phenomena of removal of crystal violet from...

Research ArticlePhenomena of Removal of Crystal Violet fromWastewater UsingKhulays Natural Bentonite

Saad Al-Shahrani

Department of Chemical and Material Engineering King Abdulaziz University Jeddah Saudi Arabia

Correspondence should be addressed to Saad Al-Shahrani ssaalshahranikauedusa

Received 9 October 2019 Revised 14 January 2020 Accepted 21 February 2020 Published 21 March 2020

Academic Editor Jose Morillo

Copyright copy 2020 Saad Al-Shahrani 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

e study investigates the phenomena involved in the crystal violet (CV) removal using the Khulays natural bentonite from thewastewater e batch technique was utilized for performing the adsorption experimentse operating systems were used for theinvestigation of the adsorption behaviour in the study which included the initial CV concentration time taken for shaking thedosage of adsorbent and the initial solution pHe Freundlich isotherm framework and the Langmuir data were assessed in theexperiment e study outcome revealed that the equilibrium in the study was reached when shaking takes place for about 40minutes Additionally the data of the sorption revealed that the enhancement of the CV concentration at the start mitigates thepercentage of the CV removal as a result of which saturation integration in the Khulays bentonite dye occurs e initialimprovement in the solution pH led to improved CV adsorption e data achieved at the isotherm adsorption were foundadequate with the frameworks of Freundlich isotherm and Langmuir Along with it the model of pseudo-second-order kineticswas used to exhibit the adsorption of crystal violet with the Khulays natural bentonite e Khulays natural bentonite adsorptionof CV was demonstrated by the thermodynamic data exhibiting its spontaneous as well as endothermic nature e studyconcludes that basic dyes can be effectively removed from the wastewater by the use of Khulays natural bentonite

1 Introduction

Pollution accounts for substantial threats globally for bothliving organisms and the environment [1] Majorly a sub-stantial impact of dyes is observed in the changing envi-ronment due to its significant production of several goodsnotably papers textiles plastics leather rubber cosmeticsand food [2] e textile industry alone is estimated toproduce 7x metric tons of dye on an annual basis [3] ewidespread of these dyes and immense utilization increas-ingly contribute to the wastewater causing a detrimentaleffect on the environment Along with it the colour effluentspresent in the dyes negatively impact the penetration ca-pacity of the sunlight detrimental to the aquatic environ-ment Studies reveals that dyes constitute synthetic origin aswell as complicated aromatic structures which improvestheir stability with light heat as well as an oxidizing agent[1 4] Most studies confirm that throughout the dyingprocess 2 to 20 percent of aqueous effluents are dischargedin the environment [3 5]

Primarily the dye effluents discharge in the water leadsto adverse outcome not only because of its colour but alsodue to its release as well as a breakdown of products in-cluding toxic mutagenic or carcinogenic components toother living organisms including compounds such as ben-zidine naphthalene and another aromatic element [6] eabsence of adequate treatment for the removal of these islikely to affect the environment in the long-run For ex-ample the hydrolyzed Reactive Blue 19rsquos half-life is almost46 years with a pH value of 7 at 25degC

e use of water across different disciplines includingdomestic agriculture and industrial impact pose adverseand undesirable pollutants which can become toxic Effortsare needed for the protection of the water resources [7ndash9]One specific agent which is immensely used in the printingof papers dying of textile the colouring of leather andsometimes as a dermatological agent is crystal violet alsorecognized as gentian violet [10] e dye becomes toxic andcan be the cause of irritation on the skin when inhaled oringested [11] Numerous procedures are used for the

HindawiJournal of ChemistryVolume 2020 Article ID 4607657 8 pageshttpsdoiorg10115520204607657

treatment of the waster waters comprising coagulationreverse osmosis flocculation biological methods and moreSeveral of these methods constitute one or more limitationsand cannot completely clear the water of any dye [12] Incontrast the process of adsorption stands strong for thetreatment of the wastewater concerning its design costfunctionality as well as insensitivity to the formed toxicsludge [13]

For the adsorption process the use of bentonite hassignificantly increased in various disciplines such as thetreatment of the contaminated water comprising heavymetals dyes and phenols Realizing the impact caused by thedyes efforts are being made at the global level to overcomethe environmental hazards using adsorbent that is eco-nomical and easily available from the agricultural waste [14]e developing countries such as Saudi Arabia are alsomaking efforts to set the base for new industries by utilizingnatural resources also aimed at the achievement of its SaudiVision 2030 Considering the global scenario the studyassesses the feasibility of treating the wastewater which isachieved upon the utilization of the Khulays natural ben-tonite for clearing it off the crystal violet e increasedavailability as well as the cost-effectiveness associated withKhulays natural bentonite made its selection all morepreferable

2 Materials and Methods

21 Chemicals andReagents In the present study the crystalviolet (CV) was obtained from Loba Chemie a chemicalmanufacturer e obtained crystal violet was used as it iswithout undergoing the purification process e molecularweight of it is C25H30N3Cl with a number of CAS as 548-62-9 and a molecular weight of 40798 the maximum ad-sorption was found at 590 nm [10] Figure 1 represents theCV molecular structure e CV stock solution (1000mgL)was prepared by dissolving a known quantity of CV indistilled water e preparation of various solutions with thepreferred concentration was done by diluting a properamount of stock solution with distilled water

22 Adsorbent e samples of the bentonite were gatheredfrom Khulays which is situated in the north of Jeddah at95 km in Saudi Arabia e samples were collected in theform of ungrounded rocks which further underwent theprocess of drying and grinding for the reduction of their sizeas per the requirement After the grinding process bentonitesamples were sieved with 200 mesh sieving trays e sus-pended clay residue was sent back to the ceramic ball mill-grinding machine and the passed bentonite was used in theadsorption process without any treatment Table 1 dem-onstrates the chemical composition of the Khulays naturalbentonite [14] e measurement of the surface area was645m2g computed using the computer-generated programbased on BET e image scanning electron microscopy(SEM) of the natural Khulays natural bentonite is shown inFigure 2 e image shows spherical shape surfaces withsemiflowered structure with high pores on the bentonite

surface which give a good indication for Khulays bentoniteto be a good adsorbent

23 Characterization of the Bentonite Absorbent FTIRspectroscopy (ermo Nicolet NEXUS 670 Spectropho-tometer) and XRD (Philips XrsquoPert Pro) was used for thecharacterization of the activated bentonite Figures 3 and 4presents the FTIR and XRD analysis which shows that theactivated bentonite ranges from 600 to 3800 cmminus1 It showsthat FTIR spectra are substantially sensitive to the bentonitestructure modification when treated with acid Concerningthe XRD analysis the decline in the intensity as well as theupsurge in the peak width shows that acid activation affectsthe bentonite crystallinity It also shows the decompositionof the crystalline bentonite structure which shows the ap-pearance of the amorphous phase Overall the findingsshowed similar chemical nature though the physical andmorphological properties were found to be highly variablePrevious results show similar statistics as observed in thestudy of Ajemba [15]

24 Experiments for Adsorption In the study the batchmethod was used for all the performed adsorption experi-ments e solution was prepared by mixing the adequateamount of Khulays natural Bentonite and CV (50ml) in theconical flasks (100ml) Following it the conical flask wasplaced in a water bath with a horizontal shaker (JULABOSW 22) at a temperature of 25degC at 200 rpm Preparation ofthe CV stock solution took place by dissolving the definiteCV quantity in the distilled water e stock solution wasdiluted according to the requirement needed for variousstandards solutions containing CV in the 50ndash300mgLamount e exploration of the effects such as pH of asolution time for shaking the concentration of CV anddosage of adsorbent took place by performing the experi-ments for adsorption After shaking the shaker was thenemptied of the samples at regular intervals for contact timewhich were separated at 4000 rpm by centrifuging for fifteenminutes with the utilization of the ROTOFIX 321 model(Hettich Zentrifugen) e measurement of the CV con-centration took place following every run in the solution

Clndash

CH3

CH3CH3

H3C

CH3H3C

NN

N+

Figure 1 Structure of crystal violet

2 Journal of Chemistry

with the use of a UV-visible spectrophotometer in the PD-303 UV (Apel) model ese were used for the calculation ofthe adsorbent when the wavelength is maximum that is590 nm [16] e calculation of the collected data for theadsorbed quantity of CV qe (mgg) was done as per thegiven equation

qe V Co minus Ce( 1113857

m (1)

where qe adsorbed amount of CV at equilibrium (mgg)Co initial CV concentration in the aqueous solution (mgL) Ce aqueous solution equilibrium concentration of CV(mgL) V solution volume (L) andmmixture bentoniteamount (g)

e percentage calculation for the removal was doneusing the given equation

CVRemoval V Co minus Ct( 1113857

Co

times 100 (2)

where Ct concentration of CV concentration in ldquotrdquo time(mgL)

3 Results and Discussion

31 Outcomes of the Time for Shaking and the StartingConcentration of the Solution e impact of the shakingtime was evaluated at various concentration levels with theuse of Khulays natural bentonite is evaluation wascentred on the exploration of the CV removal where theconcentration level lies in the range from 50 to 300mgLe bentonite dosage was 0025 g50ml e pH value of thesolution was not changed throughout the process Figure 5highlights that an increased rate of CV removal at the startgradually reduced until it reached the equilibrium pointeCV adsorption on the natural bentonite Khulays wascomparatively swift as the equilibrium point was reached in40 minutes Furthermore the percentage of the removaldeclined as a result of the initial increase in the concen-tration of CV because of the saturation of active sites on theadsorbent Similar observations were reported by otherresearchers [17ndash19] which showed the increase in an ab-sorbent dose reduces the amount of adsorbed dye per unitmass It is because in it the equilibrium time is consideredfast compared to what was reported before [17]

32 Effect of pH One factor that is significantly associatedwith the adsorption of dye is the pH of the solution Ad-ditionally the adsorbent surface change is also immenselyaffected by the pH value of the solution [20ndash22] e initialeffect caused by the initial solution pH was explored whichwas found to range from 3 to more than 11 In addition thechange is no longer significant from 7 to 8 and not 11 eequilibrium was reached after 40 minutes of contact timee CV was 150mgL while the constant dosage of ben-tonite was 002550ml in the dye solution with 200 rpm ofshaking time at 25degC In the beginning the solution pH wascontrolled using 1N HCl and 1N NaOH

e percentage of a CV that was removed at variousinitial solution pH is demonstrated in Figure 6 e removalpercentage of CV by Khulays natural bentonite increasedgradually with the increase in initial solution pH up to pH 5where about 85 of CV was removed from the solution Nosignificant results were found by increasing the pH of thesolution up to 10 e enhancement of the pH value drivesthe positive surface charge low while simultaneously in-creasing the negative charge given that the ions of hydrogencompete with the cations present in the dye [23]

e increase of the site negative charge on the clay in-creases the cationic dye adsorption which results due toincreased electrostatic attraction Previous studies haveestablished that the increase in the solution pH improves thesorption of the cationic dye at an increasing pH level [24]

is behaviour reflects the positive charges on bentonitesurface decline with the rise in solution pH increasing thenegatively charged number on the bentonite sites On acidic

Table 1 Chemical compositions of Khulays natural bentonite () [14]

Sio2 Al2O3 Fe2O2 TiO2 MgO CaO K2O Na2O MnO SO3 P2O5 LOI (1000oC)5288 1759 1015 11 23 126 064 126 015 lt005 027 1149

Figure 2 Scanning electron microscopic (SEM) image of Khulaysnatural bentonite

0010203040506070809

600 1000 1400 1800 2200 2600 3000 3400 3800

Abs

orba

nce

Wave number (cmndash1)

Figure 3 FTIR analysis

Journal of Chemistry 3

medium the Khulays natural bentonite negative chargedecreases when the increase of the positive charge numbertakes place Accordingly the removal efficiency is impacted

by the electrostatic impulsion existing between the surfacethat is positively charged and the CV [25]

33 Effect of Adsorbent Dosage In the provided operationalcondition the dosage adsorbent procedure assists in theevaluation of the adsorbent capacity For this the Khulaysnatural bentonite quantity was investigated for the elimi-nation of the CV when the 50ml solution of the CV wasshaken with constant dye concentration value at 150mgLIn it the dosage of bentonite ranges from 0005 to 0125 g50mL (given the results in Figure 7) It also had 40 minutesfor contact with a pH value of 53 (given the results in 6) anda temperature of 25degC e results in Figure 7 show thatincreased dosage leads to increased removal of a dye such asat 0005 g the removal percentage was 15 while at 0075 git was about 999 Following it the removal percentage ofCV was kept above 99 with the increase of the clay dosagethat is 0125 Consequently the Khulays natural bentoniteamount of 0075 was considered adequate for the CV re-moval from a CV solution of 150mgL in the presence of thementioned conditions e results predict that the increasein bentonite dosage quantity causes increased absorption atsites which increases CV absorption is is observed fromthe use of 0075 g of Khulays natural bentonite which re-moved better absorption capacity for the active bentonitesurfaces

34 Adsorption Isotherms Adsorption isotherms are used todescribe the equilibrium relationships between adsorbentand adsorbate In this study two different adsorption iso-therm models the Langmuir [26] and Freundlich [27]isotherm equations were used to fit the experimental dataobtained from this study ese two models were tested tofind out the sorption capacity of crystal violet using Khulaysnatural bentonite e best-fitting model is estimated byusing the correlation coefficient for the regression (R2)where the isotherm giving an R2 value closest to unity isconsidered to give the best fit [28]

ndash2000

0

2000

4000

6000

8000

10000

12000

14000

0 20 40 60 80 100 120

Inte

nsity

(au

)

2θ

Figure 4 XRD analysis

0

20

40

60

80

100

120

0 10 20 30 40 50 60 70

C

V re

mov

al

Time (min)

100mgL200mgL

50mgL150mgL300mgL

Figure 5 Effect of shaking time on the removal of CV

0

20

40

60

80

100

120

C

V re

mov

al

3 5 7 9 11 131pH

Figure 6 Result of starting pH solution on the removal of CV


e adsorption isotherms for CV removal were carriedout by initially utilizing multiple concentrations of dye (ie50ndash300mgL) the constant adsorbent mass of 0025 gconstant temperature (25degC) and solution pH at 53 Af-terward the experimental data were fitted to the Langmuirand Freundlich equations

e Langmuir sorption isotherm is based on the as-sumption that when the adsorbate occupies a bentonite siteno further sorption can take place at that site [29] It is usedto evaluate maximum dye adsorption capacity and can beexplained by the following equation

Ce

qe

1

bqmax+

Ce

qmax (3)

where Ce is the equilibrium concentration of CV (mgL) qeis the amount of CV adsorbed per unit weight of bentonite(mgg) qmax is the amount of maximum adsorption capacity(mgg) and b is the Langmuir constant (Lmg)

e data obtained from the linear Langmuir isothermplot for the adsorption of CV onto Khulays natural bentoniteare shown in Table 2 and plotted in Figure 6 where themodel gives the best fit for the experimental data emaximum adsorption qmax (monolayer coverage) for CV onKhulays natural bentonite equals to 263mgg

Freundlich isotherm is an empirical equation used todescribe the adsorption process on heterogeneous surfacesand is expressed by the following equation [30]

log qe logK +1nlog Ce (4)

whereK and n are the systems Freundlich isotherm constantTable 2 provides a brief on the best predictable values for theoverall equation parameters (see Figure 8)

e data obtained from the linear Freundlich isothermplot for the adsorption of CV onto Khulays natural bentoniteis shown in Table 2 and plotted in Figure 9 e Freundlichisotherm model showed an excellent fit for the adsorptiondata of CV e value of Freundlich constant lies between 1and 10 which means good adsorption of crystal violet onKhulays natural bentonite [31]

35 Adsorption Kinetic For evaluating the effective processfor utilization of the kinetic model the adsorption of thekinetic onto Khulaysrsquo natural bentonite concerning thecrystal violet was explored e kinetic model utilization isdone for designing and modeling the system of adsorptionPseudo-first-order and pseudo-second-order models wereused to determine which mechanism is controlling theprocess of adsorption like a chemical reaction mass transferas well as diffusion controlled

002 004 006 008 01 012 0140Bentonite dosage (g)

0

20

40

60

80

100

120

C

V re

mov

al

Figure 7 Effect of bentonite dosage on the removal of CV

Table 2 Langmuir and Freundlich constant calculated from ad-sorption isotherm data of CV onto Khulays natural bentonite

Isotherm parameters ValuesLangmuirqmax (mgg) 263b (Lmg) 057R2 0999FreundlichK (mgg) 139N 75R2 0983

C eq

e

06

05

04

03

02

01

07

020 40 60 80 100 120 140 160 1800

Ce

Figure 8 Langmuir adsorption isotherm of CV onto Khulaysrsquonatural bentonite

0

05

1

15

2

25

3

35

4

Log

(qe)

05 1 15 2 250Log (Ce)

Figure 9 CV Freundlich adsorption isotherm using Khulaysnatural bentonite


Lagergren provided the framework for the pseudo-first-order kinetic e following is its equation [32]

log qe minus qt( 1113857 log qe minusk1

2303t (5)

where K1 constant for pseudo-first-order rate (minminus1)qe bentonite adsorbed dye quantity at equilibrium (mgg)and qt quantity of adsorbed CV (mgg) t time (min)

e framework of pseudo-second-order kinetics is asfollows [33]

t

qt

1

k2q2e

+1qe

t (6)

where K1 constant for pseudo-second-order (g(mgmin))qe bentonite adsorbed dye quantity at equilibrium (mgg)and qt quantity of adsorbed CV (mgg) at t tTime (min)

e batch method was used for the exploration of thekinetic parameters part of the adsorption process with a 25degCroom temperature e CV concentration was 300mgLinitially 0025 g50ml was the dosage of bentonite in thesolution of CV with a shaking speed of 200 rpm

Both models such as pseudo-first-order and pseudo-second-order were evaluated for the experimental data asplotted in Figures 10 and 11 e results exhibit a goodconsensus between the Pseudo-second order kinetic modeland experimental data e achieved value for the regressioncoefficients (R2) was 072 for pseudo-first-order and 1 for thepseudo-second-order model which were obtained by in-putting the experimental data us it can be reflected thatpseudo-second-order rate kinetics controls the CV removalthrough adsorption using Khulays natural bentonite

36 2ermodynamic Study e temperature affects theadsorption process when there is an increase in the diffusionrate of the adsorbent In contrast the change in temperatureaffects the adsorbent capacity at equilibrium [34] ementioned equation below is used for the calculation of theparameters for thermodynamic [35]

ΔG minusRT lnK

lnK ΔSR

minusΔHR

1113874 11138751T

(7)

where G Gibbs free energy alteration (kJmol) S changein entropy (Jmol K) H change in enthalpy (kJmol)T temperature (Kelvin) R gas constant (8314 Jmol K)and K coefficient for distribution which is measured usingthe given equation [35]

K qe

Ce

(8)

e experiments for thermodynamics were performed ata different temperature such as 25 35 and 45degC where theCV concentration of 150ml1 was used e bentoniteamount used was 0075 g for shaking for 40 minutes with aCV solution of 50ml Figure 12 shows that the temperatureincreases such as 25 to 45 led to the percentage increase ofremoval at equilibrium such as 62 to 69 e plot of Vanrsquot

Hoff of LnK to1T is shown in Figure 13 where the valueassessment of the ΔH and ΔS is done at the straight-lineslope as well as intercept e ΔG negative value is observedwhich signifies the spontaneous processing of adsorption

ndash2

ndash1

0

1

2

3

4

5

6

0 10 20 30 40 50 60 70

ln (q

e ndash qt)

Time (min)

Figure 10 Crystal violet adsorption model for pseudo-first-orderkinetic

0

02

04

0 10 20 30 40 50 60 70

tqt

Time (min)

Figure 11 Crystal violet adsorption model for pseudo-second-order kinetic

0

10

20

30

40

50

60

70

80

0 20 40 60 80

C

V re

mov

al

T (degC)

T = 45degCT = 35degCT = 25degC

Figure 12 Effect of temperature on the removal of CV


along with it the ΔH positive value that is 67 kJmolhighlights the endothermic nature of the adsorption processe ΔS positive value (573 Jmol K) highlights that CVadsorption in Khulays natural bentonite improves therandomness at the interface of the bentonite or dye solution[36] Bendaho et al [37] also found similar results for theadsorption of acid dye onto activated Algerian clay Sari andIthornyldak [38] study on the stearic acid onto untreated kao-linite also found the ΔS positive value at the solid Liquidinterface leads to an increase in the process of adsorption(see Table 3)

4 Conclusion

e present study investigated the treatment of water for CVremoval with the use of Khulays natural bentonite followingmultivariate conditions e crystal violet sorption ontoKhulaysrsquo natural bentonite was comparatively swift such asat 40minutes the acquisition of equilibrium was madepossible Moreover CV concentration enhancement at theinitial stages reduces the percentage for removal as a result ofthe active adsorbent site saturation e improved pH of thesolution served as a stimulant for the advancing percentageof CV removal using the Khulays natural bentonite CVabsorbance increased with the increase in the dosage ofbentonite which improves the absorbents site number edata for the adsorption isotherm is adequate for the bothmodels that is Langmuir and Freundlich where themaximum capacity of the Khulays natural bentonite ad-sorption was achieved 263mgg In the experiments ad-sorption kinetic exhibits that the adsorption of CV againstKhulays natural bentonite is regulated using pseudo-second-order rate kinetics e findings of the research determinethat the established thermodynamic process of adsorption is

spontaneous and is endothermic e study positionsKhulaysrsquo natural bentonite as a promising adsorbent for thetreatment of water for the removal of the basic dyesHowever the findings of the study are limited given itslimited characterization where the use of pH

pzc could haveexpanded the research findings and provided better inter-pretation Given this the present study recommends futurestudies to perform a comparison of similar natural materialsand their regeneration capacity (recycling) for improving theresearch scope is would also assist in evaluating the re-producibility of the found results

Data Availability

e datasets used and analysed during the current study areavailable from the author upon reasonable request

Conflicts of Interest

e author declares that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

e author is very thankful to all the associated personnel inany reference that contributed to the purpose of thisresearch

References

[1] F A Awadallah and S A Al-Muhtaseb ldquoRemoval of crystalviolet from wastewater using resorcinol-formaldehyde carbonxerogelsrdquo Separation Science and Technology vol 51 no 3pp 403ndash415 2016

[2] L Akinola and A Umar ldquoAdsorption of crystal violet ontoadsorbents derived from agricultural wastes kinetic andequilibrium studiesrdquo Journal of Applied Sciences and Envi-ronmental Management vol 19 no 2 p 279 2015

[3] Z Carmen and S Daniel ldquoTextile organic dyesmdashchar-acteristics polluting effects and separationelimination pro-cedures from industrial effluentsmdasha critical overviewrdquoOrganic Pollutants Ten Years After the Stockholm Convention -Environmental and Analytical Update IntechOpen LondonUK 2012

[4] R D Saini ldquoSynthetic textile dyes constitution dying processand environmental impactsrdquo Asian Journal of Research inChemistry vol 11 no 1 p 206 2018

[5] I A Aneyo F V Doherty O A Adebesin andM O Hammed ldquoBiodegradation of pollutants in waste waterfrom pharmaceutical textile and local dye effluent in lagosNigeriardquo Journal of Health and Pollution vol 6 no 12pp 34ndash42 2016

[6] G Crini and E Lichtfouse ldquoAdvantages and disadvantages oftechniques used for wastewater treatmentrdquo EnvironmentalChemistry Letters vol 17 no 1 pp 145ndash155 2018

[7] M N Khalaf Green Polymers and Environmental PollutionControl Apple Academic Press New York NY USA 2016

[8] K Rathoure and V K Dhatwalia Eds ldquoToxicity and wastemanagement using bioremediationrdquo Advances in Environ-mental Engineering and Green Technologies IGI GlobalHershey PA USA 2016

R2 = 09975

0

1

2

3

4

5

6

7

00031 00032 00033 00034

ln K

1T

Figure 13 Vanrsquot Hoff plot

Table 3 CV adsorption thermodynamic data onto Khulaysrsquo nat-ural bentonite

Temperature (degC) G (kJmol) H (kJmol) S (Jmol K)25 minus16169435 minus183852 67 57345 minus204611


[9] N Morin-Crini G Crini and L Roy Eaux IndustriellesContaminees PUFC Besanccedilon France 2017

[10] D Jayganesh R Tamilarasan M Kumar MMurugavelu andV Sivakumar ldquoEquilibrium and Modelling Studies for theRemoval of Crystal Violet Dye from aqueous solution usingeco-friendly activated carbon prepared from Sargassm wightiiseaweedsrdquo Journal of Materials and Environmental Sciencesvol 8 no 4 pp 1508ndash1517 2017

[11] M Kumar and R Tamilarasan ldquoModeling of experimentaldata for the adsorption of methyl orange from aqueous so-lution using a low cost activated carbon prepared fromProsopis juliflorardquo Polish Journal of Chemical Technologyvol 15 no 2 pp 29ndash39 2013

[12] G Vijayakumar R Tamilarasan and M DharmendirakumarldquoAdsorption Kinetic Equilibrium and ermodynamicstudies on the removal of basic dye Rhodamine-B fromaqueous solution by the use of natural adsorbent perliterdquoJournal of Materials and Environmental Sciences vol 3pp 157ndash170 2012

[13] M Nageeb ldquoAdsorption technique for the removal of organicpollutants from water and wastewaterrdquo Organic Pollu-tantsmdashMonitoring Risk and Treatment IntechOpen LondonUK 2013

[14] Saad Al-Shahrani ldquoTreatment of wastewater contaminatedwith cobalt using Saudi activated bentoniterdquo AlexandriaEngineering Journal vol 53 no 1 pp 205ndash211 2014

[15] R Ajemba ldquoEnhancement of physicochemical properties ofnteje clay to increase its bleaching performance using acidactivationrdquo International Journal of Engineering Research andApplications (IJERA) vol 2 no 4 pp 281ndash288 2012

[16] F H Kamar F E Niamat A A H Faisal A A MohammedA C Nechifor and G Nechifor ldquoUse of artificial neuralnetwork for modeling and prediction of reactive red dyeremoval from wastewater using banana peels bio-sorbentrdquoRevista de Chimie vol 69 no 8 pp 1919ndash1926 2018

[17] A R Obiageli ldquoldquoAdsroption of cationic dye onto low-costadsorbent synthesized from bentonite clay part I Kinetic andthermodynamic studiesrdquo Journal of Chemical Technology ampMetallurgy vol 52 2017

[18] G K Cheruiyot W C Wanyonyi J J Kiplimo andE N Maina ldquoAdsorption of toxic crystal violet dye usingcoffee husks equilibrium kinetics and thermodynamicsstudyrdquo Scientific African vol 5 Article ID e00116 2019

[19] K S Bharathi and S T Ramesh ldquoRemoval of dyes usingagricultural waste as low-cost adsorbents a reviewrdquo AppliedWater Science vol 3 no 4 pp 773ndash790 2013

[20] M Alshabanat G Alsenani and R Almufarij ldquoRemoval ofcrystal violet dye from aqueous solutions onto date palm fiberby adsorption techniquerdquo Journal of Chemistry vol 2013Article ID 210239 pp 1ndash6 2013

[21] W Zou K Li H Bai X Shi and R Han ldquoEnhanced cationicdyes removal from aqueous solution by oxalic acid modifiedrice huskrdquo Journal of Chemical amp Engineering Data vol 56no 5 pp 1882ndash1891 2011

[22] K Al-Essa ldquoAdsorption of humic acid onto Jordanian kao-linite clay effects of humic acid concentration pH andtemperaturerdquo Science Journal of Chemistry vol 6 no 1pp 1ndash10 2018

[23] M T Yagub T K Sen S Afroze and H M Ang ldquoDye and itsremoval from aqueous solution by adsorption a reviewrdquoAdvances in Colloid and Interface Science vol 209 pp 172ndash184 2014

[24] H H A Ghafar T Salem E K Radwan A A El-SayedM A Embaby and M Salama ldquoModification of waste wool

fiber as low cost adsorbent for the removal of methylene bluefrom aqueous solutionrdquo Egyptian Journal of Chemistryvol 60 pp 395ndash406 2017

[25] E G Sogut and N Caliskan ldquoIsotherm and kinetic studies ofpb (II) adsorption on raw and modified diatomite by usingnon-linear regression methodrdquo Fresenius EnvironmentalBulletin vol 26 pp 2720ndash2728 2017

[26] I Langmuir ldquoe adsorption of gases on plane surfaces ofglass mica and platinumrdquo Journal of the American ChemicalSociety vol 40 no 9 pp 1361ndash1403 1918

[27] H Freundlich Colloid amp Capillary Chemistry Methuen amp CoLtd London UK 1926

[28] H Singh and F Javadpour ldquoLangmuir slip-Langmuir sorp-tion permeability model of shalerdquo Fuel vol 164 pp 28ndash372016

[29] X Chen ldquoModeling of experimental adsorption isothermdatardquo Information vol 6 no 1 pp 14ndash22 2015

[30] N Laskar and U Kumar ldquoAdsorption of crystal violet fromwastewater by modified bambusa tuldardquo KSCE Journal ofCivil Engineering vol 22 no 8 pp 2755ndash2763 2017

[31] V O Shikuku F F Donato C O KowenjE R Zanella andO D Prestes ldquoA comparison of adsorption equilibriumkinetics and thermodynamics of aqueous phase clomazonebetween faujasite X and a natural zeolite from Kenyardquo SouthAfrican Journal of Chemistry vol 68 pp 245ndash252 2015

[32] J-P Simonin ldquoOn the comparison of pseudo-first order andpseudo-second order rate laws in the modeling of adsorptionkineticsrdquoChemical Engineering Journal vol 300 pp 254ndash2632016

[33] M B Ahmed J L Zhou H H Ngo W Guo and M ChenldquoProgress in the preparation and application of modifiedbiochar for improved contaminant removal from water andwastewaterrdquo Bioresource Technology vol 214 pp 836ndash8512016

[34] U Pathak P Das P Banerjee and S Datta ldquoTreatment ofwastewater from a dairy industry using rice husk as adsorbenttreatment efficiency isotherm thermodynamics and kineticsmodellingrdquo Journal of 2ermodynamics vol 2016 Article ID3746316 7 pages 2016

[35] D C d Santos M A Adebayo E C Lima et al ldquoApplicationof carbon composite adsorbents prepared from coffee wasteand clay for the removal of reactive dyes from aqueous so-lutionsrdquo Journal of the Brazilian Chemical Society vol 26no 5 pp 924ndash938 2015

[36] 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

[37] D Bendaho T A Driss and D Bassou ldquoAdsorption of aciddye onto activated Algerian clayrdquo Bulletin of the ChemicalSociety of Ethiopia vol 31 no 1 p 51 2017

[38] A Sari and O Ithornyldak ldquoldquoAdsorption properties of stearic acidonto untreated kaoliniterdquo Bulletin of the Chemical Society ofEthiopia vol 20 no 2 2006


treatment of the waster waters comprising coagulationreverse osmosis flocculation biological methods and moreSeveral of these methods constitute one or more limitationsand cannot completely clear the water of any dye [12] Incontrast the process of adsorption stands strong for thetreatment of the wastewater concerning its design costfunctionality as well as insensitivity to the formed toxicsludge [13]

For the adsorption process the use of bentonite hassignificantly increased in various disciplines such as thetreatment of the contaminated water comprising heavymetals dyes and phenols Realizing the impact caused by thedyes efforts are being made at the global level to overcomethe environmental hazards using adsorbent that is eco-nomical and easily available from the agricultural waste [14]e developing countries such as Saudi Arabia are alsomaking efforts to set the base for new industries by utilizingnatural resources also aimed at the achievement of its SaudiVision 2030 Considering the global scenario the studyassesses the feasibility of treating the wastewater which isachieved upon the utilization of the Khulays natural ben-tonite for clearing it off the crystal violet e increasedavailability as well as the cost-effectiveness associated withKhulays natural bentonite made its selection all morepreferable

2 Materials and Methods

21 Chemicals andReagents In the present study the crystalviolet (CV) was obtained from Loba Chemie a chemicalmanufacturer e obtained crystal violet was used as it iswithout undergoing the purification process e molecularweight of it is C25H30N3Cl with a number of CAS as 548-62-9 and a molecular weight of 40798 the maximum ad-sorption was found at 590 nm [10] Figure 1 represents theCV molecular structure e CV stock solution (1000mgL)was prepared by dissolving a known quantity of CV indistilled water e preparation of various solutions with thepreferred concentration was done by diluting a properamount of stock solution with distilled water

22 Adsorbent e samples of the bentonite were gatheredfrom Khulays which is situated in the north of Jeddah at95 km in Saudi Arabia e samples were collected in theform of ungrounded rocks which further underwent theprocess of drying and grinding for the reduction of their sizeas per the requirement After the grinding process bentonitesamples were sieved with 200 mesh sieving trays e sus-pended clay residue was sent back to the ceramic ball mill-grinding machine and the passed bentonite was used in theadsorption process without any treatment Table 1 dem-onstrates the chemical composition of the Khulays naturalbentonite [14] e measurement of the surface area was645m2g computed using the computer-generated programbased on BET e image scanning electron microscopy(SEM) of the natural Khulays natural bentonite is shown inFigure 2 e image shows spherical shape surfaces withsemiflowered structure with high pores on the bentonite

surface which give a good indication for Khulays bentoniteto be a good adsorbent

23 Characterization of the Bentonite Absorbent FTIRspectroscopy (ermo Nicolet NEXUS 670 Spectropho-tometer) and XRD (Philips XrsquoPert Pro) was used for thecharacterization of the activated bentonite Figures 3 and 4presents the FTIR and XRD analysis which shows that theactivated bentonite ranges from 600 to 3800 cmminus1 It showsthat FTIR spectra are substantially sensitive to the bentonitestructure modification when treated with acid Concerningthe XRD analysis the decline in the intensity as well as theupsurge in the peak width shows that acid activation affectsthe bentonite crystallinity It also shows the decompositionof the crystalline bentonite structure which shows the ap-pearance of the amorphous phase Overall the findingsshowed similar chemical nature though the physical andmorphological properties were found to be highly variablePrevious results show similar statistics as observed in thestudy of Ajemba [15]

24 Experiments for Adsorption In the study the batchmethod was used for all the performed adsorption experi-ments e solution was prepared by mixing the adequateamount of Khulays natural Bentonite and CV (50ml) in theconical flasks (100ml) Following it the conical flask wasplaced in a water bath with a horizontal shaker (JULABOSW 22) at a temperature of 25degC at 200 rpm Preparation ofthe CV stock solution took place by dissolving the definiteCV quantity in the distilled water e stock solution wasdiluted according to the requirement needed for variousstandards solutions containing CV in the 50ndash300mgLamount e exploration of the effects such as pH of asolution time for shaking the concentration of CV anddosage of adsorbent took place by performing the experi-ments for adsorption After shaking the shaker was thenemptied of the samples at regular intervals for contact timewhich were separated at 4000 rpm by centrifuging for fifteenminutes with the utilization of the ROTOFIX 321 model(Hettich Zentrifugen) e measurement of the CV con-centration took place following every run in the solution

Clndash

CH3

CH3CH3

H3C

CH3H3C

NN

N+

Figure 1 Structure of crystal violet




m (1)




Co

times 100 (2)











0010203040506070809

600 1000 1400 1800 2200 2600 3000 3400 3800

Abs

orba

nce








ndash2000

0

2000

4000

6000

8000

10000

12000

14000

0 20 40 60 80 100 120

Inte

nsity

(au

)

2θ


0

20

40

60

80

100

120

0 10 20 30 40 50 60 70

C

V re

mov

al

Time (min)

100mgL200mgL

50mgL150mgL300mgL


0

20

40

60

80

100

120

C

V re

mov

al

3 5 7 9 11 131pH





Ce

qe

1

bqmax+

Ce

qmax (3)









0

20

40

60

80

100

120

C

V re

mov

al




C eq

e

06

05

04

03

02

01

07

020 40 60 80 100 120 140 160 1800

Ce


0

05

1

15

2

25

3

35

4

Log

(qe)

05 1 15 2 250Log (Ce)





2303t (5)



t

qt

1

k2q2e

+1qe

t (6)





ΔG minusRT lnK

lnK ΔSR

minusΔHR

1113874 11138751T

(7)


K qe

Ce

(8)



ndash2

ndash1

0

1

2

3

4

5

6

0 10 20 30 40 50 60 70

ln (q

e ndash qt)

Time (min)


0

02

04

0 10 20 30 40 50 60 70

tqt

Time (min)


0

10

20

30

40

50

60

70

80

0 20 40 60 80

C

V re

mov

al

T (degC)





4 Conclusion




Data Availability




Acknowledgments


References









R2 = 09975

0

1

2

3

4

5

6

7

00031 00032 00033 00034

ln K

1T







































m (1)




Co

times 100 (2)











0010203040506070809

600 1000 1400 1800 2200 2600 3000 3400 3800

Abs

orba

nce








ndash2000

0

2000

4000

6000

8000

10000

12000

14000

0 20 40 60 80 100 120

Inte

nsity

(au

)

2θ


0

20

40

60

80

100

120

0 10 20 30 40 50 60 70

C

V re

mov

al

Time (min)

100mgL200mgL

50mgL150mgL300mgL


0

20

40

60

80

100

120

C

V re

mov

al

3 5 7 9 11 131pH





Ce

qe

1

bqmax+

Ce

qmax (3)









0

20

40

60

80

100

120

C

V re

mov

al




C eq

e

06

05

04

03

02

01

07

020 40 60 80 100 120 140 160 1800

Ce


0

05

1

15

2

25

3

35

4

Log

(qe)

05 1 15 2 250Log (Ce)





2303t (5)



t

qt

1

k2q2e

+1qe

t (6)





ΔG minusRT lnK

lnK ΔSR

minusΔHR

1113874 11138751T

(7)


K qe

Ce

(8)



ndash2

ndash1

0

1

2

3

4

5

6

0 10 20 30 40 50 60 70

ln (q

e ndash qt)

Time (min)


0

02

04

0 10 20 30 40 50 60 70

tqt

Time (min)


0

10

20

30

40

50

60

70

80

0 20 40 60 80

C

V re

mov

al

T (degC)





4 Conclusion




Data Availability




Acknowledgments


References









R2 = 09975

0

1

2

3

4

5

6

7

00031 00032 00033 00034

ln K

1T









































ndash2000

0

2000

4000

6000

8000

10000

12000

14000

0 20 40 60 80 100 120

Inte

nsity

(au

)

2θ


0

20

40

60

80

100

120

0 10 20 30 40 50 60 70

C

V re

mov

al

Time (min)

100mgL200mgL

50mgL150mgL300mgL


0

20

40

60

80

100

120

C

V re

mov

al

3 5 7 9 11 131pH





Ce

qe

1

bqmax+

Ce

qmax (3)









0

20

40

60

80

100

120

C

V re

mov

al




C eq

e

06

05

04

03

02

01

07

020 40 60 80 100 120 140 160 1800

Ce


0

05

1

15

2

25

3

35

4

Log

(qe)

05 1 15 2 250Log (Ce)





2303t (5)



t

qt

1

k2q2e

+1qe

t (6)





ΔG minusRT lnK

lnK ΔSR

minusΔHR

1113874 11138751T

(7)


K qe

Ce

(8)



ndash2

ndash1

0

1

2

3

4

5

6

0 10 20 30 40 50 60 70

ln (q

e ndash qt)

Time (min)


0

02

04

0 10 20 30 40 50 60 70

tqt

Time (min)


0

10

20

30

40

50

60

70

80

0 20 40 60 80

C

V re

mov

al

T (degC)





4 Conclusion




Data Availability




Acknowledgments


References









R2 = 09975

0

1

2

3

4

5

6

7

00031 00032 00033 00034

ln K

1T







































Ce

qe

1

bqmax+

Ce

qmax (3)









0

20

40

60

80

100

120

C

V re

mov

al




C eq

e

06

05

04

03

02

01

07

020 40 60 80 100 120 140 160 1800

Ce


0

05

1

15

2

25

3

35

4

Log

(qe)

05 1 15 2 250Log (Ce)





2303t (5)



t

qt

1

k2q2e

+1qe

t (6)





ΔG minusRT lnK

lnK ΔSR

minusΔHR

1113874 11138751T

(7)


K qe

Ce

(8)



ndash2

ndash1

0

1

2

3

4

5

6

0 10 20 30 40 50 60 70

ln (q

e ndash qt)

Time (min)


0

02

04

0 10 20 30 40 50 60 70

tqt

Time (min)


0

10

20

30

40

50

60

70

80

0 20 40 60 80

C

V re

mov

al

T (degC)





4 Conclusion




Data Availability




Acknowledgments


References









R2 = 09975

0

1

2

3

4

5

6

7

00031 00032 00033 00034

ln K

1T







































2303t (5)



t

qt

1

k2q2e

+1qe

t (6)





ΔG minusRT lnK

lnK ΔSR

minusΔHR

1113874 11138751T

(7)


K qe

Ce

(8)



ndash2

ndash1

0

1

2

3

4

5

6

0 10 20 30 40 50 60 70

ln (q

e ndash qt)

Time (min)


0

02

04

0 10 20 30 40 50 60 70

tqt

Time (min)


0

10

20

30

40

50

60

70

80

0 20 40 60 80

C

V re

mov

al

T (degC)





4 Conclusion




Data Availability




Acknowledgments


References









R2 = 09975

0

1

2

3

4

5

6

7

00031 00032 00033 00034

ln K

1T






































4 Conclusion




Data Availability




Acknowledgments


References









R2 = 09975

0

1

2

3

4

5

6

7

00031 00032 00033 00034

ln K

1T





































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