research article solid-phase extraction of trace amounts...

Hindawi Publishing CorporationJournal of ChemistryVolume 2013 Article ID 671564 10 pageshttpdxdoiorg1011552013671564

Research ArticleSolid-Phase Extraction of Trace Amounts of Uranium(VI) inEnvironmental Water Samples Using an Extractant-ImpregnatedResin Followed by Detection with UV-Vis Spectrophotometry

Ahmad Hosseini-Bandegharaei Masoud Sarwghadi Aliasghar HeydarbeigiSeyyed Hossein Hosseini and Mehdi Nedaie

Water Division Department of Engineering Kashmar Branch Islamic Azad University 96716-97718 Kashmar Iran

Correspondence should be addressed to Ahmad Hosseini-Bandegharaei ahoseinibyahoocom

Received 19 May 2013 Revised 14 September 2013 Accepted 19 September 2013

Academic Editor Daryoush Afzali

Copyright copy 2013 Ahmad Hosseini-Bandegharaei et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

A stable extractant-impregnated resin (EIR) containing Chrome Azurol B was prepared using Amberlite XAD-2010 as aporous polymeric support The new EIR was employed for trace separation and preconcentration of U(VI) ion followed byspectrophotometric determination with the arsenazo III procedure CABXAD-2010 exhibited excellent selectivity for U(VI) ionover coexisting ions Experimental parameters including pH contact time shaking speed and ionic strength were investigatedby batch extraction methods Maximum sorption of U(VI) ions occurred at pH 43ndash69 The capacity of EIR was found to be0632mmolsdotgminus1 Equilibriumwas reached in 25min and the loading half-time t

12

was less than 6minThe equilibrium adsorptionisotherm of U(VI) was fitted with the Langmuir adsorption model In addition a column packed with CABXAD-2010 was usedfor column-mode separation and preconcentration of U(VI) ion For the optimization of the dynamic procedure effects of samplevolume sample and eluent flow rate eluent concentration and its volumewere investigatedThe preconcentration factors for U(VI)were found out to be 160 But for convenience a preconcentration factor of 150 was utilized for the column-mode preconcentrationThe dynamic procedure gave a detection limit of 50 times 10minus10molsdotLminus1 (012120583gsdotLminus1) for U(VI) ion The proposed dynamic methodshowed good performance in analyzing environmental water samples

1 Introduction

Nowadays a great attention is paid to the analytical mon-itoring of uranium in environmental samples due to itsserious toxic effects even at low concentrations [1 2] Amongthe eminent techniques developed for the determination ofuranium in environmental samples [3ndash7] preconcentrativeseparation of trace amounts of uranium from these samplesfollowed by spectrophotometric determination using arse-nazo III procedure has attracted much attention in the lastdecades [8ndash13] This fact is due to availability easy operationand relative low operational and instrumental costs

Solid-phase extraction (SPE) has come to the forefrontcompared with other preconcentration techniques becauseof the development of solid adsorbents including chelatingpolymeric supports and the advantages in the use of these

adsorbents in metal ions preconcentration SPE offers severalimportant advantages such as [12ndash18] the following

(i) higher enrichment factors(ii) absence of emulsion(iii) safety with respect to hazardous samples(iv) minimal costs due to low consumption of reagents(v) flexibility(vi) ease of automation

In addition several properties such as selectivity sim-plicity of equipment ease of operation and the possibility ofusing adsorbents for many separation and preconcentrationcycles without losses in the metal ion sorption capacity havemade their use popular

2 Journal of Chemistry

Extractant-impregnated resins EIRs have recently beendeveloped for designing chelating polymeric supports andseparating transition metal ions from aqueous mediabecause the preparation of chelating polymeric ion exchang-ers with chelating ligand connected to the polymer matrix bychemical bonds is usually very complex time consuming andcostlyThe preparation of chelating polymeric ion exchangersby the impregnation methods is exceedingly easy to performmerely requiring stirring of an adequate extractant andthe polymeric support In addition there is a wide choiceof reagents for desired selectivity [19ndash26] Therefore bypreparing a stable impregnated resin one can combine thespecific properties of an extractant such as its selectivity withthe advantages of solid-ion-exchange technology for process-ing highly diluted solutions Consequently the extractant-impregnated resins (EIRs) are more suitable than conven-tional solvent extraction for recovering a specified metal ionwith high selectivity Among the studies concerning EIRsseveral studies have been reported for polymeric supportsin which an inert support is impregnated with a selectiveorganic extractant to produce a solid sorbent used to separateand preconcentrate U(VI) from various analytical matrices[12 13 23ndash26]

In the followup of our group researches on the EIRs appli-cations [12 13 27ndash31] this work focuses on the selective sep-aration and preconcentration of trace amounts of uranium invarious environmental water samples using a new EIR con-taining Amberlite XAD-2010 resin beads impregnated withChrome Azurol B Our new EIR sorbent showed excellentselectivity for U(VI) sorption from aqueous solutions TheadsorbedU(VI) ions stripped easily with 050MHCl solutionand the regenerated EIR could be used in subsequent cyclesfor U(VI) separation and preconcentration In this paperperformance testing of the newEIR for solid-phase extractionof uranium is discussed

2 Experimental

21 Reagents and Apparatus Deionized water was usedto prepare all solutions Unless stated all solventsand reagents used were analytical reagent grade andpurchased from Merck (Darmstadt Germany) Stockstandard solution of U(VI) was prepared by dissolvingthe appropriate amounts of uranyl nitrate in deionizedwater acidified with a small amount of HNO

3

Thesolutions of uranium(VI) were standardized gravimetrically(as U

3

O8

) Buffer solutions of pH 1ndash3 4ndash6 and 7ndash9were prepared by mixing appropriate ratios of 01MHCl and KCl 05M acetic acid and ammonium acetateand 05M ammonia and NH

4

Cl solutions respectivelyChrome Azurol B (Chromazurol B Mordant Blue 1 CIMordant Blue 1 CI Mordant Blue 1 free acid EriochromeBlue SBB Eriochrome Azurol B free form EriochromeAzurol 6B free form EINECS 239-098-7) CAB (4-[(3-Carboxy-5-methyl-4-oxo-1-cyclohexa-25-dienylidene)(26-dichlorophenyl)methyl]-2-hydroxy-3-ethylbenzoic acid)and Amberlite XAD-2010 (surface area of 660m2 gminus1 porediameter 280 nm and bead size 20ndash60 mesh) were obtained

from Sigma Chem Co St Louis The surface area porediameter and mesh size of the resin were quoted by thesupplier

For the determination of U(VI) in solutions using arse-nazo III procedure adsorption measurements were recordedon a Shimadzu double-beams UV-Vis (2150-PC Japan) spec-trophotometer equipped with quartz cuvettes of 1 cm thick-ness The pH measurements were made on a model PHS-3BW pH-meter (Bel Italy) A Fine PCR automatic shakermodel SH30L-t Korea was used for the batch experimentsThe flow of sample and eluent solutions through the shortcolumn was controlled with a BT100-1L peristaltic pumpand a DG-2 head pump (Longer pump China) A Sartoriusmembrane filter of pore size 045 120583m was used to removeparticles in analysis of real samples

22 Preparation of the EIR The dry procedure was usedfor preparing CAB-impregnated XAD-2010 resin beads [29]Before the impregnation process Amberlite XAD-2010 resinbeadswere treatedwith 1 1methanol-water solution contain-ing 6MHCl for 12 h in order to remove remainingmonomersand other types of impurities which may be found withthe fabricated beads The resin was thoroughly rinsed withdoubly-distilled water and placed into a drying oven at 323Kfor 30min To prepare the impregnated resin portions ofAmberlite XAD-2010 resin (1 g of dry resin) were transferredinto a series of glass stoppered bottles containing differentconcentrations of CAB in 200mL methanol which was usedas the solvent The mixtures were slowly shaken for 10 hto complete the impregnation process and then heated at333 K in a drying oven to remove the solvent Each EIRsample was then transferred to a porous filter and washedsuccessively with HCl (3M) solution and large amountsof distilled water until no CAB was found in the filtratespectrophotometrically Finally the impregnated resins weredried at 323K andweighedThe amount of CAB impregnatedonin the resin beads was determined from theweight changeof polymeric resin To avoid surface peeling and crackingwhich cause the leaching of some extractant molecules fromthe resin beads the prepared EIR beads were stored underdeionized water in a stoppered glass bottle

23 Sorption Procedures

231 Static Sorption of U(VI) Ions A batch technique wasused to sorb the U(VI) ions at 298 plusmn 1KThe 100mL aliquotsof aqueous solution containing suitable concentrations ofU(VI) were taken in glass-stoppered bottles and adjusted toa known pH The CAB-impregnated XAD-2010 resin beads(0150 g) were added to each bottle and the mixtures wereequilibrated for a fixed period of time The EIR beads werefiltered and the sorbed U(VI) ions were desorbed by shakingwith 5mL of 050M HCl The desorbed U(VI) ions weremeasured spectrophotometrically by the arsenazo III pro-cedure described in Section 24 For adsorption equilibriumstudies the mixtures were shaken at a fixed temperatureusing a temperature controlled shaker set at 180 rpm for aperiod of desired time at the optimum pH value and desired

Journal of Chemistry 3

ionic strength After that the suspensions were filtered andthe filtrates were analyzed spectrophotometrically by thearsenazo III procedure described in Section 24The amountsof uranium adsorbed per gram of the EIR beads werecalculated at various time ldquo119905rdquo (119902

119905

) and at equilibrium (119902119890

) bythe mass balance equations

119902

119905

=

(119862

0

minus 119862

119905

) 119881

119898

119902

119890

=

(119862

0

minus 119862

119890

) 119881

119898

(1)

where 119902119905

is the amount of the uranium adsorbed onto the EIRbeads at time ldquo119905rdquo (mgsdotgminus1) 119902

119890

the amount of the uraniumadsorbed onto the EIR beads at equilibrium (mgsdotgminus1) 119862

0

the initial concentration of U(VI) in the aqueous solutions(mgsdotLminus1) 119862

119905

the U(VI) concentration remaining in the solu-tions at time ldquo119905rdquo (mgsdotLminus1) 119862

119890

the equilibrium concentrationof U(VI) in the solutions (mgsdotLminus1) 119881 the volume of thesolutions used (119871) and 119898 the weight of the EIR beads usedin g

232 Dynamic Sorption of U(VI) Ions Five hundred mil-ligrams of new EIR was slurried in water and then packedinto a polyethylene column with an internal diameter of04 cm The ends were fitted with a small amount of glasswool to keep the EIR beads inside of the column and toprevent any loss of the EIR beads during the sample runningThe bed length of EIR in the column was about 32mmWorking solutions containing U(VI) metal ion with theconcentration exceeding the detection limit prepared inwhich the pH and ionic strength were respectively adjustedto 45 and 01M using the acetic acid and ammonium acetatesolutions and passed through the column at a known flowrate After this step stripping experiments were performedFor this purpose the column was washed with distilled water(5mL) and then 5mL of 050mol Lminus1 HCl was used tostrip U(VI) ions The desorbed metal ions were analyzedspectrophotometrically by arsenazo III procedure describedin Section 24

24 Spectrophotometric Arsenazo III Method for the Deter-mination of U(VI) The arsenazo III procedure was utilizedfor the determination of U(VI) in solutions [32] A pH 20buffer solution of KClHCl was prepared by mixing 81mLof 020mol Lminus1 HCl and 419mL of 02mol Lminus1 KCl solutionsand diluting to 100mL with doubly-distilled water A reagentblank solution containing arsenazo III 1 (wv) and buffersolution was freshly prepared before each measurementWorking solutions (25mL) containing U(VI) + 02mL ofarsenazo III solution + 20mL of buffer solution were dilutedto 50mL with distilled water and measured at 6530 nm

3 Results and Discussion

31 Preparation of CAB-Impregnated Resin Chrome AzurolB (CAB) is one of the triphenylmethane dyes It is a dicar-boxylic acid with molecular formula of C

23

H16

Cl2

O6

(struc-ture is shown in Figure 1) It is slightly soluble in alcoholsoluble in water and gives a reddish orange color solution

HO

O

O

O

Cl Cl

OH

OH

Figure 1 Molecular structure of CAB

This solution turns blue violet at pH 13 (595 nm) It is a highlysensitive colorimetric reagent for Fe(III) and is utilized forthe determination of the iron content in blood serum at pH44ndash55 in the presence of cetyltrimethylammonium bromide[33 34] The dye has been utilized for spectrophotometricdetermination of protein (human serum albumin) usingChromAzurol B-beryllium(II) complex bymanual and flow-injection methods [35] Also it has been used as a precipitat-ing reagent in the presence of a nonionic surfactant (TritonX-100) for preparing a membrane and its application toeffective collection of iron(III) from homogeneous aqueoussolutions [36]

In the current study CAB was impregnated ontointoAmberlite XAD-2010 which is used for the preconcentrationand isolation of organic materials at trace levels The resinalso has been used as a polymeric support for solid-phaseextraction and preconcentration of certain metal ions [37ndash39]

To prepare the appropriate formof the EIR the impregna-tion process was carried out at various impregnation ratios (gCABg dry polymer adsorbent) Figure 2 depicts the weightchange obtained against theCAB concentration afterwashingthe EIR with HCl and distilled water A maximum weightchange (1508) was found at the concentrations more than250 g CAB per 200mLmethanol which was used for the EIRpreparation

32 Stabilizing Extractant Capacity Impregnated on the Poly-mer The impregnation of porous matrices leads to theimmobilization of the extractant both in pores and in the gelregions of the polymer beads The impregnating extractantlocated in the pore volume is weakly retained by the polymer(mainly due to the capillary forces) and can be easily leachedout from the freshly prepared EIR samples during the firstdays of its use (unstable part of EIR capacity)The impregnat-ing extractant taken up by the gel regions of the matrix repre-sents the most stable part of the EIR capacity which remainspractically constant for a long period [40 41]Thus for stabi-lizing the EIR capacity (the amount of extractant impregnatedon the resin) several sorption-desorption cycles were carriedout by treating the EIR samples obtained in Figure 2 (EIRsample with maximum impregnated extractant 151 g CAB


CABresin ratio (gg)

Wei

ght c

hang

e of r

esin

()

160

140

120

100

80

60

40

20

000 05 10 15 20 25 30

Figure 2 Effect of CABresin ratio (g CABg dry resin) on theEIR preparation at the conditions in which portions of 1 g of thedry polymer beads of Amberlite XAD-2010 were subjected to theimpregnation process in 200mL methanol

per 1 g XAD-2010 resin beads) with 100mL aliquots of U(VI)solution having high concentration (001M at the optimumpH and ionic strength) and 10mL aliquots of HCl 2mol Lminus1solution as eluent The sorption-desorption cycles lead tothe gradual removal of the extractant molecules from thepore volume of the polymer matrixThe experiments showedthat after 13 sorption-desorption cycles the impregnatedextractant capacity of EIR was constant Figure 3 showsthe decreasing impregnating extractant capacity (decreasingextractant weight percent impregnated onto 1 g XAD-2010resin) on the resin against the number of sorption-desorptioncycles In addition Figure 3 shows that the impregnatingextractant molecules which were mainly retained due to thecapillary forces on the EIR samples were leached out after13 cycles of U(VI) sorption-desorption and final washingthe EIR samples with HCl 4molsdotLminus1 and distilled water AlsoFigure 3 depicts that almost 369of impregnating extractantcapacity immobilized on the untreated EIR prepared at themaximum impregnating ratio leach out from the EIR beadsby 13 cycles of sorption and desorption Hence themaximumweight change is 951 (1508 in untreated EIR) which canobtain at the concentrations more than 625 g CAB per 1 Lmethanol

The chemical stability of the EIR was examined bysequentially suspending a 0150-g portion of the EIR indifferent pHs and shaking for 10 h After filtering the solutionsand rinsing the EIR with distilled water the released amountof CAB in solution was examined spectrophotometricallyThe EIR demonstrated high chemical stability since noquantity of CAB was released into the solutions

33 Effect of pHand Ionic Strength onU(VI) Sorption ontointoNew EIR Initially these experiments were carried out toselect the optimum sorption medium Buffer solutions of pH

Number of sorptiondesorption cycles

Wei

ght c

hang

e of r

esin

()

170

150

130

110

90

700 5 10 15 20 25

Figure 3 Stabilizing impregnating extractant capacity on the resinweight change after stabilizing extractant content of EIR beads bycarrying out sorption-desorption cycles

pH

Reco

very

()

120

90

60

30

00 2 4 6 8 10

Figure 4 Effect of pH on the recovery percent of U(VI) using100mL of model solutions of 100120583g Lminus1 U(VI) containing 0150 g ofthe EIR at 298 plusmn 1K

1ndash8 were used to measure the pH effect on the sorption ofU(VI) ionsThe concentration and volume ofU(VI) solutionsused for this study were 100 120583g Lminus1 and 100mL at 298 plusmn 1KThe adsorbent dosage was 0150 g of dry EIR at maximumimpregnation ratio (095 gCABg dryXAD-2010)The shakerspeed was 180 rpm and time contact was about 30min Theresults are shown in Figure 4 The sorption increases withincreasing pH of sorptive solution and attains a maximumvalue at pH 42ndash47 This indicates that the sorption processinvolves the release of H+ ions to allow the firm complexationof U(VI) ions to CABXAD-2010 at the optimum pH At thelow pHs the release of H+ ions was not efficient because of


the low acidic dissociation constant of Chrome Azurol BHowever the amount of metal ions sorbed decreased whenpH was very high This may be due to the hydrolysis ofthe U(VI) metal ions in high pH solutions [25] Because ofthese considerations the buffer pH of 45 was selected forsubsequent investigations

The effect of ionic strength on the sorption process wasalso studied at the presence of sodium nitrate within the con-centration range 001ndash040molsdotLminus1 For this purpose 100mLaliquots of U(VI) solution (pH 45) having concentrationof 100 120583g Lminus1 U(VI) were treated with 0150-g portions ofEIR at 298 plusmn 1K and different ionic strengths It was foundthat the sorption efficiencies were diminished at the ionicstrength values greater than 03mol Lminus1 This behavior isalmost predictable since by increasing the ionic strengththe salt effect is enhanced and consequently the sorptionprocess is inhibited Hence the ionic strength did not exceed03molsdotLminus1 at subsequent investigations

34 Effect of Shaking Speed on U(VI) Ions Sorption Sorptionof metal ions as a function of shaking speed was studied inthe range of 30ndash200 rpm The aliquots of 100mL of U(VI)solution having concentration of 100 120583g Lminus1 were treatedwith 0150-g portions of EIR at the optimum conditions Itwas found that percent sorption increases with increasingshaking speed and attains a maximum sorption at 180 rpmFor further studies shaking speed of 180 rpm was employedfor U(VI) ions sorption in batch experiments

35 Effect of Contact Time on U(VI) Ions Sorption Thesorption of U(VI) ions ontointo EIR was studied as afunction of shaking time Sorption process was very rapidand 11990512

is smaller than 6min Also 25min was found tobe sufficient time to attain maximum sorption of U(VI)ions ontointo new EIR The fast kinetics of resin-metalinteraction at optimum pH (45) may be attributed to betteraccessibility of the chelating sites of the modified resin formetal ions Beyond 25min no increase in percent sorptionwas observed therefore for further investigations 25minagitation time was applied Also this fast equilibration ratemay be related to the large surface area and pore size ofAmberlite XAD-2010 Accordingly the EIR can be applied tocolumn separation and preconcentration of U(VI) ions

36 Sorption Capacity The sorption capacity of the Amber-lite XAD-2010 resin impregnatedwith CAB for the extractionof uranium was also determined Increasing amounts ofuranium were added to 0150 g of impregnated resin Thesorption curve (not shown) appears to be linear in the rangeof 15 times 10minus6ndash15 times 10minus4mol of U(VI) per 1500mL and itreaches a plateau at maximum sorption capacity that is0632mmol Uraniumg EIR at pH 45 To compare the sorp-tion capacity of the EIR with that of nonimpregnated Amber-lite XAD-2010 the sorption capacity of the nonimpregnatedAmberlite XAD-2010 resin also was determined at theabove mentioned concentrationsThe results showed that thesorption capacity of the nonimpregnated Amberlite XAD-2010 resin was negligibleThis indicates that CABXAD-2010

Table 1 Effect of type and concentration of eluting acid on recoveryof U(VI) ions (119899 = 3)

Eluent Volume (mL) Concentration (M) Recovery ()HNO3 10 05 831HNO3 10 10 875HCl 10 10 989HCl 10 05 989HCl 5 10 988HCl 5 05 989HCl 5 04 946H2SO4 10 05 923H2SO4 5 10 940H2SO4 5 20 938HAC 10 05 381HAC 10 10 408

resin could be used as a good sorbent for preconcentration ofuranium in the trace concentration range

37 Desorption Studies Various mineral acids were studiedas eluent to investigate their efficiency for desorbing andseparating U(VI) ions from the EIR using different volumesand concentrations of each eluent The results were sum-marized in Table 1 It was found that 5mL of 050molsdotLminus1HCl was sufficient for quantitative recovery of U(VI) ionsTherefore 5mL of 050molsdotLminus1 HCl specified as the eluentfor desorption of metal U(VI) ions from EIR and was usedfor the subsequent studies

38 Adsorption Equilibrium Studies Equilibrium propertiesof adsorption systems are usually expressed as adsorptionisotherms Adsorption isotherm is a function that correlatesthe amount of metal ion adsorbed per unit weight of theadsorbent 119902

119890

(mgsdotgminus1) and the equilibrium concentrationof metal ion in bulk solution 119862

119890

(mgsdotLminus1) at a given tem-perature The isotherm function deals with the adsorptionmodel which is an important physicochemical feature forthe description of how metal ions interact with active sitesin the adsorbent surface The adsorption model is critical inevaluating the basic characteristics of a good adsorbent Inan EIR system the adsorption process results in the sorptionof metal ions from the solution onto the polymeric matrixuntil the remaining metal ions in the solution are in dynamicequilibrium with metal ions on the EIR surface At equilib-rium there is a finite distribution of the metal ion betweenthe solution and EIR phase which can be described by manyisotherms and adsorption models that can be used to fitthe observed experimental data and determining the modelparametersThree isotherm equations have been tested in thepresent study namely Langmuir [42] Tempkin and Pyzhev[43] and Freundlich [44] These isotherm equations arerepresented by the following

Langmuir isotherm

119902

119890

=

119902max1198871198621198901 + 119887119862

119890

(2)


Ceq

e(m

gmiddotLminus

1m

gmiddotgminus

1)

100

075

050

025

0000 50 100

Ce (mgmiddotLminus1)

(a)

25

2

15

1

05

0minus15 minus05 05 15 25

logCe

logqe

(b)

qe

(mgmiddot

gminus1)

lnCe

200

150

100

50


(c)

Figure 5 Langmuir (a) Freundlich (b) and Tempkin (c) adsorption isotherms for U(VI) adsorption by EIR (pH 45 and temperature 298K)

freundlich isotherm

119902

119890

= 119870

119865

119862

1119899

119890

(3)

tempkin isotherm

119902

119890

=

RT119887

(ln119870119879

119862

119890

) (4)

The linear form of the Langmuir Freundlich and Temp-kin isotherms can be expressed by (5)ndash(7) respectivelyConsider

119862

119890

119902

119890

=

119862

119890

119902max+

1

119887119902max (5)

log 119902119890

= log119870119891

+

1

119899

log119862119890

(6)

119902

119890

= 119861 ln119870119879

+ 119861 ln119862119890

(7)

where 119862119890

is the equilibrium concentration (mgsdotLminus1) 119902119890

is theadsorption capacity at equilibrium (mgsdotgminus1) 119902max (mgsdotgminus1)represents the maximum adsorption capacity 119887 (Lsdotmgminus1)relates the energy of adsorption119870

119891

indicates relative adsorp-tion capacity (mg1minus(1119899)sdotL1119899sdotgminus1) 119899 is an empirical parameterrelated to the intensity of adsorption 119861 is the Tempkinconstant related to the heat of adsorption (119861 = RT119887) and119870

119879

is the equilibrium binding constant (Lsdotgminus1) corresponding tothe maximum binding energy

Table 2 Parameters of the Langmuir and Freundlich isothermmodels for the adsorption of U(II) ion by CAB-impregnated XAD-2010

Isotherm model MagnitudeLangmuir119902max (mgsdotgminus1) 1562119887 (Lsdotmgminus1) 4885 times 10

minus2

119877

2 09998Freundlich119870

119865

(mg1minus(1119899)sdotL1119899sdotgminus1) 5102119899 3323119877

2 08181Tempkin119861 2241119870

119879

(Lsdotgminus1) 16013119877

2 09641

The isotherm plots were drawn using (5)ndash(7) and theresulted plots are depicted in Figure 5 The values ofisotherms parameters are presented in Table 2 As seen fromTable 2 and Figure 5 the Langmuir isotherm shows a highercorrelation coefficient and a better fit to adsorption data thanthe other isotherm equations This explains the suitability ofLangmuir model for describing the adsorption equilibriumof U(VI) onto CABXAD-2010


The Langmuir adsorption isotherm is based on theassumption that all adsorption sites are equivalent and thatadsorption in an active site is independent of whether theadjacent sites are occupied or notThe fact that the Langmuirisotherm fits the experimental data very well may be due tohomogenous distribution of extractant molecules or activechelating sites on the polymeric surface since the Langmuirequation assumes that the adsorbent surface is homogenous[28]

39 Dynamic Sorption

391 Effect of Column Flow Rate on Sorption and DesorptionThe effect of column flow rate on the sorption of U(VI)was separately studied in the range of 1ndash18mLminminus1 using1 L of solution with U(VI) concentration of 10 120583g Lminus1 at thepH chosen for maximum sorption for both metal ions Theoptimum flow rates for U(VI) absorption were 11mLminminus1(Figure 6) Therefore a flow rate of 11mLminminus1 was selectedfor further studies in the preconcentration of U(VI) ionsOptimum column desorption flow rates were investigatedusing 5mL of the recommended eluent solution 050molsdotLminus1HCl after loading the column with 1 L of sample solutionswith concentration of 10 120583g Lminus1 with respect to U(VI) fol-lowed by rinsing the column with 5mL double-distilledwater Figure 6 shows that optimum flow rate for desorptingU(VI) is 05mLminminus1

392 Effect of Sample Volume and Preconcentration FactorSince the concentrations of uranium in real samples are lowthe amounts of uranium in these samples should be taken intosmaller volumes for high preconcentration factor Thereforethe limit of preconcentration was determined by increasingthe dilution of the U(VI) ion in solution keeping the totalamount of loaded U(VI) ion at 10 120583g Adsorbed metal ionswere stripped (desorbed) with the optimum concentrationand volume of specified eluent Complete recovery can becarried out from solutions with volumes up to 1600mLwith a recovery of gt98 yielding in the preconcentrationfactor of 160 Thus for convenience the sample volume of1500mL (the preconcentration factor of 150) was chosen forthe column-mode separation and preconcentration of U(VI)ions

In order to determine the detection limit of the proposeddynamic method 1500mL aliquots of blank solutions wereadjusted to optimized conditions and passed through thecolumn After eluting the column and determining uraniumthe detection limit of the procedure (based on 3120575 of theblank solution 119899 = 8) was found to be 50 times 10minus10molsdotLminus1(012 120583gsdotLminus1)

310 Effect of Foreign Ions Theperformance of the techniquefor the quantitative separation and preconcentration ofU(VI)ions in the presence of foreign cations and anions wasinvestigated by measuring the recovery () of U(VI) underoptimized conditions For this purpose 1500mL aliquots ofU(VI) solution with concentration of 70120583g Lminus1 were takenwith different amounts of foreign ions and the recommended

Reco

very

()

SampleEluent

110

90

70

50

300 5 10 15 20

Flow rate (mL minminus1)

Figure 6 Effect of sample and eluent flow rates on the recoveryof U(VI) using 1 L of model solution of 10 120583g Lminus1 U(VI) elutingwith 5mL eluent solution of 050MHClThe data presented are theaverage of five experiments

Table 3 Effect of foreign ions on the determination of 70 120583g ofU(VI) in 1500-mL aliquots of the solution

Foreign ion Tolerance ratioNa+ K+ Mg2+ Ca2+ Ba2+ Zn2+ NH4

+ ClminusIminus Co2+ Sr2+ 5000

SO42minus Pb2+ CrO4

2minus Mn2+ Cd2+ 3000MoO4

2minus Citrate 1000Ag+ 500Ni2+ 300a

Ce3+ 200Th4+ 200b

Cu2+ 150a

Zr4+ La3+ 100Fe3+ 80Ni2+ 5Cu2+ 2Th4+ 1aIn the presence of potassium cyanide (1 times 10minus3M)bIn the presence of EDTA (1 times 10minus3M)

column-mode procedure was followed The tolerance limitwas defined as the highest ratio of foreign ions that producedan error not exceeding plusmn5 in the determination of U(VI)ions by the combination of the column solid-phase extractionand arsenazo III method as described above The seriousinterference from Ni(II) and Cu(II) was avoided by maskingwith potassium cyanide [45] whereas the interference dueto Th(VI) was removed by adding EDTA [46] The toleratedamounts of the foreign ions are given in Table 3 The results


Table 4 Application of the proposed method for the determination of U(VI) in 1500 aliquots of environmental water samples

Sample Added (120583g Lminus1) Found (120583g Lminus1) Recovery ()00 14 (29)a mdash

Spring water 20 33 (26) 970(Ghazi Spring) 50 62 (27) 969

100 110 (26) 965200 207 (26) 96700 57 (23) mdash

River water 20 78 (22) 1013(Shesh-Taraz) 100 158 (22) 1006

200 259 (19) 1007300 356 (20) 997000 mdash mdash

Well water 1000 98 (19) 980(Argha) 2000 196 (17) 980

3000 293 (13) 9774000 391 (12) 978

aRSD of five replicate measurements

Table 5 Results of the accuracy test of proposed method for U(VI) determination in two geological standard reference materials

Samples U(VI) content (120583g gminus1) Found (120583g gminus1) Recovery ()JG-1aa 47 463 (31)b 986JR-1a 89 881 (30)b 990aThe treatments were carried out on 05 g of the sample

b RSD of five replicate measurements

show that the proposedmethod can be adequately applied forthe selective determination of U(VI) in the aqueous samples

311 Application of Proposed Method for Natural Water Sam-ples Theproposedmethod was applied to the determinationof U(VI) in natural water samples including spring well andriver water samples that they were isokinetically collected inpolyethylene bottles from different areas of Kashmar a cityin Iran Khorasan Razavi provinceThese water samples werepassed through amembrane filter with a pore size of 045mmto remove their particulates and then pH was brought to45 By adding sufficient amounts of potassium cyanide andEDTA as masking agents their concentration reached upto 10 times 10minus3M Then 1500mL aliquots of the sampleswere subjected to the recommended dynamic procedure Arecovery test was also performed by determining the spikedamounts of U(VI) to the samples The obtained results aresummarized in Table 4 As observed from the results therecoveries for the various amounts spiked to the samplesolutions were in the range 961ndash1013 which reflect thesuitability of the present EIR as a preconcentration tool beforeactual measurement of U(VI) in contaminated water samplesusing arsenazo III method

312 Application of Proposed Method for Standard GeologicalSamples For testing the accuracy of the measurements twomodel solutions were prepared just according to the compo-sition of JG-1a and JR-1 (Geological Survey of Japan reference

samples) by precisely following the literature considerations[47]The results of the expected and found values are detailedin Table 5The agreement between found and expected valuesdemonstrated that the described method was accurate fortrace analysis of U(VI) in the complex matrices

4 Conclusions

Chrome Azurol B-impregnated XAD-2010 resin beads wereprepared and used for solid-phase extraction and preconcen-tration of U(VI) in various environmental water samplesTheproposed procedure for the determination of trace amountsof U(VI) ions combines preconcentration of the analyte withspectrophotometric measurement with the arsenazo III pro-cedure The sorption equilibrium data were analyzed usingwidely used isotherm models The Langmuir isotherm gavethe best fit of the experimental equilibrium data Thus thedistribution of extractant molecules on the polymeric surfaceis homogenous and the adsorption process is monolayerTheoptimized experimental parameters for the new solid-phaseextraction system have been summarized in Table 6 Thenew EIR benefits from high sorption capacities and excellentselectivity Also the proposed preconcentration method wassimple and rapid and it is a convenient and low cost oneThenew EIR had excellent selectivity for U(VI) in the complexmatrixes of geological samples and the matrix effects withthe method were reasonably tolerable The system was alsosuccessful in pre-concentrating metal ions from large sample


Table 6 Optimized experimental parameters for separation andpre-concentration of U(VI) ions by CAB-impregnated XAD-2010

Experimental parameter Optimum magnitudeBatch parameters

pH 42ndash47Ionic strength 001ndash030molsdotLminus1

Shaking speed 180 rpmContact time 25min119905

12

6minCapacity 0632mmolsdotgminus1

Concentration of eluent (HCl) 050MVolume of eluent 5mL

Dynamic parametersSample flow rate 11mLsdotminminus1

Eluent flow rate 05mLsdotminminus1

Sample volume 1600mLLOD 50 times 10

minus10molsdotLminus1

volume Overall some of the practical benefits of the newmethod include its capacity selectivity good detection limithigh preconcentration factor low cost speed convenienceand ease of regeneration of the EIR

Acknowledgments

The authors wish to thank Dr M J Mosavi (the president ofIslamic AzadUniversity-Kashmar branch Kashmar Iran) forsincere support and ProfessorMS Hosseini (BirjandUniver-sity Birjand Iran) for a great help during the experimentalworks Also they acknowledge the financial and technicalsupport provided by the Research Center of Islamic AzadUniversity-Kashmar branch Kashmar Iran

References

[1] WHO Guidelines for Drinking Water Quality WHO GenevaSwitzerland 2nd edition Addendum to vol 2 Health Criteriaand Other Supporting Information WHOEOS98 1 1998

[2] T P Rao P Metilda and J M Gladis ldquoPreconcentrationtechniques for uranium(VI) and thorium(IV) prior to analyticaldetermination an overviewrdquo Talanta vol 68 no 4 pp 1047ndash1064 2006

[3] R K Singhal U Narayanan R Karpe A Kumar A Ranadeand V Ramachandran ldquoSelective separation of iron fromuranium in quantitative determination of traces of uranium byalpha spectrometry in soilsediment samplerdquoApplied Radiationand Isotopes vol 67 no 4 pp 501ndash505 2009

[4] A R Byrne and L Benedik ldquoAn internal standard methodin a spectrometric determination of uranium and thoriumradioisotopes using instrumental neutron activation analysisrdquoAnalytical Chemistry vol 69 no 6 pp 996ndash999 1997

[5] J S Santos L S G Teixeira R GO Araujo A P FernandesMG A Korn and S L C Ferreira ldquoOptimization of the operatingconditions using factorial designs for determination of uraniumby inductively coupled plasma optical emission spectrometryrdquoMicrochemical Journal vol 97 no 2 pp 113ndash117 2011

[6] F A Aydin and M Soylak ldquoSolid phase extraction andpreconcentration of uranium(VI) and thorium(IV) on DuoliteXAD761 prior to their inductively coupled plasma mass spec-trometric determinationrdquo Talanta vol 72 no 1 pp 187ndash1922007

[7] M S Hosseini H Raissi and H R Yavari ldquoSynergistic flota-tion of U(VI)-alizarin complex with some diamines followedby spectrophotometric determination of U(VI) using 441015840-diaminophenylmethanerdquo Analytica Chimica Acta vol 559 no2 pp 181ndash185 2006

[8] D Prabhakaran and M S Subramanian ldquoSelective extractionand sequential separation of actinide and transition ions usingAXAD-16-BTBED polymeric sorbentrdquo Reactive and FunctionalPolymers vol 57 no 2-3 pp 147ndash155 2003

[9] J Avivar L Ferrer M Casas and V Cerda ldquoSmart thoriumand uranium determination exploiting renewable solid-phaseextraction applied to environmental samples in a wide concen-tration rangerdquo Analytical and Bioanalytical Chemistry vol 400no 10 pp 3585ndash3594 2011

[10] A M Starvin and T P Rao ldquoSolid phase extractive precon-centration of uranium(VI) onto diarylazobisphenol modifiedactivated carbonrdquo Talanta vol 63 no 2 pp 225ndash232 2004

[11] P Metilda K Sanghamitra J Mary Gladis G R K Naiduand T Prasada Rao ldquoAmberlite XAD-4 functionalized withsuccinic acid for the solid phase extractive preconcentrationand separation of uranium(VI)rdquo Talanta vol 65 no 1 pp 192ndash200 2005

[12] M S Hosseini and A Hosseini-Bandegharaei ldquoCompari-son of sorption behavior of Th(IV) and U(VI) on modifiedimpregnated resin containing quinizarin with that conventionalprepared impregnated resinrdquo Journal of Hazardous Materialsvol 190 no 1ndash3 pp 755ndash765 2011

[13] A Hosseini-Bandegharaei M S Hosseini Y Jalalabadi et alldquoA novel extractant-impregnated resin containing carminic acidfor selective separation and pre-concentration of uranium(VI)and thorium(IV)rdquo International Journal of Environmental Ana-lytical Chemistry vol 93 pp 108ndash124 2013

[14] K Pyrzynska and M Trojanowicz ldquoFunctionalized cellulosesorbents for preconcentration of trace metals in environmentalanalysisrdquoCritical Reviews in Analytical Chemistry vol 29 no 4pp 313ndash321 1999

[15] J M Gladis and T Prasada Rao ldquoSolid phase extractivepreconcentration of uranium on to 57-dichloroquinoline-8-olmodified naphthalenerdquoAnalytical Letters vol 35 no 3 pp 501ndash515 2002

[16] M Ghaedi K Niknam S Zamani H Abasi Larki M Roostaand M Soylak ldquoSilica chemically bonded N-propyl kriptofix21 and 22 with immobilized palladium nanoparticles for solidphase extraction and preconcentration of some metal ionsrdquoMaterials Science and Engineering C vol 33 pp 3180ndash3189 2013

[17] M Ghaedi K Mortazavi M Montazerozohori A ShokrollahiandM Soylak ldquoFlame atomic absorption spectrometric (FAAS)determination of copper iron and zinc in food samples aftersolid-phase extraction on Schiff base-modified duolite XAD761rdquoMaterials Science and Engineering C vol 33 pp 3180ndash31892013

[18] V Dharmendra and A Krishnaiah ldquoPreconcentration separa-tion and determination of Pb(II) and Cd(II) in water sampleswith inductively coupled plasma atomic emission spectrome-ter (ICP-AES) using 3-(2-Hydroxyphenyl)-1H-1 2 4-triazole-5(4H)-thione (HTT)rdquo Journal of Chemistry vol 2013 Article ID658132 20 pages 2013


[19] R Navarro I Saucedo A Nunez M Avila and E GuiballdquoCadmium extraction from hydrochloric acid solutions usingAmberlite XAD-7 impregnated with Cyanex 921 (tri-octylphosphine oxide)rdquo Reactive and Functional Polymers vol 68no 2 pp 557ndash571 2008

[20] I Narin and M Soylak ldquoThe uses of 1-(2-pyridylazo) 2-naphtol(PAN) impregnated Ambersorb 563 resin on the solid phaseextraction of traces heavy metal ions and their determinationsby atomic absorption spectrometryrdquo Talanta vol 60 no 1 pp215ndash221 2003

[21] M H A Melo S L C Ferreira and R E Santelli ldquoDetermi-nation of cadmium by FAAS after on-line enrichment using amini column packedwithAmberlite XAD-2 loadedwith TAMrdquoMicrochemical Journal vol 65 no 1 pp 59ndash65 2000

[22] J L Cortina and N Miralles ldquoKinetic studies on heavymetal ions removal by impregnated resins containing di-(244-trymethylpentyl) phosphinic acidrdquo Solvent Extraction and IonExchange vol 15 no 6 pp 1067ndash1083 1997

[23] N Demirel M Merdivan N Pirinccioglu and CHamamci ldquoThorium(IV) and uranium(VI) sorption studieson octacarboxymethyl-C-methylcalix[4]resorcinareneimpregnated on a polymeric supportrdquo Analytica ChimicaActa vol 485 no 2 pp 213ndash219 2003

[24] S Seyhan M Merdivan and N Demirel ldquoUse of o-phenylenedioxydiacetic acid impregnated in Amberlite XAD resin forseparation and preconcentration of uranium(VI) and tho-rium(IV)rdquo Journal of Hazardous Materials vol 152 no 1 pp79ndash84 2008

[25] E Metwally ldquoKinetic studies for sorption of some metal ionsfrom aqueous acid solutions onto TDA impregnated resinrdquoJournal of Radioanalytical and Nuclear Chemistry vol 270 no3 pp 559ndash566 2006

[26] MMerdivanM ZDuz andCHamamci ldquoSorption behaviourof uranium(VI) with NN-dibutyl-N1015840-benzoylthiourea impreg-nated in amberlite XAD-16rdquo Talanta vol 55 no 3 pp 639ndash6452001

[27] M S Hosseini A Hosseini-Bandegharaei H Raissi andF Belador ldquoSorption of Cr(VI) by Amberlite XAD-7 resinimpregnated with brilliant green and its determination byquercetin as a selective spectrophotometric reagentrdquo Journal ofHazardous Materials vol 169 no 1ndash3 pp 52ndash57 2009

[28] A Hosseini-Bandegharaei M S Hosseini Y Jalalabadi et alldquoRemoval of Hg(II) from aqueous solutions using a novelimpregnated resin containing 1-(2-thiazolylazo)-2-naphthol(TAN)rdquo Chemical Engineering Journal vol 168 no 3 pp 1163ndash1173 2011

[29] M S Hosseini A Hosseini-Bandegharaei and M HosseinildquoColumn-mode separation and pre-concentration of someheavy metal ions by solvent-impregnated resins containingquinizarin before the determination by flame atomic absorptionspectrometryrdquo International Journal of Environmental Analyti-cal Chemistry vol 89 no 1 pp 35ndash48 2009

[30] M SHosseini andAHosseini-Bandegharaei ldquoSelective extrac-tion of Th(IV) over U(VI) and other co-existing ions usingeosin B-impregnatedAmberlite IRA-410 resin beadsrdquo Journal ofRadioanalytical and Nuclear Chemistry vol 283 no 1 pp 23ndash30 2010

[31] A Hosseini-Bandegharaei M S Hosseini M Sarw-Ghadi SZowghi E Hosseini and H Hosseini-Bandegharaei ldquoKineticsequilibrium and thermodynamic study of Cr(VI) sorptioninto toluidine blue o-impregnated XAD-7 resin beads and its

application for the treatment of wastewaters containingCr(VI)rdquoChemical Engineering Journal vol 160 no 1 pp 190ndash198 2010

[32] S B Savvin ldquoAnalytical use of arsenazo III Determination ofthorium zirconium uranium and rare earth elementsrdquoTalantavol 8 no 9 pp 673ndash685 1961

[33] A Garcic ldquoA highly sensitive simple determination of serumiron using chromazurol Brdquo Clinica Chimica Acta vol 94 no 2pp 115ndash119 1979

[34] A Tabacco E Moda P Tarli and P Neri ldquoAn improved highlysensitive method for the determination of serum iron usingchromazurol Brdquo Clinica Chimica Acta vol 114 no 2-3 pp 287ndash290 1981

[35] Y Fujita IMori andMToyoda ldquoSpectrophotometric determi-nation of protein with chromazurol B-beryllium(II) complex bymanual and flow-injection methodsrdquoAnalytical Sciences vol 8pp 313ndash316 1992

[36] K Ihara S-I Hasegawa and K Naito ldquoCollection of iron(III)from homogeneous aqueous solutions on membrane filtersusing Chromazurol B with Triton X-100rdquo Analytical Sciencesvol 19 no 2 pp 265ndash268 2003

[37] V N Bulut C Duran M Tufekci L Elci and M SoylakldquoSpeciation of Cr(III) and Cr(VI) after column solid phaseextraction on Amberlite XAD-2010rdquo Journal of HazardousMaterials vol 143 no 1-2 pp 112ndash117 2007

[38] C Duran A Gundogdu V N Bulut et al ldquoSolid-phaseextraction of Mn(II) Co(II) Ni(II) Cu(II) Cd(II) and Pb(II)ions from environmental samples by flame atomic absorptionspectrometry (FAAS)rdquo Journal of HazardousMaterials vol 146no 1-2 pp 347ndash355 2007

[39] A Gundogdu C Duran H Basri Senturk L Elci andM Soylak ldquoSimultaneous preconcentration of trace met-als in environmental samples using amberlite XAD-20108-hydroxyquinoline systemrdquo Acta Chimica Slovenica vol 54 no2 pp 308ndash316 2007

[40] D Muraviev ldquoSurface impregnated sulfonate ion exchangerspreparation properties and applicationrdquo Solvent Extraction andIon Exchange vol 16 no 1 pp 381ndash457 1998

[41] D Muraviev L Ghantous and M Valiente ldquoStabilization ofsolvent-impregnated resin capacities by different techniquesrdquoReactive and Functional Polymers vol 38 no 2-3 pp 259ndash2681998

[42] I Langmuir ldquoThe constitution and fundamental properties ofsolids and liquidsrdquo Journal of the American Chemical Societyvol 38 no 2 pp 2221ndash2295 1916

[43] M J Tempkin and V Pyzhev ldquoKinetics of ammonia synthesison promoted iron catalystsrdquo Acta Physiochimica URSS vol 12pp 217ndash222 1940

[44] H Freundlich ldquoUber die adsorption in lunsungenrdquo Journal ofPhysical Chemistry vol 57 pp 387ndash470 1985

[45] M N Bale and A D Sawant ldquoSolvent extraction andspectrophotometric determination of uranium(VI) withpyridine-2-carboxaldehyde 2-hydroxybenzoylhydrazonerdquoJournal of Radioanalytical and Nuclear Chemistry vol 247 no3 pp 531ndash534 2001

[46] J L Guzman Mar L Lopez Martınez P L Lopez de Alba NOrnelas Soto andV CerdaMartın ldquoMultisyringe flow injectionspectrophotometric determination of uranium in water sam-plesrdquo Journal of Radioanalytical andNuclear Chemistry vol 281pp 433ndash439 2009

[47] M J Benoliel and P Quevauviller ldquoGeneral considerations onthe preparation of water certified reference materialsrdquo Analystvol 123 no 5 pp 977ndash979 1998

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


Extractant-impregnated resins EIRs have recently beendeveloped for designing chelating polymeric supports andseparating transition metal ions from aqueous mediabecause the preparation of chelating polymeric ion exchang-ers with chelating ligand connected to the polymer matrix bychemical bonds is usually very complex time consuming andcostlyThe preparation of chelating polymeric ion exchangersby the impregnation methods is exceedingly easy to performmerely requiring stirring of an adequate extractant andthe polymeric support In addition there is a wide choiceof reagents for desired selectivity [19ndash26] Therefore bypreparing a stable impregnated resin one can combine thespecific properties of an extractant such as its selectivity withthe advantages of solid-ion-exchange technology for process-ing highly diluted solutions Consequently the extractant-impregnated resins (EIRs) are more suitable than conven-tional solvent extraction for recovering a specified metal ionwith high selectivity Among the studies concerning EIRsseveral studies have been reported for polymeric supportsin which an inert support is impregnated with a selectiveorganic extractant to produce a solid sorbent used to separateand preconcentrate U(VI) from various analytical matrices[12 13 23ndash26]

In the followup of our group researches on the EIRs appli-cations [12 13 27ndash31] this work focuses on the selective sep-aration and preconcentration of trace amounts of uranium invarious environmental water samples using a new EIR con-taining Amberlite XAD-2010 resin beads impregnated withChrome Azurol B Our new EIR sorbent showed excellentselectivity for U(VI) sorption from aqueous solutions TheadsorbedU(VI) ions stripped easily with 050MHCl solutionand the regenerated EIR could be used in subsequent cyclesfor U(VI) separation and preconcentration In this paperperformance testing of the newEIR for solid-phase extractionof uranium is discussed

2 Experimental

21 Reagents and Apparatus Deionized water was usedto prepare all solutions Unless stated all solventsand reagents used were analytical reagent grade andpurchased from Merck (Darmstadt Germany) Stockstandard solution of U(VI) was prepared by dissolvingthe appropriate amounts of uranyl nitrate in deionizedwater acidified with a small amount of HNO

3

Thesolutions of uranium(VI) were standardized gravimetrically(as U

3

O8

) Buffer solutions of pH 1ndash3 4ndash6 and 7ndash9were prepared by mixing appropriate ratios of 01MHCl and KCl 05M acetic acid and ammonium acetateand 05M ammonia and NH

4

Cl solutions respectivelyChrome Azurol B (Chromazurol B Mordant Blue 1 CIMordant Blue 1 CI Mordant Blue 1 free acid EriochromeBlue SBB Eriochrome Azurol B free form EriochromeAzurol 6B free form EINECS 239-098-7) CAB (4-[(3-Carboxy-5-methyl-4-oxo-1-cyclohexa-25-dienylidene)(26-dichlorophenyl)methyl]-2-hydroxy-3-ethylbenzoic acid)and Amberlite XAD-2010 (surface area of 660m2 gminus1 porediameter 280 nm and bead size 20ndash60 mesh) were obtained

from Sigma Chem Co St Louis The surface area porediameter and mesh size of the resin were quoted by thesupplier

For the determination of U(VI) in solutions using arse-nazo III procedure adsorption measurements were recordedon a Shimadzu double-beams UV-Vis (2150-PC Japan) spec-trophotometer equipped with quartz cuvettes of 1 cm thick-ness The pH measurements were made on a model PHS-3BW pH-meter (Bel Italy) A Fine PCR automatic shakermodel SH30L-t Korea was used for the batch experimentsThe flow of sample and eluent solutions through the shortcolumn was controlled with a BT100-1L peristaltic pumpand a DG-2 head pump (Longer pump China) A Sartoriusmembrane filter of pore size 045 120583m was used to removeparticles in analysis of real samples

22 Preparation of the EIR The dry procedure was usedfor preparing CAB-impregnated XAD-2010 resin beads [29]Before the impregnation process Amberlite XAD-2010 resinbeadswere treatedwith 1 1methanol-water solution contain-ing 6MHCl for 12 h in order to remove remainingmonomersand other types of impurities which may be found withthe fabricated beads The resin was thoroughly rinsed withdoubly-distilled water and placed into a drying oven at 323Kfor 30min To prepare the impregnated resin portions ofAmberlite XAD-2010 resin (1 g of dry resin) were transferredinto a series of glass stoppered bottles containing differentconcentrations of CAB in 200mL methanol which was usedas the solvent The mixtures were slowly shaken for 10 hto complete the impregnation process and then heated at333 K in a drying oven to remove the solvent Each EIRsample was then transferred to a porous filter and washedsuccessively with HCl (3M) solution and large amountsof distilled water until no CAB was found in the filtratespectrophotometrically Finally the impregnated resins weredried at 323K andweighedThe amount of CAB impregnatedonin the resin beads was determined from theweight changeof polymeric resin To avoid surface peeling and crackingwhich cause the leaching of some extractant molecules fromthe resin beads the prepared EIR beads were stored underdeionized water in a stoppered glass bottle

23 Sorption Procedures

231 Static Sorption of U(VI) Ions A batch technique wasused to sorb the U(VI) ions at 298 plusmn 1KThe 100mL aliquotsof aqueous solution containing suitable concentrations ofU(VI) were taken in glass-stoppered bottles and adjusted toa known pH The CAB-impregnated XAD-2010 resin beads(0150 g) were added to each bottle and the mixtures wereequilibrated for a fixed period of time The EIR beads werefiltered and the sorbed U(VI) ions were desorbed by shakingwith 5mL of 050M HCl The desorbed U(VI) ions weremeasured spectrophotometrically by the arsenazo III pro-cedure described in Section 24 For adsorption equilibriumstudies the mixtures were shaken at a fixed temperatureusing a temperature controlled shaker set at 180 rpm for aperiod of desired time at the optimum pH value and desired



119905



119902

119905

=

(119862

0

minus 119862

119905

) 119881

119898

119902

119890

=

(119862

0

minus 119862

119890

) 119881

119898

(1)

where 119902119905


119890


0


119905


119890






23

H16

Cl2

O6


HO

O

O

O

Cl Cl

OH

OH







CABresin ratio (gg)

Wei

ght c

hang

e of r

esin

()

160

140

120

100

80

60

40

20

000 05 10 15 20 25 30






Wei

ght c

hang

e of r

esin

()

170

150

130

110

90

700 5 10 15 20 25


pH

Reco

very

()

120

90

60

30

00 2 4 6 8 10















119890


119890


Langmuir isotherm

119902

119890

=

119902max1198871198621198901 + 119887119862

119890

(2)


Ceq

e(m

gmiddotLminus

1m

gmiddotgminus

1)

100

075

050

025

0000 50 100


(a)

25

2

15

1

05


logCe

logqe

(b)

qe

(mgmiddot

gminus1)

lnCe

200

150

100

50


(c)


freundlich isotherm

119902

119890

= 119870

119865

119862

1119899

119890

(3)

tempkin isotherm

119902

119890

=

RT119887

(ln119870119879

119862

119890

) (4)


119862

119890

119902

119890

=

119862

119890

119902max+

1

119887119902max (5)

log 119902119890

= log119870119891

+

1

119899

log119862119890

(6)

119902

119890

= 119861 ln119870119879

+ 119861 ln119862119890

(7)

where 119862119890



119891


119879




minus2

119877


119865


2 08181Tempkin119861 2241119870

119879


2 09641




39 Dynamic Sorption





Reco

very

()

SampleEluent

110

90

70

50

300 5 10 15 20






SO42minus Pb2+ CrO4



Ce3+ 200Th4+ 200b

Cu2+ 150a







100 110 (26) 965200 207 (26) 96700 57 (23) mdash


200 259 (19) 1007300 356 (20) 997000 mdash mdash

Well water 1000 98 (19) 980(Argha) 2000 196 (17) 980

3000 293 (13) 9774000 391 (12) 978









4 Conclusions







12








Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



119905



119902

119905

=

(119862

0

minus 119862

119905

) 119881

119898

119902

119890

=

(119862

0

minus 119862

119890

) 119881

119898

(1)

where 119902119905


119890


0


119905


119890






23

H16

Cl2

O6


HO

O

O

O

Cl Cl

OH

OH







CABresin ratio (gg)

Wei

ght c

hang

e of r

esin

()

160

140

120

100

80

60

40

20

000 05 10 15 20 25 30






Wei

ght c

hang

e of r

esin

()

170

150

130

110

90

700 5 10 15 20 25


pH

Reco

very

()

120

90

60

30

00 2 4 6 8 10















119890


119890


Langmuir isotherm

119902

119890

=

119902max1198871198621198901 + 119887119862

119890

(2)


Ceq

e(m

gmiddotLminus

1m

gmiddotgminus

1)

100

075

050

025

0000 50 100


(a)

25

2

15

1

05


logCe

logqe

(b)

qe

(mgmiddot

gminus1)

lnCe

200

150

100

50


(c)


freundlich isotherm

119902

119890

= 119870

119865

119862

1119899

119890

(3)

tempkin isotherm

119902

119890

=

RT119887

(ln119870119879

119862

119890

) (4)


119862

119890

119902

119890

=

119862

119890

119902max+

1

119887119902max (5)

log 119902119890

= log119870119891

+

1

119899

log119862119890

(6)

119902

119890

= 119861 ln119870119879

+ 119861 ln119862119890

(7)

where 119862119890



119891


119879




minus2

119877


119865


2 08181Tempkin119861 2241119870

119879


2 09641




39 Dynamic Sorption





Reco

very

()

SampleEluent

110

90

70

50

300 5 10 15 20






SO42minus Pb2+ CrO4



Ce3+ 200Th4+ 200b

Cu2+ 150a







100 110 (26) 965200 207 (26) 96700 57 (23) mdash


200 259 (19) 1007300 356 (20) 997000 mdash mdash

Well water 1000 98 (19) 980(Argha) 2000 196 (17) 980

3000 293 (13) 9774000 391 (12) 978









4 Conclusions







12








Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


CABresin ratio (gg)

Wei

ght c

hang

e of r

esin

()

160

140

120

100

80

60

40

20

000 05 10 15 20 25 30






Wei

ght c

hang

e of r

esin

()

170

150

130

110

90

700 5 10 15 20 25


pH

Reco

very

()

120

90

60

30

00 2 4 6 8 10















119890


119890


Langmuir isotherm

119902

119890

=

119902max1198871198621198901 + 119887119862

119890

(2)


Ceq

e(m

gmiddotLminus

1m

gmiddotgminus

1)

100

075

050

025

0000 50 100


(a)

25

2

15

1

05


logCe

logqe

(b)

qe

(mgmiddot

gminus1)

lnCe

200

150

100

50


(c)


freundlich isotherm

119902

119890

= 119870

119865

119862

1119899

119890

(3)

tempkin isotherm

119902

119890

=

RT119887

(ln119870119879

119862

119890

) (4)


119862

119890

119902

119890

=

119862

119890

119902max+

1

119887119902max (5)

log 119902119890

= log119870119891

+

1

119899

log119862119890

(6)

119902

119890

= 119861 ln119870119879

+ 119861 ln119862119890

(7)

where 119862119890



119891


119879




minus2

119877


119865


2 08181Tempkin119861 2241119870

119879


2 09641




39 Dynamic Sorption





Reco

very

()

SampleEluent

110

90

70

50

300 5 10 15 20






SO42minus Pb2+ CrO4



Ce3+ 200Th4+ 200b

Cu2+ 150a







100 110 (26) 965200 207 (26) 96700 57 (23) mdash


200 259 (19) 1007300 356 (20) 997000 mdash mdash

Well water 1000 98 (19) 980(Argha) 2000 196 (17) 980

3000 293 (13) 9774000 391 (12) 978









4 Conclusions







12








Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of













119890


119890


Langmuir isotherm

119902

119890

=

119902max1198871198621198901 + 119887119862

119890

(2)


Ceq

e(m

gmiddotLminus

1m

gmiddotgminus

1)

100

075

050

025

0000 50 100


(a)

25

2

15

1

05


logCe

logqe

(b)

qe

(mgmiddot

gminus1)

lnCe

200

150

100

50


(c)


freundlich isotherm

119902

119890

= 119870

119865

119862

1119899

119890

(3)

tempkin isotherm

119902

119890

=

RT119887

(ln119870119879

119862

119890

) (4)


119862

119890

119902

119890

=

119862

119890

119902max+

1

119887119902max (5)

log 119902119890

= log119870119891

+

1

119899

log119862119890

(6)

119902

119890

= 119861 ln119870119879

+ 119861 ln119862119890

(7)

where 119862119890



119891


119879




minus2

119877


119865


2 08181Tempkin119861 2241119870

119879


2 09641




39 Dynamic Sorption





Reco

very

()

SampleEluent

110

90

70

50

300 5 10 15 20






SO42minus Pb2+ CrO4



Ce3+ 200Th4+ 200b

Cu2+ 150a







100 110 (26) 965200 207 (26) 96700 57 (23) mdash


200 259 (19) 1007300 356 (20) 997000 mdash mdash

Well water 1000 98 (19) 980(Argha) 2000 196 (17) 980

3000 293 (13) 9774000 391 (12) 978









4 Conclusions







12








Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


Ceq

e(m

gmiddotLminus

1m

gmiddotgminus

1)

100

075

050

025

0000 50 100


(a)

25

2

15

1

05


logCe

logqe

(b)

qe

(mgmiddot

gminus1)

lnCe

200

150

100

50


(c)


freundlich isotherm

119902

119890

= 119870

119865

119862

1119899

119890

(3)

tempkin isotherm

119902

119890

=

RT119887

(ln119870119879

119862

119890

) (4)


119862

119890

119902

119890

=

119862

119890

119902max+

1

119887119902max (5)

log 119902119890

= log119870119891

+

1

119899

log119862119890

(6)

119902

119890

= 119861 ln119870119879

+ 119861 ln119862119890

(7)

where 119862119890



119891


119879




minus2

119877


119865


2 08181Tempkin119861 2241119870

119879


2 09641




39 Dynamic Sorption





Reco

very

()

SampleEluent

110

90

70

50

300 5 10 15 20






SO42minus Pb2+ CrO4



Ce3+ 200Th4+ 200b

Cu2+ 150a







100 110 (26) 965200 207 (26) 96700 57 (23) mdash


200 259 (19) 1007300 356 (20) 997000 mdash mdash

Well water 1000 98 (19) 980(Argha) 2000 196 (17) 980

3000 293 (13) 9774000 391 (12) 978









4 Conclusions







12








Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



39 Dynamic Sorption





Reco

very

()

SampleEluent

110

90

70

50

300 5 10 15 20






SO42minus Pb2+ CrO4



Ce3+ 200Th4+ 200b

Cu2+ 150a







100 110 (26) 965200 207 (26) 96700 57 (23) mdash


200 259 (19) 1007300 356 (20) 997000 mdash mdash

Well water 1000 98 (19) 980(Argha) 2000 196 (17) 980

3000 293 (13) 9774000 391 (12) 978









4 Conclusions







12








Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





100 110 (26) 965200 207 (26) 96700 57 (23) mdash


200 259 (19) 1007300 356 (20) 997000 mdash mdash

Well water 1000 98 (19) 980(Argha) 2000 196 (17) 980

3000 293 (13) 9774000 391 (12) 978









4 Conclusions







12








Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of






12








Acknowledgments


References



























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of









































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

research article solid-phase extraction of trace amounts...

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