly among the particles at the beginning of the
adsorption process, and then the diffusion slows down and stabilizes. Thermodynamic parameters such as ΔG, ΔH, and ΔS were also calculated. The negative Gibbs free energy change and the positive enthalpy change indicated the spontaneous and
endothermic nature of the adsorption, and the positive entropy change indicated that the adsorption process was aided by increased
randomness. 相似文献
8.
Abdelhakim Kadous Mohamed Amine Didi Didier Villemin 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(2):553-561
Removal of uranium(VI) ions from acetate medium in aqueous solution was investigated using Lewatit TP260 (weakly acidic, macroporous-type
ion exchange resin with chelating aminomethylphosphonic functional groups) in batch system. The parameters that affect the
uranium(VI) sorption, such as contact time, solution pH, initial uranium(VI) concentration, adsorbent dose and temperature
have been investigated. Results have been analyzed by Langmuir and Freundlich isotherm; the former was more suitable to describe
the sorption process. The moving boundary particle diffusion model only fits the initial metal adsorption on the resin. The
rate constant for the uranium sorption by Lewatit TP260 was 0.441 min−1 from the first order rate equation. The total sorption capacity was found to be 58.33 mg g−1 under optimum experimental conditions. Thermodynamic parameters (ΔH = 61.74 kJ/mol; ΔS = 215.3 J/mol K; ΔG = −2.856 kJ/mol) showed the adsorption of an endothermic process and spontaneous nature, respectively. 相似文献
9.
The adsorption of dibenzothiophene (DBT) in hexadecane onto NaY zeolite has been studied by performing equilibrium and kinetic
adsorption experiments. The influence of several variables such as contact time, initial concentration of DBT and temperature
on the adsorption has been investigated. The results show that the isothermal equilibrium can be represented by the Langmuir
equation. The maximum adsorption capacity at different temperatures and the corresponding Langmuir constant (K
L
) have been deduced. The thermodynamic parameters (ΔG
0,ΔH
0,ΔS
0) for the adsorption of DBT have also been calculated from the temperature dependence of K
L
using the van’t Hoff equation. The value of ΔH
0,ΔS
0 are found to be −30.3 kJ mol−1 and −33.2 J mol−1 K−1 respectively. The adsorption is spontaneous and exothermic. The kinetics for the adsorption process can be described by either
the Langmuir model or a pseudo-second-order model. It is found that the adsorption capacity and the initial rate of adsorption
are dependent on contact time, temperature and the initial DBT concentration. The low apparent activation energy (12.4 kJ mol−1) indicates that adsorption has a low potential barrier suggesting a mass transfer controlled process. In addition, the competitive
adsorption between DBT, naphthalene and quinoline on NaY was also investigated. 相似文献
10.
Sabriye Yusan Mahmoud A. A. Aslani D. Alkim Turkozu Hasan A. Aycan Sule Aytas Sema Akyil 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(1):231-238
In this work, sorption of uranium ions on volcanic tuff collected from the deposits located at the Tendurek of Eastern Turkey
was investigated in batch technique. The effect of different parameters such as pH of the medium, contact time, uranium concentration
and temperature were investigated. The maximum removal of U(VI) was found to be 68% at pH 5.0, initial U(VI) concentration
of 75 mg L−1 and 30 °C. Thermodynamic parameters, such as enthalpy of adsorption ∆H°, free energy change ∆G° and entropy change ∆S° have been also calculated and interpreted. The suitability of the Langmuir, Freundlich and Dubinin-Radushkhevic adsorption
models to the equilibrium data was investigated for uranium-volcanic tuff system. The results suggest that volcanic tuff can
be used as efficient and cost effective adsorbents for uranium ion removal. 相似文献
11.
In this study, the adsorption of an industrial dye Supranol Yellow 4GL onto Cetyltrimethylammonium-bentonite (CTAB-bentonite)
is investigated. The organobentonite is synthesised by exchanging cetyltrimethylammonium cations (CTAB) with inorganic ions
on the surface of bentonite. The adsorption of Supranol Yellow 4GL onto organobentonite is found to be maximum when the concentration
of CTAB exchanged is 100% according to the cation exchange capacity of the clay (CEC). The modification of organobentonite
is examined using XRD and FTIR techniques.
The effect of the process parameters such as: contact time, adsorbate concentration, adsorbent dose, pH and temperature are
reported. Nearly 1200 seconds of contact time are found to be sufficient for the adsorption to reach equilibrium. The pseudo
second order model is used to describe the kinetic data, and the rate constant is therefore evaluated. The dye adsorption
to organobentonite is characterized by monolayer isotherm and caused by adsorption with relatively strong uptake. The Langmuir
and Freundlich models adsorption are applied to describe the isotherm equilibrium and to determine its constants. The Langmuir
and Freundlich models agree well with the experimental data with a adsorption capacity of 0.5 g of dye per g of organobentonite.
A better fixation was obtained at acidic pH. The effect of temperature on the adsorption of dye has been also studied and
the thermodynamic parameters ΔH, ΔS, ΔG, were determined. Organobentonite is found to be effective for removing Supranol Yellow 4GL dye from wastewater. 相似文献
12.
M. Mufazzal Saeed Abdul Ghaffar 《Journal of Radioanalytical and Nuclear Chemistry》1998,232(1-2):171-177
The nature of adsorption behavior of Au(III) on polyurethane (PUR) foam was studied in 0.2M HCl aqueous solution. The effect
of shaking time and amount of adsorbent were optimized for 3.16·10−5M solution of Au(III) in 0.2M HCl. The classical Freundlich and Langmuir adsorption isotherms have been employed successfully.
The Freundlich parameters 1/n and adsorption capacityK are 0.488±0.016 and (1.40±0.22)·10−2 mol·g−1, respectively. The Langmuir constants of saturation capacityM and binding energyb are (1.66±0.08)·10−4mol·g−1 and 40294±2947 l·g−1, respectively, indicating the monolayer chemical sorption. The mean free energy (E) of adsorption of Au(III) on PUR foam has been evaluated using D-R isotherm and found to be 11.5±0.16 kJ·mol−1 reflecting the ion exchange type of chemical adsorption. The effect of temperature on the adsorption has also been studied.
the isosteric heat of adsorption was found to be 44.03±1.66 kJ·mol−1. The thermodynamic parameters of ΔG, ΔH, ΔS and equilibrium constantK
c
have been calculated. The negative values of ΔG, ΔH and ΔS support that the adsorption of Au(III) on PUR foam is spontaneous, exothermic and of ion exchange chemisorption. The nature
of the Au(III) species sorbed on PUR foam have been discussed. 相似文献
13.
Adsorption kinetic,thermodynamic and desorption studies of phosphate onto hydrous niobium oxide prepared by reverse microemulsion method 总被引:1,自引:0,他引:1
A type of Nb2O5⋅3H2O was synthesized and its phosphate removal potential was investigated in this study. The kinetic study, adsorption isotherm,
pH effect, thermodynamic study and desorption were examined in batch experiments. The kinetic process was described by a pseudo-second-order
rate model very well. The phosphate adsorption tended to increase with a decrease of pH. The adsorption data fitted well to
the Langmuir model with which the maximum P adsorption capacity was estimated to be 18.36 mg-P g−1. The peak appearing at 1050 cm−1 in IR spectra after adsorption was attributed to the bending vibration of adsorbed phosphate. The positive values of both
ΔH° and ΔS° suggest an endothermic reaction and increase in randomness at the solid-liquid interface during the adsorption. ΔG° values obtained were negative indicating a spontaneous adsorption process. A phosphate desorbability of approximately 68%
was observed with water at pH 12, which indicated a relatively strong bonding between the adsorbed phosphate and the sorptive
sites on the surface of the adsorbent. The immobilization of phosphate probably occurs by the mechanisms of ion exchange and
physicochemical attraction. Due to its high adsorption capacity, this type of hydrous niobium oxide has the potential for
application to control phosphorus pollution. 相似文献
14.
J. Satyanarayana G. S. Murthy P. Sasidhar 《Journal of Radioanalytical and Nuclear Chemistry》1999,242(1):11-16
The applicability of ammonium molybdophosphate-alumina (AMP-Al2O3) for the efficient removal of Cs from aqueous solution by adsorption has been investigated. The kinetics of adsorption of
cesium ions has been studied by using radioanalytical procedure over a concentration range of 10−4−10−2 mol.dm−3 and in the temperature range of 303–318 K. The results showed that the uptake follows the first order rate law with respect
to cesium concentration and obeys Langmuir and modified Freundlich adsorption isotherm in the concentration range studied.
Equilibrium adsorption values at different temperatures have been utilised to evaluate change in standard thermodynamic parameters
(ΔH
0, ΔG
0 and ΔS
0). From the thermodynamic parameters it is found that the process is exothermic in nature. 相似文献
15.
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
16.
YunHai Wu Yue Hu ZhengWei Xie ShiXun Feng Bin Li XianMiao Mi 《Applied biochemistry and biotechnology》2011,163(7):882-894
The use of cheap, high-efficiency, and ecofriendly adsorbent has been studied as an alternative way for the removal of dyes
from wastewater. This paper investigated the use of waste brewery’s yeast for the removal of acid orange 7 from aqueous solution.
The optimum removal of acid orange 7 was found to be 3.561 mg/g at pH 2.0, 10 mg/L initial concentration and 303 K. The kinetic
studies indicated that the biosorption process of acid orange 7 agreed well with the pseudo-second-order model. The external
diffusion is the rate-controlling step of the initial fast adsorption (<20 min) and then the intraparticle diffusion dominated
the mass transfer process. Langmuir, Freundlich, and Dubinin–Radushkevich models were applied to describe the biosorption
isotherm of acid orange 7 by waste brewery’s yeast. Langmuir isotherm model fits the equilibrium data, at all the studied
temperatures, better than the other isotherm models which indicates monolayer dye biosorption process. The highest monolayer
biosorption capacity was found to be 2.27 × 10−3 mol/g at 303 K. The calculated thermodynamic parameters (ΔG, ΔS, ΔH) showed the biosorption process to be spontaneous and exothermic in nature. Amine or amino, amide, carboxyl, phosphate groups
are responsible for the dyes biosorption based on the result of Fourier transform infrared analysis. 相似文献
17.
R. Donat G. K. Cılgı S. Aytas H. Cetisli 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(1):271-280
This paper discusses the sorption properties for U(VI) by alginate coated CaSO4·2H2O sepiolite and calcined diatomite earth (Kieselguhr) (ACSD). The removal of U(VI) from aqueous solution by sorption onto
ACSF in a single component system with various contact times, pH, temperatures, and initial concentrations of U(VI) was investigated.
The sorption patterns of uranium on the composite adsorbent followed the Langmuir, Freundlich and Dubinin-Radushkhevic (D-R)
isotherms. The Freundlich, Langmuir, and D-R models have been applied and the data correlated well with Freundlich model and
that the sorption was physical in nature (sorption energy, E
a
= 17.05 kJ/mol). The thermodynamic parameters such as variation of enthalpy ΔH, variation of entropy ΔS and variation of Gibbs free energy ΔG were calculated from the slope and intercept of lnK
0 vs. 1/T plots. Thermodynamic parameters (ΔH
ads = 31.83 kJ/mol, ΔS
ads = 167 J/mol·K, ΔG
o
ads (293.15 K) = −17.94 kJ/mol) showed the endothermic heat of sorption and the feasibility of the process. The thermodynamics
of U(VI) ion/ACSD system indicates the spontaneous and endothermic nature of the process. It was noted that an increase in
temperature resulted in a higher uranium loading per unit weight of the adsorbent. 相似文献
18.
Yating Liu Yunhai Liu Xiaohong Cao Rong Hua Youqun Wang Cui Pang Ming Hua Xiaoyan Li 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(2):231-239
The cross-linked chitosan (CS) gels synthesized by using glutaraldehyde (GLA), epichlorohydrin (EC), and ethylene glycol diglycidyl
ether (EGDE) as cross-linkers respectively were used to investigate the adsorption of U(VI) ions in an aqueous solution. The
pure chitosan (PCS) and the cross-linked chitosan gels were characterized by FTIR and SEM analysis. The kinetic, thermodynamic
adsorption and adsorption isotherms of U(VI) ions onto unmodified and modified cross-linked chitosan were studied in a batch
adsorption experiments. The effect of pH, contact time and temperature on the adsorption capacity were also carried out. At
the optimum pH, the maximum adsorbed amount of PCS, GLACS, ECCS and EGDECS were 483.05, 147.05, 344.83 and 67.56 mg/g, respectively.
The uranium (VI) adsorption process of PCS and ECCS followed better with pseudo-second-order kinetic model, while GLACS and
EGDECS followed pseudo-first-order kinetic model well. The results obtained from the equilibrium isotherms adsorption studied
of U(VI) ions were analyzed in two adsorption models, namely, Langmuir and Freundlich isothms models, the results showed that
the Langmuir isotherm had better conformity to the equilibrium data. The thermodynamic parameters such as enthalpy (ΔHo), entropy (ΔSo), and Gibbs free energy (ΔGo) showed that the adsorption process was both spontaneous and endothermic. 相似文献
19.
L. A. Kochergina A. V. Emel’yanov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(10):1742-1747
Heats of reaction of glycylglycine with nitric acid and potassium hydroxide solutions are determined by two calorimetric procedures
at 288.15, 298.15, 308.15 K and an ionic strength of solution of 0.25, 0.50, and 0.75 in the presence of KNO3. Standard thermodynamic characteristics (Δr
H°, Δr
G°, Δr
S°, and Δp
C°) are calculated for the acid-base reactions in aqueous peptide solutions. The effects of the concentration of background
electrolyte and temperature on the heats of dissociation of glycylglycine are considered. 相似文献
20.
Yones Khazaei Hossein Faghihian Mahdi Kamali 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(2):529-536
Adsorptive behavior of natural clinoptilolite was assessed for removal of thorium from aqueous solutions. Natural zeolite
was characterized by X-ray diffraction and X-ray fluorescence. The zeolite sample composed mainly of clinoptilolite. Na-exchanged
form of zeolite was prepared and its sorption capacity for removal of thorium from aqueous solutions was examined. The effects
of relevant parameters, including initial concentration, contact time, solid to liquid ratio, temperature and initial pH on
the removal efficiency were investigated in batch studies. The pH strongly influenced thorium adsorption capacity and maximal
capacity was obtained at pH 4.0. Kinetics and isotherm of adsorption were also studied. The pseudo-first-order, pseudo-second-order,
Elovich and intra-particle diffusion models were used to describe the kinetic data. The pseudo-second-order kinetic model
provided excellent kinetic data fitting (R
2 > 0.999) with rate constant of 1.25, 1.37 and 1.44 g mmol−1 min−1 respectively for 25, 40 and 55 °C. The Langmuir and Freundlich models were applied to describe the equilibrium isotherms
for thorium uptake and the Langmuir model agrees very well with experimental data. Thermodynamic parameters were determined
and are discussed. 相似文献