separation and determination of fe(iii) and fe(ii) in...

Research ArticleSeparation and Determination of Fe(III) and Fe(II) in Naturaland Waste Waters Using Silica Gel Sequentially Modified withPolyhexamethylene Guanidine and Tiron

Svetlana Didukh1 Vladimir Losev1 Elena Borodina1 Nikolay Maksimov2

Anatoly Trofimchuk3 and Olga Zaporogets3

1Scientific Research Engineering Centre ldquoKristallrdquo Siberian Federal University Krasnoyarsk Russia2Institute of Chemistry and Chemical Technology Siberian Branch Russian Academy of Sciences Krasnoyarsk Russia3Taras Shevchenko National University of Kyiv Kyiv Ukraine

Correspondence should be addressed to Svetlana Didukh semdidmailru

Received 27 June 2017 Accepted 12 September 2017 Published 31 October 2017

Academic Editor Krishna K Verma

Copyright copy 2017 Svetlana Didukh et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Silica gel sequentiallymodifiedwith polyhexamethylene guanidine and pyrocatechin-35-disulfonic acid (Tiron) was suggested forsorption separation and determination of Fe(III) and Fe(II) It was found that quantitative extraction of Fe(III) and its separationfrom Fe(II) were attained at pH 25ndash40 while quantitative extraction of Fe(II) was observed at pH 60ndash75 An intensive signalwith 119892 = 427 which is characteristic for Fe(III) appeared in EPR spectra of the sorbents after Fe(II) and Fe(III) sorption Duringinteraction between Fe(II) and Tiron fixed on the sorbent surface its oxidation up to Fe(III) occurred Red-lilac complexes of thecomposition FeL

3were formed on the sorbent surface during sorption regardless of initial oxidation level of iron Diffuse reflectance

spectrum of surface complexes exhibited wide band with slightly expressed maxima at 480 and 510 nm Procedures for separationand photometric determination of Fe(III) and Fe(II) at the joint presence and total Fe content determination as Fe(II) in waste andnatural waters was developedThe limit of detection for iron was 005 120583g per 0100 g of the sorbentThe calibration graph was linearup to 200 120583g of Fe per 0100 g of the sorbent The RSD in the determination of more than 02 120583g of Fe was less than 006

1 Introduction

Element speciation including determination of various oxi-dation states of the elements in environmental objects is animportant challenge of analytical chemistry Iron refers tobioactive metals and plays an important biological role inplants animals and human beings Natural waters containiron in oxidation states +2 and+3 and Fe(III) content ismuchhigher than Fe(II) content at that

Photometricmethods of analysis are themostwidely usedmethods for determination of iron in various oxidation states[1 2] they are highly sensitive and selective Organic reagentsused in photometricmethods form complex compoundswitheither Fe(III) or Fe(II) The best known organic reagents forthe photometric determination of Fe(II) are N-heterocyclicbases 110-phenantroline and 221015840-dipyridyl [2] Sulfosalicylic

acid and Tiron [3] are the most widely used photometricreagents for Fe(III) determination

Some reagents-derivatives of di-2-pyridyl ketone hydra-zone di-2-pyridyl ketone benzoylhydrazone and di-2-pyridylketone salicyloylhydrazone [4 5] are known to form com-plex compounds with both Fe(II) and Fe(III) Detection ofFe(II) is carried out at one wavelength and then the otherwavelength is used for determination of the total iron contentFe(III) content is calculated as a difference between total ironand Fe(II) content

The following approaches are used for the photometricdetermination of Fe(II) and Fe(III) in one sample

The first one is based on the application of the reagentswhich formcomplex compoundswith Fe(II) or Fe(III) In thiscase if the reagent forming complexes with Fe(II) is appliedthe concentration of Fe(III) is calculated as a difference

HindawiJournal of Analytical Methods in ChemistryVolume 2017 Article ID 8208146 9 pageshttpsdoiorg10115520178208146

2 Journal of Analytical Methods in Chemistry

between total iron (after reduction of Fe(III) to Fe(II) usingascorbic acid hydroxylamine or reductor minicolumn) andFe(II) content If the reagent forming complexes with Fe(III)is applied concentration of Fe(II) is calculated as a differencebetween total iron (after oxidation of Fe(II) to Fe(III) usinghydrogen peroxide) and Fe(III) content [3 6ndash8]

The second approach is based on the application of twochelating reagents one of which is selective to Fe(II) andthe other one is selective to Fe(III) For example spec-trophotometric sequential injection system was proposedfor simultaneous determination of Fe(II) and Fe(III) basedon introduction of reagents (110-phenanthroline and sul-fosalicylic acid) into a stream of samples The subsequentintroduction of EDTA into a stream resulted in decom-position of Fe(III) compound with sulfosalicylic acid andabsorption of Fe(II) compound with 110-phenanthrolinewas measured [9] Fe(III) and Fe(II) were separated bysilica microcolumn ion chromatography and determined viacomplexation with salicylic acid and 110-phenanthrolinerespectively [10] Capillary zone electrophoresis was appliedfor the simultaneous determination of iron(II) and iron(III)selectively complexed with 110-phenanthroline and trans-cyclohexane-12-diaminetetraacetic acid [11]

The third approach is based on different optical charac-teristics or different rates of formation of colored complexesof Fe(II) and Fe(III) with some organic reagents for examplegallic acid [12] or Tiron [13]

Organic reagents are used in the combination of variousmethods of separation and determination of Fe(II) andFe(III) Two-line manifold flow injection system with opto-electrochemical detection was used for separate determina-tion of Fe(II) and Fe(III) [14] Fe(III) was determined usingphotometric method as complex compound with sulfosali-cylic acid and Fe(II) was determined using electrochemicalmethod Method of separate determination of Fe(II) andFe(III) using atomic absorption spectroscopy was suggestedMethod is based on sorption separation of Fe(II) as itscomplex with ferrozine on a C

18-modified silica column and

direct atomic absorption determination of Fe(III) in solutionpassed through the column then Fe(II) was determined ineluate after desorption of iron(II)-ferrozine complex usingatomic absorption spectroscopy [15]

Photometric method is used in coupling with sorptionpreconcentration in order to improve its sensitivity and selec-tivity Iron may be determined directly in the sorbent phase[16ndash21] or in the solution after desorption [22ndash24] Sor-bents based on ion-exchange resins [16ndash18] polymethacrylatematrixes [20] silica [19 24] cellulose [22] and naphthalene[23] are suggested

Colorless sorbents are preferred to be used for sorption-photometric determination of Fe(III) and Fe(II) From thispoint of view silica based sorbents modified with colorlessorganic reagents which can form colored complexes withiron ions are very promising Examples of such reagentsinclude Tiron (45-dihydroxybenzene-13-disulfonic acid)which forms colored complex compounds with Fe(III) [2526]

Sorption of Fe(III) complexes with Tiron from aqueoussolutions using ion-exchange resin AV-17 was studied in [27]

Fe(III) forms complex with Tiron in solution at pH of 35ndash90and Fe(II) ndash at pH of 60ndash90 this phenomenon was used forsorption-photometric determination of Fe(III) at pH of 35and the total content of Fe(II) and Fe(III) was determined atpH of 6ndash9

At the present work silica gel sequentially modified withpolyhexamethylene guanidine and Tiron was suggested forsorption separation and sorption-photometric determina-tion of Fe(III) and Fe(II) Procedures for separate sorption-photometric determination of Fe(III) and Fe(II) from onesample of water and sorption-photometric and test-methodfor determination of the total iron content as Fe(II) in naturalwaters were developed

2 Experimental

21 Reagents and Chemicals All reagents were of analyticalgrade Deionized water was used for the preparation of thesolutions

A stock standard solutions of Fe(III) and Fe(II)(100mg Lminus1) were prepared by dissolving of FeSO

4and

Fe2(SO4)3in 01M H

2SO4 Working solutions with lower

concentrations were prepared by dilution of stock solutionwith deionized water immediately prior to use

The required pH was adjusted by adding HCl NaOH oracetic buffer solution (pH 40ndash65) and ammonium chloridebuffer solution (pH 75ndash90) Hydroxylamine hydrochloride(01M solution) was used in order to reduce Fe(III) intoFe(II)

Silica gel Silokhrom S-120 (fraction of 01ndash02mm spe-cific surface area sim120m2 gminus1 and average pore diametersim45 nm) was used as a matrix for the sorbent synthesis

Stock solution of polyhexamethylene guanidine hydro-chloride (PHMG) (75 ww solution) was prepared bydissolving weighted portion of BIOPAG-D reagent (Instituteof Ecotechnological problems Moscow Russian Federation)in deionized water

A 0016M Tiron stock solution was prepared by dissolv-ing accurately weighted portion of the reagent in deionizedwater Solutions with lower concentrations were prepared bydilution of the initial solution with deionized water

22 Apparatus Diffuse reflectance spectra (DRS) over therange of 380ndash720 nm were registered using Pulsar Spectro-photocolorimeter (Himavtomatika Russia) Spectra wereplotted against coordinates calculated using the Kubelka-Munk function that is 119865(119877) = (1 minus 119877)22119877 is wavelength(nm) where 119877 is diffuse reflectance coefficient

TheUV-Vis spectra and absorbancy were registered usingCary 100 Spectrophotometer (Varian Australia) Induc-tively coupled plasma optical emission spectrometer Optima5300DV (Perkin-Elmer USA) was used to determine metalions concentration in solutions The EPR spectra wererecorded with an Elexsys E-580 instrument (Bruker Ger-many) The pH measurements were carried out with a Sev-enEasy pHMeter S20 (Mettler-Toledo Switzerland)

Peristaltic pump Masterflex LS (Thermo Fisher Scien-tific USA) was used for pumping solutions through a mini-column with a sorbent

Journal of Analytical Methods in Chemistry 3

(4)Fe(II) + Fe(III)

solv pH 3(1)

(3)

(2)

Buffer pH 62

Sorption of Fe(III) Sorption of Fe(II)

SiO2-PHMG-Tiron SiO2-PHMG-Tiron

Figure 1 Scheme of the sorption separation of Fe(III) and Fe(II) in flow analysis using SiO2-PHMG-Tiron (minicolumn (1 2) tee-joint (3)

and peristaltic pump (4))

23 Synthesis of SiO2-PHMG-Tiron Sorbent SiO2-PHMG

sorbent was synthesized according to procedure describedin article [28] Weighted portions of SiO

2-PHMG (0100 g)

were placed into test-tubes with ground stoppers 10mL ofTiron solution of appropriate concentration was added andthe tube was stirred for 5min The resulting SiO

2-PHMG-

Tiron sorbent was separated from the solution by decantationand washed two times with deionized water Tiron extractionwas determined by the photometric analysis of water phase atthe absorption band of the reagents 120582max = 292 nm (aX 1ndash7)and 120582max = 297 nm (aX gt 8)

24 Preconcentration of Fe(II) and Fe(III) by SiO2-PHMG-Tiron In the batch experiment Fe(II) or Fe(III) solution wasplaced into a graduated test tube with a ground stopper10mL of 01M hydroxylamine solution was added (in Fe(II)sorption experiment)NaOH acetic (pH4ndash6) or ammoniumchloride (pHgt 7) buffer solutionwas added to adjust requiredpH and water was added to a total volume of 100mL SiO

2-

PHMG-Tiron sorbent mass of 0100 g was added the tubewas stopped and stirred for 1ndash30 minutes The solution wasdecantated the sorbent moved into the fluoroplastic cell anddiffuse reflectance coefficient was measuredThe distributionof iron was controlled by the analysis of water phase usinginductively coupled plasma optical emission spectroscopy(ICP-OES)

A schematic diagram of the flow analysis system is shownin Figure 1 Two minicolumns (inner diameter 3mm height50mm) (1 2) each filled with 0100 g of SiO

2-PHMG-Tiron

sorbent were connected sequentially one after another via atee-joint (3) Solution (20mL) at pH 3 containing 10ndash50120583gFe(II) and 10ndash50 120583g Fe(III) in various ratios was pumpedthrough the first minicolumn (1) at flow rate 05mLminminus1using peristaltic pump (4) Acetic buffer solution with pH62 was introduced continuously through the tee-joint (3)The resulting solution was pumped through the secondminicolumn (2) Fe(III) was sorbed in the firstminicolumn atpH 30 while Fe(II) was passed through the first minicolumn(1) and quantitatively extracted in the second one (2) at pH62

3 Results and Discussion

31 Tiron Fixation on the SiO2-PHMG Surface Maximumrecovery (ge98) of Tiron from solution of 016mMLminus1 bySiO2-PHMG sorbent was attained at pH of 30ndash75 (Figure 2

(1)

(2)

0

20

40

60

80

100

Reco

very

()

2 3 4 5 6 7 81рН

Figure 2 Recovery of Tiron (1) and catechol (2) by the SiO2-PHMG

sorbent versus aX (119862Tiron = 016mM (1 2) 0100 g of the sorbent119881 = 10mL contact time 10min)

curve (1)) The time of attainment of sorption equilibriumwas less than 5min Tiron fixation on the surface of SiO

2-

PHMG occurs due to interaction between deprotonatedsulfonic groups of the reagent and positively charged aminegroups of PHMG This assumption was confirmed by com-paring the recovery curves of Tiron and its unsulfonatedanalogmdashcatechol versus pH In contrast to Tiron catecholrecovery by SiO

2-PHMG sorbent (Figure 2 curve (2)) in the

pH range of 2ndash7 did not exceed 1ndash3Maximum sorption capacity of SiO

2-PHMG for Tiron

was 69 120583mol gminus1 at pH 30 and 33 120583mol gminus1 at pH 60(Figure 3 curves (1) (2)) The difference in sorption capac-ities connected with the fact that at pH 3 Tiron sorptionproceeds due to electrostatic interaction between sulfonicgroups of the reagent and amine groups of PHMG fixed onthe silica surface in this case Tiron molecule is arrangedperpendicular to the sorbent surface (Scheme 1(a)) At pH60 Tiron fixation occurs due to both electrostatic interactionof sulfonic groups of the reagent with amine groups ofPHMG and interaction of deprotonated hydroxyl groupsof the reagent (aP11 = 77) with amine groups of PHMGresulting in parallel arrangement of Tiron molecules to thesurface of the sorbent (Scheme 1(b))


(a) (b)

ОН

ОН

（3+

（3+

（3+ （3

+

（3+

（3+

（3+

（3+

（3+ （3

+

（3+

３3minusminus

3３

ОН

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

３3minus

minus

minus3３

Scheme 1 Expected arrangement of the Tiron molecules on the surface of the sorbent at aX 3 (a) and aX 60 (b)

05 1 150C４ＣＬＩＨ (mM

minus1)

(1)

(2)

(3)

0

002

004

006

008

Capa

city

(mM

gminus1)

Figure 3 Sorption isotherms of SiO2-PHMG sorbent for Tiron at

aX 30 (1) aX 60 (2) after sequential sorption of Tiron at aX 60and then at aX 30 (3)

This assumption is confirmed by the fact that duringsequential treatment of SiO

2-PHMG with Tiron solutions

first at pH 60 and then at pH 30 an additional adsorptionoccurred and total sorption capacity for Tironwas 69 120583Mgminus1(Figure 3 curve (3)) This value coincides with the sorptioncapacity of the sorbent obtained at pH 30 When passingfrom pH 60 to pH 30 changes in Tiron arrangement proceedfrom parallel to perpendicular against the sorbent surfacethis process leads to the release of seats (amine groups ofPHMG) for additional fixation of Tiron molecules

Treatment of SiO2-PHMG-firon sorbent obtained at pH

30 with solutions at pH 60 did not lead to the reagent des-orption This was confirmed by the absence of characteristicfor Tiron absorption bands in solution

Thus for the sorbent with a maximum Tiron surfaceconcentration it should be synthesized at pH 30

Tiron fixation on the SiO2-PHMG surface is strong

enough Quantitative desorption of Tiron is achieved in 2M

0

20

40

60

80

100

Reco

very

()

3 5 7 91рН

0

1

ΔF(R

)

2

3

(4)

(1)

(3)

(2)

Figure 4 Extraction of metal Fe(III) (1) and Fe(II) (2) by SiO2-

PHMG-firon sorbent and Δ119865(119877) of the sorbent after sorption ofFe(III) (3) and Fe(II) (4) versus pH (0100 g of the sorbent 119862Tiron =16 120583mol gminus1 119862Fe 120583gmLminus1 10 (1 2) 05 (3 4) 119881 = 10mL)

HCl or in highly saline solutions (ge50 g Lminus1 of NaCl) thisindirectly confirms electrostatic mechanism of fixation

32 Fe(III) or Fe(II) Sorption by SiO2-PHMG-Tiron in theBatch Mode Maximum Fe(III) recovery (98-99) by SiO

2-

PHMG-Tiron sorbent was observed at pH of 25ndash40 and thatof Fe(II) at pH of 60ndash75 (Figure 4 curves (1) (2)) Decreasein the recovery of Fe(III) at pH gt 4 was connected with itshydrolysis Decrease in the recovery of Fe(II) at pH lt 6 iscoincided with conditions of its interaction with Tiron inaqueous solution Recovery of Fe(II) at pH 30 was less than 1-2The time of attainment of sorption equilibrium of Fe(III)(at pH 25ndash40) and Fe(II) (at pH 60ndash75) extraction did notexceed 10min

Sorption capacity for Fe(III) determined from thehorizontal section of the sorption isotherms of SiO

2-

PHMG-Tiron sorbent with the surface concentration ofTiron 33 120583mol gminus1 and 92 120583mol gminus1 was 12 120583mol gminus1 and36 120583mol gminus1 respectively (Figure 5 curves (1) (2)) Similar


002 004 006 0080C (mM Lminus1)

0

2

4

6

8

10

12Ca

paci

ty (m

M g

minus1)

(4)

(1)(3)

(2)

Figure 5 Sorption isotherms of SiO2-PHMG-firon sorbent for

Fe(III) (1 2) and Fe(II) (3 4) (aX 30 (1 2) 62 (3 4) 01VNH2OH

(2 4) 119862Tiron = 33 (1 3) 92 (2 4) 120583V gminus1)

(1)

(2)

440 500 560 620 680380 (nm)

0

04

08

12

16

2

24

F(R

)

Figure 6 Diffuse reflectance spectra of the surface complexes afterFe(III) (1) and Fe(II) (2) sorption by SiO

2-PHMG-Tiron sorbent

(aX 30 (1) 62 (2) 119862Fe = 05 120583gmLminus1 119881 = 10mL 0100 g of thesorbent)

values of sorption capacity of SiO2-PHMG-Tiron sorbent

were obtained for Fe(II) (Figure 5 curves (3) (4)) The dataindicate that during Fe(III) and Fe(II) sorption complexeswith the ratio Fe Tiron sim 1 3 are mainly formed on thesurface of the sorbents with different surface concentrationof Tiron

During Fe(III) sorption at pH 25ndash40 the sorbent surfaceacquired a red-lilac color The DRS was a wide band withslightly expressed maxima at 480 and 510 nm (Figure 6spectrum (1)) It is known that in aqueous solutions Fe(III)forms complexes with Tiron with the stoichiometry 1 1 1 2or 1 3 [25 26] Blue complex FeL (120582max = 665 nm) is formedat pHlt 35 violet complex FeL

2(120582max = 553 nm) is formed in

the pH range of 35ndash65 and red-lilac complex FeL3(120582max =

480 nm) is formed at aX ge 65After comparison of the maxima in the DRS of Fe(III)

surface complexes with the maxima of their absorption spec-tra in aqueous solutions it could be assumed that complexesof Fe(III) with Tiron with the composition FeL

3are mainly

formed on the surface of the SiO2-PHMG-Tiron sorbent

FeL3complex is formed at the pH values that are charac-

teristic for FeL and FeL2complexes formation in solutions

because SiO2-PHMG surface promotes an additional coor-

dination of FeL and FeL2surface complexes with Tiron

moleculesSimilar shift of FeL

3complex formation in acid area with

expended pH range of its formation up to 4ndash8 was observedduring interaction of Fe(III) with Tiron on the surface ofanion-exchange resin Amberlyst A-27 [29]

During Fe(II) sorption in the pH range of 60ndash75 at bothpresence and absence of 0001ndash01V hydroxylamine solutionthe surface of SiO

2-PHMG-Tiron sorbent acquired a red-lilac

color DRS of the sorbent after Fe(II) sorption from solutionswith pH 60ndash75 was identical to DRS of the sorbent afterFe(III) sorption at pH 25ndash40 and had slightly expressedmaxima at 480 and 510 nm (Figure 6 spectrum (2))

Intensities of the bands in DRS of the sorbents aftersorption of Fe(III) and Fe(II) were equal which is evidenceof identity of the surface complexes composition

Maximum intensity of the sorbent color was observed inthe pH range coinciding with the pH ranges of the quantita-tive extraction of Fe(III) and Fe(II) (Figure 4 curves (3) (4))

33 Study of Fe(III) Complexes with Tiron on the Surface ofSiO2-PHNG-Tiron Sorbent and in Aqueous Solutions UsingEPR In order to determine the oxidation state of iron inits complexes with Tiron using EPR method at 77K thefollowing objects were studied

(i) SiO2-PHMG-Tiron sorbents after Fe(III) and Fe(II)

sorption at various pH values(ii) solutions after mixing of Fe(III) and Fe(II) solutions

with Tiron at various pH values

In the low-field region of EPR spectra of SiO2-PHMG-

Tiron sorbent after Fe(III) and Fe(II) sorption an intensivesignal with 119892 = 427 was observed (Figure 7 curves (1) (2))Similar EPR signal was observed for Fe(III) complexes withdesferrioxamine [30] EPR spectra of SiO

2-PHMG-Tiron

after Fe(III) and Fe(II) sorption in optimum conditions wereidentical which is an evidence of the oxidation state of ironwithin the surface complex +3 On the basis of EPR data it canbe concluded that during interaction of Fe(II) with Tiron atpH 60ndash75 on the surface of SiO

2-PHMG-Tiron it is oxidized

up to Fe(III)Even though Fe(III) complexes with Tiron of different

composition (Fe Tiron= 1 1 1 2 1 3) are formed in solutionat different pH values EPR spectra of solutions after mixingFe(III) and Tiron solutions (Figure 7 curve (3)) in the pHrange of 30ndash90 are identical to each other and to EPR spectraof Fe(III) complexes which are formed on the surface ofSiO2-PHMG-Tiron sorbent and characterized by intensive


(4)

(1)

(3)(2)

24501950 29501450950450G

Figure 7 EPR spectra of Fe(III) complexes formed on the surfaceof SiO

2-PHMG-firon sorbent during the sorption of Fe(III) (1) and

Fe(II) (2) and Fe(III) complexes with Tiron in aqueous solution afterinteraction between Fe(III) (3) or Fe(II) (4) and Tiron (aX 30 (1)62 (2) and 80 (3 4) 0200 g of the sorbent (1 2)and 119862Fe = 20 120583gper 0200 g of the sorbent (1 2) 036mV (3 4)119862Tiron = 16 120583mol gminus1(1 2) 16mV (3 4))

EPR signal with 119892 = 427 EPR spectra of the solutions aftermixing Fe(II) and Tiron solutions at pH 60ndash90 are also char-acterized by intensive signal with 119892 = 427 (Figure 7 curve(4)) The shape of the spectra and EPR signals intensities areidentical for the solutions obtained by mixing of the sameconcentrations of Fe(III) or Fe(II) with Tiron Even in thepresence of 0001ndash01M hydroxylamine in the solution Fe(II)formed complex with Tiron at pH 60ndash75 having intensivesignal with 119892 = 427 in EPR spectrum The identity of ESRspectra in this case indicates that hydroxylamine does notprevent oxidation of iron (II) during complexationwithTironat pH 60ndash75

Thus from the EPR data it can be concluded that duringinteraction of Fe(II) with Tiron both in solution and on thesurface of the sorbent it is oxidized to Fe(III) Both dissolvedin water oxygen and the reagent itself can be an oxidant ofFe(II) [13] The rate of Fe(II) oxidation increases with therising of degree of saturation of solution with oxygen at pH gt5 in the presence of acetate ions that coincides with the areaof its quantitative extraction by SiO

2-PHMG-Tiron

The identity of EPR spectra of SiO2-PHMG-Tiron sorbent

after Fe(III) and Fe(II) sorption is the evidence of oxidationlevel of iron within the surface complex +3 and the identityof color and DRS of Fe(III) complexes on the surfaceof SiO

2-PHMG-Tiron sorbent is the evidence of identical

composition of the surface complexes

34 Sorption-Photometric Determination of Fe(III) and Fe(II)Using SiO2-PHMG-Tiron As the iron content on the sorbentsurface increased the intensity of sorbent color increasedproportionally and shape of DRS and position of its maximadid not depend on iron concentration Formation of inten-sively colored complexes on SiO

2-PHMG-Tiron surface was

used for development of the following procedures

(i) Sorption-photometric determination of Fe(III) andFe(II)

Table 1 RSD for determination of iron concentration per 01 g ofSiO2-PHMG-Tiron (n = 5)

Added 120583g Found 120583g RSD 010 009 plusmn 001 91020 021 plusmn 002 62050 050 plusmn 002 4010 100 plusmn 004 3250 51 plusmn 03 45

(ii) Sorption-photometric determination of total iron innatural waters

The analytical characteristics of the developed methodsuch as the limit of detection linear range and correlationcoefficient were obtained by processing standard solutionsunder optimum conditions A linear calibration graph wasobtained for the determination of iron (II) under the pro-posed experimental conditions The calibration equations incoordinates Δ119865(119877)minus 119888 where 119888 is iron content (120583g per 0100 gof the sorbent) were as follows

(i) Δ119865(119877) = (0593 plusmn 0003)119888 (1198772 = 0999) for Fe(II)sorption

(ii) Δ119865(119877) = (0596 plusmn 0003)119888 (1198772 = 0998) for Fe(III)sorption

The detection limit for iron determination calculatedusing 3s-criterion was 005120583g per 0100 g of the sorbent Thecalibration graphs were linear up to 200120583g of Fe per 0100 gof the sorbent The relative standard deviation (RSD = (119904119909)times 100) in the determination of more than 02 120583g of Fe per0100 g of the sorbent was less than 62 119899 = 5 (Table 1) Thedetection limits the range of linearity of calibration graphsand RSD are independent of initial oxidation level of iron

SiO2-PHMG-Tiron sorbent is characterized by good

kinetics As the ratio volume of solution to the sorbent mass(119881 119898) rises from 102 to 103 and the time of attainment ofsorption equilibrium did not exceed 10min An increase ofvolume of solution from 10 to 100mL (using 0100 g of thesorbent) leads to decrease of the relative detection limit from5 ngmLminus1 to 05 ngmLminus1

35 Effect of Potentially Interfering Ions Solutions containingFe(II) or Fe(III) (01120583gmLminus1) and other ions were preparedand the developed procedure was applied in order to deter-mine the selectivity of the sorbent

Sorption preconcentration from solution at pH 30and sorption-photometric determination of Fe(III) was notaffected by the following cations (in multiple amounts) Na+K+ Sr2+ ba2+ Vg2+ (1000) `b2+ Ni2+ Zn2+ Hg2+ (500)Bi3+ (500) Sn2+ Al3+ Cr3+ and Cu2+ (100)

Sorption preconcentration from solution at pH 62and sorption-photometric determination of Fe(II) was notaffected by the following cations (in multiple amounts) Na+K+ Sr2+ ba2+Vg2+ `b2+ (1000) Ni2+ (500) Zn2+ (250)Bi3+ Hg2+ (100) Sn2+ Al3+ (50) Cr3+ and Cu2+ (10) Saltbackground up to 50 g Lminus1 for NaCl 5 g Lminus1 for Na

2SO4


Table 2 Results of Fe(III) and Fe(II) determination in model solutions using minicolumn (119899 = 5)

Added 120583g Length of colored zone mm Found 120583gFe(III) Fe(II) Fe(III) Fe(II) Fe(III) Fe(II)mdash 50 mdash 10 plusmn 1 mdash 50 plusmn 0550 mdash 10 plusmn 1 mdash 50 plusmn 05 mdash10 50 2 plusmn 1 10 plusmn 1 10 plusmn 05 50 plusmn 0520 50 4 plusmn 1 10 plusmn 1 20 plusmn 05 50 plusmn 0550 10 10 plusmn 1 2 plusmn 1 50 plusmn 05 10 plusmn 0550 20 10 plusmn 1 4 plusmn 1 50 plusmn 05 20 plusmn 0550 50 10 plusmn 1 10 plusmn 1 50 plusmn 05 50 plusmn 05

Table 3 Results of Fe(III) and Fe(II) determination in well waters (119899 = 5)

SampleFound 120583gmLminus1 Total Fe

120583gmLminus1Fe(III) Fe(II)05 h 6 h 24 h 05 h 6 h 24 h

Well water number 1 0 014 lowast 018 005 0 018Well water number 2 01 10 lowast 17 06 01 18lowastIron (III) hydroxide precipitation

and 25 g Lminus1 for Na2SO3did not prevent Fe(III) and Fe(II)

preconcentration and determinationSelectivity of Fe(III) determination is higher compared

to Fe(II) determination because Fe(III) complexation withTiron occurs in more acidic area where no interaction withother metal ions (forming complexes at pH gt 4) with Tirontakes place [31 32]

36 Sorption Separation and Determination of Fe(III) andFe(II) Dependence of Fe(II) and Fe(III) quantitative extrac-tion by SiO

2-PHMG-Tiron sorbent versus pH and formation

of intensively colored Fe(III) surface complexes was used forsequential sorption isolation and separate determination ofFe(III) and Fe(II) from one sample of the solution

During sorption in the batch mode Fe(III) content wasfound almost 15 times higher than it was added and Fe(II)content 15 times lower than it was added But the totalFe(III) and Fe(II) content were equal to when they wereadded Overestimated results of Fe(III) determination andunderestimated results of Fe(II) determination are explainedby saturation of solution by atmospheric oxygen duringintensive stirring at pH 3 the optimum conditions for Fe(III)extraction and Fe(II) is oxidized up to Fe(III)

Sorption in flow analysis using minicolumn allows elim-inating saturation of solution by atmospheric oxygen andaccomplishing both separation and determination of Fe(II)and Fe(III) from one sample of solution by the length ofcolored zone of the sorbent using system represented onFigure 1 The sorbent in minicolumns became red-lilac color

The length of colored zone of the sorbents after passingFe(III) and Fe(II) solutions of equal concentrationswas equaland it increased proportionally to their content in solutionThe calibration function for Fe(II) and Fe(III) determinationby the length of the colored zone (119897) was as follows 119897 (mm) =2119888plusmn1 where 119888 is iron content inminicolumn 120583g Iron contentdetermined by the length of the colored zone in the model

solution is represented in Table 2 An increase of the flow rateof the solution from 05 to 30mLminminus1 led to the erosion ofthe colored zone

Procedure for the separate determination of Fe(III) andFe(II) by the length of the colored zone in minicolumn wasused for the analysis of well water during storage in 30min6 h and 24 h after sampling Obtained results are representedin Table 3

In well waters that are of high iron content (gt2mg Lminus1)and free of organic compounds (humic and fulvic acids)in contact with air oxidation of Fe(II) to Fe(III) proceedswith subsequent precipitation of slightly soluble iron (III)hydroxide Fe(II) content was determined in well waters withhigh iron content after separation of iron (III) hydroxidesediment using membrane filter

The data represented in Table 3 shows that in the casesof low iron content in natural waters the results of sorption-photometric determination of total content of Fe(III) andFe(II) are in agreement with the results of total iron deter-mination using ICP-OES

37 Determination of Total Iron in Natural Waters In orderto decompose metal complexes with organic compoundsnatural waters were boiled with nitric acid Organic com-plexes of iron were destroyed and iron was oxidized up toFe(III) as a result which was hydrolyzed forming poorlysoluble compounds Despite higher selectivity of sorption-photometric determination of Fe(III) at pH 30 in order todetermine the total iron content it is reasonable to reduceFe(III) to Fe(II) because it is less hydrolyzed in aqueoussolutions and does not form poorly soluble compoundsHydroxylamine is preferred to be used as the reducing agentbecause its presence does not affect the formation of thesurface complex of Fe(III) with Tiron

Developed procedure was applied for total iron determi-nation in waste waters (samples number 1 and number 2)


Table 4 Results of total iron determination in natural and mineral waters (119899 = 5)

Sample Found Fe mg Lminus1

Sorption-photometric method Column method ICP-AESWaste water No 1 18 plusmn 01a 20 plusmn 05a 16 plusmn 01Waste water No 2 21 plusmn 01a 20 plusmn 05a 21 plusmn 01River water 060 plusmn 004a 05 plusmn 05a 060 plusmn 003Mineral water laquoUchumskayaraquo 0045 plusmn 0008a sim005a 0050 plusmn 0007Mineral water laquoZagorieraquo 144 plusmn 07b mdash 150 plusmn 06aSample volume 5mL bSample volume 1mL

taken in various districts of Krasnoyarsk city river waterdrink waters low mineralized water ldquoUchumskayardquo andhighlymineralized water ldquoZagorierdquo produced in KrasnoyarskKrai The accuracy of procedure was confirmed by ICP-OESmethod The results of iron determination are represented inTable 4

An intensely colored zone appeared when a samplewas passed through a minicolumn filled with a sorbentDependence of the length of colored zone of the sorbent oniron content was used for total iron determination in naturalwaters (Table 4)

4 Conclusion

SiO2-PHMG-Tiron sorbent proposed for preconcentration

separation and determination of Fe(II) and Fe(III) is char-acterized by simplicity of synthesis from widespread andavailable reagents and does not require complex and expen-sive equipment The sorbent allows quantitative sequentialisolation and determination of Fe(II) and Fe(III) from onesample of water Developed procedures are comparable toFAAS and ICP-OES in terms of detection limits Applicationof minicolumn filled with SiO

2-PHMG-Tiron sorbent allows

rapid and accurate visual estimation of Fe(II) and Fe(III)content in natural waters Procedure of iron determination bythe length of colored zone in minicolumn does not requireequipment and can be applied for iron determination innatural waters in the field

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

This study was supported by the Ministry of Education andScience of the Russian Federation (Project no 463432017 forSiberian Federal University)

References

[1] S Pehkonen ldquoDetermination of the oxidation states of iron innaturalwatersAReviewrdquoAnalyst vol 120 no 11 pp 2655ndash26631995

[2] Z Marczenko and M Balcerzak Separation Preconcentrationand Spectrophotometry in Inorganic Analysis Elsevier Amster-dam Netherlands 2001

[3] M Kass and A Ivaska ldquoSpectrophotometric determinationof iron(III) and total iron by sequential injection analysistechniquerdquo Talanta vol 58 no 6 pp 1131ndash1137 2002

[4] S O Pehkonen Y Erel and M R Hoffmann ldquoSimultaneousspectrophotometricmeasurement of Fe(II) and Fe(III) in atmo-spheric waterrdquo Environmental Science amp Technology vol 26 no9 pp 1731ndash1736 1992

[5] M C Da Cunha Areias L H S Avila-Terra I Gaubeur andM E V Suarez-Iha ldquoA new simultaneous spectrophotometricmethod for determination of iron(II) and iron(III) in naturalwatersrdquo Spectroscopy Letters vol 34 no 3 pp 289ndash300 2001

[6] A de Assis Gonsalves C R M Araujo C X Galhardo M OF Goulart and F C de Abreu ldquoHydralazine hydrochlorideAn alternative complexometric reagent for total iron spec-trophotometric determinationrdquo American Journal of AnalyticalChemistry vol 2 no 11 pp 776ndash782 2011

[7] M Hoshino H Yasui H Sakurai T Yamaguchi and Y FujitaldquoImproved spectrophotometric determination of total iron andiron (III) with o-hydroxyhydroquinonephthalein and theircharacterizationrdquo Yakugaku Zasshi vol 131 no 7 pp 1095ndash11012011

[8] J Paluch J KozakMWieczorek et al ldquoNovel approach to two-component speciation analysis Spectrophotometric flow-baseddeterminations of Fe(II)Fe(III) and Cr(III)Cr(VI)rdquo Talantavol 171 pp 275ndash282 2017

[9] J Kozak J Paluch AWęgrzecka et al ldquoSingle peak parameterstechnique for simultaneous measurements Spectrophotomet-ric sequential injection determination of Fe(II) and Fe(III)rdquoTalanta vol 148 pp 626ndash632 2016

[10] B Oktavia L W Lim and T Takeuchi ldquoSimultaneous determi-nation of Fe(III) and Fe(II) ions via complexation with salicylicacid and 110-phenanthroline in microcolumn ion chromatog-raphyrdquo Analytical Sciences vol 24 no 11 pp 1487ndash1492 2008

[11] S PozdniakovaA Padarauskas andG Schwedt ldquoSimultaneousdetermination of iron(II) and iron(III) in water by capillaryelectrophoresisrdquo Analytica Chimica Acta vol 351 no 1-3 pp41ndash48 1997

[12] J Zolgharnein H Abdollahi D Jaefarifar and G H AzimildquoSimultaneous determination of Fe(II) and Fe(III) by kineticspectrophotometric H-point standard addition methodrdquoTalanta vol 57 no 6 pp 1067ndash1073 2002

[13] S Abe T Saito and M Suda ldquoSimultaneous determination ofiron(II) and iron(III) in aqueous solution by kinetic spec-trophotometry with tironrdquo Analytica Chimica Acta vol 181 noC pp 203ndash209 1986

[14] B Haghighi and A Safavi ldquoSimultaneous flow injection deter-mination of iron(II) and iron(III) with opto-electrochemicaldetectionrdquo Analytica Chimica Acta vol 354 no 1-3 pp 43ndash501997


[15] Y Chen S Feng Y Huang and D Yuan ldquoRedox speciationanalysis of dissolved iron in estuarine and coastal waters withon-line solid phase extraction and graphite furnace atomicabsorption spectrometry detectionrdquoTalanta vol 137 pp 25ndash302015

[16] J L AMiranda R B RMesquita A Nunes M Rangel and AO S S Rangel ldquoIron speciation in natural waters by sequentialinjection analysis with a hexadentate 3-hydroxy-4-pyridinonechelator as chromogenic agentrdquo Talanta vol 148 pp 633ndash6402016

[17] R Suarez R B R Mesquita M Rangel V Cerda and AO S S Rangel ldquoIron speciation by microsequential injectionsolid phase spectrometry using 3-hydroxy-1(H)-2-methyl-4-pyridinone as chromogenic reagentrdquo Talanta vol 133 pp 15ndash20 2015

[18] Sarenqiqige A Maeda and K Yoshimura ldquoDetermination oftrace iron in the boiler water used in power generation plantsby solid-phase spectrophotometryrdquo Analytical Sciences vol 30no 10 pp 1013ndash1017 2014

[19] O Y Nadzhafova M V Drozdova E V Nebesnaya and VB Ishchenko ldquoOptimization and use of composite coatingsbased on silicon oxide and polyvinylsulfonic acid for theadsorption-spectrophotometric determination of iron(II) andzinc(II) phenanthrolinatesrdquo Journal of Analytical Chemistryvol 62 no 12 pp 1136ndash1142 2007

[20] N A Gavrilenko and O V Mokhova ldquoSorption-spectropho-tometric determination of iron(II III) with the use of organicreagents immobilized in a polymethacrylate matrixrdquo Journal ofAnalytical Chemistry vol 63 no 11 pp 1038ndash1043 2008

[21] M A Kassem and A S Amin ldquoSpectrophotometric determi-nation of iron in environmental and food samples using solidphase extractionrdquo Food Chemistry vol 141 no 3 pp 1941ndash19462013

[22] Y Chen C-M Ding T-Z Zhou and D-Y Qi ldquoOrganicsolvent-soluble Membrane Filters for the preconcentration andspectrophotometric determination of iron(II) traces in waterwith Ferrozinerdquo Freseniusrsquo Journal of Analytical Chemistry vol363 no 1 pp 119-120 1999

[23] B K Puri and S Balani ldquoPreconcentration of iron (III)cobalt (II) and copper (II) nitroso-R complexes on tetrade-cyldimethylbenzylammonium iodide-naphthalene adsorbentrdquoTalanta vol 42 no 3 pp 337ndash344 1995

[24] N Pourreza S Rastegarzadeh A R Kiasat and H YahyavildquoSpectrophotometric determination of iron(II) after solidphase extraction of its 221015840 bipyridine complex on silica gel-polyethylene glycolrdquo Journal of Spectroscopy vol 1 no 1 ArticleID 548345 2013

[25] W A E McBryde ldquoSpectrophotometric reexamination of thespectra and stabilities of the iron (III)-tiron complexesrdquo Cana-dian Journal of Chemistry vol 42 pp 1917ndash1927 1964

[26] M J Sever and J J Wilker ldquoVisible absorption spectra ofmetal-catecholate andmetal-tironate complexesrdquoDalton Trans-actions no 7 pp 1061ndash1072 2004

[27] O V Kuznetsova V M Ivanov and N V Kazennov ldquoSorption-spectroscopic determination of iron in the sorbate phase inthe form of pyrocatechol-35-disulfonaterdquo Moscow UniversityChemistry Bulletin vol 38 pp 53ndash56 1997

[28] V Losev S Didukh A Trofimchuk and O ZaporozhetsldquoAdsorption-photometric and test determination of copperusing silica gel sequentially modified with polyhexamethyleneguanidine and bathocuproinedisulphonic acidrdquoAdsorption Sci-ence amp Technology vol 32 no 6 pp 443ndash452 2014

[29] M M A Shriadah and K Ohzekit ldquoEffect of anion-exchangeresin on the formation of iron(III) - Tiron complexesrdquo Analystvol 111 no 2 pp 197ndash200 1986

[30] D Y Yegorov A V Kozlov O A Azizova and Y A VladimirovldquoSimultaneous determination of Fe(III) and Fe(II) in watersolutions and tissue homogenates using desferal and 110-phenanthrolinerdquo Free Radical Biology amp Medicine vol 15 no6 pp 565ndash574 1993

[31] M Kumar D P S Rathore and A K Singh ldquoMetal ionenrichment with Amberlite XAD-2 functionalized with TironAnalytical applicationsrdquo Analyst vol 125 no 6 pp 1221ndash12262000

[32] T I Tikhomirova S S Kubyshev N M Sorokina and V AGoloviznin ldquoPreconcentration of metal ions on aluminumoxide modified with tironrdquo Journal of Analytical Chemistry vol66 no 1 pp 2ndash5 2011

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 201

International Journal ofInternational Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal ofInternational 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


between total iron (after reduction of Fe(III) to Fe(II) usingascorbic acid hydroxylamine or reductor minicolumn) andFe(II) content If the reagent forming complexes with Fe(III)is applied concentration of Fe(II) is calculated as a differencebetween total iron (after oxidation of Fe(II) to Fe(III) usinghydrogen peroxide) and Fe(III) content [3 6ndash8]

The second approach is based on the application of twochelating reagents one of which is selective to Fe(II) andthe other one is selective to Fe(III) For example spec-trophotometric sequential injection system was proposedfor simultaneous determination of Fe(II) and Fe(III) basedon introduction of reagents (110-phenanthroline and sul-fosalicylic acid) into a stream of samples The subsequentintroduction of EDTA into a stream resulted in decom-position of Fe(III) compound with sulfosalicylic acid andabsorption of Fe(II) compound with 110-phenanthrolinewas measured [9] Fe(III) and Fe(II) were separated bysilica microcolumn ion chromatography and determined viacomplexation with salicylic acid and 110-phenanthrolinerespectively [10] Capillary zone electrophoresis was appliedfor the simultaneous determination of iron(II) and iron(III)selectively complexed with 110-phenanthroline and trans-cyclohexane-12-diaminetetraacetic acid [11]

The third approach is based on different optical charac-teristics or different rates of formation of colored complexesof Fe(II) and Fe(III) with some organic reagents for examplegallic acid [12] or Tiron [13]

Organic reagents are used in the combination of variousmethods of separation and determination of Fe(II) andFe(III) Two-line manifold flow injection system with opto-electrochemical detection was used for separate determina-tion of Fe(II) and Fe(III) [14] Fe(III) was determined usingphotometric method as complex compound with sulfosali-cylic acid and Fe(II) was determined using electrochemicalmethod Method of separate determination of Fe(II) andFe(III) using atomic absorption spectroscopy was suggestedMethod is based on sorption separation of Fe(II) as itscomplex with ferrozine on a C

18-modified silica column and

direct atomic absorption determination of Fe(III) in solutionpassed through the column then Fe(II) was determined ineluate after desorption of iron(II)-ferrozine complex usingatomic absorption spectroscopy [15]

Photometric method is used in coupling with sorptionpreconcentration in order to improve its sensitivity and selec-tivity Iron may be determined directly in the sorbent phase[16ndash21] or in the solution after desorption [22ndash24] Sor-bents based on ion-exchange resins [16ndash18] polymethacrylatematrixes [20] silica [19 24] cellulose [22] and naphthalene[23] are suggested

Colorless sorbents are preferred to be used for sorption-photometric determination of Fe(III) and Fe(II) From thispoint of view silica based sorbents modified with colorlessorganic reagents which can form colored complexes withiron ions are very promising Examples of such reagentsinclude Tiron (45-dihydroxybenzene-13-disulfonic acid)which forms colored complex compounds with Fe(III) [2526]

Sorption of Fe(III) complexes with Tiron from aqueoussolutions using ion-exchange resin AV-17 was studied in [27]

Fe(III) forms complex with Tiron in solution at pH of 35ndash90and Fe(II) ndash at pH of 60ndash90 this phenomenon was used forsorption-photometric determination of Fe(III) at pH of 35and the total content of Fe(II) and Fe(III) was determined atpH of 6ndash9

At the present work silica gel sequentially modified withpolyhexamethylene guanidine and Tiron was suggested forsorption separation and sorption-photometric determina-tion of Fe(III) and Fe(II) Procedures for separate sorption-photometric determination of Fe(III) and Fe(II) from onesample of water and sorption-photometric and test-methodfor determination of the total iron content as Fe(II) in naturalwaters were developed

2 Experimental

21 Reagents and Chemicals All reagents were of analyticalgrade Deionized water was used for the preparation of thesolutions

A stock standard solutions of Fe(III) and Fe(II)(100mg Lminus1) were prepared by dissolving of FeSO

4and

Fe2(SO4)3in 01M H

2SO4 Working solutions with lower

concentrations were prepared by dilution of stock solutionwith deionized water immediately prior to use

The required pH was adjusted by adding HCl NaOH oracetic buffer solution (pH 40ndash65) and ammonium chloridebuffer solution (pH 75ndash90) Hydroxylamine hydrochloride(01M solution) was used in order to reduce Fe(III) intoFe(II)

Silica gel Silokhrom S-120 (fraction of 01ndash02mm spe-cific surface area sim120m2 gminus1 and average pore diametersim45 nm) was used as a matrix for the sorbent synthesis

Stock solution of polyhexamethylene guanidine hydro-chloride (PHMG) (75 ww solution) was prepared bydissolving weighted portion of BIOPAG-D reagent (Instituteof Ecotechnological problems Moscow Russian Federation)in deionized water

A 0016M Tiron stock solution was prepared by dissolv-ing accurately weighted portion of the reagent in deionizedwater Solutions with lower concentrations were prepared bydilution of the initial solution with deionized water

22 Apparatus Diffuse reflectance spectra (DRS) over therange of 380ndash720 nm were registered using Pulsar Spectro-photocolorimeter (Himavtomatika Russia) Spectra wereplotted against coordinates calculated using the Kubelka-Munk function that is 119865(119877) = (1 minus 119877)22119877 is wavelength(nm) where 119877 is diffuse reflectance coefficient

TheUV-Vis spectra and absorbancy were registered usingCary 100 Spectrophotometer (Varian Australia) Induc-tively coupled plasma optical emission spectrometer Optima5300DV (Perkin-Elmer USA) was used to determine metalions concentration in solutions The EPR spectra wererecorded with an Elexsys E-580 instrument (Bruker Ger-many) The pH measurements were carried out with a Sev-enEasy pHMeter S20 (Mettler-Toledo Switzerland)

Peristaltic pump Masterflex LS (Thermo Fisher Scien-tific USA) was used for pumping solutions through a mini-column with a sorbent


(4)Fe(II) + Fe(III)

solv pH 3(1)

(3)

(2)

Buffer pH 62







2-PHMG (0100 g)


2-PHMG-



2-



2-PHMG-Tiron




(1)

(2)

0

20

40

60

80

100

Reco

very

()

2 3 4 5 6 7 81рН




2-




2-PHMG for Tiron



(a) (b)

ОН

ОН

（3+

（3+

（3+ （3

+

（3+

（3+

（3+

（3+

（3+ （3

+

（3+

３3minusminus

3３

ОН

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

３3minus

minus

minus3３


05 1 150C４ＣＬＩＨ (mM

minus1)

(1)

(2)

(3)

0

002

004

006

008

Capa

city

(mM

gminus1)











0

20

40

60

80

100

Reco

very

()

3 5 7 91рН

0

1

ΔF(R

)

2

3

(4)

(1)

(3)

(2)





2-



2-



002 004 006 0080C (mM Lminus1)

0

2

4

6

8

10

12Ca

paci

ty (m

M g

minus1)

(4)

(1)(3)

(2)



(2 4) 119862Tiron = 33 (1 3) 92 (2 4) 120583V gminus1)

(1)

(2)

440 500 560 620 680380 (nm)

0

04

08

12

16

2

24

F(R

)











3are mainly




















2-PHMG-Tiron






(4)

(1)

(3)(2)

24501950 29501450950450G






2-PHMG-Tiron





















2SO4





























4 Conclusion







Acknowledgments


References











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


(4)Fe(II) + Fe(III)

solv pH 3(1)

(3)

(2)

Buffer pH 62







2-PHMG (0100 g)


2-PHMG-



2-



2-PHMG-Tiron




(1)

(2)

0

20

40

60

80

100

Reco

very

()

2 3 4 5 6 7 81рН




2-




2-PHMG for Tiron



(a) (b)

ОН

ОН

（3+

（3+

（3+ （3

+

（3+

（3+

（3+

（3+

（3+ （3

+

（3+

３3minusminus

3３

ОН

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

３3minus

minus

minus3３


05 1 150C４ＣＬＩＨ (mM

minus1)

(1)

(2)

(3)

0

002

004

006

008

Capa

city

(mM

gminus1)











0

20

40

60

80

100

Reco

very

()

3 5 7 91рН

0

1

ΔF(R

)

2

3

(4)

(1)

(3)

(2)





2-



2-



002 004 006 0080C (mM Lminus1)

0

2

4

6

8

10

12Ca

paci

ty (m

M g

minus1)

(4)

(1)(3)

(2)



(2 4) 119862Tiron = 33 (1 3) 92 (2 4) 120583V gminus1)

(1)

(2)

440 500 560 620 680380 (nm)

0

04

08

12

16

2

24

F(R

)











3are mainly




















2-PHMG-Tiron






(4)

(1)

(3)(2)

24501950 29501450950450G






2-PHMG-Tiron





















2SO4





























4 Conclusion







Acknowledgments


References











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


(a) (b)

ОН

ОН

（3+

（3+

（3+ （3

+

（3+

（3+

（3+

（3+

（3+ （3

+

（3+

３3minusminus

3３

ОН

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

（3+

３3minus

minus

minus3３


05 1 150C４ＣＬＩＨ (mM

minus1)

(1)

(2)

(3)

0

002

004

006

008

Capa

city

(mM

gminus1)











0

20

40

60

80

100

Reco

very

()

3 5 7 91рН

0

1

ΔF(R

)

2

3

(4)

(1)

(3)

(2)





2-



2-



002 004 006 0080C (mM Lminus1)

0

2

4

6

8

10

12Ca

paci

ty (m

M g

minus1)

(4)

(1)(3)

(2)



(2 4) 119862Tiron = 33 (1 3) 92 (2 4) 120583V gminus1)

(1)

(2)

440 500 560 620 680380 (nm)

0

04

08

12

16

2

24

F(R

)











3are mainly




















2-PHMG-Tiron






(4)

(1)

(3)(2)

24501950 29501450950450G






2-PHMG-Tiron





















2SO4





























4 Conclusion







Acknowledgments


References











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


002 004 006 0080C (mM Lminus1)

0

2

4

6

8

10

12Ca

paci

ty (m

M g

minus1)

(4)

(1)(3)

(2)



(2 4) 119862Tiron = 33 (1 3) 92 (2 4) 120583V gminus1)

(1)

(2)

440 500 560 620 680380 (nm)

0

04

08

12

16

2

24

F(R

)











3are mainly




















2-PHMG-Tiron






(4)

(1)

(3)(2)

24501950 29501450950450G






2-PHMG-Tiron





















2SO4





























4 Conclusion







Acknowledgments


References











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


(4)

(1)

(3)(2)

24501950 29501450950450G






2-PHMG-Tiron





















2SO4





























4 Conclusion







Acknowledgments


References











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





























4 Conclusion







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

separation and determination of fe(iii) and fe(ii) in...

Documents