metal-organicframeworkmil-53(fe)asanadsorbentfor...

Research ArticleMetal-Organic Framework MIL-53(Fe) as an Adsorbent forIbuprofen Drug Removal from Aqueous Solutions ResponseSurface Modeling and Optimization

Duyen Thi Cam Nguyen 1 Hanh Thi Ngoc Le2 Trung Sy Do3 Van Thinh Pham4

Dai Lam Tran 5 Van Thi Thanh Ho 6 Thuan Van Tran 7 Duy Chinh Nguyen 7

Trinh Duy Nguyen 7 Long Giang Bach 7 Huynh Ky Phuong Ha 8

and Van Thuan Doan 7

1Faculty of Pharmacy Nguyen Tat anh University Ho Chi Minh City Vietnam2Institute of Hygiene and Public Health Ho Chi Minh City Vietnam3Institute of Chemistry Vietnam Academy of Science and Technology Hanoi Vietnam4Dong Nai Technology University Bien Hoa City Dong Nai Province Vietnam5Institute for Tropical Technology Vietnam Academy of Science and Technology Hanoi Vietnam6Ho Chi Minh University of Natural Resources and Environment Ho Chi Minh City Vietnam7NTT Hi-Tech Institute Nguyen Tat anh University Ho Chi Minh City Vietnam8Faculty of Chemical Engineering Ho Chi Minh City University of Technology Ho Chi Minh City Vietnam

Correspondence should be addressed to Van uan Doan doanthuanmsgmailcom

Received 1 December 2018 Revised 21 January 2019 Accepted 3 February 2019 Published 3 March 2019

Guest Editor Nguayen Van Noi

Copyright copy 2019 Duyen i Cam Nguyen et al is is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in anymedium provided the original work isproperly cited

Ibuprofen contamination from water sources has been increasingly alarming due to its environmentally accumulative retentionhowever the strategies for ibuprofen-containing water treatment are still an enormous challenge Herein we described theutilization of metal-organic frameworks MIL-53(Fe) (MILMaterials of Institute Lavoisier) for the adsorption of ibuprofen insynthetic solution Firstly the MIL-53(Fe) was solvothemally synthesized and then characterized using the X-ray diffraction andFourier-transform infrared spectroscopy techniques e optimization of ibuprofen adsorption over MIL-53(Fe) was performedwith three independent variables including ibuprofen concentration (16ndash184mgL) adsorbent dosage (016ndash184 gL) and pH(26ndash94) according to the experimental design from response surface methodology Under the optimized conditions more than80 of ibuprofen could be eliminated from water indicating the promising potential of the MIL-53(Fe) material for treatment ofthis drug Kinetic and isotherm models also were used to elucidate the chemisorption and monolayer behavior mechanisms ofibuprofen over MIL-53(Fe)

1 Introduction

Ibuprofen ((plusmnR S)-2-(4-(2-methylpropyl)phenyl)propanoicacid IBU) a nonsteroidal anti-inflammatory drugs(NSAIDs) has widely been used for the treatment ofbacterial infection-related diseases in many countries (itschemical structure is shown in Figure 1) [1ndash4] Howeverthere is a rapid acceleration in IBU contamination due to

the ineffective treatment of wastewater sources derivedfrom hospitals and pharmaceutical manufacturers [5ndash7]According to recent environmental reports varyingamounts of the IBU residue have been detected in somerivers (ie ames River UK (0783 μgL) and AuraRiver Finland (20 μgL)) significantly exceeding thepermissible standards for human health [8] Besides theaccumulation of the IBU pollutant in water may support

HindawiJournal of ChemistryVolume 2019 Article ID 5602957 11 pageshttpsdoiorg10115520195602957

the antibiotics-resistant bacteria existing in the environ-ment [1 5 9] erefore techniques for eliminating thiscontaminant have received a great attention

Adsorption is often regarded as a common method forthe removal of pollutants in gas and liquid phases [10ndash15]Several strong points of this approach include cost-effectiveness and high performance [16 17] anks tothe good reusability of absorbents the overall cost can bereduced Moreover the adsorption is highly compatible withorganic-derived hazardous wastes including IBU contami-nant [4] erefore the IBU degradation by the adsorptionprocess has been rapidly developed

In the adsorption process solid adsorbents play a de-cisive role in removing the contaminants [18] Heteroge-neous materials have undergone a long history especiallynanostructured zeolites and mesoporous silica [4 19ndash22]anks to the highly porous structure along with open metalsites these materials have been considered as ideal platformstowards diverse applications in fuel cells chemical sensingenergy conversion catalysis drug delivery and thin films[23ndash25] However the synthesis strategies for such materialswere carried out via many elaborate steps combined withsevere condition-controlled reactions limiting their wide-spread applications [26] Several studies reported the use ofhazardous and expensive agents (ie reversible addition-fragmentation chain transfer (RAFT)) as vital componentsthat control the growing of polymeric organic chains incontrolled radical polymerizations thus imposing the ad-verse impacts on the environment [26] It is evident thatfinding out the greener and sustainable pathways for thefabrication of nanostructured materials is necessary

Metal-organic frameworks (MOFs) are advanced ma-terials constructed by metal ions or clusters and organicligands via the coordination bonds [27ndash30] Recently theyare considered as remarkable and promising materials be-cause of good crystallinity complex topologies high po-rosity tunable chemical properties and large metal clusterdensity and thereby MOFs have attractedmuch attention inmany fields such as drug delivery catalysis gas storagesensor and adsorption [31] MIL-53(Fe) or Fe(III)(OH)(14-BDC) is a typical class of MOFs generated by a combinationbetween iron(III) cations and 14-dicarboxylic acid [32 33]is structure consists of FeO6 hexagonal chains connectingwith dicarboxylate anions to form the three-dimensionalnetworks or SBUs (secondary building units) [34ndash36]One of the most emergent features of MIL-53(Fe) comparedwith otherMOFs is the ldquobreathing effectrdquo which experiencesa breathing transition in the presence of guest moleculesthus creating the structural flexibility [37] Moreover this

material can be easily synthesized via the conventionalstrategies such as microwave or solvothermal method[38 39] Unlike the other MOFs such as MIL-88B(Cr) orMIL-101(Cr) which also represents the same ldquobreathingeffectrdquo MIL-53(Fe) is chemically stable and constituted oflower toxic metal centers and thus has gained much at-tention [40]

In this work we described the MIL-53(Fe) synthesis bythe solvothermal method and its application in IBU ad-sorption Some techniques including XRD and FT-IR wereused to analyze the as-synthesized products Moreover theexperiments were optimized based on the response surfacemethodology

2 Experimental

21 Chemicals and Instruments All chemicals in this studywere directly used without any purification 14-Benzene-dicarboxylic acid (H2BDC 98) was purchased fromMerckIron(III) chloride hexahydrate (FeCl3middot6H2O 990) andNN-dimethylformamide (DMF 995) were purchasedfrom Xilong Chemical China

e D8 Advance Bruker powder diffractometer was usedto record the X-ray powder diffraction (XRD) profiles usingCu-Kα beams as excitation sources e FT-IR spectra wererecorded on the Nicolet 6700 spectrophotometer to explorethe functional groups e UV-Vis spectrophotometer wasused to determine the IBU concentration at wavelength222 nm All analytic samples were reactivated at 105degC undernitrogen atmosphere

22 Synthesis of MIL-53(Fe) e MIL-53(Fe) was sol-vothermally prepared according to a recent study [37]Firstly 135 g of FeCl3middot6H2O and 083 g of H2BDC weredissolved in 25mL DMF e mixture was then transferredinto a Teflon-lined autoclave and heated up at 150degC for 6 he yellow solid was extracted refluxed with DMF over-night washed with C2H5OH for three times (3times10mL)and then dried at 80degC for storage in a desiccator Figure 2illustrates the synthesis strategy of MIL-53(Fe)

23 Experimental Batches e stock solutions (20mgL)were prepared by dissolving the IBU substrate in distilledwater Various levels of concentration (18ndash184mgL) forthe adsorption were generated by consecutively diluting theinitial stock solutions A series of HCl and KOH solutionswas utilized to adjust the pH indexes Herein twenty ex-perimental runs were randomly performed at room tem-perature following the response surface methodology (RSM)[42] Firstly MIL-53(Fe) samples (016ndash184 gL) were mixedwith 50mL of ibuprofen solutions (18ndash184mgL) at variousranges of pH e flasks were sealed and placed in theshaking tables (200 rpm) After the adsorption processreached the equilibrium state at 120min the adsorbentsolids were dispended and separated using the simplecentrifugation e IBU residual concentrations wereidentified using UV-Vis spectroscopy at the wavelength of

H3C

CH3

CH3

OH

O

Figure 1 2D structure of the IBU molecule by ChemDrawreg ultra120 program

2 Journal of Chemistry

222 nm e percentage of removal y () and adsorptioncapacity Q (mgg) can be mathematically defined as follows

y() C0 minusCe

C0middot 100

Qt C0 minusCt

mmiddot V

Qe C0 minusCe

mmiddot V

(1)

where C0 Ct and Ce are denoted for the initial concen-tration concentration at time t (min) and equilibriumconcentrations (mgL) andm (g) andV (mL) are denoted foradsorbent mass and solution volume respectively

24 Optimization Model with Response Surface MethodologyResponse surface methodology is the empirically statisticalmethod which allows optimizing the target (y) or ldquoresponserdquobased on the evaluation of chosen variables (xi) [43] In thisstudy three factors as input parameters were selected toinvestigate including IBU concentration (x1) MIL-53 dosage(x2) and pH (x3) eir random experimental runs weredesigned according to the guide of the Design-Expert ver-sion 10 (DX10) program (Table 1)

e ldquoresponserdquo of the model was the removal efficiency(y) and thus the target of this model is to maximize theldquoresponserdquo the function of three variables is given by thefollowing equation

y f(x) βo + 1113944k

i1βixi + 1113944

k

i11113944

k

j1βijxixj + 1113944

k

i1βiix

2i (2)

where y is the predicted response and xi and xj are theindependent variables (i j 1 2 3 4 k) e parameterβo is the offset coefficient βi is the linear coefficient βii isthe second-order coefficient and βij is the interaction co-efficient [44]

25 Error Analysis In this study we explored the nonlinearkinetic and isotherm models using error functions whichwere fitted by the Origin 90 program Error analysis aims todetermine the suitability of any models and their confidencelevel could be assessed via commonplace error functions

[45] us coefficient of determination (R2) mean relativeerror (MRE) and sum square error (SSE) were used andtheir mathematical forms were shown in equations (3)ndash(5)Moreover Qical and Qi exp are the respective calculated andexperimental adsorption capacity values

R2

1113936

ni1 Qiexp minusQiexp1113872 1113873

2minus1113936

ni1 Qiexp minusQical1113872 1113873

2

1113936ni1 Qiexp minusQiexp1113872 1113873

2

(3)

MRE() 100n

1113944

n

i1

Qical minusQiexp

Qiexp

111386811138681113868111386811138681113868111386811138681113868

111386811138681113868111386811138681113868111386811138681113868 (4)

SSE 1113944n

i1Qical minusQiexp1113872 1113873

2 (5)

3 Results and Discussion

31 Structural Characterization of MIL-53(Fe) Figure 3describes the structural characterization of MIL-53(Fe)using the X-ray diffraction patterns and FT-IR spectraAccording to Figure 3(a) several emerging peaks were foundat scanning degree of 95deg (101) 186deg (002) and 282deg (302)indicating that the MIL-53(Fe) obtained a crystallinestructure is observation was also commensurate withseveral previous reports [33 46 47] suggesting that theMIL-53(Fe) was solvothermally synthesized

Moreover the FT-IR spectrum in Figure 3(b) reveals thecollection of functional groups that features the structure ofMIL-53(Fe) (Table 2) [48] In detail a broad vibration ataround 3420 cmminus1 was ascribed to the presence of O-Hgroups which adsorbed water existing in the surface of MIL-53(Fe) [49] e asymmetric (cas C-O) and symmetric(cs C-O) stretching of dicarboxylate linkers could be verified

1 4-BDC FeCl3middot6H2O MIL-53(Fe)

150degC 6hO

O

OH

HO

+

Figure 2 Schematic illustration for the synthesis of the MIL-53(Fe) e simulated structure of MIL-53(Fe) and iron(III) clusters wasreproduced from [41]

Table 1 List of independent variables and their levels

Factors Unit CodeLevels

minusα minus1 0 +1 +αInitial concentration mgL x1 16 5 10 15 184Adsorbent dosage gL x2 016 05 1 15 184pH mdash x3 26 4 6 8 94

Journal of Chemistry 3

by the appearance of sharp vibrations at 1550 cmminus1 and1390 cmminus1 respectively [37] Moreover the carbonyl groups(CO) of carboxylate ligand (COO) were visible at1678 cmminus1 whereas a very sharp peak at 745 cmminus1 wasconsistently corresponding to Csp2-H bending vibrationswhich belong to the aromatic rings of carboxylates [50]Especially the characteristic coordination bonds betweenFe3+ cations and -OOC-C6H4-COO- carboxylate anionswere observed at the low wavenumber (540 cmminus1) revealingthe existence of a Fe-oxo bond inherent in the structure ofMIL-53(Fe) [51] erefore a combination of two charac-terization results demonstrates that the crystals of MIL-53(Fe) were successfully fabricated

e morphological properties of MIL-53(Fe) can be an-alyzed by the SEM technique Figure 4 showed the MIL-53(Fe) particles at 100 and 10 microm which generally well-described the polyhedron-like crystalline structure [32]However a clear difference of MIL-53(Fe) samples could beobserved between before and after purification Figure 4(b)demonstrated that a certain part of as-synthesized MIL-53(Fe) morphology was not homogeneous which may beattributable to the residual 14-BDC components A previousstudy also implied that this precursor may encapsulate the as-synthesized MIL-53(Fe) crystals [52] Meanwhile Figure 4(c)showed a relatively smooth surface of refined MIL-53(Fe)along with the complete disappearance of amorphous solidphases suggesting that the refinement of as-synthesized MIL-53(Fe) was necessary to eliminate the 14-BDC trace [52]

Figure 5(a) diagnosed the textual feature of MIL-53(Fe)using the Raman spectrum Clearly a shape peak could beobserved at the Raman shift of 464 cmminus1 revealing theexistence of gamma bond of Fe-oxo in the structure ofMIL-53(Fe) Also typical peaks of the aromatic C-H bondwere found at 632 and 865 cmminus1 while the single peak at

1141 cmminus1 was ascribed for the bonds between two sp2-hydrid carbon atoms of benzene rings and carboxylategroups Importantly the asymmetric (cas C-O) andsymmetric (cs C-O) footprints of COO- linkers were againconfirmed via a couple of consecutive peaks at 1451 and1501 cmminus1 respectively Finally ](CC) was a kind oftypical bond of aromatic cycles which were emergent at1616 cmminus1

To gain the insights into the nature of porosity and poresize in MIL-53(Fe) the pore size distribution was measuredand shown in Figure 5(b) It is evident that pore diameters ofMIL-53(Fe) exhibited a wide range of sizes revealing theexistence of both micropore and macropore in the structurebut macrosize pore (more than 50 nm) was utterly domi-nant Notice that there was an infinitesimal amount ofmicropore which was less than 2 nm in length Moreoverthe surface area of MIL-53(Fe) was determined by the N2adsorption-desorption isotherm at 77K which was found tobe 55m2g Tuan et al also reported the very low surfacearea at about 14m2g which may be attributable to theclosed pores of MIL-53(Fe) that prevent the arrival of ni-trogen molecules [49]

32 Optimization of the Ibuprofen Absorbability of MIL-53(Fe) by RSM Tool Herein we applied the RSM to opti-mize the removal of IBU in water using theMIL-53(Fe) as anadsorbent All experiments were designed and analyzedstatistically using the DX10 [11] In detail three independentvariables including initial IBU concentration MIL-53(Fe)adsorbent dosage and pH solution at various five levels wereinvestigated e relationship between IBU removal effi-ciency and three independent variables can be described bythe following equation

5 10 15 20 25 302θ (deg)

Inte

nsity

(au

)

(101) (002)

(302)

(a)

Inte

nsity

(au

)

500 1000 1500 2000 2500 3000 3500 4000Wavenumber (cmndash1)

C-HFe-O

C=O

OH

γs (C-O)

γas (C-O)

(b)

Figure 3 X-ray diffraction patterns (a) and FT-IR spectra of MIL-53(Fe) (b)

Table 2 e surface functional groups analysis of MIL-53(Fe)

Functional groups O-H CO cas (C-O) cs (C-O) C-H Fe-OWavenumber (cmminus1) 3420 1678 1550 1390 745 540


y() 2156minus 521x1 + 715x2 minus 1958x3

+ 683x1x2 + 088x1x3 minus 435x2x3

+ 497x21 + 569x

22 + 1110x

23

or IBU removal() 2156minus 521(C) + 715(dose)

minus 1958(pH) + 683(C)(dose)

+ 088(C)(pH)

minus 435(dose)(pH) + 497(C)2

+ 569(dose)2 + 1110(pH)2

(6)

e actual and predicted values for the experimentalmatrix were listed in Table 3 Table 4 illustrates the co-efficients of ANOVA data including the sum of squaresdegree of freedom mean square F value and Probgt F [43]

Interestingly determination coefficients (R2) and P values ofthe regression model were found to be 09621 and lt00001with the confidence level of 95 respectively us theproposed quadratic model was statistically significant andcould be used to assess the effect of factors (initial IBUconcentration MIL-53(Fe) adsorbent dosage and pH) on theIBU absorbability of MIL-53(Fe) [48] Figure 6(a) also in-dicates the high compatibility of experimental and predictedvalues as their data points were closely distributed to the 45-degree line

Figures 6(b)ndash6(d) showing the three-dimensional re-sponse surfaces reveal the consistent impacts of three factorson the IBU drug removal efficiencies of MIL-53(Fe) Gen-erally the removal process of IBU was conducive with anincrease in the amount of the MIL-53 adsorbent or a de-crease in pH values of IBU solutions Meanwhile the initialconcentration of IBU solution shows a negligible effect onthe IBU removal efficiency

10 μm10 μm100 μm

Figure 4 SEM images of MIL-53(Fe) before (a b) and after refinement (c)

7000

5000

3000

1000

Ram

an in

tens

ity (a

u)

0 500 1000 1500 2000 2500 3000Raman shi (cmndash1)

632 cmndash1

1616 cmndash1

1501 cmndash1

1451 cmndash1

1141 cmndash1

865 cmndash1

(a)

1 10 100Pore diameter (nm)

004

003

002

001

000

dVd

log(D

) por

e vol

ume (

cm3 g

)

dVdlog(D)pore volume (cm3g)

(b)

Figure 5 Raman spectrum (a) and pore size distribution (b) of MIL-53(Fe)


Understandably the improvement of IBU removalpercentage may be ascribed to the presence of ldquoadsorptionsitesrdquo [53] When an addition of adsorbent was considerableldquoadsorption sitesrdquo containing the surface functional groupsbecame more dominant thus increasing the number of IBUmolecules captured [54 55] By contrast a decline in theamount of the MIL-53(Fe) adsorbent may result in the rapidsaturation of adsorption sites possibly rendering thetreatment of IBU drug ineffective

Importantly the decontamination of the IBU pollutantreached the excellent results in the acidic media while thefigures for the basicneutral solutions were clearly un-favorable In detail Figure 6(d) indicates that nearly 100 ofIBU could be removed from water at the very low pH values(ie pH 26ndash43) and high adsorbent dosage (15ndash184 gL)

By applying the RSM via model confirmation severaloptimal conditions were proposed including the factorsalong with the predicted response value (Table 5) To test theprecision and confidence of proposed optimized conditionsa verification experiment was performed using the aboveproposed conditions e observed results were in goodagreement with the predicted results because there was anineligible error between predicted and tested results andldquodesirabilityrdquo values were obtained up to 100 reflecting theexcellent closeness of response (y) to their ideal values [56]In other words the model for the optimization of IBUadsorption over MIL-53(Fe) in this study achieved the highcompatibility and thus could be used to design and optimizethe experimental conditions

33 Adsorption Studies To gain deeper insights intothe adsorption mechanism and behavior of IBU over

MIL-53(Fe) herein the nonlinear kinetic and isothermmodels could be adopted All experiments were conducted atroom temperature and other experimental conditions werechosen from model optimization (Table 5) at initial con-centration (10mgL) dosage (10 gL) and pH 26 Note thatsamples were extracted for regular time intervals (0 10 2040 60 80 100 and 120min) to investigate the kinetic studywhile IBU concentrations were in range from 5 to 20mgLFinal IBU content could be measured by using a UV-Visspectrophotometer at 222 nm

Any selected model needs to meet the requirements interms of R2 MRE () and SSE Amodel with a high R2 valueindicates that the predicted data are fitted well with actualdata [45] Meanwhile lower MRE and SSE values reveal thenegligible magnitude of error functions To assess themodels therefore terms of R2 MRE () and SSE wereadded herein

For the kinetic models we optioned four equationsincluding pseudo-first-order pseudo-second-order Elovichand Bangham which their mathematical forms were illus-trated in the equations given in Table 6 Figure 7(a) illus-trates the effect of uptake capacity on contact time It isevident that the adsorption process reached an equilibriumnature after 90min According to Table 6 all kinetic modelsobtained an excellent fitness based on R2 values (0981ndash0992) indicating the high compatibility between actual andproposed data Nevertheless among the models the pseudo-second-order equation offered the highest degree of suit-ability because of the highest R2 smallest SSE and very lowMRE () In fact Elovich model showed the lowest MRE(315) but its SSE value was so far higher than the pseudo-second-order model 744 compared with 039 respectivelyerefore the pseudo-second-order model could be used toexplore the adsorption mechanism of the IBU species ontothe adsorbent which chemisorption plays a crucial role

For the isotherm models four equations includingLangmuir Freundlich Temkin and Dubinin and Radush-kevich (D-R) were applied Similar to the kinetic modelstheir mathematical forms were explained in equations givenin Table 7 Obviously the Langmuir demonstrated the mostappropriate model via the highest R2 and lowest MRE andSSE values suggesting that the monolayer mechanism ismore inclining to others e maximum adsorption capacity(Qm) obtained from the Langmuir equation was calculated at1067mgg revealing the favorable adsorption and goodcapacity of IBU onto MIL-53(Fe)

4 Conclusion

e MIL-53(Fe) material was successfully synthesized fromthe precursors including FeCl3middot6H2O and 14-BDC via thesolvothermal method and structurally characterized usingthe X-ray diffraction patterns FT-IR spectra SEM pore sizedistribution and Raman e characterization results im-plied that the MIL-53(Fe) possessed the crystalline structurealong with a low surface area (55m2g) Moreover im-portant functional groups were found (Fe-O COO COC-O C-H and O-H) proving the presence of these chemicalbonds in the structure of MIL-53(Fe) For the optimization

Table 3 Experimental design used for investigation of IBU re-moval over MIL-53(Fe)

NVariables IBU removal

efficiency ()x1 x2 x3 Observed Predicted

1 5 05 4 698 6432 15 05 4 438 3853 5 15 4 80 7374 15 15 4 787 7515 5 05 8 358 3216 15 05 8 107 987 5 15 8 26 2418 15 15 8 308 2909 16 1 6 375 44410 184 1 6 235 26911 10 016 6 20 25612 10 184 6 451 49713 10 1 26 771 85914 10 1 104 186 20015 10 1 6 226 21616 10 1 6 177 21617 10 1 6 238 21618 10 1 6 25 21619 10 1 6 20 21620 10 1 6 22 216


experiment of ibuprofen over MIL-53(Fe) the RSM resultsindicated that all variables (IBU initial concentration MIL-53(Fe) dosage and pH had a vital impact on the IBU re-moval efficiency through the very high determination ofcoefficient (R2gt 09) and very low P value (Plt 00001) Also

the proposed model was statistically significant and could beused to find out the optimal conditions e confirmationtests also proved that the model was highly compatible withexperimental data because the observed values was con-sistent with the predicted values and high removal efficiency

Table 4 ANOVA data for the IBU removal models

Source Sum of squares Freedom degree Mean square F value Probgt F NoteModel 909312 9 101035 2818 lt00001S

SSignificant at plt 005NNonsignificant at pgt 005

x1 37063 1 37063 1034 00093S

x2 69769 1 69769 1946 00013S

x3 523508 1 523508 14600 lt00001S(x1)2 37265 1 37265 1039 00091S

(x2)2 613 1 613 01708 06881N

(x3)2 15138 1 15138 422 00670N

x1 middot x2 35618 1 35618 993 00103S

x1 middot x3 46761 1 46761 1304 00048S

x2 middot x3 177741 1 177741 4957 lt00001S

Fit statistics standard deviations (Std) 317 mean 3643 CV () 1644 R2 09621

100

80

60

40

20

0

Pred

icte

d

0 20 40 60 80 100Actual

107 80

(a)

016058

1142

184

Dosage (gL)

70

58

46

34

22

10

1658

10142

184Concentration (mgL)

IBU

rem

oval

()

(b)

100

82

64

46

28

10

2643

677

94pH (ndash)

1658

10142


IBU

rem

oval

()

(c)

100

82

64

46

28

10

2643

677

94pH (ndash)

016058

1142

184Dosage (gL)

IBU

rem

oval

()

(d)

Figure 6 Actual versus predicted plots (a) and three-dimensional response surfaces (b)ndash(d) presenting the effect of factors on the response


Table 5 Optimal conditions and confirmation runs

Concentration (mgL) Dosage (gL) pH (ndash)IBU removal efficiency ()

ldquoDesirabilityrdquoPredicted () Tested () Error ()

547 067 30 823 802 minus255 100001000 100 26 859 808 minus594 10000811 151 35 832 800 minus373 10000

Table 6 Nonlinear kinetic constants for the adsorption of IBU over MIL-53(Fe)

Kinetic models Equation Parameters Value

Pseudo-first-order Qt Q1 middot (1minus exp(minusk1t))

k1 (minminus1) 00496Q1 (mgg) 787MRE () 529

SSE 083(Radj)2 0983

Pseudo-second-order Qt t((1k2Q22) + (tQ2))

H k2 middot Q22

k2 (gmgmiddotmin) 00063Q2 (mgg) 928

H (mggmiddotmin) 0543MRE () 367

SSE 039(Radj)2 0992

Elovich Qt (1β)(ln(1 + αβt))

α (mggmiddotmin) 11β (gmg) 05MRE () 315

SSE 744(Radj)2 0989

Bangham Qt kB middot tαB

kB (mL(gL)) 198αB 030

MRE () 502SSE 1305

(Radj)2 0981

10

8

6

4

2

00 30 60 90 120 150

Pseudo-second-order

Pseudo-first-order

Elovich

Contact time (min)

Qt (

mg

g)

BanghamAdsorptioncapacity (mgg)

(a)

12

9

6

3

00 5 10 15 20

LangmuirFreundlichTemkin

Ce (mgL)

Qe (

mg

g)

D-REquilibriumcapacity (mgg)

(b)

Figure 7 Kinetic and isotherm models for adsorption of IBU onto MIL-53(Fe) Experimental conditions consisted of initial concentration(10mgL) dosage (10 gL) and pH 26 at room temperature


obtained (800ndash808) Kinetic and isotherm models alsosuggested that the adsorption process obeyed the chemi-sorption and monolayer behavior mechanisms

Data Availability

No data were used to support this study

Conflicts of Interest

e authors declare that there are no conflicts of interest

Acknowledgments

is research was funded by NTTU Foundation for Scienceamp Technology Development (Grant no 20180115HETH-KHCN) and Center of Science and Technology Develop-ment for Youth Ho Chi Minh City Communist YouthUnion Vietnam (no 062018HETH-KHCN-VƯ)

References

[1] S Sarre L Maattanen T L J Tammela A Auvinen andT J Murtola ldquoPostscreening follow-up of the Finnishprostate cancer screening trial on putative prostate cancer riskfactors vitamin and mineral use male pattern baldnesspubertal development and non-steroidal anti-inflammatorydrug userdquo Scandinavian Journal of Urology vol 50 no 4pp 267ndash273 2016

[2] B R da Costa S Reichenbach N Keller et al ldquoEffectivenessof non-steroidal anti-inflammatory drugs for the treatment ofpain in knee and hip osteoarthritis a network meta-analysisrdquoe Lancet vol 390 no 10090 pp e21ndashe33 2017

[3] T-S Vo D-H Ngo L G Bach D-N Ngo and S-K Kimldquoe free radical scavenging and anti-inflammatory activities

of gallate-chitooligosaccharides in human lung epithelialA549 cellsrdquo Process Biochemistry vol 54 pp 188ndash194 2017

[4] A K Nguyen T H Nguyen B Q Bao L G Bach andD H Nguyen ldquoEfficient self-assembly of mPEG end-cappedporous silica as a redox-sensitive nanocarrier for controlleddoxorubicin deliveryrdquo International Journal of Biomaterialsvol 2018 Article ID 1575438 8 pages 2018

[5] T D Brezinova J Vymazal M Kozeluh and L KuleldquoOccurrence and removal of ibuprofen and its metabolites infull-scale constructed wetlands treating municipal wastewa-terrdquo Ecological Engineering vol 120 pp 1ndash5 2018

[6] S Adityosulindro C Julcour and L Barthe ldquoHeterogeneousFenton oxidation using Fe-ZSM5 catalyst for removal ofibuprofen in wastewaterrdquo Journal of Environmental ChemicalEngineering vol 6 no 5 pp 5920ndash5928 2018

[7] H A Hasan S R S Abdullah A W N Al-Attabi et alldquoRemoval of ibuprofen ketoprofen COD and nitrogencompounds from pharmaceutical wastewater using aerobicsuspension-sequencing batch reactor (ASSBR)rdquo Separationand Purification Technology vol 157 pp 215ndash221 2016

[8] S Saeid P Tolvanen N Kumar et al ldquoAdvanced oxidationprocess for the removal of ibuprofen from aqueous solution anon-catalytic and catalytic ozonation study in a semi-batchreactorrdquo Applied Catalysis B Environmental vol 230pp 77ndash90 2018

[9] Y Luo W Guo H H Ngo et al ldquoA review on the occurrenceof micropollutants in the aquatic environment and their fateand removal during wastewater treatmentrdquo Science of theTotal Environment vol 473-474 pp 619ndash641 2014

[10] T Vanuan B T P Quynh T D Nguyen V T T Ho andL G Bach ldquoResponse surface methodology approach foroptimization of Cu2+ Ni2+ and Pb2+ adsorption using KOH-activated carbon from banana peelrdquo Surfaces and Interfacesvol 6 pp 209ndash217 2017

[11] T Van Tran Q T P Bui T D Nguyen N T H Le andL G Bach ldquoA comparative study on the removal efficiency ofmetal ions (Cu2+ Ni2+ and Pb2+) using sugarcane bagasse-

Table 7 Nonlinear isotherm constants for the adsorption of IBU over MIL-53(Fe)


Langmuir Qe (QmKLCe)(1 + KLCe)

RL 1(1 + KLCo)

kL (Lmg) 180Qm (mgg) 1067

RL 003MRE () 246

SSE 018(Radj)2 0997

Freundlich Qe KFC1ne

kF (mgg)(mgL)1n 6391n 022

MRE () 643SSE 098

(Radj)2 0980

Temkin Qe BT ln(kTCe)

BT (RT)b

kT (Lmg) 3924BT 177

MRE () 313SSE 031

(Radj)2 0993

D-R Qe Qm exp(minusBε2)ε RT ln(1 + (1Ce))

E 1(2B

radic)

B 008Qm (mgg) 972E (kJmol) 247MRE () 534

SSE 118(Radj)2 0978


derived ZnCl2-activated carbon by the response surfacemethodologyrdquo Adsorption Science amp Technology vol 35no 1-2 pp 72ndash85 2017

[12] T Van Tran Q T P Bui T D Nguyen V T T Ho andL G Bach ldquoApplication of response surface methodology tooptimize the fabrication of ZnCl2-activated carbon fromsugarcane bagasse for the removal of Cu2+rdquo Water Scienceand Technology vol 75 no 9 pp 2047ndash2055 2017

[13] H N Tran Y-F Wang S-J You and H-P Chao ldquoInsightsinto the mechanism of cationic dye adsorption on activatedcharcoal the importance of π-π interactionsrdquo Process Safetyand Environmental Protection vol 107 pp 168ndash180 2017

[14] H N Tran H-P Chao and S-J You ldquoActivated carbonsfrom golden shower upon different chemical activationmethods synthesis and characterizationsrdquo Adsorption Scienceamp Technology vol 36 no 1-2 pp 95ndash113 2018

[15] S-A Sajjadi A Mohammadzadeh H N Tran et al ldquoEfficientmercury removal from wastewater by pistachio wood wastes-derived activated carbon prepared by chemical activationusing a novel activating agentrdquo Journal of EnvironmentalManagement vol 223 pp 1001ndash1009 2018

[16] T V Pham T T Nguyen D T Nguyen et al ldquoe prep-aration and characterization of expanded graphite via mi-crowave irradiation and conventional heating for thepurification of oil contaminated waterrdquo Journal of Nano-science and Nanotechnology vol 19 no 2 pp 1122ndash11252019

[17] P Boakye H N Tran D S Lee and S H Woo ldquoEffect ofwater washing pretreatment on property and adsorptioncapacity of macroalgae-derived biocharrdquo Journal of Envi-ronmental Management vol 233 pp 165ndash174 2019

[18] S Sabale V Jadhav V Khot X Zhu M Xin and H ChenldquoSuperparamagnetic MFe2O4 (MNi Co Zn Mn) nano-particles synthesis characterization induction heating andcell viability studies for cancer hyperthermia applicationsrdquoJournal of Materials Science Materials in Medicine vol 26no 3 p 127 2015

[19] B Q Bao N H Le D H T Nguyen et al ldquoEvolution andpresent scenario of multifunctionalized mesoporous nano-silica platform a mini reviewrdquo Materials Science and Engi-neering C vol 91 pp 912ndash928 2018

[20] S Singh M B Bahari B Abdullah et al ldquoBi-reforming ofmethane on NiSBA-15 catalyst for syngas production in-fluence of feed compositionrdquo International Journal of Hy-drogen Energy vol 43 no 36 pp 17320ndash17243 2018

[21] S Zhao Z Zhang G Sebe et al ldquoMultiscale assembly ofsuperinsulating silica aerogels within silylated nanocellulosicscaffolds improved mechanical properties promoted bynanoscale chemical compatibilizationrdquo Advanced FunctionalMaterials vol 25 no 15 pp 2326ndash2334 2015

[22] H Q Pham T T Huynh A Van Nguyen T Van uanL G Bach and V T anh Ho ldquoAdvanced Ti07W03O2nanoparticles prepared via solvothermal process using tita-nium tetrachloride and tungsten hexachloride as precursorsrdquoJournal of Nanoscience and Nanotechnology vol 18 no 10pp 7177ndash7182 2018

[23] D W Kim L G Bach S-S Hong C Park and K T Lim ldquoAfacile route towards the synthesis of Fe3O4graphene oxidenanocomposites for environmental applicationsrdquo MolecularCrystals and Liquid Crystals vol 599 no 1 pp 43ndash50 2014

[24] Y V Kaneti J Tang R R Salunkhe et al ldquoNanoarchitectureddesign of porous materials and nanocomposites from metal-organic frameworksrdquo Advanced Materials vol 29 no 12article 1604898 2017

[25] M-H Sun S-Z Huang L-H Chen et al ldquoApplications ofhierarchically structured porous materials from energystorage and conversion catalysis photocatalysis adsorptionseparation and sensing to biomedicinerdquo Chemical SocietyReviews vol 45 no 12 pp 3479ndash3563 2016

[26] L G Bach V T T Ho B T P Quynh K T Lim andT C Anh ldquoSynthesis of well-defined amphiphilic diblockcopolymer brushes on halloysite nanotubes via surface-initiated reversible addition-fragmentation chain transferpolymerizationrdquo Journal of Nanoscience and Nanotechnologyvol 17 no 8 pp 5834ndash5838 2017

[27] H V Dang Y T N Le D T M Tran A N Q Phan andN T S Phan ldquoSynthesis of benzo[14]thiazines via ring ex-pansion of 2-aminobenzothiazoles with terminal alkynesunder metalndashorganic framework catalysisrdquo Catalysis Lettersvol 148 no 5 pp 1383ndash1395 2018

[28] V D Nguyen C K Nguyen K N Tran et al ldquoZeoliteimidazolate frameworks in catalysis synthesis of benzimid-azoles via cascade redox condensation using Co-ZIF-67 as anefficient heterogeneous catalystrdquoApplied Catalysis A Generalvol 555 pp 20ndash26 2018

[29] T V Tran H T N Le H Q Ha et al ldquoA five coordinationCu(II) cluster-based MOF and its application in the synthesisof pharmaceuticals via sp3 C-HN-H oxidative couplingrdquoCatalysis Science amp Technology vol 7 no 16 pp 3453ndash34582017

[30] H T N Le T V Tran N T S Phan and T Truong ldquoEfficientand recyclable Cu2(BDC)2(BPY)-catalyzed oxidative amida-tion of terminal alkynes role of bipyridine ligandrdquo CatalysisScience amp Technology vol 5 no 2 pp 851ndash859 2015

[31] Y-Z Chen R Zhang L Jiao and H-L Jiang ldquoMetalndashorganicframework-derived porous materials for catalysisrdquo Co-ordination Chemistry Reviews vol 362 pp 1ndash23 2018

[32] Z Yan W Zhang J Gao et al ldquoReverse-phase high per-formance liquid chromatography separation of positionalisomers on a MIL-53(Fe) packed columnrdquo RSC Advancesvol 5 no 50 pp 40094ndash40102 2015

[33] N D Trinh and S-S Hong ldquoPhotocatalytic decomposition ofmethylene blue over MIL-53(Fe) prepared using microwave-assisted process under visible light irradiationrdquo Journal ofNanoscience and Nanotechnology vol 15 no 7 pp 5450ndash5454 2015

[34] S H Doan K D Nguyen T T Nguyen and N T S PhanldquoDirect arylation of benzoazoles with aldehydes utilizingmetalndashorganic framework Fe3O(BDC)3 as a recyclable het-erogeneous catalystrdquo RSC Advances vol 7 no 3 pp 1423ndash1431 2017

[35] H L Nguyen ldquoe chemistry of titanium-based metalndashorganic frameworksrdquo New Journal of Chemistry vol 41no 23 pp 14030ndash14043 2017

[36] P H Pham S H Doan H T T Tran et al ldquoA new trans-formation of coumarins via direct C-H bond activation utilizingan iron-organic framework as a recyclable catalystrdquo CatalysisScience amp Technology vol 8 no 5 pp 1267ndash1271 2018

[37] Y Zhang G Li H Lu Q Lv and Z Sun ldquoSynthesischaracterization and photocatalytic properties of MIL-53(Fe)-graphene hybrid materialsrdquo RSC Advances vol 4 no 15pp 7594ndash7600 2014

[38] T H Tu P T N Cam L V T Huy M T Phong H M Namand N H Hieu ldquoSynthesis and application of graphene oxideaerogel as an adsorbent for removal of dyes from waterrdquoMaterials Letters vol 238 pp 134ndash137 2019

[39] T V Tran D T C Nguyen H T N Le et al ldquoMIL-53 (Fe)-directed synthesis of hierarchically mesoporous carbon and its


utilization for ciprofloxacin antibiotic remediationrdquo Journalof Environmental Chemical Engineering vol 7 no 1 article102881 2019

[40] J-J Du Y-P Yuan J-X Sun et al ldquoNew photocatalysts basedon MIL-53 metalndashorganic frameworks for the decolorizationof methylene blue dyerdquo Journal of Hazardous Materialsvol 190 no 1ndash3 pp 945ndash951 2011

[41] W Lu Z Wei Z-Y Gu et al ldquoTuning the structure andfunction of metalndashorganic frameworks via linker designrdquoChemical Society Reviews vol 43 no 16 pp 5561ndash5593 2014

[42] V T Tran D T Nguyen V T T Ho P Q H HoangP Q Bui and L G Bach ldquoEfficient removal of Ni2 ions fromaqueous solution using activated carbons fabricated from ricestraw and tea wasterdquo Journal of Materials and EnvironmentalScience vol 8 pp 426ndash437 2017

[43] T Van uan V T T Ho N D Trinh N T uongB T P Quynh and L G Bach ldquoFacile one-spot synthesis ofhighly porous KOH-activated carbon from rice husk re-sponse surface methodology approachrdquo Carbon-Science andTechnology vol 8 pp 63ndash69 2016

[44] P Samoila C Cojocaru I Cretescu et al ldquoNanosized spinelferrites synthesized by sol-gel autocombustion for opti-mized removal of azo dye from aqueous solutionrdquo Journalof Nanomaterials vol 2015 Article ID 713802 13 pages2015

[45] T V Tran V D Cao V H Nguyen et al ldquoMIL-53 (Fe)derived magnetic porous carbon as a robust adsorbent for theremoval of phenolic compounds under the optimized con-ditionsrdquo Journal of Environmental Chemical Engineeringvol 7 article 102902 2019

[46] J Gordon H Kazemian and S Rohani ldquoRapid and efficientcrystallization of MIL-53(Fe) by ultrasound and microwaveirradiationrdquoMicroporous and Mesoporous Materials vol 162pp 36ndash43 2012

[47] P Horcajada T Chalati C Serre et al ldquoPorous metalndashorganic-framework nanoscale carriers as a potential platformfor drug delivery and imagingrdquoNature Materials vol 9 no 2pp 172ndash178 2010

[48] L G Bach T Van Tran T D Nguyen T Van Pham andS T Do ldquoEnhanced adsorption of methylene blue ontographene oxide-doped XFe2O4 (XCo Mn Ni) nano-composites kinetic isothermal thermodynamic and recy-clability studiesrdquo Research on Chemical Intermediates vol 44no 3 pp 1661ndash1687 2018

[49] T A Vu G H Le C D Dao et al ldquoArsenic removal fromaqueous solutions by adsorption using novel MIL-53(Fe) as ahighly efficient adsorbentrdquo RSC Advances vol 5 no 7pp 5261ndash5268 2015

[50] R Liang F Jing L Shen N Qin and LWu ldquoMIL-53(Fe) as ahighly efficient bifunctional photocatalyst for the simulta-neous reduction of Cr(VI) and oxidation of dyesrdquo Journal ofHazardous Materials vol 287 pp 364ndash372 2015

[51] P Serra-Crespo E Gobechiya E V Ramos-Fernandez et alldquoInterplay of metal node and amine functionality in NH2-MIL-53 modulating breathing behavior through intra-framework interactionsrdquo Langmuir vol 28 no 35pp 12916ndash12922 2012

[52] M-T H Nguyen andQ-T Nguyen ldquoEfficient refinement of ametalndashorganic framework MIL-53(Fe) by UV-vis irradiationin aqueous hydrogen peroxide solutionrdquo Journal of Photo-chemistry and Photobiology A Chemistry vol 288 pp 55ndash592014

[53] S-S Li W-Y Zhou M Jiang et al ldquoInsights into diverseperformance for the electroanalysis of Pb(II) on Fe2O3

nanorods and hollow nanocubes toward analysis of ad-sorption sitesrdquo Electrochimica Acta vol 288 pp 42ndash51 2018

[54] H N Tran C-C Lin S H Woo and H-P Chao ldquoEfficientremoval of copper and lead by MgAl layered double hy-droxides intercalated with organic acid anions adsorptionkinetics isotherms and thermodynamicsrdquo Applied ClayScience vol 154 pp 17ndash27 2018

[55] H N Tran P V Viet and H-P Chao ldquoSurfactant modifiedzeolite as amphiphilic and dual-electronic adsorbent for re-moval of cationic and oxyanionic metal ions and organiccompoundsrdquo Ecotoxicology and Environmental Safetyvol 147 pp 55ndash63 2018

[56] M A Bezerra R E Santelli E P Oliveira L S Villar andL A Escaleira ldquoResponse surface methodology (RSM) as atool for optimization in analytical chemistryrdquo Talanta vol 76no 5 pp 965ndash977 2008


TribologyAdvances in

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Advances inPhysical Chemistry

Hindawiwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2018

Bioinorganic Chemistry and ApplicationsHindawiwwwhindawicom Volume 2018

SpectroscopyInternational Journal of


Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Medicinal ChemistryInternational Journal of


NanotechnologyHindawiwwwhindawicom Volume 2018

Journal of

Applied ChemistryJournal of



Biochemistry Research International


Enzyme Research


Journal of

SpectroscopyAnalytical ChemistryInternational Journal of


MaterialsJournal of



BioMed Research International Electrochemistry

International Journal of


Na

nom

ate

ria

ls


Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

the antibiotics-resistant bacteria existing in the environ-ment [1 5 9] erefore techniques for eliminating thiscontaminant have received a great attention

Adsorption is often regarded as a common method forthe removal of pollutants in gas and liquid phases [10ndash15]Several strong points of this approach include cost-effectiveness and high performance [16 17] anks tothe good reusability of absorbents the overall cost can bereduced Moreover the adsorption is highly compatible withorganic-derived hazardous wastes including IBU contami-nant [4] erefore the IBU degradation by the adsorptionprocess has been rapidly developed

In the adsorption process solid adsorbents play a de-cisive role in removing the contaminants [18] Heteroge-neous materials have undergone a long history especiallynanostructured zeolites and mesoporous silica [4 19ndash22]anks to the highly porous structure along with open metalsites these materials have been considered as ideal platformstowards diverse applications in fuel cells chemical sensingenergy conversion catalysis drug delivery and thin films[23ndash25] However the synthesis strategies for such materialswere carried out via many elaborate steps combined withsevere condition-controlled reactions limiting their wide-spread applications [26] Several studies reported the use ofhazardous and expensive agents (ie reversible addition-fragmentation chain transfer (RAFT)) as vital componentsthat control the growing of polymeric organic chains incontrolled radical polymerizations thus imposing the ad-verse impacts on the environment [26] It is evident thatfinding out the greener and sustainable pathways for thefabrication of nanostructured materials is necessary

Metal-organic frameworks (MOFs) are advanced ma-terials constructed by metal ions or clusters and organicligands via the coordination bonds [27ndash30] Recently theyare considered as remarkable and promising materials be-cause of good crystallinity complex topologies high po-rosity tunable chemical properties and large metal clusterdensity and thereby MOFs have attractedmuch attention inmany fields such as drug delivery catalysis gas storagesensor and adsorption [31] MIL-53(Fe) or Fe(III)(OH)(14-BDC) is a typical class of MOFs generated by a combinationbetween iron(III) cations and 14-dicarboxylic acid [32 33]is structure consists of FeO6 hexagonal chains connectingwith dicarboxylate anions to form the three-dimensionalnetworks or SBUs (secondary building units) [34ndash36]One of the most emergent features of MIL-53(Fe) comparedwith otherMOFs is the ldquobreathing effectrdquo which experiencesa breathing transition in the presence of guest moleculesthus creating the structural flexibility [37] Moreover this

material can be easily synthesized via the conventionalstrategies such as microwave or solvothermal method[38 39] Unlike the other MOFs such as MIL-88B(Cr) orMIL-101(Cr) which also represents the same ldquobreathingeffectrdquo MIL-53(Fe) is chemically stable and constituted oflower toxic metal centers and thus has gained much at-tention [40]

In this work we described the MIL-53(Fe) synthesis bythe solvothermal method and its application in IBU ad-sorption Some techniques including XRD and FT-IR wereused to analyze the as-synthesized products Moreover theexperiments were optimized based on the response surfacemethodology

2 Experimental

21 Chemicals and Instruments All chemicals in this studywere directly used without any purification 14-Benzene-dicarboxylic acid (H2BDC 98) was purchased fromMerckIron(III) chloride hexahydrate (FeCl3middot6H2O 990) andNN-dimethylformamide (DMF 995) were purchasedfrom Xilong Chemical China

e D8 Advance Bruker powder diffractometer was usedto record the X-ray powder diffraction (XRD) profiles usingCu-Kα beams as excitation sources e FT-IR spectra wererecorded on the Nicolet 6700 spectrophotometer to explorethe functional groups e UV-Vis spectrophotometer wasused to determine the IBU concentration at wavelength222 nm All analytic samples were reactivated at 105degC undernitrogen atmosphere

22 Synthesis of MIL-53(Fe) e MIL-53(Fe) was sol-vothermally prepared according to a recent study [37]Firstly 135 g of FeCl3middot6H2O and 083 g of H2BDC weredissolved in 25mL DMF e mixture was then transferredinto a Teflon-lined autoclave and heated up at 150degC for 6 he yellow solid was extracted refluxed with DMF over-night washed with C2H5OH for three times (3times10mL)and then dried at 80degC for storage in a desiccator Figure 2illustrates the synthesis strategy of MIL-53(Fe)

23 Experimental Batches e stock solutions (20mgL)were prepared by dissolving the IBU substrate in distilledwater Various levels of concentration (18ndash184mgL) forthe adsorption were generated by consecutively diluting theinitial stock solutions A series of HCl and KOH solutionswas utilized to adjust the pH indexes Herein twenty ex-perimental runs were randomly performed at room tem-perature following the response surface methodology (RSM)[42] Firstly MIL-53(Fe) samples (016ndash184 gL) were mixedwith 50mL of ibuprofen solutions (18ndash184mgL) at variousranges of pH e flasks were sealed and placed in theshaking tables (200 rpm) After the adsorption processreached the equilibrium state at 120min the adsorbentsolids were dispended and separated using the simplecentrifugation e IBU residual concentrations wereidentified using UV-Vis spectroscopy at the wavelength of

H3C

CH3

CH3

OH

O

Figure 1 2D structure of the IBU molecule by ChemDrawreg ultra120 program



y() C0 minusCe

C0middot 100

Qt C0 minusCt

mmiddot V

Qe C0 minusCe

mmiddot V

(1)




y f(x) βo + 1113944k

i1βixi + 1113944

k

i11113944

k


k

i1βiix

2i (2)




R2

1113936


2minus1113936


2


2

(3)

MRE() 100n

1113944

n

i1

Qical minusQiexp

Qiexp

111386811138681113868111386811138681113868111386811138681113868

111386811138681113868111386811138681113868111386811138681113868 (4)

SSE 1113944n


2 (5)





150degC 6hO

O

OH

HO

+












5 10 15 20 25 302θ (deg)

Inte

nsity

(au

)

(101) (002)

(302)

(a)

Inte

nsity

(au

)


C-HFe-O

C=O

OH

γs (C-O)

γas (C-O)

(b)





y() 2156minus 521x1 + 715x2 minus 1958x3

+ 683x1x2 + 088x1x3 minus 435x2x3

+ 497x21 + 569x

22 + 1110x

23



+ 088(C)(pH)


+ 569(dose)2 + 1110(pH)2

(6)




10 μm10 μm100 μm


7000

5000

3000

1000

Ram

an in

tens

ity (a

u)


632 cmndash1

1616 cmndash1

1501 cmndash1

1451 cmndash1

1141 cmndash1

865 cmndash1

(a)


004

003

002

001

000

dVd

log(D

) por

e vol

ume (

cm3 g

)


(b)











4 Conclusion





1 5 05 4 698 6432 15 05 4 438 3853 5 15 4 80 7374 15 15 4 787 7515 5 05 8 358 3216 15 05 8 107 987 5 15 8 26 2418 15 15 8 308 2909 16 1 6 375 44410 184 1 6 235 26911 10 016 6 20 25612 10 184 6 451 49713 10 1 26 771 85914 10 1 104 186 20015 10 1 6 226 21616 10 1 6 177 21617 10 1 6 238 21618 10 1 6 25 21619 10 1 6 20 21620 10 1 6 22 216







x1 37063 1 37063 1034 00093S

x2 69769 1 69769 1946 00013S

x3 523508 1 523508 14600 lt00001S(x1)2 37265 1 37265 1039 00091S

(x2)2 613 1 613 01708 06881N

(x3)2 15138 1 15138 422 00670N

x1 middot x2 35618 1 35618 993 00103S

x1 middot x3 46761 1 46761 1304 00048S

x2 middot x3 177741 1 177741 4957 lt00001S


100

80

60

40

20

0

Pred

icte

d

0 20 40 60 80 100Actual

107 80

(a)

016058

1142

184

Dosage (gL)

70

58

46

34

22

10

1658

10142


IBU

rem

oval

()

(b)

100

82

64

46

28

10

2643

677

94pH (ndash)

1658

10142


IBU

rem

oval

()

(c)

100

82

64

46

28

10

2643

677

94pH (ndash)

016058

1142

184Dosage (gL)

IBU

rem

oval

()

(d)











SSE 083(Radj)2 0983


H k2 middot Q22



SSE 039(Radj)2 0992



SSE 744(Radj)2 0989


kB (mL(gL)) 198αB 030

MRE () 502SSE 1305

(Radj)2 0981

10

8

6

4

2

00 30 60 90 120 150

Pseudo-second-order

Pseudo-first-order

Elovich

Contact time (min)

Qt (

mg

g)


(a)

12

9

6

3

00 5 10 15 20


Ce (mgL)

Qe (

mg

g)


(b)




Data Availability




Acknowledgments


References
















RL 1(1 + KLCo)


RL 003MRE () 246

SSE 018(Radj)2 0997



MRE () 643SSE 098

(Radj)2 0980


BT (RT)b

kT (Lmg) 3924BT 177

MRE () 313SSE 031

(Radj)2 0993


E 1(2B

radic)


SSE 118(Radj)2 0978

























































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls





y() C0 minusCe

C0middot 100

Qt C0 minusCt

mmiddot V

Qe C0 minusCe

mmiddot V

(1)




y f(x) βo + 1113944k

i1βixi + 1113944

k

i11113944

k


k

i1βiix

2i (2)




R2

1113936


2minus1113936


2


2

(3)

MRE() 100n

1113944

n

i1

Qical minusQiexp

Qiexp

111386811138681113868111386811138681113868111386811138681113868

111386811138681113868111386811138681113868111386811138681113868 (4)

SSE 1113944n


2 (5)





150degC 6hO

O

OH

HO

+












5 10 15 20 25 302θ (deg)

Inte

nsity

(au

)

(101) (002)

(302)

(a)

Inte

nsity

(au

)


C-HFe-O

C=O

OH

γs (C-O)

γas (C-O)

(b)





y() 2156minus 521x1 + 715x2 minus 1958x3

+ 683x1x2 + 088x1x3 minus 435x2x3

+ 497x21 + 569x

22 + 1110x

23



+ 088(C)(pH)


+ 569(dose)2 + 1110(pH)2

(6)




10 μm10 μm100 μm


7000

5000

3000

1000

Ram

an in

tens

ity (a

u)


632 cmndash1

1616 cmndash1

1501 cmndash1

1451 cmndash1

1141 cmndash1

865 cmndash1

(a)


004

003

002

001

000

dVd

log(D

) por

e vol

ume (

cm3 g

)


(b)











4 Conclusion





1 5 05 4 698 6432 15 05 4 438 3853 5 15 4 80 7374 15 15 4 787 7515 5 05 8 358 3216 15 05 8 107 987 5 15 8 26 2418 15 15 8 308 2909 16 1 6 375 44410 184 1 6 235 26911 10 016 6 20 25612 10 184 6 451 49713 10 1 26 771 85914 10 1 104 186 20015 10 1 6 226 21616 10 1 6 177 21617 10 1 6 238 21618 10 1 6 25 21619 10 1 6 20 21620 10 1 6 22 216







x1 37063 1 37063 1034 00093S

x2 69769 1 69769 1946 00013S

x3 523508 1 523508 14600 lt00001S(x1)2 37265 1 37265 1039 00091S

(x2)2 613 1 613 01708 06881N

(x3)2 15138 1 15138 422 00670N

x1 middot x2 35618 1 35618 993 00103S

x1 middot x3 46761 1 46761 1304 00048S

x2 middot x3 177741 1 177741 4957 lt00001S


100

80

60

40

20

0

Pred

icte

d

0 20 40 60 80 100Actual

107 80

(a)

016058

1142

184

Dosage (gL)

70

58

46

34

22

10

1658

10142


IBU

rem

oval

()

(b)

100

82

64

46

28

10

2643

677

94pH (ndash)

1658

10142


IBU

rem

oval

()

(c)

100

82

64

46

28

10

2643

677

94pH (ndash)

016058

1142

184Dosage (gL)

IBU

rem

oval

()

(d)











SSE 083(Radj)2 0983


H k2 middot Q22



SSE 039(Radj)2 0992



SSE 744(Radj)2 0989


kB (mL(gL)) 198αB 030

MRE () 502SSE 1305

(Radj)2 0981

10

8

6

4

2

00 30 60 90 120 150

Pseudo-second-order

Pseudo-first-order

Elovich

Contact time (min)

Qt (

mg

g)


(a)

12

9

6

3

00 5 10 15 20


Ce (mgL)

Qe (

mg

g)


(b)




Data Availability




Acknowledgments


References
















RL 1(1 + KLCo)


RL 003MRE () 246

SSE 018(Radj)2 0997



MRE () 643SSE 098

(Radj)2 0980


BT (RT)b

kT (Lmg) 3924BT 177

MRE () 313SSE 031

(Radj)2 0993


E 1(2B

radic)


SSE 118(Radj)2 0978

























































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls










5 10 15 20 25 302θ (deg)

Inte

nsity

(au

)

(101) (002)

(302)

(a)

Inte

nsity

(au

)


C-HFe-O

C=O

OH

γs (C-O)

γas (C-O)

(b)





y() 2156minus 521x1 + 715x2 minus 1958x3

+ 683x1x2 + 088x1x3 minus 435x2x3

+ 497x21 + 569x

22 + 1110x

23



+ 088(C)(pH)


+ 569(dose)2 + 1110(pH)2

(6)




10 μm10 μm100 μm


7000

5000

3000

1000

Ram

an in

tens

ity (a

u)


632 cmndash1

1616 cmndash1

1501 cmndash1

1451 cmndash1

1141 cmndash1

865 cmndash1

(a)


004

003

002

001

000

dVd

log(D

) por

e vol

ume (

cm3 g

)


(b)











4 Conclusion





1 5 05 4 698 6432 15 05 4 438 3853 5 15 4 80 7374 15 15 4 787 7515 5 05 8 358 3216 15 05 8 107 987 5 15 8 26 2418 15 15 8 308 2909 16 1 6 375 44410 184 1 6 235 26911 10 016 6 20 25612 10 184 6 451 49713 10 1 26 771 85914 10 1 104 186 20015 10 1 6 226 21616 10 1 6 177 21617 10 1 6 238 21618 10 1 6 25 21619 10 1 6 20 21620 10 1 6 22 216







x1 37063 1 37063 1034 00093S

x2 69769 1 69769 1946 00013S

x3 523508 1 523508 14600 lt00001S(x1)2 37265 1 37265 1039 00091S

(x2)2 613 1 613 01708 06881N

(x3)2 15138 1 15138 422 00670N

x1 middot x2 35618 1 35618 993 00103S

x1 middot x3 46761 1 46761 1304 00048S

x2 middot x3 177741 1 177741 4957 lt00001S


100

80

60

40

20

0

Pred

icte

d

0 20 40 60 80 100Actual

107 80

(a)

016058

1142

184

Dosage (gL)

70

58

46

34

22

10

1658

10142


IBU

rem

oval

()

(b)

100

82

64

46

28

10

2643

677

94pH (ndash)

1658

10142


IBU

rem

oval

()

(c)

100

82

64

46

28

10

2643

677

94pH (ndash)

016058

1142

184Dosage (gL)

IBU

rem

oval

()

(d)











SSE 083(Radj)2 0983


H k2 middot Q22



SSE 039(Radj)2 0992



SSE 744(Radj)2 0989


kB (mL(gL)) 198αB 030

MRE () 502SSE 1305

(Radj)2 0981

10

8

6

4

2

00 30 60 90 120 150

Pseudo-second-order

Pseudo-first-order

Elovich

Contact time (min)

Qt (

mg

g)


(a)

12

9

6

3

00 5 10 15 20


Ce (mgL)

Qe (

mg

g)


(b)




Data Availability




Acknowledgments


References
















RL 1(1 + KLCo)


RL 003MRE () 246

SSE 018(Radj)2 0997



MRE () 643SSE 098

(Radj)2 0980


BT (RT)b

kT (Lmg) 3924BT 177

MRE () 313SSE 031

(Radj)2 0993


E 1(2B

radic)


SSE 118(Radj)2 0978

























































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls




y() 2156minus 521x1 + 715x2 minus 1958x3

+ 683x1x2 + 088x1x3 minus 435x2x3

+ 497x21 + 569x

22 + 1110x

23



+ 088(C)(pH)


+ 569(dose)2 + 1110(pH)2

(6)




10 μm10 μm100 μm


7000

5000

3000

1000

Ram

an in

tens

ity (a

u)


632 cmndash1

1616 cmndash1

1501 cmndash1

1451 cmndash1

1141 cmndash1

865 cmndash1

(a)


004

003

002

001

000

dVd

log(D

) por

e vol

ume (

cm3 g

)


(b)











4 Conclusion





1 5 05 4 698 6432 15 05 4 438 3853 5 15 4 80 7374 15 15 4 787 7515 5 05 8 358 3216 15 05 8 107 987 5 15 8 26 2418 15 15 8 308 2909 16 1 6 375 44410 184 1 6 235 26911 10 016 6 20 25612 10 184 6 451 49713 10 1 26 771 85914 10 1 104 186 20015 10 1 6 226 21616 10 1 6 177 21617 10 1 6 238 21618 10 1 6 25 21619 10 1 6 20 21620 10 1 6 22 216







x1 37063 1 37063 1034 00093S

x2 69769 1 69769 1946 00013S

x3 523508 1 523508 14600 lt00001S(x1)2 37265 1 37265 1039 00091S

(x2)2 613 1 613 01708 06881N

(x3)2 15138 1 15138 422 00670N

x1 middot x2 35618 1 35618 993 00103S

x1 middot x3 46761 1 46761 1304 00048S

x2 middot x3 177741 1 177741 4957 lt00001S


100

80

60

40

20

0

Pred

icte

d

0 20 40 60 80 100Actual

107 80

(a)

016058

1142

184

Dosage (gL)

70

58

46

34

22

10

1658

10142


IBU

rem

oval

()

(b)

100

82

64

46

28

10

2643

677

94pH (ndash)

1658

10142


IBU

rem

oval

()

(c)

100

82

64

46

28

10

2643

677

94pH (ndash)

016058

1142

184Dosage (gL)

IBU

rem

oval

()

(d)











SSE 083(Radj)2 0983


H k2 middot Q22



SSE 039(Radj)2 0992



SSE 744(Radj)2 0989


kB (mL(gL)) 198αB 030

MRE () 502SSE 1305

(Radj)2 0981

10

8

6

4

2

00 30 60 90 120 150

Pseudo-second-order

Pseudo-first-order

Elovich

Contact time (min)

Qt (

mg

g)


(a)

12

9

6

3

00 5 10 15 20


Ce (mgL)

Qe (

mg

g)


(b)




Data Availability




Acknowledgments


References
















RL 1(1 + KLCo)


RL 003MRE () 246

SSE 018(Radj)2 0997



MRE () 643SSE 098

(Radj)2 0980


BT (RT)b

kT (Lmg) 3924BT 177

MRE () 313SSE 031

(Radj)2 0993


E 1(2B

radic)


SSE 118(Radj)2 0978

























































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls












4 Conclusion





1 5 05 4 698 6432 15 05 4 438 3853 5 15 4 80 7374 15 15 4 787 7515 5 05 8 358 3216 15 05 8 107 987 5 15 8 26 2418 15 15 8 308 2909 16 1 6 375 44410 184 1 6 235 26911 10 016 6 20 25612 10 184 6 451 49713 10 1 26 771 85914 10 1 104 186 20015 10 1 6 226 21616 10 1 6 177 21617 10 1 6 238 21618 10 1 6 25 21619 10 1 6 20 21620 10 1 6 22 216







x1 37063 1 37063 1034 00093S

x2 69769 1 69769 1946 00013S

x3 523508 1 523508 14600 lt00001S(x1)2 37265 1 37265 1039 00091S

(x2)2 613 1 613 01708 06881N

(x3)2 15138 1 15138 422 00670N

x1 middot x2 35618 1 35618 993 00103S

x1 middot x3 46761 1 46761 1304 00048S

x2 middot x3 177741 1 177741 4957 lt00001S


100

80

60

40

20

0

Pred

icte

d

0 20 40 60 80 100Actual

107 80

(a)

016058

1142

184

Dosage (gL)

70

58

46

34

22

10

1658

10142


IBU

rem

oval

()

(b)

100

82

64

46

28

10

2643

677

94pH (ndash)

1658

10142


IBU

rem

oval

()

(c)

100

82

64

46

28

10

2643

677

94pH (ndash)

016058

1142

184Dosage (gL)

IBU

rem

oval

()

(d)











SSE 083(Radj)2 0983


H k2 middot Q22



SSE 039(Radj)2 0992



SSE 744(Radj)2 0989


kB (mL(gL)) 198αB 030

MRE () 502SSE 1305

(Radj)2 0981

10

8

6

4

2

00 30 60 90 120 150

Pseudo-second-order

Pseudo-first-order

Elovich

Contact time (min)

Qt (

mg

g)


(a)

12

9

6

3

00 5 10 15 20


Ce (mgL)

Qe (

mg

g)


(b)




Data Availability




Acknowledgments


References
















RL 1(1 + KLCo)


RL 003MRE () 246

SSE 018(Radj)2 0997



MRE () 643SSE 098

(Radj)2 0980


BT (RT)b

kT (Lmg) 3924BT 177

MRE () 313SSE 031

(Radj)2 0993


E 1(2B

radic)


SSE 118(Radj)2 0978

























































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls









x1 37063 1 37063 1034 00093S

x2 69769 1 69769 1946 00013S

x3 523508 1 523508 14600 lt00001S(x1)2 37265 1 37265 1039 00091S

(x2)2 613 1 613 01708 06881N

(x3)2 15138 1 15138 422 00670N

x1 middot x2 35618 1 35618 993 00103S

x1 middot x3 46761 1 46761 1304 00048S

x2 middot x3 177741 1 177741 4957 lt00001S


100

80

60

40

20

0

Pred

icte

d

0 20 40 60 80 100Actual

107 80

(a)

016058

1142

184

Dosage (gL)

70

58

46

34

22

10

1658

10142


IBU

rem

oval

()

(b)

100

82

64

46

28

10

2643

677

94pH (ndash)

1658

10142


IBU

rem

oval

()

(c)

100

82

64

46

28

10

2643

677

94pH (ndash)

016058

1142

184Dosage (gL)

IBU

rem

oval

()

(d)











SSE 083(Radj)2 0983


H k2 middot Q22



SSE 039(Radj)2 0992



SSE 744(Radj)2 0989


kB (mL(gL)) 198αB 030

MRE () 502SSE 1305

(Radj)2 0981

10

8

6

4

2

00 30 60 90 120 150

Pseudo-second-order

Pseudo-first-order

Elovich

Contact time (min)

Qt (

mg

g)


(a)

12

9

6

3

00 5 10 15 20


Ce (mgL)

Qe (

mg

g)


(b)




Data Availability




Acknowledgments


References
















RL 1(1 + KLCo)


RL 003MRE () 246

SSE 018(Radj)2 0997



MRE () 643SSE 098

(Radj)2 0980


BT (RT)b

kT (Lmg) 3924BT 177

MRE () 313SSE 031

(Radj)2 0993


E 1(2B

radic)


SSE 118(Radj)2 0978

























































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls












SSE 083(Radj)2 0983


H k2 middot Q22



SSE 039(Radj)2 0992



SSE 744(Radj)2 0989


kB (mL(gL)) 198αB 030

MRE () 502SSE 1305

(Radj)2 0981

10

8

6

4

2

00 30 60 90 120 150

Pseudo-second-order

Pseudo-first-order

Elovich

Contact time (min)

Qt (

mg

g)


(a)

12

9

6

3

00 5 10 15 20


Ce (mgL)

Qe (

mg

g)


(b)




Data Availability




Acknowledgments


References
















RL 1(1 + KLCo)


RL 003MRE () 246

SSE 018(Radj)2 0997



MRE () 643SSE 098

(Radj)2 0980


BT (RT)b

kT (Lmg) 3924BT 177

MRE () 313SSE 031

(Radj)2 0993


E 1(2B

radic)


SSE 118(Radj)2 0978

























































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls





Data Availability




Acknowledgments


References
















RL 1(1 + KLCo)


RL 003MRE () 246

SSE 018(Radj)2 0997



MRE () 643SSE 098

(Radj)2 0980


BT (RT)b

kT (Lmg) 3924BT 177

MRE () 313SSE 031

(Radj)2 0993


E 1(2B

radic)


SSE 118(Radj)2 0978

























































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls



























































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls




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