adsorptionofcrystalvioletontoanagriculturalwasteresidue: kinetics… · 2020. 5. 1. · research...

Research ArticleAdsorption of Crystal Violet onto an Agricultural Waste ResidueKinetics Isotherm Thermodynamics andMechanism of Adsorption

IlyasseLoulidi 1FatimaBoukhlifi1MbarkaOuchabi2AbdelouahedAmar1MariaJabri1

Abderahim Kali1 Salma Chraibi1 Chaimaa Hadey3 and Faissal Aziz4

1Laboratory of Chemistry and Biology Applied to the Environment Faculty of Sciences Moulay Ismail UniversityBP 11201-Zitoune Meknes Morocco2Laboratory of Catalysis and Corrosion of Materials Chouaıb Doukkali University Faculty of Sciences El Jadida BP 20El Jadida Morocco3Engineering Sciences and Trades Laboratory ENSAM University Moulay Ismail Meknes Morocco4National Centre for Research and Study on Water and Energy (CNEREE) Cadi Ayyad University Marrakech Morocco

Correspondence should be addressed to Ilyasse Loulidi illoulidigmailcom

Received 13 September 2019 Revised 18 March 2020 Accepted 4 April 2020 Published 1 May 2020

Academic Editor Qiquan Wang

Copyright copy 2020 Ilyasse Loulidi 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

Agricultural waste can be exploited for the adsorption of dyes due to their low cost availability cost-effectiveness and efficiencyIn this study we were interested in the elimination of crystal violet dye from aqueous solutions by adsorption on almond shell-based material as a low-cost and ecofriendly adsorbent +e almond shells were first analyzed by Fourier transform infraredspectroscopy (FTIR) and X-ray diffraction then the influence of adsorbent dose initial dye concentration time and pH werestudied to assess adsorption capacity under optimal experimental conditions Experimental results indicate that almond shelladsorbent removes about 83 of the dye from the solutions at room temperature and in batch mode the kinetic study showed thatthe equilibrium time is about 90min and the model of pseudo-second order could very well describe adsorption kinetics +emodulation of adsorption isotherms showed that retention follows the Langmuir model +e thermodynamic study has shownthat the adsorption is endothermic (ΔHdeggt 0) and spontaneous (ΔGdeglt 0)

1 Introduction

Many industries such as the textile plastics and paper usedyes to hue their products and large volumes of water areconsumed Consequently they generate a considerablequantity of colored wastewaters More than 100000 dyesavailable in the trade with more than 7 105 t of dyes areproduced annually in the world [1] 1000 t of these dyes arereleased annually into the aquatic system [2]

+e dye is the first pollutant to be detected in wastewater[3] +e presence of a very low concentration of dyes inwater is very noticeable and undesirable Several treatmentmethods were used for treating effluents containing dyes[2 4] But these differ in their effectiveness cost and en-vironmental impact [5] Adsorption is the most effective

technique widely used [6 7] in which activated carbon is themost frequently used adsorbent in the purification of water+e high cost required by adsorption using activated carbon[2] pushes researchers to find other alternatives such aswaste or agricultural by-products [4] Agricultural wasteconsists mainly of cellulose hemicellulose and lignin whichare effective adsorbents for a wide range of pollutants be-cause of their richness in functional groups such as hydroxylgroups carboxyl and phenols [8] Other advantages thatmake them as excellent candidates are the capacity and therate of adsorption the high selectivity for different pollut-ants and also rapid kinetics [4] Agricultural waste is betterthan other adsorbents as they are generally used without orwith minimal treatment (washing drying and grinding) [9]Several recent studies have used various agricultural wastes

Hindawie Scientific World JournalVolume 2020 Article ID 5873521 9 pageshttpsdoiorg10115520205873521

for adsorption of dyes in effluents Table 1 shows someexamples

Almond is the fruit of almond tree which is the secondmost important fruit species cultivated in Morocco after theolive tree with a production of 101000 tyear in 2016 whichis the equivalent of 80000 tonnes of almond shellsaccording to data from the Moroccan Federation of AlmondTree Producers +ese residues are discarded as solid wastewhich poses environmental problems It is therefore nec-essary to find an appropriate method to solve the disposalproblem +e use of this inexpensive material as an ad-sorbent contributes to the solution to this problem and to theapplication of the principle of ldquoself-cleaning of wasterdquo

Crystal violet is widely used as a violet dye in the textileindustry for dyeing cotton and silk It is also used in themanufacture of paints and printing inks [10] Crystal violet iscarcinogenic and has been classified as a recalcitrant mol-ecule because it is poorly metabolized by microbes isnonbiodegradable and can persist in various environmentsIt is highly toxic to the cells [11]

+e purpose of this research paper is to investigate thepotential use of almond shells to remove the crystal violetdye from aqueous solutions Adsorption parameters in-cluding dye concentration contact time almond shell doseand pH were studied to determine the effectiveness of theadsorbent +e characterization of the adsorbent before andafter adsorption was achieved in order to identify themechanism governing the fixation of the dye molecules onthe adsorbent

2 Materials and Methods

21 Adsorbent Preparation +e almond shells (AS) werewashed dried for 24 hours at a temperature of 110degC in anoven and then crushed and sieved to obtain fine and ho-mogeneous samples (lt02mm)

22 Adsorbate Preparation Crystal violet (CV) (character-istics given in Table 2) dye was used as the adsorbate A stocksolution of crystal violet (1 gL) was first prepared by dis-solving a known quantity in deionized water +e stocksolution was finally diluted to obtain the desiredconcentration

23 Adsorption Study All adsorption experiments wererealized at room temperature (asymp25degC) and in the batchmode A mass of the adsorbent was contacted with a volumeV 40ml of the initial crystal violet solution C0 +e as-sembly was agitated for a time t of adsorption and then thesolid was separated from the solution by filtration on amicroporous filter +e absorbance of the supernatant so-lution was measured using a UV-vis spectrophotometer atthe wavelength corresponding to the maximum absorbance(λmax 590 nm) +e concentration at time t (Ct) of the dyein the mixture was calculated using a calibration curveprepared from the known concentrations of the CV +eremoval percentage (Rt ()) of the CV and the quantity

adsorbed to the surface of the AS (qt (mgg)) were deter-mined using the following equations [23]

Rt C0 minus Ct( 1113857 middot 100

C0 (1)

qt C0 minus Ct( 1113857 middot V

m (2)

where C0 and Ct are the CV initial and final concentration(mgL) at time t V is the solution volume (L) and m is theadsorbent mass (g)

3 Results and Discussion

31 X-Ray Diffraction Analysis Figure 1 shows the dif-fractograms of the AS before and after adsorption of the dyeIt can be seen on the one hand that the two diffractogramsare identical which means that the material undergoes nomodification after adsorption and on the other hand thebroadband at about 22deg justifies certain crystalline phases inthe material In fact lignocellulosic materials present defectsof structures offering the possibility of obtaining mono-crystals called whiskers [24]

32 Fourier Transform Infrared (FTIR) SpectroscopyFTIR spectroscopy is a widely used method for determiningthe functional groups that serve as adsorption sites Figure 2shows the FTIR spectra of the AS before and after CVadsorption +e analysis of the FTIR spectrum shows thepresence of many peaks in the range of wavenumbers from4000 to 500 cmminus1 which highlights the complex nature ofthe material analyzed Before adsorption the broad band atabout 3420 cmminus1 corresponds to the elongation of the O-Hgroups the band at 2910 cmminus1 relates to the elongation of theC-H group and the band at 1740 corresponds to theelongation vibration of the nonconjugated CO bonds thesevibrations are mainly due to the ester and carboxylic acidfunctions present in the lignin pectin and hemicellulosesthe 1640 cmminus1 band is characteristic for the elongation of theCC bonds of aromatic compounds and the 1045 cmminus1

band is characteristic of the deformation in the C-O plane ofaromatic compounds and acetyl and carboxylic acid func-tions After adsorption of the dye the intensity of the bandsdecreased significantly and the band of elongation of theO-H widens indicating the presence of interactions betweenthe AS and CV functional groups

33 Effect of Physicochemical Parameters on DyeRemoval Efficiency

331 Effect of Contact Time It is necessary to obtain thetime at the end of which the adsorption equilibrium isreached +is study was conducted for concentrations of25mgL and 50mgL +e results obtained are shown inFigure 3(a) which illustrate the evolution of the adsorbedquantity over time From the figure we can see that theequilibrium is reached almost at the end of 90 minutes +eresults show the existence of two phases the first rapid and

2 +e Scientific World Journal

the second slow +is is related to the high availability of theadsorbent-free active sites at the beginning of the experi-ment which decrease as the adsorption progresses +esecurves also show that the fixed quantity qt increases with C0+e curve of C0 25mgL is lower than that of C0 50mgL

332 Effect of Initial Crystal Violet Concentration For thisstudy the initial concentration was varied in the range of20mgL to 100mgL by maintaining the adsorbent dose at5 gL the temperature at 20degC and the pH at 6 +e resultsare shown in Figure 3(b) It can be observed that the CVelimination rate decreases from 84 to 49 when the initialCV concentration varies from 20 to 200mgL +e decreasein the removal rate is probably due to the increase in thenumber of CV ions in the solution for the same number ofsites and the same adsorbent surface area

333 Effect of the Initial pH of the Solution pH is a criticalparameter to be taken into account when removing dyesfrom aqueous solutions as it can affect the charge on thesurface of the adsorbent +e zero charge point pHpzc of ASwas 47 (inset in Figure 3(c)) +e percentage of CV

Table 1 Adsorption capacities of some natural adsorbents for dye removal

Adsorbents Dye Adsorption capacities (mg gminus1) ReferencesNeem bark Malachite green 036 [12]Tamarind shell Congo red 1048 [13]Grape fruit peel Reactive blue 19 1253 [14]Peanut hull Sunset yellow 1399 [15]Coir pith Acid violet 16 [16]Banana pith Acid brilliant blue 442 [17]Orange peel Acid violet 17 1988 [18]Banana peel Congo red 182 [19]Corncob Dye mixture 46 [20]Potato peel Methylene blue 3355 [21]Yellow passion fruit Methylene blue 1600 [22]

Table 2 Chemical properties and characteristics of crystal violet

Generic name Crystal violetChemical formula C25H30N3ClMolecular weight (gmol) 40798

Type of dye Cationicλmax (nm) 590 nm

Chemical structure

H3C

H3C

N

CH3

CH3

CH3

Clndash

N

CH3

+N

10 20 30 40 50 60 702θ (deg)

CVASAS

Inte

nsity

(au

)

Figure 1 X-ray diffraction spectra of almond shell before (AS) andafter adsorption (CVAS)

4000 3500 3000 2500 2000 1500 1000 500Wave number Cmndash1

CVAS

AS

3420

2910 17401640 1045

Abso

rban

ce (a

u)

Figure 2 FTIR spectra of almond shell before (AS) and after CVadsorption (CVAS)

+e Scientific World Journal 3

removal by the AS at different pH values was then studiedwhile keeping the other parameters at constant values +eresults show that the highest removal efficiency of the CV(82) was observed in the pH range of 6ndash12 +is efficiencydecreased to 62 at a pH of 2 Indeed at pH gt pHpzc thesurface of the AS is negatively charged and this chargeincreases proportionally to the pH +erefore removalefficiency increases when the pH is in the range of 3ndash6 dueto attractive forces occurring between the cationic dye andthe negatively charged surface Consequently the optimalpH value that maximizes the removal of dye from theaqueous solution is 6

334 Effect of Adsorbentrsquos Dose CV adsorption on AS wasstudied by varying the dose of the adsorbent from 40 to400mg for a concentration of 30mgL of CV and a pH 6According to Figure 3(d) it can be seen that CV removal hasincreased rapidly from 42 to 82 in the range of40ndash200mg SA and remains constant in the range of200mgndash400mg this is due to the increase in the contact

surface thus establishing the equilibrium +e adsorbentdose was set at 200mg for the subsequent experiments

34 Adsorption Equilibrium Study +e adsorption iso-therm is the curve binding at a fixed temperature thequantity of product adsorbed per initial mass of adsorbentat the concentration residual in the solution after ad-sorption equilibrium It was used to determine the max-imum adsorption capacity and the type of interactionbetween the CV and AS To exploit the data from the CVadsorption isotherm by AS the Langmuir and Freundlichequations in their linear form were used+e linear form ofthe Langmuir isotherm is indicated in the followingequation

Ce

qe

1

KL middot Qm

+Ce

Qm

(3)

+e linear form of the Freundlich isotherm is indicatedin the following equation

0 10 20 30 40 50 60 70 80 90 100 110 120 1300123456789

10

t (min)

C0 = 50mgLC0 = 25mgL

q (m

gg)

(a)

0 10 20 30 40 50 60 70 80 90 100 1100

40

50

60

70

80

90

C0 (mgL)

CV re

mov

al (

)

(b)

0 2 4 6 8 10 120

102030405060708090

100

pH

2 4 6 8 10 12

2

4

6

8

10

12

pHi

47

pHi = f (pHi)

pHi = f (pHf)

CV re

mov

al (

)

pHf

(c)

0 40 80 120 160 200 240 280 320 360 4000

20

40

60

80

100

Dose of AS (mg)

CV re

mov

al (

)

(d)

Figure 3 Effect of (a) contact time on adsorption (b) initial dye concentration on adsorption (c) pH on CV adsorption (d) the adsorbentdose on adsorption process +e inset represents the pH variation in terms of the initial pH of the solution to determine the point of zerocharge pHpzc


Lnqe LnKF +1n

LnCe (4)

where Ce (mgL) is the equilibrium concentrationQe (mgg)is the equilibrium adsorbed quantity Qm (mgg) is themaximum adsorption capacity KL (Lmg) is the Langmuirconstant and KF and n are the Freundlich constants

+e representations of the Langmuir and Freundlichmodels are given in Figure 4 and the equilibrium parametersobtained are shown in Table 3

+e value of the correlation coefficient (R2) for theLangmuir isotherm is higher than that of the Freundlichisotherm this means that the Langmuir model better rep-resents the adsorption process of CV by the AS+is suggeststhat CV fixation is done in monolayer without interactionbetween the adsorbed molecules on energetically equivalentsites In addition to that the RL value is less than 1 whichindicates that the adsorption of the dye is favorable

35 Adsorption Kinetics In order to model the adsorptionkinetics the kinetic models of the pseudo-first order andpseudo-second order were used +e expression of thepseudo-first-order model is in the form cited by Lagergren(5) [25]

Ln qe minus qt( 1113857 Lnqe minus K1t (5)

+e expression of the pseudo-second-order model is inthe form cited by Ho and Mckay (6) [26]

t

qt

1

K2q2e

+1qe

t (6)

where qt (mgmiddotgminus1) and qe (mgmiddotgminus1) are the adsorbed quantityof dye at time t and at equilibrium and k1 (minminus1) and k2(gmiddotmgminus1middotmin) are the constants of pseudo-first-order andpseudo-second-order models respectively

+e curves of both models are shown in Figure 5 and theconstants obtained from the different models are recapit-ulated in Table 4

From the R2 values reported in Table 4 it can be deducedthat the pseudo-second-order model is the one that bestdescribes the CV adsorption process on AS We also observethat the adsorbed quantities calculated by this model arecloser to those determined experimentally

36 Effect ofTemperature andAermodynamics ofAdsorption+e thermodynamic study was conducted at 25 30 40 and50degC +e tests were performed on 40ml mixtures of dyesolutions at a concentration of 30mgmiddotLminus1 with 160mgmasses of AS in 100mL flasks +ese mixtures weremaintained at constant agitation of 200 rpmminus1 for a time of 4hours Figure 6(a) shows the influence of temperature on thedye retention rate From the figure we notice that this rateincreases with increasing temperature suggesting that theprocess is endothermic and that increasing temperaturepromotes its progress

+ermodynamic parameters such as standard Gibbs freeenergy change (ΔGdeg) standard enthalpy change (ΔHdeg) and

standard entropy change (ΔSdeg) were determined by using thefollowing equations [25]

Ln Kd( 1113857 ΔSdeg

RminusΔHdeg

RT (7)

ΔGdeg ΔHdeg

minus TΔSdeg (8)

where Kd qeCe distribution constant R universal gasconstant (8314 Jmol K) and T absolute temperature (K)

Table 5 gives the values of standard Gibbs free energychange (ΔGdeg) standard enthalpy change (ΔHdeg) and standardentropy change (ΔSdeg) extrapolated from the plot ln (Kd) vs 1T (Figure 6(b)) +e positive value of ΔHdeg shows that theadsorption process of the CV on AS is endothermic and thatit is indeed a physisorption (lt40 kJmiddotmolminus1) [27]

+e negative values of ∆Gdeg indicate that the adsorption isspontaneous while the positive value of ∆Sdeg indicates theincrease in randomness at the solid-liquid interface duringsorption +is is the normal consequence of the phenom-enon of physical sorption which occurs through electro-static interactions Similar results were obtained during theadsorption of malachite green by almond gum [28] as well asthe adsorption of methylene blue by garlic straw [29]

37 Adsorption Mechanism To understand the adsorptionmechanism it is necessary to examine the structure of theadsorbate and the properties of the adsorbent surface For thispurpose it should be noted that CV is a cationic dye withamine groups in its structure and in aqueous medium dis-sociates into CV+ and Clminus [30] On the other hand AS is alignocellulosic material consisting of cellulose hemicelluloseand lignin and other minor constituents [31 32] Celluloseand hemicellulose contain the majority of functional groupasuch as hydroxyl and carboxyl (confirmed by the FTIRspectrum) while lignin is a complex systematically poly-merized and highly aromatic substance and acts as acementing matrix that is maintained between and in bothcellulose and hemicellulose units In this study the removal ofCV by AS adsorption is highly pH dependent (Figure 3(c))+e CV has been adequately adsorbed for pHge 5

Based on the experimental results of this study anddepending on the structure of the adsorbate and theproperties of the adsorbent surface the mechanism forremoving CV by AS adsorption involves the following steps

(i) Migration of the dye from the solution to the surfaceof the adsorbent

(ii) Dye diffusion through the boundary layer on thesurface of the adsorbent

(iii) Adsorption of the dye on the AS surface which canbe due to two mechanisms

+e first mechanism can explain the phenomenon ofadsorption by the formation of hydrogen bonds between thesurface hydroxyl and carboxyl groups and the nitrogenatoms of the CV as suggested in Figure 7

+e second mechanism is a dye-hydrogen ion exchangemechanism because at pHge 5 the surface functional groups


0 10 20 30 40 50 60

08

12

16

20

Ce (mgL)

C eq

e

(a)

ndash05 00 05 10 15 20 25 30

00

05

10

15

20

25

Ln (Ce)

Ln (q

e)

(b)

Figure 4 Adsorption isotherms of CV at the surface of AS (a) Langmuir isotherms (b) Freundlich isotherms

Table 3 Isotherm parameters for CV removal by AS

Langmuir isotherm parameters Freundlich isotherm parametersQm (cal)(mgmiddotgminus1) R2 KL (Lmiddotmgminus1) RL Kf (Lmiddotgminus1) n R2

122 0987 0146 0064 164 170 095807

0 10 20 30 40 50 60 70 80 90

ndash3

ndash2

ndash1

0

1

2


Linear fit of C0 = 25mgLLinear fit of C0 = 25mgL

t (min)

Log

(qe ndash

qt)

(a)

0 10 20 30 40 50 60 70 80 90 10002468

1012141618

t (qt

)

t (min)



(b)

Figure 5 Kinetic adsorption of CV at the surface of AS (a) pseudo-first-order kinetics (b) Pseudo-second-order kinetics

Table 4 Pseudo-first-order and pseudo-second-order adsorption rate constants for the different initial CV concentrations (C0)

C0 (mgL)Pseudo-first-order kinetic Pseudo-second-order kinetic

q1 (mgg) K1 (minminus1) R2 q2 (mgg) K2 (gmgminus1minminus1) R2

25 22557 004441 095606 53596 00471 09998150 29961 00344 090404 85048 03399 099963


295 300 305 310 315 320 325614

616

618

620

622

624

626

628

T (K)

q e (m

gg)

(a)

310 315 320 325 330 335 340012

014

016

018

020

022

024

026

Ln (K

d)

1000T (Kndash1)

(b)

Figure 6 (a) Effect of temperature on malachite crystal violet rate (b) plot ln (Kd) vs 1T for crystal violet adsorption into the almond shell

Table 5 +ermodynamic parameters for adsorption of crystal violet

Temperature (K) ΔHdeg (kJmiddotmolminus1) ΔSdeg (Jmiddotmolminus1middotKminus1) ΔGdeg (Jmiddotmolminus1) R2

298

3593 13230

minus34954

0980303 minus41569313 minus54799323 minus68029

Hydrogen Bonding

Almond shell surface

ClndashN+

Clndash Clndash ClndashN+ N+ N+

ClndashN+

ClndashN+

N N

NN

N

N

N N NN

N

N

HO

HO

HO

HO

HO

HOHOHO

H

HH

HH

H

H H

H

H

H

HH

H

H

HHH

H

HOH

OH

OH

OHOH

OH

OH

OH

O

O

OO

O

O

Figure 7 Schematic representation of hydrogen bonding between nitrogen atoms of CV and hydroxyl groups on the almond shell surface


are deprotonated and become negatively charged whichfacilitates their binding to the positively charged CV mol-ecules as shown in Figure 8

4 Conclusion

+e almond shell a low-cost and easily available materialhas proven to be highly effective to remove crystal violetfrom aqueous solutions +e equilibrium data were analyzedusing Langmuir and Freundlich isotherm models +emaximum monolayer adsorption capacity was equal to122mgg+e experimental data of the adsorption isothermfollow the Langmuir model and the pseudo-second-orderkinetic model +is work clearly shows that the eliminationof crystal violet by the almond shell is feasible efficient andeconomical Moreover the almond shell is a promisingcandidate for wastewater treatment

Data Availability

No data were used to support this study

Conflicts of Interest

+e authors declare that they have no conflicts of interest

References

[1] V K Garg R Kumar and R Gupta ldquoRemoval of malachitegreen dye from aqueous solution by adsorption using agro-industry waste a case study of Prosopis cinerariardquo Dyes andPigments vol 62 no 1 pp 1ndash10 2004

[2] P Velmurugan V Rathina Kumar and G Dhinakaran ldquoDyeremoval from aqueoussolution using low cost adsorbentrdquoInternational Journal of Environmental Research and PublicHealth vol 1 pp 7ndash14 2011

[3] I M Banat P Nigam D Singh and R Marchant ldquoMicrobialdecolorization of textile-dyecontaining effluents a reviewrdquoBioresource Technology vol 58 no 3 pp 217ndash227 1996

[4] G Crini ldquoNon-conventional low-cost adsorbents for dyeremoval a reviewrdquo Bioresource Technology vol 97 no 9pp 1061ndash1085 2006

[5] S Chakraborty S Chowdhury and P Das Saha ldquoAdsorptionof Crystal Violet from aqueous solution onto NaOH-modifiedrice huskrdquo Carbohydrate Polymers vol 86 no 4 pp 1533ndash1541 2011

[6] A K Jain V K Gupta A Bhatnagar and Suhas ldquoUtilizationof industrial waste products as adsorbents for the removal ofdyesrdquo Journal of Hazardous Materials vol 101 no 1pp 31ndash42 Jul 2003

[7] Y S Ho and G McKay ldquoSorption of dyes and copper ionsonto biosorbentsrdquo Process Biochemistry vol 38 no 7pp 1047ndash1061 Feb 2003

[8] B K T F Hassanein ldquoEvaluation of ad-sorption potential ofthe agricultural waste wheat straw for Basic Yellow 21rdquoJ Univ Chem Technol Metallvol 45 pp 407ndash414 2010

[9] A S Franca L S Oliveira and M E Ferreira ldquoKinetics andequilibrium studies of methylene blue adsorption by spentcoffee groundsrdquo Desalination vol 249 no 1 pp 267ndash2722009

[10] A Mittal J Mittal A Malviya D Kaur and V K GuptaldquoAdsorption of hazardous dye crystal violet from wastewaterby waste materialsrdquo Journal of Colloid and Interface Sciencevol 343 no 2 pp 463ndash473 2010

[11] R Ahmad ldquoStudies on adsorption of crystal violet dye fromaqueous solution onto coniferous pinus bark powder(CPBP)rdquo Journal of Hazardous Materials vol 171 no 1ndash3pp 767ndash773 2009

[12] R Srivastava and D C Rupainwar ldquoA comparative evalua-tion for adsorption of dye on neem bark and mango barkpowderrdquo Indian Journal of Chemical Technology vol 18pp 67ndash75 2011

[13] M C S Reddy ldquoRemoval of direct dye from aqueous solutionwith an adsorbent made from tamarind fruit shell an agri-cultural solid wasterdquo Journal of Scientific and Industrial Re-search vol 65 pp 443ndash446 2006

[14] M Abassi and N R Asl ldquoRemoval of hazardous reactive blue19 dye from aqueous solution by agricultural wasterdquo Journalof the Iranian Chemical Society vol 2 pp 221ndash230 2009

[15] R Gong Y Ding M Li C Yang H Liu and Y SunldquoUtilization of powdered peanut hull as biosorbent for re-moval of anionic dyes from aqueous solutionrdquo Dyes andPigments vol 64 no 3 pp 187ndash192 2005

[16] C Namasivayam M Dinesh Kumar K SelviR Ashruffunissa Begum T Vanathi and R T YamunaldquorsquoWastersquo coir pith-a potential biomass for the treatment ofdyeing wastewatersrdquo Biomass and Bioenergy vol 21 no 6pp 477ndash483 2001

[17] C Namasivayam D Prabha and M Kumutha ldquoRemoval ofdirect red and acid brilliant blue by adsorption on to bananapithrdquo Bioresource Technology vol 64 no 1 pp 77ndash79 1998

[18] R Sivaraj C Namasivayam and K Kadirvelu ldquoOrange peelas an adsorbent in the removal of Acid violet 17 (acid dye)from aqueous solutionsrdquo Waste Management vol 21 no 1pp 105ndash110 2001

[19] G Annadurai R Juang and D Lee ldquoUse of cellulose-basedwastes for adsorption of dyes from aqueous solutionsrdquoJournal of Hazardous Materials vol 92 no 3 pp 263ndash2742002

[20] T Robinson B Chandran and P Nigam ldquoRemoval of dyesfrom an artificial textile dye effluent by two agricultural wasteresidues corncob and barley huskrdquo Environment Interna-tional vol 28 no 1-2 pp 29ndash33 2002

[21] Y A Oktem G S Pozan Soylu and N Aytan ldquo+e ad-sorption of Methylene Blue from aqueous solution by usingwaste potato peels Equilibrium and kinetic studiesrdquo Journalof Scientific and Industrial Research vol 71 pp 817ndash821 2012

[22] F A Pavan Y Gushikem A C Mazzocato S L P Dias andE C Lima ldquoStatistical design of experiments as a tool foroptimizing the batch conditions to methylene blue bio-sorption on yellow passion fruit and Mandarin peelsrdquo Dyesand Pigments vol 72 no 2 pp 256ndash266 2007

[23] M S Slimani H Ahlafi H Moussout F Boukhlifi andO Zegaoui ldquoAdsorption of hexavalent chromium and phenolonto bentonite modified with HexaDecyl-TriMethylAmmonium bromide (HDTMABr)rdquo Journal ofAdvances in Chemistry vol 8 no 2 pp 1602ndash1611 2012

ASmdashCOOH

ASmdashCOOndash + CV+

ASmdashCOOndash + H+

ASmdashCOOCV

Figure 8 Schematic representation of dye-hydrogen ion exchangemechanism


[24] D Klemm B Philipp T Heinze U Heinze andW Wagenknecht ldquoApplication of spectroscopic analysis incellulose chemistryrdquo in Comprehensive Cellulose ChemistryFundaments and Analytical Methods vol 1 pp 181ndash195Wiley-VCH Weinheim Germany 2004

[25] S Langergren ldquoAbout the theory of so-called adsorption ofsoluble substancesrdquo Kungliga Svenska VetenskapsakademiensHandlingar vol 24 pp 1ndash39 1898

[26] Y S Ho and G McKay ldquoSorption of dye from aqueoussolution by peatrdquo Chemical Engineering Journal vol 70 no 2pp 115ndash124 1998

[27] M Aazza H Ahlafi H Moussout and H Maghat ldquoAd-sorption of metha-nitrophenol onto alumina and HDTMAmodified alumina kinetic isotherm and mechanism inves-tigationsrdquo Journal of Molecular Liquids vol 268 pp 587ndash5972018

[28] F Bouaziz M Koubaa F Kallel R E Ghorbel andS E Chaabouni ldquoAdsorptive removal of malachite greenfrom aqueous solutions by almond gum kinetic study andequilibrium isothermsrdquo International Journal of BiologicalMacromolecules vol 105 pp 56ndash65 2017

[29] F Kallel F Chaari F Bouaziz F Bettaieb R Ghorbel andS E Chaabouni ldquoSorption and desorption characteristics forthe removal of a toxic dye methylene blue from aqueoussolution by a low cost agricultural by-productrdquo Journal ofMolecular Liquids vol 219 pp 279ndash288 2016

[30] R Kumar and R Ahmad ldquoBiosorption of hazardous crystalviolet dye from aqueous solution onto treated ginger waste(TGW)rdquo Desalination vol 265 no 1ndash3 pp 112ndash118 2011

[31] H Jaman D Chakraborty and P Saha ldquoA study of thethermodynamics and kinetics of copper adsorption usingchemically modified rice huskrdquo CleanmdashSoil Air Watervol 37 no 9 pp 704ndash711 2009

[32] T G Chuah A Jumasiah I Azni S Katayon andS Y +omas Choong ldquoRice husk as a potentially low-costbiosorbent for heavy metal and dye removal an overviewrdquoDesalination vol 175 no 3 pp 305ndash316 2005


for adsorption of dyes in effluents Table 1 shows someexamples

Almond is the fruit of almond tree which is the secondmost important fruit species cultivated in Morocco after theolive tree with a production of 101000 tyear in 2016 whichis the equivalent of 80000 tonnes of almond shellsaccording to data from the Moroccan Federation of AlmondTree Producers +ese residues are discarded as solid wastewhich poses environmental problems It is therefore nec-essary to find an appropriate method to solve the disposalproblem +e use of this inexpensive material as an ad-sorbent contributes to the solution to this problem and to theapplication of the principle of ldquoself-cleaning of wasterdquo

Crystal violet is widely used as a violet dye in the textileindustry for dyeing cotton and silk It is also used in themanufacture of paints and printing inks [10] Crystal violet iscarcinogenic and has been classified as a recalcitrant mol-ecule because it is poorly metabolized by microbes isnonbiodegradable and can persist in various environmentsIt is highly toxic to the cells [11]

+e purpose of this research paper is to investigate thepotential use of almond shells to remove the crystal violetdye from aqueous solutions Adsorption parameters in-cluding dye concentration contact time almond shell doseand pH were studied to determine the effectiveness of theadsorbent +e characterization of the adsorbent before andafter adsorption was achieved in order to identify themechanism governing the fixation of the dye molecules onthe adsorbent

2 Materials and Methods

21 Adsorbent Preparation +e almond shells (AS) werewashed dried for 24 hours at a temperature of 110degC in anoven and then crushed and sieved to obtain fine and ho-mogeneous samples (lt02mm)

22 Adsorbate Preparation Crystal violet (CV) (character-istics given in Table 2) dye was used as the adsorbate A stocksolution of crystal violet (1 gL) was first prepared by dis-solving a known quantity in deionized water +e stocksolution was finally diluted to obtain the desiredconcentration

23 Adsorption Study All adsorption experiments wererealized at room temperature (asymp25degC) and in the batchmode A mass of the adsorbent was contacted with a volumeV 40ml of the initial crystal violet solution C0 +e as-sembly was agitated for a time t of adsorption and then thesolid was separated from the solution by filtration on amicroporous filter +e absorbance of the supernatant so-lution was measured using a UV-vis spectrophotometer atthe wavelength corresponding to the maximum absorbance(λmax 590 nm) +e concentration at time t (Ct) of the dyein the mixture was calculated using a calibration curveprepared from the known concentrations of the CV +eremoval percentage (Rt ()) of the CV and the quantity

adsorbed to the surface of the AS (qt (mgg)) were deter-mined using the following equations [23]

Rt C0 minus Ct( 1113857 middot 100

C0 (1)

qt C0 minus Ct( 1113857 middot V

m (2)

where C0 and Ct are the CV initial and final concentration(mgL) at time t V is the solution volume (L) and m is theadsorbent mass (g)

3 Results and Discussion

31 X-Ray Diffraction Analysis Figure 1 shows the dif-fractograms of the AS before and after adsorption of the dyeIt can be seen on the one hand that the two diffractogramsare identical which means that the material undergoes nomodification after adsorption and on the other hand thebroadband at about 22deg justifies certain crystalline phases inthe material In fact lignocellulosic materials present defectsof structures offering the possibility of obtaining mono-crystals called whiskers [24]

32 Fourier Transform Infrared (FTIR) SpectroscopyFTIR spectroscopy is a widely used method for determiningthe functional groups that serve as adsorption sites Figure 2shows the FTIR spectra of the AS before and after CVadsorption +e analysis of the FTIR spectrum shows thepresence of many peaks in the range of wavenumbers from4000 to 500 cmminus1 which highlights the complex nature ofthe material analyzed Before adsorption the broad band atabout 3420 cmminus1 corresponds to the elongation of the O-Hgroups the band at 2910 cmminus1 relates to the elongation of theC-H group and the band at 1740 corresponds to theelongation vibration of the nonconjugated CO bonds thesevibrations are mainly due to the ester and carboxylic acidfunctions present in the lignin pectin and hemicellulosesthe 1640 cmminus1 band is characteristic for the elongation of theCC bonds of aromatic compounds and the 1045 cmminus1

band is characteristic of the deformation in the C-O plane ofaromatic compounds and acetyl and carboxylic acid func-tions After adsorption of the dye the intensity of the bandsdecreased significantly and the band of elongation of theO-H widens indicating the presence of interactions betweenthe AS and CV functional groups

33 Effect of Physicochemical Parameters on DyeRemoval Efficiency

331 Effect of Contact Time It is necessary to obtain thetime at the end of which the adsorption equilibrium isreached +is study was conducted for concentrations of25mgL and 50mgL +e results obtained are shown inFigure 3(a) which illustrate the evolution of the adsorbedquantity over time From the figure we can see that theequilibrium is reached almost at the end of 90 minutes +eresults show the existence of two phases the first rapid and










Chemical structure

H3C

H3C

N

CH3

CH3

CH3

Clndash

N

CH3

+N

10 20 30 40 50 60 702θ (deg)

CVASAS

Inte

nsity

(au

)



CVAS

AS

3420

2910 17401640 1045

Abso

rban

ce (a

u)







Ce

qe

1

KL middot Qm

+Ce

Qm

(3)


0 10 20 30 40 50 60 70 80 90 100 110 120 1300123456789

10

t (min)


q (m

gg)

(a)

0 10 20 30 40 50 60 70 80 90 100 1100

40

50

60

70

80

90

C0 (mgL)

CV re

mov

al (

)

(b)

0 2 4 6 8 10 120

102030405060708090

100

pH

2 4 6 8 10 12

2

4

6

8

10

12

pHi

47

pHi = f (pHi)

pHi = f (pHf)

CV re

mov

al (

)

pHf

(c)

0 40 80 120 160 200 240 280 320 360 4000

20

40

60

80

100

Dose of AS (mg)

CV re

mov

al (

)

(d)



Lnqe LnKF +1n

LnCe (4)







t

qt

1

K2q2e

+1qe

t (6)








RminusΔHdeg

RT (7)

ΔGdeg ΔHdeg

minus TΔSdeg (8)












0 10 20 30 40 50 60

08

12

16

20

Ce (mgL)

C eq

e

(a)

ndash05 00 05 10 15 20 25 30

00

05

10

15

20

25

Ln (Ce)

Ln (q

e)

(b)




122 0987 0146 0064 164 170 095807

0 10 20 30 40 50 60 70 80 90

ndash3

ndash2

ndash1

0

1

2



t (min)

Log

(qe ndash

qt)

(a)

0 10 20 30 40 50 60 70 80 90 10002468

1012141618

t (qt

)

t (min)



(b)





25 22557 004441 095606 53596 00471 09998150 29961 00344 090404 85048 03399 099963


295 300 305 310 315 320 325614

616

618

620

622

624

626

628

T (K)

q e (m

gg)

(a)

310 315 320 325 330 335 340012

014

016

018

020

022

024

026

Ln (K

d)

1000T (Kndash1)

(b)




298

3593 13230

minus34954


Hydrogen Bonding


ClndashN+


ClndashN+

ClndashN+

N N

NN

N

N

N N NN

N

N

HO

HO

HO

HO

HO

HOHOHO

H

HH

HH

H

H H

H

H

H

HH

H

H

HHH

H

HOH

OH

OH

OHOH

OH

OH

OH

O

O

OO

O

O




4 Conclusion


Data Availability




References
























ASmdashCOOH



ASmdashCOOCV





















Chemical structure

H3C

H3C

N

CH3

CH3

CH3

Clndash

N

CH3

+N

10 20 30 40 50 60 702θ (deg)

CVASAS

Inte

nsity

(au

)



CVAS

AS

3420

2910 17401640 1045

Abso

rban

ce (a

u)







Ce

qe

1

KL middot Qm

+Ce

Qm

(3)


0 10 20 30 40 50 60 70 80 90 100 110 120 1300123456789

10

t (min)


q (m

gg)

(a)

0 10 20 30 40 50 60 70 80 90 100 1100

40

50

60

70

80

90

C0 (mgL)

CV re

mov

al (

)

(b)

0 2 4 6 8 10 120

102030405060708090

100

pH

2 4 6 8 10 12

2

4

6

8

10

12

pHi

47

pHi = f (pHi)

pHi = f (pHf)

CV re

mov

al (

)

pHf

(c)

0 40 80 120 160 200 240 280 320 360 4000

20

40

60

80

100

Dose of AS (mg)

CV re

mov

al (

)

(d)



Lnqe LnKF +1n

LnCe (4)







t

qt

1

K2q2e

+1qe

t (6)








RminusΔHdeg

RT (7)

ΔGdeg ΔHdeg

minus TΔSdeg (8)












0 10 20 30 40 50 60

08

12

16

20

Ce (mgL)

C eq

e

(a)

ndash05 00 05 10 15 20 25 30

00

05

10

15

20

25

Ln (Ce)

Ln (q

e)

(b)




122 0987 0146 0064 164 170 095807

0 10 20 30 40 50 60 70 80 90

ndash3

ndash2

ndash1

0

1

2



t (min)

Log

(qe ndash

qt)

(a)

0 10 20 30 40 50 60 70 80 90 10002468

1012141618

t (qt

)

t (min)



(b)





25 22557 004441 095606 53596 00471 09998150 29961 00344 090404 85048 03399 099963


295 300 305 310 315 320 325614

616

618

620

622

624

626

628

T (K)

q e (m

gg)

(a)

310 315 320 325 330 335 340012

014

016

018

020

022

024

026

Ln (K

d)

1000T (Kndash1)

(b)




298

3593 13230

minus34954


Hydrogen Bonding


ClndashN+


ClndashN+

ClndashN+

N N

NN

N

N

N N NN

N

N

HO

HO

HO

HO

HO

HOHOHO

H

HH

HH

H

H H

H

H

H

HH

H

H

HHH

H

HOH

OH

OH

OHOH

OH

OH

OH

O

O

OO

O

O




4 Conclusion


Data Availability




References
























ASmdashCOOH



ASmdashCOOCV

















Ce

qe

1

KL middot Qm

+Ce

Qm

(3)


0 10 20 30 40 50 60 70 80 90 100 110 120 1300123456789

10

t (min)


q (m

gg)

(a)

0 10 20 30 40 50 60 70 80 90 100 1100

40

50

60

70

80

90

C0 (mgL)

CV re

mov

al (

)

(b)

0 2 4 6 8 10 120

102030405060708090

100

pH

2 4 6 8 10 12

2

4

6

8

10

12

pHi

47

pHi = f (pHi)

pHi = f (pHf)

CV re

mov

al (

)

pHf

(c)

0 40 80 120 160 200 240 280 320 360 4000

20

40

60

80

100

Dose of AS (mg)

CV re

mov

al (

)

(d)



Lnqe LnKF +1n

LnCe (4)







t

qt

1

K2q2e

+1qe

t (6)








RminusΔHdeg

RT (7)

ΔGdeg ΔHdeg

minus TΔSdeg (8)












0 10 20 30 40 50 60

08

12

16

20

Ce (mgL)

C eq

e

(a)

ndash05 00 05 10 15 20 25 30

00

05

10

15

20

25

Ln (Ce)

Ln (q

e)

(b)




122 0987 0146 0064 164 170 095807

0 10 20 30 40 50 60 70 80 90

ndash3

ndash2

ndash1

0

1

2



t (min)

Log

(qe ndash

qt)

(a)

0 10 20 30 40 50 60 70 80 90 10002468

1012141618

t (qt

)

t (min)



(b)





25 22557 004441 095606 53596 00471 09998150 29961 00344 090404 85048 03399 099963


295 300 305 310 315 320 325614

616

618

620

622

624

626

628

T (K)

q e (m

gg)

(a)

310 315 320 325 330 335 340012

014

016

018

020

022

024

026

Ln (K

d)

1000T (Kndash1)

(b)




298

3593 13230

minus34954


Hydrogen Bonding


ClndashN+


ClndashN+

ClndashN+

N N

NN

N

N

N N NN

N

N

HO

HO

HO

HO

HO

HOHOHO

H

HH

HH

H

H H

H

H

H

HH

H

H

HHH

H

HOH

OH

OH

OHOH

OH

OH

OH

O

O

OO

O

O




4 Conclusion


Data Availability




References
























ASmdashCOOH



ASmdashCOOCV













Lnqe LnKF +1n

LnCe (4)







t

qt

1

K2q2e

+1qe

t (6)








RminusΔHdeg

RT (7)

ΔGdeg ΔHdeg

minus TΔSdeg (8)












0 10 20 30 40 50 60

08

12

16

20

Ce (mgL)

C eq

e

(a)

ndash05 00 05 10 15 20 25 30

00

05

10

15

20

25

Ln (Ce)

Ln (q

e)

(b)




122 0987 0146 0064 164 170 095807

0 10 20 30 40 50 60 70 80 90

ndash3

ndash2

ndash1

0

1

2



t (min)

Log

(qe ndash

qt)

(a)

0 10 20 30 40 50 60 70 80 90 10002468

1012141618

t (qt

)

t (min)



(b)





25 22557 004441 095606 53596 00471 09998150 29961 00344 090404 85048 03399 099963


295 300 305 310 315 320 325614

616

618

620

622

624

626

628

T (K)

q e (m

gg)

(a)

310 315 320 325 330 335 340012

014

016

018

020

022

024

026

Ln (K

d)

1000T (Kndash1)

(b)




298

3593 13230

minus34954


Hydrogen Bonding


ClndashN+


ClndashN+

ClndashN+

N N

NN

N

N

N N NN

N

N

HO

HO

HO

HO

HO

HOHOHO

H

HH

HH

H

H H

H

H

H

HH

H

H

HHH

H

HOH

OH

OH

OHOH

OH

OH

OH

O

O

OO

O

O




4 Conclusion


Data Availability




References
























ASmdashCOOH



ASmdashCOOCV













0 10 20 30 40 50 60

08

12

16

20

Ce (mgL)

C eq

e

(a)

ndash05 00 05 10 15 20 25 30

00

05

10

15

20

25

Ln (Ce)

Ln (q

e)

(b)




122 0987 0146 0064 164 170 095807

0 10 20 30 40 50 60 70 80 90

ndash3

ndash2

ndash1

0

1

2



t (min)

Log

(qe ndash

qt)

(a)

0 10 20 30 40 50 60 70 80 90 10002468

1012141618

t (qt

)

t (min)



(b)





25 22557 004441 095606 53596 00471 09998150 29961 00344 090404 85048 03399 099963


295 300 305 310 315 320 325614

616

618

620

622

624

626

628

T (K)

q e (m

gg)

(a)

310 315 320 325 330 335 340012

014

016

018

020

022

024

026

Ln (K

d)

1000T (Kndash1)

(b)




298

3593 13230

minus34954


Hydrogen Bonding


ClndashN+


ClndashN+

ClndashN+

N N

NN

N

N

N N NN

N

N

HO

HO

HO

HO

HO

HOHOHO

H

HH

HH

H

H H

H

H

H

HH

H

H

HHH

H

HOH

OH

OH

OHOH

OH

OH

OH

O

O

OO

O

O




4 Conclusion


Data Availability




References
























ASmdashCOOH



ASmdashCOOCV













295 300 305 310 315 320 325614

616

618

620

622

624

626

628

T (K)

q e (m

gg)

(a)

310 315 320 325 330 335 340012

014

016

018

020

022

024

026

Ln (K

d)

1000T (Kndash1)

(b)




298

3593 13230

minus34954


Hydrogen Bonding


ClndashN+


ClndashN+

ClndashN+

N N

NN

N

N

N N NN

N

N

HO

HO

HO

HO

HO

HOHOHO

H

HH

HH

H

H H

H

H

H

HH

H

H

HHH

H

HOH

OH

OH

OHOH

OH

OH

OH

O

O

OO

O

O




4 Conclusion


Data Availability




References
























ASmdashCOOH



ASmdashCOOCV














4 Conclusion


Data Availability




References
























ASmdashCOOH



ASmdashCOOCV













adsorptionofcrystalvioletontoanagriculturalwasteresidue: kinetics… · 2020. 5. 1. · research...

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