Adsorption of Malachite Green Dye from Liquid Phase Using ...

Research ArticleAdsorption of Malachite Green Dye from Liquid Phase UsingHydrophilic Thiourea-ModifiedPoly(acrylonitrile-co-acrylic acid)Kinetic and Isotherm Studies

Abel A Adeyi 12 Siti N A M Jamil 3 Luqman C Abdullah 1

and Thomas S Y Choong 1

1Department of Chemical and Environmental Engineering Faculty of Engineering Universiti Putra Malaysia (UPM)Serdang 43400 Malaysia2Department of Chemical and Petroleum Engineering College of Engineering Afe Babalola University Ado-Ekiti (ABUAD)PMB 5454 Ekiti State Nigeria3Department of Chemistry Faculty of Science Universiti Putra Malaysia (UPM) Serdang 43400 Malaysia

Correspondence should be addressed to Siti N A M Jamil ctnurulainupmedumy

Received 3 September 2018 Accepted 19 December 2018 Published 3 February 2019

Academic Editor Frederic Dumur

Copyright copy 2019 Abel A Adeyi et al)is is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

)iourea-modified poly(acrylonitrile-co-acrylic acid) (TU-poly(AN-co-AA)) adsorbent was a surface modification of poly(-acrylonitrile-co-acrylic acid) synthesized by facile redox polymerization Surface functionalization with thiourea was carried out toprovide hydrophilicity on the surface of a polymeric adsorbent Fourier transform infrared (FTIR) spectrometer scanningelectron microscope (SEM) and Zetasizer characterized the morphology and structures of TU-poly(AN-co-AA) Co-polymerization of poly(acrylonitrile-co-acrylic acid) and its successful incorporation of the thioamide group was confirmed by theFTIR spectra )e SEM micrographs depicted uniform and porous surface morphologies of polymeric particles )e averagediameter of modified and unmodified poly(acrylonitrile-co-acrylic acid) was 289 nm and 279 nm respectively Zeta potentials ofTU-poly(AN-co-AA) revealed the negatively charged surface of the prepared polymer Adsorption capacities of hydrophilic TU-poly(AN-co-AA) were investigated using malachite green (MG) as an adsorbate by varying experimental conditions (pH initialconcentration and temperature) Results showed that the pseudo-second-order reaction model best described the adsorptionprocess with chemisorption being the rate-limiting step Furthermore Elovich and intraparticle diffusions play a significant role inadsorption kinetics )e equilibrium isotherm has its fitness in the following order Freundlich modelgtTemkin mod-elgt Langmuir model )ermodynamic analysis indicates that the sorption process is spontaneous and exothermic in nature )ereusability results suggested potential applications of the TU-poly(AN-co-AA) polymer in adsorption and separation of cationicmalachite green dye from wastewater

1 Introduction

)e treatment of dye bearing industrial wastewater is aglobal environmental challenge faced by governmentagencies and scientific community )is is due to adverseeffects on environment and human beings [1 2] Presence ofdyes in waterbodies pollute natural habitat and constitutehealth problems because they are not biodegradable andcomplex by nature [3 4] Malachite green (MG) dye is notonly used in textile paper rubber and leather industries forproduct colouring but equally used as antiprotozoan

fungicide in fishery and medical disinfectant Researchhowever showed that MG is harmful to freshwater animalsin acute and chronic exposure [5] It is highly toxic tomammalian cells and organs like liver kidney lung spleenand skin [6 7] )erefore it is imperative to eliminatedyestuff from coloured wastewater for environmental safetyand health benefits

Adsorption [8] photocatalytic degradation [9] bio-degradation [10] and chemical oxidation [11] are devel-oped physical and chemical treatmentpurification methodsto remove dye from wastewater Adsorption stands out

HindawiJournal of ChemistryVolume 2019 Article ID 4321475 14 pageshttpsdoiorg10115520194321475

amongst all treatment technologies as the most effective foradsorption of dye due to its design flexibility relatively lowcost adaptation to broad range of dyes and simple operation[12 13] However sludge generation poor selectivity longcontact time poor site accessibility and nonrecyclability ofadsorbents are limitation to adsorption application)erefore it is required to prepare functional adsorbentswith reasonable cost efficiency and regeneration ability

Recently chemical modification of reactive functionalgroups for creation of different new or additional func-tionalities has become attention-grabbing art in materialscience and engineering field Design of materials withdesired specified formulation and morphology is madepossible with this modification technology [14] With thisdevelopment polymeric materials containing amine amidethioamide or amidoxime groups that cannot be synthesizeddirectly by polymerization can now be easily produced bypostpolymerization modification )ese functionalized ormodified polymers possess complexing capacity with variousorganic pollutants especially synthetic dyes and other pol-lutants in liquid phase environment [15 16] Its applicationis not limited to wastewater treatment but catalysis bio-medical and others [17 18]

Acrylonitrile (AN) as the high carbon source materialcan be polymerized with monomers like methyl acrylateacrylic acid vinylbenzyl chloride and itaconic acid for in-direct synthesis of polymers with thio-functionalities [19ndash21] Different shapes (spherical) fibres and hydrogelpolymers can be prepared by AN copolymerization Oncehydrophobic nitrile groups containing polymer is prepareddipole of nitrile groups can be modified into thioamidegroups via postpolymerization Nitrile groups can also beconverted to amidoxime amine hydrazine amidrazoneand carboxyl groups by the above similar chemical modi-fication route [18 19 21ndash23] For instance Kampalanonwatand Supaphol report the modification of polyacrylonitrile(PAN) with NaOH ethanolic solution for metal ion ad-sorption although it is a costly and complicated process[24] Goscianska et al produced an ordered mesoporouscarbon material functionalized with amine group and ap-plied as an adsorbent to remove solophenyl red 3BL (SR)[25] Bayramoglu et al synthesized magnetic beads con-taining aminated fibrous surfaces for sorption of reactivegreen 19 dye from aqueous solution [26] Sheng et alprepared polyacrylonitrile (PAN) functionalized with thio-to enhance it adsorptive properties Faghihi and Hazendonkalso described the postpolymerization modification ofvinylbenzyl chloride (VBC 15mol) and methyl methac-rylate (MMA 85mol) with thiouronium [27] Postsurfacemodification of poly(vinylbenzyl chloride) beads with theamidoxime group for high sorption of organic dyes andheavy metals was reported by Ajmal et al [15]

)e potential of modified polymeric materials as theadsorbent largely depends on various reactions that can beperformed on the inorganic surface and expanded chain onthe modifying agent )iourea is chosen among functionalgroups due to its high content of nitrogen and sulphur aselectron donor atoms [28ndash30] and its capacity to attach tothe pendant polymer chain [31] Herein new hydrophilic

thiourea-modified poly(acrylonitrile-co-acrylic acid) deno-ted as TU-poly(AN-co-AA) was prepared by redox poly-merization of acrylonitrile (AN) and acrylic acid (AA) andfunctionalized with thiourea )ioamide groups on polymerchains act as binding sites for the positively charged dyemolecules )e characterization adsorption kinetics andadsorption isotherms studies of prepared adsorbents on theMG adsorbate were investigated

2 Materials and Methods

21 Chemicals Acrylonitrile (AN) and acrylic acid (AA)(monomers) were taken from Acros Organics New JerseyUSA and purified by passing through an alumina columnSodium bisulphate (SBS) and potassium persulphate (KPS)(initiators) and thiourea (TU) were purchased from RampMChemicals Essex UK Ethanol and methanol were pur-chased from System ChemAR Shah Alam Malaysia Mal-achite green (MG) dye (from Acros Organics New JerseyUSA) was used as the adsorbate All chemical reagents wereof analytical grade

22 Synthesis andModification of Poly(acrylonitrile-co-acrylicacid) Redox polymerization of acrylonitrile- (AN-) 970and acrylic acid- (AA-) 30 was performed at 60degC undernitrogen gas in a three-necked round bottom flask fittedwith a water condenser )e reaction medium deionizedwater (200mL) was initially purge with nitrogen gas at 40degCfor 30minutes )en 209 g of SBS and 216 g of KPS wereadded to the reaction medium followed by 0275mol of ANand 0029mol of AA )e solution was mechanically stirredat 200 rpm using an egg-shaped magnetic stirrer )e freeradical polymerization reaction was allowed for 2 hours )epoly(AN-co-AA) polymer formed was precipitated inmethanol for an hour and then successfully washed withmethanol and deionized water )e polymer was oven-driedin vacuo at 45degC until constant weight is obtained It is amodified technique employed by Zahri et al [20]

)e surface of the synthesized polymer poly(AN-co-AA) was modified with thiourea to produced hydrophilicthiourea-modified poly(AN-co-AA) )e modificationprocess was as follows 60 g of TU and ethanol-watermixture (12 vol) were stirred at 200 rpm for 30minutesat a constant temperature of 50degC )en 50 g of poly(AN-co-AA) was added to the solution at 100degC for 5 hours )eresulting crystal TU-poly(AN-co-AA) was rinsed in ethanoldeionized water solution filtered and dried to constantweight at 50degC )e overall preparation and modificationprocess is illustrated in Scheme 1

23 Preparation of Aqueous Dye Solutions Malachite green(MG) (Scheme 2) dye of a commercial grade and purity wasused without purification )e dye stock solution of con-centration of 1000mgL was prepared by dissolving 10 g ofdye in distilled water)e experimental solutions of differentinitial concentrations ranging from 20 to 100mgL wereobtained by diluting the MG dye stock solution

2 Journal of Chemistry

24 Characterization of the Modied and UnmodiedPoly(AN-co-AA)

241 FTIR Analysis e modied and unmodied pol-y(AN-co-AA) were analysed to detect the functional groupspresent in it using Fourier transform infrared spectropho-tometer (PerkinElmer 1750X-PerkinElmer Inc WalthamMA USA) e region of the infrared was between 4000 and500 cmminus1 at room temperature

242 SEM Images e morphology of modied andunmodied poly(AN-co-AA) samples were obtained us-ing the scanning electron microscope (SEM) (Hitachi S-3400N High-Technologies Corporation Minato TokyoJapan) and operated at 10 to 20 kV Samples were coated inAu lm prior to analysis e diameters and particle sizedistributions were measured using ImageJTM software(version 152a) from SEM image analysis of 100 individualparticles

243 Zeta Potential Zeta potential provides essential in-formation about surface charges of the adsorbent for raptunderstanding of interaction between the adsorbate andthe adsorbent Zetasizer Nano Series (Malvern PanalyticalLimited United Kingdom) was used to measure the surfacecharge(s) of synthesized and chemically modiedpolymers

25 Batch Adsorption Experiments Adsorptive tests of MGdye on thiourea-modied poly(AN-co-AA) in the batchsystem was studiedperformed using 250mL volumetricasks 100mL dye solutions (MG) at varying concentrations(20 to 100mgL) were prepared and a known amount (g) ofTU-poly(AN-co-AA) was mixed with solution for single dyeadsorption tests Under constant stirring speed of 100 rpmthe solutions were controlled at 25degC and 100 rpm agitationspeed At the varying time interval 10ml solution waswithdrawn and ltered and supernatant dye concentrationwas measured by Lambda 35 UV-Vis spectrophotometer at617 nm maximum wavelength e dye removal percentageR was calculated using equation (1) and adsorption capacityat the equilibrium (qe) condition using equation (2)

R C0 minusCe

C0times 100 (1)

qe VC0 minusCe

m (2)

where C0 and Ce are the initial and equilibrium liquid-phaseconcentrations of the cationic dye (mgL) respectively qe isthe amount of the adsorbed dye (mgg) V is the volume ofthe solution (L) andm is the weight of the TU-poly(AN-co-AA) adsorbent used (g)

Classical approach was adopted to investigate the eiexclectof various key process parameters adsorbent dose reactiontime initial concentration temperature and pH on theremoval of MG

H2CO

OH

Acrylonitrile (AN) Acrylic acid (AA) Poly(AN-co-AA)

N O OH

p q

+H2C

NCH

(a)

+H2N

CNH2

S

Np q

O OHH2NHN NH

C S p qO

OH

Poly(AN-co-AA) iourea (TU) TU-poly(AN-co-AA)

(b)

Scheme 1 Polymerization of poly(AN-co-AA) (a) and modication of poly(AN-co-AA) with thiourea (b)

(a)

H3C

CH3 CH3

CH3

Clndash

N N+

(b)

Scheme 2 Physical and chemical structures of malachite green (MG)

Journal of Chemistry 3

26 Adsorption Kinetics Adsorption kinetics studies werecarried out in 250mL flasks containing 100mL of MG dyesolution with a known quantity of the TU-poly(AN-co-AA)adsorbent )e volumetric flasks were agitated for timeintervals between 0 and 120minutes on a water bath shakerat 100 rpm at room temperature (25degC) )e samples weretaken at varied time interval and filtered and supernatantdye concentration was analysed )e data obtained wereanalysed using pseudo-first-order (PFO) pseudo-second-order (PSO) Elovich and intraparticle diffusion (IPD) ki-netic models

27 Adsorption Equilibrium Adsorption equilibrium in-vestigation was performed also in 250mL flasks containing100mL of MG dye solution of different initial concentra-tions (20 to 100mgL) with a known amount of adsorbents)emixture was constantly agitated in a water bath shaker at100 rpm at 25degC for 1 hour )e equilibrium concentrationwas determined and analysed using various isothermmodelssuch as Langmuir Freundlich and Temkin adsorptionisotherm models

28 Adsorption 9ermodynamics Adsorption of MG cat-ionic dye was investigated at various temperatures rangingfrom 298 to 328K in the water bath shaker at 100 rpmagitation speed for 60minutes )e enthalpy changes (ΔH0)entropy changes (ΔS0) and Gibbs free energy changes (ΔG0)were thermodynamic parameters employed to determine thenature and spontaneity of the adsorption process

3 Results and Discussion

31 Characterization of Poly(AN-co-AA) and TU-Poly(AN-co-AA) FTIR technique was used to analyse and identify thefunctional groups present in synthesized poly(AN-co-AA)and evaluate postmodification changes in chemical struc-tures FTIR spectra and absorption bands of the two sampleswere recorded in the range of 4000ndash500 cmminus1 as shown inFigure 1 )e characteristic peaks at 1725 cmminus1 and2932 cmminus1 correspond to the bonds -CO and -CH re-spectively )e broad band at 2244 cmminus1 and 3516 cmminus1respectively represents - CequivN (nitrile group) and -OH(hydroxyl group) of the poly(AN-co-AA) copolymer[19 20 33] After thiourea modification some of thefunctional group(s) in poly(AN-co-AA) diminished or in-creased and disappeared and formation of new functionalgroups was observed )e disappearance of the peak at2244 cmminus1 shift of bands at 3516 cmminus1 to 3345 cmminus1 andappearance of bands at 1614 cmminus1 (-CN) and 729 cmminus1

(-CS) confirmed successful incorporation of thioamide tothe polymer surface according to report of Zahri et al [20]

)e scanning electron microscope (SEM) micrographsof the raw poly(AN-co-AA) and TU-poly(AN-co-AA)polymers are shown in Figure 2 )e morphologies of bothwere similar to each other and the surface of the TU-pol-y(AN-co-AA) polymer shows no significant cracks or deg-radation signal )ey have almost uniform sphericalmorphology and porous surface suitable for adsorption

binding sites )e SEM photos of modified and unmodifiedsynthesized polymers depicted the spherical beads ag-glomerated morphologies due to intraparticle bonds existedbetween monomers solution low viscosity and complexpolymerization reaction nature [34ndash37])e average particlesize of TU-poly(AN-co-AA) slightly increased from 279 nmto 289 nm and this increment in average particle size of thepolymer beads is an evidence that the thioamide group hasbeen successfully incorporated to the nitrile group of syn-thesized poly(AN-co-AA) Similar trend of increase inparticle size was also observed and reported in[19 20 34 38]

Zeta potentials of poly(AN-co-AA) (P) and TU-pol-y(AN-co-AA) (MP) samples at a varied pH value werenegative both in acidic and alkaline conditions (Figure 3))e aqueous dispersion of TU-poly(AN-co-AA) was alsofound negative in the neutral pH emanated from the lownegative value of zeta potential (minus34mV) )ese negativesurface charges confirmed the availability of negativelycharged functional groups at the edges of the modifiedpolymer surface since thioamide carbonyl and hydroxylgroups leads to extreme hydrophilicity with negative chargedensity [39ndash41]

32 Dye Adsorption Application of Poly(AN-co-AA) and TU-Poly(AN-co-AA) Malachite green dye adsorption potentialsof synthesized poly(AN-co-AA) and TU-poly(AN-co-AA)were studied in the batch system )e effect of thioureamodification on MG dye adsorptive performance of pre-pared polymer samples is presented in Table 1 )e ad-sorption capacity of poly(AN-co-AA) (at an varied dosage) islow as observed from Table 1 )e surface of the unmodifiedpolymer contains only -COOH groups which permit onlyhydrogen bonding interaction with a hydrogen donor site ofthe MG molecules [14]

After modification with thiourea decoration of pendantthioamide groups on the polymer surface culminated tocreation of more negatively charged surfaces )en ad-sorption capacity was improved significantly at 05 g dosageby 2081 for sorption of MG compared with the ad-sorption capacity of the nonmodified sample In this eval-uation the thiourea ligand creates a multianionic centre forinteraction with cationic MG molecules and enhanced thesorption capacity Henceforth the modified poly(AN-co-AA) adsorbent was selected for a detailed study of the MGdye adsorption process

33 Effect of Adsorbent Dosage )e doses of TU-poly(AN-co-AA) varied from 03 to 12 g100mL Figure 4 revealedthat percentage of MG removal sharply increased with in-crease in the amount of the adsorbent from 03 to 05 g100mL and then reached almost a constant value )is isattributed to the availability of more adsorbent binding sitesand adsorptive surface area [42ndash44] No significant im-provement in the MG removal percentage was observed asdosage increased beyond 05 g to 12 g100mL hence 05 gof adsorbent dose was selected for successive studies as theoptimal load of TU-poly(AN-co-AA)


34 Effect of Contact Time and Initial MG Concentration)e adsorption of MG molecules on the surface of adsor-bents is a time-dependent process Hence the time necessaryfor sorption of MG was optimized in order to evaluate theTU-poly(AN-co-AA) polymerrsquos utilization period )e timedependency of the adsorption of MG onto TU-poly(AN-co-AA) was investigated for different dye concentrations overthe range of 20 to 100mgL and the results obtained arepresented in Figure 5)e adsorption experiments were carriedout for a contact time up to 120minutes )e time-dependentadsorption ofMGdye indicates that 60minutes of contact time

was required for most of the sorption of dye molecules to reachequilibrium )e results revealed that quantity of MG removalincreases fast as the initial concentration increases)is may beattributed to the increase in driving force induced by a con-centration gradient from high initial solution concentrationand availability of maximum active sites

It was observed that over 60 of the MG removal oc-curred in the first 30minutes and subsequently increases tillthe 60min contact time where maximum treatment ensuedBeyond 60min till 120min as the treatment time dye re-moval was constant which can be ascribed to the equilibrium

4000 3500 3000 2500 2000 1500 1000 500Wave number (cmndash1)

3516-OH

2932-CH

2244-C=-N

1725-C=O

Tran

smitt

ance

()

PMP

3345-NH2 -OH

2935-CH

1728-C=O

1614-C=N

729-C=S

Figure 1 FTIR spectra of poly(AN-co-AA) (P) and TU-poly(AN-co-AA) (MP) polymers

(a) (b)

Figure 2 SEM micrographs of poly(AN-co-AA) (a) and TU-poly(AN-co-AA) (b)


attainment Based on reduction in the number of availableactive sites the MG removal percentage gradually slowsdown Hence all the subsequent batch experiments wereperformed for time of 60min Same trend was also observedand reported in [8 45] for the adsorption of brilliant greenand direct yellow 50 (DY50) dyes respectively

35Eect of Initial SolutionpH e initial pH of dye solutionis a key parameter inuencing the adsorption of MG ontoTU-poly(AN-co-AA)e range of pH studies choose forMGis 30 to 110 e reasons of using wide ranges of pH are dueto MG sensitivity to pH and to avoid the pH range that maylead to fading and loss of colour intensity Figure 6 shows theeiexclect of pH on sorption of MG onto TU-poly(AN-co-AA)e maximum and minimum MG removal was observed atpH 5 and pH 11 respectively MG as cationic dye givespositive charge when dissolved in water In the acidic me-dium the negatively charged surface of the adsorbent tends toattract adsorption of the cationic adsorbate ere is nosignicant drop or increase inMG adsorptionwhen pHof dyesolution was increased Implying that the adsorption of MG isnot solely by electrostatic interaction but other attractiveforces like hydrophobic-hydrophobic interaction and hy-drogen bonding may dominate signicantlyis observationand behaviour was also noticed in [44 46 47] e resultssubmitted that the adsorption of MG onto TU-poly(AN-co-AA) was not strongly inuenced by pH since it can be seenthat there were only slight variations in the dye uptake fromacidic to alkaline conditions Azha et al reported similarobservation [48] However the highest adsorption was ob-served at pH 5 closed to the ambient pH (45) hence no pHadjustment was made in the following MG experiments

36 Eect of Temperature e eiexclect of temperature on MGadsorption was studied from 298 to 328K with other

0 2 4 6 8 10 12

ndash30

ndash25

ndash20

ndash15

ndash10

ndash5

Zeta

pot

entia

l (m

V)

pH

PMP

Figure 3 Zeta potentials of poly(AN-co-AA) (P) and TU-pol-y(AN-co-AA) (MP) under diiexclerent pH values

Table 1 Adsorption test of poly(AN-co-AA) and TU-poly(AN-co-AA)

Adsorbent Dosage(g)

Extent ofremoval()

Improvement()

Poly(AN-co-AA)

03 5307 mdash05 6544 mdash10 6830 mdash

TU-poly(AN-co-AA)

03 6488 118105 8625 208110 8998 2168

MG concentration 80mgL agitation speed 100 rpm temperature25plusmn 2degC contact time 2 hrs

00 02 04 06 08 10 120

10

20

30

40

50

60

70

80

90

100

MG

rem

oval

()

Adsorbent dosage (g)

Figure 4 Eiexclect of adsorbent dosage on the adsorption of MG ontoTU-poly(AN-co-AA) (concentration 50mgL temperature 298Kcontact time 60min agitation speed 100 rpm)

0 10 20 30 40 50 60 70 80 90 100 110 120 130

0

10

20

30

40

50

60

70

80

90

100

MG

rem

oval

()

Time (min)

20 mgL40 mgL60 mgL

80 mgL100 mgL

Figure 5 Eiexclect of contact time on MG adsorption on TU-pol-y(AN-co-AA) (adsorbent dosage 05 g temperature 298K agi-tation speed 100 rpm)


parameters being kept constant (Figure 7) From the resultsit was observed that quantity of MG adsorbed decreases asthe temperature was raisedis may be attributed to the factthat as the temperature was increased the solubility of MGin solution also increased resulting in stronger interactionforces betweenMG and solute more than those betweenMGand TU-poly(AN-co-AA) polymer [49ndash51] High temper-ature might lead to the breaking of existing intermolecularhydrogen bonds between adsorbent and adsorbate whichwas found to be an important contribution to the ad-sorption process e adsorption capacity qe for MG re-moval decreases with an increase in temperature indicatingthat the adsorption of MG is not favourable at highertemperatures (an exothermic process) is may be asso-ciated with the tendency of MG dye ions to escape from the

adsorbent phase to the bulk phase with an elevated tem-perature of the solutione decrease in the removal of MGdye with increase in temperature may also be due toweakness of the adsorptive forces between the MG dyemolecules and the surface active sites of TU-poly(AN-co-AA) polymer [52]

37AdsorptionKinetic Study Study of adsorption kinetics isimportant because the rate of adsorption which is one of thecriteria for enotciency of adsorbent and the mechanism ofadsorption can be established from the kinetic studies Forthis study experimental data were tested using pseudo-rst-order pseudo-second-order Elovich and intraparticle dif-fusion models respectively and represented in [53ndash56]

ln qe minus qt( ) ln qe( )minus k1 ln(t)

t

qt

1k2q2e

+1qet

qt 1βln(αβ) +

1βln(t)

qt kIPt05 + CIP

(3)

where qe (mgg) and qt (mgg) are adsorption capacity atequilibrium and at time t respectively k1 (minminus1) k2 (gmgmiddotmin) and kIP (mggmiddotmin05) are the rate constants ofpseudo-rst-order pseudo-second-order and intraparticlediiexclusion intercept CIP reects the boundary layer thicknesseiexclect and β (gmg) and α (mggmiddotmin) are the Elovichconstants corresponding to the extent of surface coverageand rate of sorption at zero coverage (initial sorption rateconstant) respectively

Pseudo-rst-order and pseudo-second-order kineticmodels are limited in identication of roles of diiexclusion (lmor external diiexclusion pore diiexclusion or both) in the ad-sorption process In order to fully comprehend the ad-sorption mechanism experimental data were also modeledwith Elovich and intraparticle diiexclusion equations [57 58]

Figure 8 shows the model graphs describing the kineticcharacteristic of the adsorption of MG onto the TU-pol-y(AN-co-AA) Relevant kinetic parameters and correlationcoenotcients are presented in Table 2 e qe(cal) values werecalculated for pseudo-rst-order and pseudo-second-orderand compared with experimental values as stated in Table 2e calculated value of qe(exp) for pseudo-rst-order kineticwas far from the experimental value while it showed goodagreement in the case of pseudo-second-order indicatingthe suitability of the pseudo-second-order kinetic modele positive value of CIP (1295mgg) of the intraparticlediiexclusion model indicates surface and faster initial sorptionprocess [59] although the value did not agree with qe(exp)e linear line did not pass through the origin and thissuggests that intraparticle diiexclusion was not the only limitingmechanism in MG adsorption [58 60]

e correlation coenotcients (R2) indicated the followingorder to the tted kinetic models PSOgt Elovichgt

642 8 10 1230

40

50

60

70

80

90

100

MG

rem

oval

()

pH

Figure 6 Eiexclect of initial pH onMG adsorption onto TU-poly(AN-co-AA) (initial concentration 50mgL adsorbent dosage 05 gtemperature 298K agitation speed 100 rpm)

295 300 305 310 315 320 325 330

14

15

16

17

18

q e (m

gg)

T (K)

Figure 7 Eiexclect of initial temperature on MG adsorption onto TU-poly(AN-co-AA) (initial concentration 100mgL adsorbent dos-age 05 g agitation speed 100 rpm)


IPDgt PFO )ese values suggested that the pseudo-second-order model best described the adsorption process )ere-fore chemisorption was found to be the rate determiningstep controlling adsorption of MG onto the TU-poly(AN-co-AA) polymer [61ndash65] )e sorption process probablyinvolves sharing and or transferring of the electron betweenadsorbents and adsorbate

38 Adsorption Isotherms Information regarding the re-lationship between MG concentration and amount of MGadsorbed on the adsorbent surface when both phases arein equilibrium is given via adsorption isotherms )ree

adsorption isotherm models were tried to obtain the best fitto MG adsorption by TU-poly(AN-co-AA) )e isothermdata were fitted to Langmuir Freundlich and Temkinmodels )e linear form of the three models is expressedrespectively in [53 66 67]

Ce

qe

1KLqmax

+Ce

qmax (4)

ln qe( 1113857 ln KF( 1113857 +1n

1113874 1113875ln Ce( 1113857 (5)

qe BT ln KT + BT ln Ce (6)

0 10 20 30 40 50 60 70 80 90 100 110 120 130

ndash6

ndash5

ndash4

ndash3

ndash2

ndash1

0

1

2

ln(q

endashq t

)

t (min)

ExperimentalLinear fit

(a)

0 10 20 30 40 50 60 70 80 90 100 110 120 130

0

1

2

3

4

5

6

7

tqt

t (min)


(b)

0 1 2 3 4 512

13

14

15

16

17

18


q t

ln(t)

(c)

q t


0 2 4 6 8 10 1212

13

14

15

16

17

18

t05

(d)

Figure 8 Plot of pseudo-first-order (a) pseudo-second-order (b) Elovich kinetic (c) and intraparticle diffusion (d) models


RL 1

1 + KLC0 (7)

where qe (mgg) qmax (mgg) Ce (mgL) and KL (Lmg) aredefined as the adsorption capacity at equilibrium themaximum adsorption capacity the concentration of MG insolution at equilibrium and the Langmuir constant corre-sponding to monolayer coverage respectively

RL (equation (7)) is the Langmuir isotherm di-mensionless constant (or equilibrium parameter) essentiallyto define the nature of the adsorption process RL 00ltRL lt 1 RL 1 or RL gt 1 are respectively defined asirreversible favourable linear or unfavourable [4 68 69]

KF (mgngLn) and 1n are Freundlich constant andadsorption intensity or Freundlich exponent

1n 1 0lt 1nlt 1 and 1ngt 1 indicate irreversiblefavourable and unfavourable isotherm type respectively [4]

BT RTb represents the heat of adsorption associatedwith Temkinrsquos constant KT is the equilibrium bindingconstant corresponding to the maximum binding energy forthe Temkin isotherm (Lmg) R represents the universal gasconstant (8314 JmolmiddotK) and b is a Temkin isotherm con-stant (Jmol) while T refers to the absolute temperature ofthe solution (K)

)e isotherm data and correlation coefficient obtainedfrom the three different adsorption isotherm models aregiven in Table 3 Langmuir adsorption isotherm revealedthat the data could be fitted into the Langmuir equationwell with the correlation coefficient of 09309 )e value ofthe separation factor or the equilibrium parameter RLequals 06083ndash02369 indicating favourable adsorption ofMG onto the TU-poly(AN-co-AA) polymer with26954mgg of maximum adsorption capacity Temkinrsquosisotherm data of BT and KT established the heat of ad-sorption and corresponding maximum binding energy ofinteraction between adsorbate and adsorbent )e corre-lation coefficient values R2 for the three models are veryclose to unity Based on R2 values of the adsorption iso-therm Freundlich model is the most appropriate for de-scribing adsorption behaviour of MG onto the modifiedpolymer In addition the value of 1n being less unity wasobserved to be an indication that the adsorption of MG byTU-poly(AN-co-AA) was favourable and not a physicaltype It signifies that adsorption occurred on heterogeneoussurfaces according to Ayawei et al and Dabhade et al[53 70]

39 9ermodynamic Analyses Investigating process of ad-sorption with respect to temperature can give informationabout thermodynamic parameters such as Gibbs free energyenthalpy and entropy change )e effect of temperature onthe MG adsorption capacity of TU-poly(AN-co-AA) wasperformed at 298 308 318 and 328K (Figure 7)

)e difference in the extent of the MG adsorption ontoTU-poly(AN-co-AA) has been explained on the fundamentalof the thermodynamic parameters )e Gibbrsquos free energychange is calculated employing the following equation

ΔG0 ΔH0 minusTΔS0

ΔG0 minusRT lnKd

(8)

where R is the universal gas constant (8314 JmolmiddotK)T is thetemperature (K) and Kd is the thermodynamic equilibriumconstant defined as follows

Kd qe

Ce (9)

Stated in equation (10) is the relationship betweenthermodynamic equilibrium constant enthalpy and en-tropy change defined by the Vanrsquot Hoff equation

lnKd ΔS0

RΔH0

RT (10)

)e values of ΔH0 and ΔS0 were deduced from gradientand intercept of ln Kd versus 1T plot (Figure 9) and Table 4shows the values of thermodynamic parameters )e negativevalues of ΔH0 (minus1706 kJmol) affirms quantitatively that theprocess is exothermic and MG adsorption process was notfavoured at higher temperatures [52 71] )erefore thesorption of MG by TU-poly(AN-co-AA) is feasible and there

Table 2 Kinetic parameters and correlation coefficients of MG onto TU-poly(AN-co-AA)

Kinetic models Parameters

Pseudo-first-order k1 (minminus1) qe(exp) (mgg) qe(cal) (mgg) R2

0040 1719 28866 04533

Pseudo-second-order k2 (gmgmiddotmin) qe(exp) (mgg) qe(cal) (mgg) R2

00033 1719 1730 09997

Elovich β (gmg) α (mggmiddotmin) R2

09066 7211342 09515

Intraparticle kIP (mggmiddotmin05) CIP (mgg) R2

04769 1295 08218

Table 3 Isotherm parameters and correlation coefficients of MGonto TU-poly(AN-co-AA)

Isotherm models Parameters

Langmuir KL (mgg) qm (mgg) R2

00322 26954 09309

Freundlich KF (Lmg) 1n R2

19004 08359 09960

Temkin KT (Lg) b (Jmol) R2

06878 35620 09475


is no need for external energy [72]e spontaneous characterof the adsorption process was conrmed by negative values ofΔG0 while its positive change suggests that desorption tookplace at an elevated temperature In addition the negativeΔS0(change in entropy) value signies decrease in disorder atadsorbentsolution interface during the sorption processaccording to Sadaf et al and Ma et al [8 73]

Based on the results of kinetic isotherm and ther-modynamic analyses adsorption of MG is exothermic andspontaneous of chemisorption and physiosorption processascribed to the electrostatic interaction between TU-pol-y(AN-co-AA) and MG Proposed adsorption mechanismand process kinetic are shown schematically in Figure 10Adsorption as a multistage process involves transfersharing of MG ions from bulk solution to the TU-pol-y(AN-co-AA) surface and diiexclusion into hydrophilicpolymer beads

310 Adsorbent Regeneration and Reusability Study ereusability of the adsorbents is a key evaluation index indetermining the potential of their applications in industryfrom economic and technological points [69 74] ereforerecoverability and reusability of TU-poly(AN-co-AA) wereinvestigated in the adsorption of cationic MG dye Five cycleruns on adsorption-desorption were conducted for MG on

TU-poly(AN-co-AA) using mixed solution of 10M HNO3and 05M thiourea (CH4N2S) as desorption solvent (im-mersed and shaken for 3 h) e adsorbents were washedwith distilled water and dried at 50degC in vacuum ovenovernight for the next adsorption process e resultsindicated that TU-poly(AN-co-AA) could be regeneratedand reused with no signicant activity depletion Ap-proximately 89 (Figure 11) enotciency was observed afterve consecutive cycles is established that the preparedTU-poly(AN-co-AA) demonstrated excellent durabilityand maintained maximum MG sorption capacities formultiple usage

305 310 315 320 325 330 335 340ndash06

ndash05

ndash04

ndash03

ndash02

ndash01

00

01

02

ln K

d

1T lowast E ndash 3 (Kndash1)


Figure 9 Vanrsquot Hoiexcl plot for MG adsorption onto TU-poly(AN-co-AA) (MG concentration 100mgL dosage 05 g contact time60min agitation speed 100 rpm)

Table 4 ermodynamic parameters for adsorption of MG ontoTU-poly(AN-co-AA)

Temperature ParametersT (K) ΔG0 (kJmol) ΔH0 (kJmol) ΔS0 (JmolmiddotK)298 minus038 minus1706 minus5599308 018318 074328 130

q

NHHN

CSO

HO

HN NH

C S p

OOH

MG+ MG+

NH2

H2N

(a)

Chemical reaction stage

(b)

Diffusion stage

(c)

Equilibrium stage

(d)

Figure 10 Proposed adsorption mechanism (a) and kinetic pro-cess (bndashd)


4 Conclusions

Poly(acrylonitrile-co-acrylic acid) microsphere were syn-thesized via the free radical polymerization method andsurface modied with thiourea Prepared TU-poly(AN-co-AA) was used as an adsorbent for the adsorptive removal ofmalachite green (MG) from aqueous solution in a batchmode Kinetic studies showed the best tness of pseudo-second-order model on experimental data Equilibriumisotherm data were tted using Langmuir Freundlich andTemkin models and the data were best described by theFreundlich isotherm model e values of thermodynamicparameters such as change in Gibbs free energy enthalpyand entropy revealed the exothermic and spontaneous na-ture of the adsorption process TU-poly(AN-co-AA) exhibitshigh adsorption capacity for malachite green which ismainly due to the strong electrostatic interactions betweennegatively charged functional groups of the adsorbent andcationic MG TU-poly(AN-co-AA) might be an attractivefunctional material for the adsorptive removal of cationicdyes from wastewater considering its high adsorption ca-pacity (270mgg) rapid separation from water and ca-pacities for multiple usage

Data Availability

e data used to support the ndings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that there are no conicts of interestregarding the publication of this paper

Acknowledgments

e authors would like to express gratitude to the Ministryof Higher EducationMalaysia for nancial support providedunder the Fundamental Research Grant Scheme (FRGS)with project code 03-01-16-1844FR anks are due to

Chemistry Department Faculty of Science Universiti PutraMalaysia and Department of Chemical and EnvironmentalEngineering Faculty of Engineering Universiti PutraMalaysia for providing the research facilities

References

[1] M Santhi P E Kumar and B Muralidharan ldquoRemoval ofmalachite green dyes by adsorption onto activatedcarbonndashMnO2ndashnanocompositendashkinetic study and equilib-rium isotherm analysesrdquo IOSR Journal of Applied Chemistryvol 8 no 4 pp 33ndash41 2015

[2] J Dasgupta J Sikder S Chakraborty S Curcio and E DriolildquoRemediation of textile esup3uents by membrane based treat-ment techniques a state of the art reviewrdquo Journal of Envi-ronmental Management vol 147 pp 55ndash72 2015

[3] S Ziane F Bessaha K Marouf-Khelifa and A KhelifaldquoSingle and binary adsorption of reactive black 5 and Congored on modied dolomite performance and mechanismrdquoJournal of Molecular Liquids vol 249 pp 1245ndash1253 2018

[4] A Maleki U Hamesadeghi H Daraei et al ldquoAmine func-tionalized multi-walled carbon nanotubes single and binarysystems for high capacity dye removalrdquo Chemical EngineeringJournal vol 313 pp 826ndash835 2017

[5] G Bayramoglu and M Y Arica ldquoRemoval of reactive dyesfrom wastewater by acrylate polymer beads bearing aminogroups isotherm and kinetic studiesrdquo Coloration Technologyvol 129 no 2 pp 114ndash124 2013

[6] J Zhang Y Li C Zhang and Y Jing ldquoAdsorption of mal-achite green from aqueous solution onto carbon preparedfrom Arundo donax rootrdquo Journal of Hazardous Materialsvol 150 no 3 pp 774ndash782 2008

[7] M E Yonar and S M Yonar ldquoChanges in selected immu-nological parameters and antioxidant status of rainbow troutexposed to malachite green (Oncorhynchus mykiss Walbaum1792)rdquo Pesticide Biochemistry and Physiology vol 97 no 1pp 19ndash23 2010

[8] S Sadaf H N Bhatti S Nausheen and M Amin ldquoAppli-cation of a novel lignocellulosic biomaterial for the removal ofDirect Yellow 50 dye from aqueous solution batch andcolumn studyrdquo Journal of the Taiwan Institute of ChemicalEngineers vol 47 pp 160ndash170 2015

[9] S Natarajan H C Bajaj and R J Tayade ldquoRecent advancesbased on the synergetic eiexclect of adsorption for removal ofdyes from waste water using photocatalytic processrdquo Journalof Environmental Sciences vol 65 pp 201ndash222 2018

[10] S R Vijayalakshmidevi and K Muthukumar ldquoImprovedbiodegradation of textile dye esup3uent by coculturerdquo Eco-toxicology and Environmental Safety vol 114 pp 23ndash302015

[11] O Turgay G Ersoz S Atalay J Forss and UWelander ldquoetreatment of azo dyes found in textile industry wastewater byanaerobic biological method and chemical oxidationrdquo Sep-aration and Purication Technology vol 79 no 1 pp 26ndash332011

[12] K Varaprasad T Jayaramudu and E R Sadiku ldquoRemoval ofdye by carboxymethyl cellulose acrylamide and grapheneoxide via a free radical polymerization processrdquo CarbohydratePolymers vol 164 pp 186ndash194 2017

[13] C Ma L Cao X Wang L Zhang M Shi and J WangldquoCharacterization and adsorption capacity of a novel high-performance polymeric sorbent synthesized in supercriticalcarbon dioxiderdquo Journal of Supercritical Fluids vol 62pp 232ndash239 2012

1st 2nd 3rd 4th 5th0

20

40

60

80

100

Reco

very

()

Regeneration cycle

Figure 11 Recyclability of TU-poly(AN-co-AA) for adsorption ofMG


[14] T A Arica E Ayas and M Y Arica ldquoMagnetic MCM-41silica particles grafted with poly(glycidylmethacrylate) brushmodification and application for removal of direct dyesrdquoMicroporous andMesoporous Materials vol 243 pp 164ndash1752017

[15] M Ajmal S Demirci Y Uzun M Siddiq N Aktas andN Sahiner ldquoIntroduction of double amidoxime group bydouble post surface modification on poly(vinylbenzyl chlo-ride) beads for higher amounts of organic dyes As(V) andCr(VI) removalrdquo Journal of Colloid and Interface Sciencevol 470 pp 39ndash46 2016

[16] L C de Santa Maria M C V Amorim M R M P Aguiaret al ldquoChemical modification of cross-linked resin based onacrylonitrile for anchoring metal ionsrdquo Reactive and Func-tional Polymers vol 49 no 2 pp 133ndash143 2001

[17] X-L Shi Q Hu F Wang W Zhang and P Duan ldquoAp-plication of the polyacrylonitrile fiber as a novel support forpolymer-supported copper catalysts in terminal alkynehomocoupling reactionsrdquo Journal of Catalysis vol 337pp 233ndash239 2016

[18] K S Perera M A K L Dissanayake S Skaarup and KWestldquoApplication of polyacrylonitrile-based polymer electrolytesin rechargeable lithium batteriesrdquo Journal of Solid StateElectrochemistry vol 12 no 7-8 pp 873ndash877 2007

[19] N S M Rapeia S N A M Jamil L C Abdullah et alldquoPreparation and characterization of hydrazine-modified poly(acrylonitrile-co-acrylic acid)rdquo Journal of Engineering Scienceand Technology vol 4 no 1 pp 61ndash70 2015

[20] N A M Zahri S N A M Jamil L C Abdullah et alldquoImproved method for preparation of amidoxime modifiedpoly(acrylonitrile-co-acrylic acid) characterizations and ad-sorption case studyrdquo Polymers vol 7 no 7 pp 1205ndash12202015

[21] S N A M Jamil R Daik and I Ahmad ldquoRedox synthesisand thermal behaviorof acrylonitrile-methyl acrylate-fumaronitrile terpolymer as precursor for carbon fiberrdquo In-ternational Journal of Chemical Engineering and Applicationsvol 3 no 6 pp 416ndash420 2012

[22] Y Qin L Wang C Zhao D Chen Y Ma and W YangldquoAmmonium-functionalized hollow polymer particles as apH-responsive adsorbent for selective removal of acid dyerdquoACS Applied Materials amp Interfaces vol 8 no 26pp 16690ndash16698 2016

[23] Y Chengran Z Yumei and W Biao ldquoSynthesis and char-acterization of polyacrylonitrile copolymers containing aminegroupsrdquo in Proceedings of 2015 Asia-Pacific Energy EquipmentEngineering Research Conference (AP3ER 2015) vol 9pp 127ndash130 Zhuhai China June 2015

[24] P Kampalanonwat and P Supaphol ldquo)e study of compet-itive adsorption of heavy metal ions from aqueous solution byaminated polyacrylonitrile nanofiber matsrdquo Energy Procediavol 56 pp 142ndash151 2014

[25] J Goscianska N A Fathy and R M M Aboelenin ldquoAd-sorption of solophenyl red 3BL polyazo dye onto amine-functionalized mesoporous carbonsrdquo Journal of Colloid andInterface Science vol 505 pp 593ndash604 2017

[26] G Bayramoglu B Altintas and M Y Arica ldquoSynthesis andcharacterization of magnetic beads containing aminatedfibrous surfaces for removal of Reactive Green 19 dye ki-netics and thermodynamic parametersrdquo Journal of ChemicalTechnology amp Biotechnology vol 87 no 5 pp 705ndash7132012

[27] F Faghihi and P Hazendonk ldquoRAFT polymerizationcharacterization and post-polymerization modification of

a copolymer of vinylbenzyl chloride towards thiolate func-tionalized copolymersrdquo Polymer vol 128 pp 31ndash39 2017

[28] Y Zhao L Xu M Liu Z Duan and H Wang ldquoMagneticmesoporous thiourea-formaldehyde resin as selective ad-sorbent a simple and highly-sensitive electroanalysisstrategy for lead ions in drinking water and milk by solidstate-based anodic strippingrdquo Food Chemistry vol 239pp 40ndash47 2018

[29] T Yang L Zhang L Zhong X Han S Dong and Y LildquoSelective adsorption of Ag(I) ions with poly(vinyl alcohol)modified with thiourea (TU-PVA)rdquo Hydrometallurgyvol 175 pp 179ndash186 2018

[30] X Gao Y Zhang and Y Zhao ldquoBiosorption and reduction ofAu(III) to gold nanoparticles by thiourea modified alginaterdquoCarbohydrate Polymers vol 159 pp 108ndash115 2017

[31] F J V E Oliveira E C da Silva Filho M A Melo andC Airoldi ldquoModified coupling agents based on thioureaimmobilized onto silica )ermodynamics of copper ad-sorptionrdquo Surface Science vol 603 no 14 pp 2200ndash22062009

[32] N N S Subri P A G Cormack S N A JamilL C Abdullah and R Daik ldquoSynthesis of poly(acrylonitrile-co-divinylbenzene-co-vinylbenzyl chloride)-derived hyper-crosslinked polymer microspheres and a preliminary evalu-ation of their potential for the solid-phase capture ofpharmaceuticalsrdquo Journal of Applied Polymer Science vol 135no 2 article 45677 2018

[33] M S M Eldin M R Elaassar A A Elzatahry andM M B Al-Sabah ldquoPoly(acrylonitrile-co-methyl methacry-late) nanoparticles I Preparation and characterizationrdquoArabian Journal of Chemistry vol 10 no 8 pp 1153ndash11662017

[34] F Huang Y Xu S Liao D Yang Y-L Hsieh and Q WeildquoPreparation of amidoxime polyacrylonitrile chelatingnanofibers and their application for adsorption of metal ionsrdquoMaterials vol 6 no 3 pp 969ndash980 2013

[35] J Wang P A G Cormack D C Sherrington andE Khoshdel ldquoSynthesis and characterization of micrometer-sized molecularly imprinted spherical polymer particulatesprepared via precipitation polymerizationrdquo Pure and AppliedChemistry vol 79 no 9 pp 1505ndash1519 2007

[36] LWang R Xing S Liu et al ldquoStudies on adsorption behaviorof Pb(II) onto a thiourea-modified chitosan resin with Pb(II)as templaterdquo Carbohydrate Polymers vol 81 no 2pp 305ndash310 2010

[37] T Renkecz G Mistlberger M Pawlak V Horvath andE Bakker ldquoMolecularly imprinted polymer microspherescontaining photoswitchable spiropyran-based binding sitesrdquoACS Applied Materials amp Interfaces vol 5 no 17pp 8537ndash8545 2013

[38] H Gao and K Matyjaszewski ldquoSynthesis of functionalpolymers with controlled architecture by CRP of monomersin the presence of cross-linkers from stars to gelsrdquo Progress inPolymer Science vol 34 no 4 pp 317ndash350 2009

[39] H N Catherine M-H Ou B Manu and Y-h Shih ldquoAd-sorption mechanism of emerging and conventional phenoliccompounds on graphene oxide nanoflakes in waterrdquo Scienceof the Total Environment vol 635 pp 629ndash638 2018

[40] K Krishnamoorthy M Veerapandian K Yun and S Kimldquo)e chemical and structural analysis of graphene oxide withdifferent degrees of oxidationrdquo Carbon vol 53 pp 38ndash492012

[41] F-F Liu J Zhao S Wang and B Xing ldquoAdsorption ofsulfonamides on reduced graphene oxides as affected by pH


and dissolved organic matterrdquo Environmental Pollutionvol 210 pp 85ndash93 2016

[42] A Almasian M E Olya and N M Mahmoodi ldquoSynthesis ofpolyacrylonitrilepolyamidoamine composite nanofibers us-ing electrospinning technique and their dye removal capac-ityrdquo Journal of the Taiwan Institute of Chemical Engineersvol 49 pp 119ndash128 2015

[43] N M Mahmoodi ldquoNickel ferrite nanoparticle synthesismodification by surfactant and dye removal abilityrdquo WaterAir amp Soil Pollution vol 224 no 2 pp 1ndash11 2015

[44] D Pathania S Sharma and P Singh ldquoRemoval of methyleneblue by adsorption onto activated carbon developed fromFicus carica bastrdquo Arabian Journal of Chemistry vol 10pp S1445ndashS1451 2017

[45] N Akter M A Hossain M J Hassan et al ldquoAmine modifiedtannin gel for adsorptive removal of Brilliant Green dyerdquoJournal of Environmental Chemical Engineering vol 4 no 1pp 1231ndash1241 2016

[46] Y Aldegs M Elbarghouthi A Elsheikh and G WalkerldquoEffect of solution pH ionic strength and temperature onadsorption behavior of reactive dyes on activated carbonrdquoDyes and Pigments vol 77 no 1 pp 16ndash23 2008

[47] M K Dahri M R R Kooh L B L Lim and L B L LimldquoApplication of Casuarina equisetifolia needle for the removalof methylene blue and malachite green dyes from aqueoussolutionrdquo Alexandria Engineering Journal vol 54 no 4pp 1253ndash1263 2015

[48] S F Azha M Shahadat and S Ismail ldquoAcrylic polymeremulsion supported bentonite clay coating for the analysis ofindustrial dyerdquoDyes and Pigments vol 145 pp 550ndash560 2017

[49] A M Aljeboree A N Alshirifi and A F Alkaim ldquoKineticsand equilibrium study for the adsorption of textile dyes oncoconut shell activated carbonrdquo Arabian Journal of Chem-istry vol 10 pp S3381ndashS3393 2017

[50] Z Zhou S Lin T Yue and T-C Lee ldquoAdsorption of fooddyes from aqueous solution by glutaraldehyde cross-linkedmagnetic chitosan nanoparticlesrdquo Journal of Food Engineer-ing vol 126 pp 133ndash141 2014

[51] G L Dotto E C Lima and L A A Pinto ldquoBiosorption offood dyes onto Spirulina platensis nanoparticles equilibriumisotherm and thermodynamic analysisrdquo Bioresource Tech-nology vol 103 no 1 pp 123ndash130 2012

[52] S K Ponnusamy ldquoEffect of temperature on the adsorption ofmethylene blue dye onto sulfuric acidmdashtreated orange peelrdquoChemical Engineering Communications vol 201 pp 1526ndash1547 2015

[53] N Ayawei A N Ebelegi and D Wankasi ldquoModelling andinterpretation of adsorption isothermsrdquo Journal of Chemistryvol 2017 Article ID 3039817 11 pages 2017

[54] S P D Monte Blanco F B Scheufele A N Modenes et alldquoKinetic equilibrium and thermodynamic phenomenologicalmodeling of reactive dye adsorption onto polymeric adsor-bentrdquo Chemical Engineering Journal vol 307 pp 466ndash4752017

[55] M F Elkady A M Ibrahim and M M A El-Latif ldquoAs-sessment of the adsorption kinetics equilibrium and ther-modynamic for the potential removal of reactive red dye usingeggshell biocomposite beadsrdquo Desalination vol 278 no 1ndash3pp 412ndash423 2011

[56] M Erhayem F Al-Tohami R Mohamed and K AhmidaldquoIsotherm kinetic and thermodynamic studies for thesorption of mercury(II) onto activated carbon from Ros-marinus officinalis leavesrdquo American Journal of AnalyticalChemistry vol 6 no 1 pp 1ndash10 2015

[57] A A Farghali M Bahgat andWM A El Rouby ldquoDecorationof multi-walled carbon nanotubes (MWCNTs) with differentferrite nanoparticles and its use as an adsorbentrdquo Journal ofNanostructure in Chemistry vol 3 no 1 p 50 2013

[58] A L Cazetta A M M Vargas E M Nogami et al ldquoNaOH-activated carbon of high surface area produced from coconutshell kinetics and equilibrium studies from the methyleneblue adsorptionrdquo Chemical Engineering Journal vol 174no 1 pp 117ndash125 2011

[59] T M Berhane J Levy M P S Krekeler and N D DanielsonldquoKinetic sorption of contaminants of emerging concern by apalygorskite-montmorillonite filter mediumrdquo Chemospherevol 176 pp 231ndash242 2017

[60] L Lonappan T Rouissi S Kaur Brar M Verma andR Y Surampalli ldquoAn insight into the adsorption of diclofenacon different biochars mechanisms surface chemistry andthermodynamicsrdquo Bioresource Technology vol 249 pp 386ndash394 2018

[61] F Ogata T Nakamura and N Kawasaki ldquoAdsorption ca-pability of virgin and calcined wheat bran for molybdenumpresent in aqueous solution and elucidating the adsorptionmechanism by adsorption isotherms kinetics and re-generationrdquo Journal of Environmental Chemical Engineeringvol 6 no 4 pp 4459ndash4466 2018

[62] J Fu Q Xin X Wu et al ldquoSelective adsorption and sepa-ration of organic dyes from aqueous solution on polydop-amine microspheresrdquo Journal of Colloid and Interface Sciencevol 461 pp 292ndash304 2015

[63] N Gupta A K Kushwaha and M C ChattopadhyayaldquoApplication of potato (Solanum tuberosum) plant wastes forthe removal of methylene blue and malachite green dye fromaqueous solutionrdquo Arabian Journal of Chemistry vol 9pp S707ndashS716 2016

[64] S Mishra A Mukul G Sen and U Jha ldquoMicrowave assistedsynthesis of polyacrylamide grafted starch (St-g-PAM) and itsapplicability as flocculant for water treatmentrdquo InternationalJournal of Biological Macromolecules vol 48 no 1 pp 106ndash111 2011

[65] A K Sarkar A Pal S Ghorai N R Mandre and S PalldquoEfficient removal of malachite green dye using biodegradablegraft copolymer derived from amylopectin and poly(acrylicacid)rdquo Carbohydrate Polymers vol 111 pp 108ndash115 2014

[66] H Zheng D Liu Y Zheng S Liang and Z Liu ldquoSorptionisotherm and kinetic modeling of aniline on Cr-bentoniterdquoJournal of Hazardous Materials vol 167 no 1ndash3 pp 141ndash1472009

[67] M Y Abdelnaeim I Y El Sherif A A Attia N A Fathy andM F El-Shahat ldquoImpact of chemical activation on the ad-sorption performance of common reed towards Cu(II) andCd(II)rdquo International Journal of Mineral Processing vol 157pp 80ndash88 2016

[68] K Y Foo and B H Hameed ldquoPreparation characterizationand evaluation of adsorptive properties of orange peel basedactivated carbon via microwave induced K2CO3 activationrdquoBioresource Technology vol 104 pp 679ndash686 2012

[69] B Hayati N M Mahmoodi and A Maleki ldquoDendrimer-titania nanocomposite synthesis and dye-removal capacityrdquoResearch on Chemical Intermediates vol 41 no 6pp 3743ndash3757 2013

[70] M A Dabhade M B Saidutta and D V R Murthy ldquoAd-sorption of phenol on granular activated carbon from nutrientmedium equilibrium and kinetic studyrdquo InternationalJournal of Environmental Research vol 3 no 4 pp 557ndash5682009


[71] N Fadzilah A Razak M Shamsuddin and S L LeeldquoChemical engineering research and design adsorption ki-netics and thermodynamics studies of gold(III) ions usingthioctic acid functionalized silica coated magnetite nano-particlesrdquo Chemical Engineering Research and Designvol 130 pp 18ndash28 2017

[72] G Bayramoglu A Akbulut G Liman and M Y AricaldquoRemoval of metal complexed azo dyes from aqueous solutionusing tris(2-aminoethyl)amine ligand modified magneticp(GMA-EGDMA) cationic resin adsorption isotherm andkinetic studiesrdquo Chemical Engineering Research and Designvol 124 pp 85ndash97 2017

[73] A Mittal J Mittal A Malviya D Kaur and V K GuptaldquoDecoloration treatment of a hazardous triarylmethane dyeLight Green SF (Yellowish) by waste material adsorbentsrdquoJournal of Colloid and Interface Science vol 342 no 2pp 518ndash527 2010

[74] J Zhang F Li and Q Sun ldquoRapid and selective adsorption ofcationic dyes by a unique metal-organic framework withdecorated pore surfacerdquo Applied Surface Science vol 440pp 1219ndash1226 2018


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Submit your manuscripts atwwwhindawicom

amongst all treatment technologies as the most effective foradsorption of dye due to its design flexibility relatively lowcost adaptation to broad range of dyes and simple operation[12 13] However sludge generation poor selectivity longcontact time poor site accessibility and nonrecyclability ofadsorbents are limitation to adsorption application)erefore it is required to prepare functional adsorbentswith reasonable cost efficiency and regeneration ability

Recently chemical modification of reactive functionalgroups for creation of different new or additional func-tionalities has become attention-grabbing art in materialscience and engineering field Design of materials withdesired specified formulation and morphology is madepossible with this modification technology [14] With thisdevelopment polymeric materials containing amine amidethioamide or amidoxime groups that cannot be synthesizeddirectly by polymerization can now be easily produced bypostpolymerization modification )ese functionalized ormodified polymers possess complexing capacity with variousorganic pollutants especially synthetic dyes and other pol-lutants in liquid phase environment [15 16] Its applicationis not limited to wastewater treatment but catalysis bio-medical and others [17 18]

Acrylonitrile (AN) as the high carbon source materialcan be polymerized with monomers like methyl acrylateacrylic acid vinylbenzyl chloride and itaconic acid for in-direct synthesis of polymers with thio-functionalities [19ndash21] Different shapes (spherical) fibres and hydrogelpolymers can be prepared by AN copolymerization Oncehydrophobic nitrile groups containing polymer is prepareddipole of nitrile groups can be modified into thioamidegroups via postpolymerization Nitrile groups can also beconverted to amidoxime amine hydrazine amidrazoneand carboxyl groups by the above similar chemical modi-fication route [18 19 21ndash23] For instance Kampalanonwatand Supaphol report the modification of polyacrylonitrile(PAN) with NaOH ethanolic solution for metal ion ad-sorption although it is a costly and complicated process[24] Goscianska et al produced an ordered mesoporouscarbon material functionalized with amine group and ap-plied as an adsorbent to remove solophenyl red 3BL (SR)[25] Bayramoglu et al synthesized magnetic beads con-taining aminated fibrous surfaces for sorption of reactivegreen 19 dye from aqueous solution [26] Sheng et alprepared polyacrylonitrile (PAN) functionalized with thio-to enhance it adsorptive properties Faghihi and Hazendonkalso described the postpolymerization modification ofvinylbenzyl chloride (VBC 15mol) and methyl methac-rylate (MMA 85mol) with thiouronium [27] Postsurfacemodification of poly(vinylbenzyl chloride) beads with theamidoxime group for high sorption of organic dyes andheavy metals was reported by Ajmal et al [15]

)e potential of modified polymeric materials as theadsorbent largely depends on various reactions that can beperformed on the inorganic surface and expanded chain onthe modifying agent )iourea is chosen among functionalgroups due to its high content of nitrogen and sulphur aselectron donor atoms [28ndash30] and its capacity to attach tothe pendant polymer chain [31] Herein new hydrophilic

thiourea-modified poly(acrylonitrile-co-acrylic acid) deno-ted as TU-poly(AN-co-AA) was prepared by redox poly-merization of acrylonitrile (AN) and acrylic acid (AA) andfunctionalized with thiourea )ioamide groups on polymerchains act as binding sites for the positively charged dyemolecules )e characterization adsorption kinetics andadsorption isotherms studies of prepared adsorbents on theMG adsorbate were investigated

2 Materials and Methods

21 Chemicals Acrylonitrile (AN) and acrylic acid (AA)(monomers) were taken from Acros Organics New JerseyUSA and purified by passing through an alumina columnSodium bisulphate (SBS) and potassium persulphate (KPS)(initiators) and thiourea (TU) were purchased from RampMChemicals Essex UK Ethanol and methanol were pur-chased from System ChemAR Shah Alam Malaysia Mal-achite green (MG) dye (from Acros Organics New JerseyUSA) was used as the adsorbate All chemical reagents wereof analytical grade

22 Synthesis andModification of Poly(acrylonitrile-co-acrylicacid) Redox polymerization of acrylonitrile- (AN-) 970and acrylic acid- (AA-) 30 was performed at 60degC undernitrogen gas in a three-necked round bottom flask fittedwith a water condenser )e reaction medium deionizedwater (200mL) was initially purge with nitrogen gas at 40degCfor 30minutes )en 209 g of SBS and 216 g of KPS wereadded to the reaction medium followed by 0275mol of ANand 0029mol of AA )e solution was mechanically stirredat 200 rpm using an egg-shaped magnetic stirrer )e freeradical polymerization reaction was allowed for 2 hours )epoly(AN-co-AA) polymer formed was precipitated inmethanol for an hour and then successfully washed withmethanol and deionized water )e polymer was oven-driedin vacuo at 45degC until constant weight is obtained It is amodified technique employed by Zahri et al [20]

)e surface of the synthesized polymer poly(AN-co-AA) was modified with thiourea to produced hydrophilicthiourea-modified poly(AN-co-AA) )e modificationprocess was as follows 60 g of TU and ethanol-watermixture (12 vol) were stirred at 200 rpm for 30minutesat a constant temperature of 50degC )en 50 g of poly(AN-co-AA) was added to the solution at 100degC for 5 hours )eresulting crystal TU-poly(AN-co-AA) was rinsed in ethanoldeionized water solution filtered and dried to constantweight at 50degC )e overall preparation and modificationprocess is illustrated in Scheme 1

23 Preparation of Aqueous Dye Solutions Malachite green(MG) (Scheme 2) dye of a commercial grade and purity wasused without purification )e dye stock solution of con-centration of 1000mgL was prepared by dissolving 10 g ofdye in distilled water)e experimental solutions of differentinitial concentrations ranging from 20 to 100mgL wereobtained by diluting the MG dye stock solution







R C0 minusCe

C0times 100 (1)

qe VC0 minusCe

m (2)



H2CO

OH


N O OH

p q

+H2C

NCH

(a)

+H2N

CNH2

S

Np q

O OHH2NHN NH

C S p qO

OH


(b)


(a)

H3C

CH3 CH3

CH3

Clndash

N N+

(b)




















3516-OH

2932-CH

2244-C=-N

1725-C=O

Tran

smitt

ance

()

PMP

3345-NH2 -OH

2935-CH

1728-C=O

1614-C=N

729-C=S


(a) (b)






0 2 4 6 8 10 12

ndash30

ndash25

ndash20

ndash15

ndash10

ndash5

Zeta

pot

entia

l (m

V)

pH

PMP



Adsorbent Dosage(g)

Extent ofremoval()

Improvement()

Poly(AN-co-AA)


TU-poly(AN-co-AA)

03 6488 118105 8625 208110 8998 2168


00 02 04 06 08 10 120

10

20

30

40

50

60

70

80

90

100

MG

rem

oval

()



0 10 20 30 40 50 60 70 80 90 100 110 120 130

0

10

20

30

40

50

60

70

80

90

100

MG

rem

oval

()

Time (min)

20 mgL40 mgL60 mgL

80 mgL100 mgL







t

qt

1k2q2e

+1qet

qt 1βln(αβ) +

1βln(t)

qt kIPt05 + CIP

(3)





642 8 10 1230

40

50

60

70

80

90

100

MG

rem

oval

()

pH


295 300 305 310 315 320 325 330

14

15

16

17

18

q e (m

gg)

T (K)






Ce

qe

1KLqmax

+Ce

qmax (4)

ln qe( 1113857 ln KF( 1113857 +1n

1113874 1113875ln Ce( 1113857 (5)


0 10 20 30 40 50 60 70 80 90 100 110 120 130

ndash6

ndash5

ndash4

ndash3

ndash2

ndash1

0

1

2

ln(q

endashq t

)

t (min)


(a)

0 10 20 30 40 50 60 70 80 90 100 110 120 130

0

1

2

3

4

5

6

7

tqt

t (min)


(b)

0 1 2 3 4 512

13

14

15

16

17

18


q t

ln(t)

(c)

q t


0 2 4 6 8 10 1212

13

14

15

16

17

18

t05

(d)



RL 1

1 + KLC0 (7)










ΔG0 minusRT lnKd

(8)


Kd qe

Ce (9)


lnKd ΔS0

RΔH0

RT (10)





0040 1719 28866 04533


00033 1719 1730 09997


09066 7211342 09515


04769 1295 08218




00322 26954 09309


19004 08359 09960


06878 35620 09475






305 310 315 320 325 330 335 340ndash06

ndash05

ndash04

ndash03

ndash02

ndash01

00

01

02

ln K

d






q

NHHN

CSO

HO

HN NH

C S p

OOH

MG+ MG+

NH2

H2N

(a)


(b)

Diffusion stage

(c)

Equilibrium stage

(d)



4 Conclusions


Data Availability




Acknowledgments



References















20

40

60

80

100

Reco

very

()

Regeneration cycle










































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls









R C0 minusCe

C0times 100 (1)

qe VC0 minusCe

m (2)



H2CO

OH


N O OH

p q

+H2C

NCH

(a)

+H2N

CNH2

S

Np q

O OHH2NHN NH

C S p qO

OH


(b)


(a)

H3C

CH3 CH3

CH3

Clndash

N N+

(b)




















3516-OH

2932-CH

2244-C=-N

1725-C=O

Tran

smitt

ance

()

PMP

3345-NH2 -OH

2935-CH

1728-C=O

1614-C=N

729-C=S


(a) (b)






0 2 4 6 8 10 12

ndash30

ndash25

ndash20

ndash15

ndash10

ndash5

Zeta

pot

entia

l (m

V)

pH

PMP



Adsorbent Dosage(g)

Extent ofremoval()

Improvement()

Poly(AN-co-AA)


TU-poly(AN-co-AA)

03 6488 118105 8625 208110 8998 2168


00 02 04 06 08 10 120

10

20

30

40

50

60

70

80

90

100

MG

rem

oval

()



0 10 20 30 40 50 60 70 80 90 100 110 120 130

0

10

20

30

40

50

60

70

80

90

100

MG

rem

oval

()

Time (min)

20 mgL40 mgL60 mgL

80 mgL100 mgL







t

qt

1k2q2e

+1qet

qt 1βln(αβ) +

1βln(t)

qt kIPt05 + CIP

(3)





642 8 10 1230

40

50

60

70

80

90

100

MG

rem

oval

()

pH


295 300 305 310 315 320 325 330

14

15

16

17

18

q e (m

gg)

T (K)






Ce

qe

1KLqmax

+Ce

qmax (4)

ln qe( 1113857 ln KF( 1113857 +1n

1113874 1113875ln Ce( 1113857 (5)


0 10 20 30 40 50 60 70 80 90 100 110 120 130

ndash6

ndash5

ndash4

ndash3

ndash2

ndash1

0

1

2

ln(q

endashq t

)

t (min)


(a)

0 10 20 30 40 50 60 70 80 90 100 110 120 130

0

1

2

3

4

5

6

7

tqt

t (min)


(b)

0 1 2 3 4 512

13

14

15

16

17

18


q t

ln(t)

(c)

q t


0 2 4 6 8 10 1212

13

14

15

16

17

18

t05

(d)



RL 1

1 + KLC0 (7)










ΔG0 minusRT lnKd

(8)


Kd qe

Ce (9)


lnKd ΔS0

RΔH0

RT (10)





0040 1719 28866 04533


00033 1719 1730 09997


09066 7211342 09515


04769 1295 08218




00322 26954 09309


19004 08359 09960


06878 35620 09475






305 310 315 320 325 330 335 340ndash06

ndash05

ndash04

ndash03

ndash02

ndash01

00

01

02

ln K

d






q

NHHN

CSO

HO

HN NH

C S p

OOH

MG+ MG+

NH2

H2N

(a)


(b)

Diffusion stage

(c)

Equilibrium stage

(d)



4 Conclusions


Data Availability




Acknowledgments



References















20

40

60

80

100

Reco

very

()

Regeneration cycle










































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls





















3516-OH

2932-CH

2244-C=-N

1725-C=O

Tran

smitt

ance

()

PMP

3345-NH2 -OH

2935-CH

1728-C=O

1614-C=N

729-C=S


(a) (b)






0 2 4 6 8 10 12

ndash30

ndash25

ndash20

ndash15

ndash10

ndash5

Zeta

pot

entia

l (m

V)

pH

PMP



Adsorbent Dosage(g)

Extent ofremoval()

Improvement()

Poly(AN-co-AA)


TU-poly(AN-co-AA)

03 6488 118105 8625 208110 8998 2168


00 02 04 06 08 10 120

10

20

30

40

50

60

70

80

90

100

MG

rem

oval

()



0 10 20 30 40 50 60 70 80 90 100 110 120 130

0

10

20

30

40

50

60

70

80

90

100

MG

rem

oval

()

Time (min)

20 mgL40 mgL60 mgL

80 mgL100 mgL







t

qt

1k2q2e

+1qet

qt 1βln(αβ) +

1βln(t)

qt kIPt05 + CIP

(3)





642 8 10 1230

40

50

60

70

80

90

100

MG

rem

oval

()

pH


295 300 305 310 315 320 325 330

14

15

16

17

18

q e (m

gg)

T (K)






Ce

qe

1KLqmax

+Ce

qmax (4)

ln qe( 1113857 ln KF( 1113857 +1n

1113874 1113875ln Ce( 1113857 (5)


0 10 20 30 40 50 60 70 80 90 100 110 120 130

ndash6

ndash5

ndash4

ndash3

ndash2

ndash1

0

1

2

ln(q

endashq t

)

t (min)


(a)

0 10 20 30 40 50 60 70 80 90 100 110 120 130

0

1

2

3

4

5

6

7

tqt

t (min)


(b)

0 1 2 3 4 512

13

14

15

16

17

18


q t

ln(t)

(c)

q t


0 2 4 6 8 10 1212

13

14

15

16

17

18

t05

(d)



RL 1

1 + KLC0 (7)










ΔG0 minusRT lnKd

(8)


Kd qe

Ce (9)


lnKd ΔS0

RΔH0

RT (10)





0040 1719 28866 04533


00033 1719 1730 09997


09066 7211342 09515


04769 1295 08218




00322 26954 09309


19004 08359 09960


06878 35620 09475






305 310 315 320 325 330 335 340ndash06

ndash05

ndash04

ndash03

ndash02

ndash01

00

01

02

ln K

d






q

NHHN

CSO

HO

HN NH

C S p

OOH

MG+ MG+

NH2

H2N

(a)


(b)

Diffusion stage

(c)

Equilibrium stage

(d)



4 Conclusions


Data Availability




Acknowledgments



References















20

40

60

80

100

Reco

very

()

Regeneration cycle










































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls







0 2 4 6 8 10 12

ndash30

ndash25

ndash20

ndash15

ndash10

ndash5

Zeta

pot

entia

l (m

V)

pH

PMP



Adsorbent Dosage(g)

Extent ofremoval()

Improvement()

Poly(AN-co-AA)


TU-poly(AN-co-AA)

03 6488 118105 8625 208110 8998 2168


00 02 04 06 08 10 120

10

20

30

40

50

60

70

80

90

100

MG

rem

oval

()



0 10 20 30 40 50 60 70 80 90 100 110 120 130

0

10

20

30

40

50

60

70

80

90

100

MG

rem

oval

()

Time (min)

20 mgL40 mgL60 mgL

80 mgL100 mgL







t

qt

1k2q2e

+1qet

qt 1βln(αβ) +

1βln(t)

qt kIPt05 + CIP

(3)





642 8 10 1230

40

50

60

70

80

90

100

MG

rem

oval

()

pH


295 300 305 310 315 320 325 330

14

15

16

17

18

q e (m

gg)

T (K)






Ce

qe

1KLqmax

+Ce

qmax (4)

ln qe( 1113857 ln KF( 1113857 +1n

1113874 1113875ln Ce( 1113857 (5)


0 10 20 30 40 50 60 70 80 90 100 110 120 130

ndash6

ndash5

ndash4

ndash3

ndash2

ndash1

0

1

2

ln(q

endashq t

)

t (min)


(a)

0 10 20 30 40 50 60 70 80 90 100 110 120 130

0

1

2

3

4

5

6

7

tqt

t (min)


(b)

0 1 2 3 4 512

13

14

15

16

17

18


q t

ln(t)

(c)

q t


0 2 4 6 8 10 1212

13

14

15

16

17

18

t05

(d)



RL 1

1 + KLC0 (7)










ΔG0 minusRT lnKd

(8)


Kd qe

Ce (9)


lnKd ΔS0

RΔH0

RT (10)





0040 1719 28866 04533


00033 1719 1730 09997


09066 7211342 09515


04769 1295 08218




00322 26954 09309


19004 08359 09960


06878 35620 09475






305 310 315 320 325 330 335 340ndash06

ndash05

ndash04

ndash03

ndash02

ndash01

00

01

02

ln K

d






q

NHHN

CSO

HO

HN NH

C S p

OOH

MG+ MG+

NH2

H2N

(a)


(b)

Diffusion stage

(c)

Equilibrium stage

(d)



4 Conclusions


Data Availability




Acknowledgments



References















20

40

60

80

100

Reco

very

()

Regeneration cycle










































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls








t

qt

1k2q2e

+1qet

qt 1βln(αβ) +

1βln(t)

qt kIPt05 + CIP

(3)





642 8 10 1230

40

50

60

70

80

90

100

MG

rem

oval

()

pH


295 300 305 310 315 320 325 330

14

15

16

17

18

q e (m

gg)

T (K)






Ce

qe

1KLqmax

+Ce

qmax (4)

ln qe( 1113857 ln KF( 1113857 +1n

1113874 1113875ln Ce( 1113857 (5)


0 10 20 30 40 50 60 70 80 90 100 110 120 130

ndash6

ndash5

ndash4

ndash3

ndash2

ndash1

0

1

2

ln(q

endashq t

)

t (min)


(a)

0 10 20 30 40 50 60 70 80 90 100 110 120 130

0

1

2

3

4

5

6

7

tqt

t (min)


(b)

0 1 2 3 4 512

13

14

15

16

17

18


q t

ln(t)

(c)

q t


0 2 4 6 8 10 1212

13

14

15

16

17

18

t05

(d)



RL 1

1 + KLC0 (7)










ΔG0 minusRT lnKd

(8)


Kd qe

Ce (9)


lnKd ΔS0

RΔH0

RT (10)





0040 1719 28866 04533


00033 1719 1730 09997


09066 7211342 09515


04769 1295 08218




00322 26954 09309


19004 08359 09960


06878 35620 09475






305 310 315 320 325 330 335 340ndash06

ndash05

ndash04

ndash03

ndash02

ndash01

00

01

02

ln K

d






q

NHHN

CSO

HO

HN NH

C S p

OOH

MG+ MG+

NH2

H2N

(a)


(b)

Diffusion stage

(c)

Equilibrium stage

(d)



4 Conclusions


Data Availability




Acknowledgments



References















20

40

60

80

100

Reco

very

()

Regeneration cycle










































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls







Ce

qe

1KLqmax

+Ce

qmax (4)

ln qe( 1113857 ln KF( 1113857 +1n

1113874 1113875ln Ce( 1113857 (5)


0 10 20 30 40 50 60 70 80 90 100 110 120 130

ndash6

ndash5

ndash4

ndash3

ndash2

ndash1

0

1

2

ln(q

endashq t

)

t (min)


(a)

0 10 20 30 40 50 60 70 80 90 100 110 120 130

0

1

2

3

4

5

6

7

tqt

t (min)


(b)

0 1 2 3 4 512

13

14

15

16

17

18


q t

ln(t)

(c)

q t


0 2 4 6 8 10 1212

13

14

15

16

17

18

t05

(d)



RL 1

1 + KLC0 (7)










ΔG0 minusRT lnKd

(8)


Kd qe

Ce (9)


lnKd ΔS0

RΔH0

RT (10)





0040 1719 28866 04533


00033 1719 1730 09997


09066 7211342 09515


04769 1295 08218




00322 26954 09309


19004 08359 09960


06878 35620 09475






305 310 315 320 325 330 335 340ndash06

ndash05

ndash04

ndash03

ndash02

ndash01

00

01

02

ln K

d






q

NHHN

CSO

HO

HN NH

C S p

OOH

MG+ MG+

NH2

H2N

(a)


(b)

Diffusion stage

(c)

Equilibrium stage

(d)



4 Conclusions


Data Availability




Acknowledgments



References















20

40

60

80

100

Reco

very

()

Regeneration cycle










































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls




RL 1

1 + KLC0 (7)










ΔG0 minusRT lnKd

(8)


Kd qe

Ce (9)


lnKd ΔS0

RΔH0

RT (10)





0040 1719 28866 04533


00033 1719 1730 09997


09066 7211342 09515


04769 1295 08218




00322 26954 09309


19004 08359 09960


06878 35620 09475






305 310 315 320 325 330 335 340ndash06

ndash05

ndash04

ndash03

ndash02

ndash01

00

01

02

ln K

d






q

NHHN

CSO

HO

HN NH

C S p

OOH

MG+ MG+

NH2

H2N

(a)


(b)

Diffusion stage

(c)

Equilibrium stage

(d)



4 Conclusions


Data Availability




Acknowledgments



References















20

40

60

80

100

Reco

very

()

Regeneration cycle










































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls








305 310 315 320 325 330 335 340ndash06

ndash05

ndash04

ndash03

ndash02

ndash01

00

01

02

ln K

d






q

NHHN

CSO

HO

HN NH

C S p

OOH

MG+ MG+

NH2

H2N

(a)


(b)

Diffusion stage

(c)

Equilibrium stage

(d)



4 Conclusions


Data Availability




Acknowledgments



References















20

40

60

80

100

Reco

very

()

Regeneration cycle










































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls




4 Conclusions


Data Availability




Acknowledgments



References















20

40

60

80

100

Reco

very

()

Regeneration cycle










































































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




Adsorption of Malachite Green Dye from Liquid Phase Using ...

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Transcript of Adsorption of Malachite Green Dye from Liquid Phase Using ...