research article remediation of rhodamine b dye …downloads.hindawi.com/archive/2016/9497378.pdf(b)...

Research ArticleRemediation of Rhodamine B Dye fromAqueous Solution Using Casuarina equisetifolia ConePowder as a Low-Cost Adsorbent

Muhammad Khairud Dahri Muhammad Raziq Rahimi Kooh and Linda B L Lim

Faculty of Science Universiti Brunei Darussalam Jalan Tungku Link Pengkalan GadongBandar Seri Begawan BE1410 Brunei Darussalam

Correspondence should be addressed to Muhammad Raziq Rahimi Kooh chernyuanhotmailcom

Received 28 July 2016 Accepted 22 September 2016

Academic Editor Leonardo Palmisano

Copyright copy 2016 Muhammad Khairud Dahri et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

The removal of toxic dye rhodamine B (RB) from aqueous solution was achieved by using Casuarina equisetifolia cone (CEC) as anadsorbent Batch experiment method was used in order to investigate the effects of contact time pH temperature ionic strengthand dye concentration on the adsorption process Kinetics and isotherm theoretical models were applied on the experimental dataand it was found that the pseudo-2nd-order kinetics and the Langmuir isotherm model best fitted into the data The Langmuirmaximum adsorption capacity for CEC was determined as 495mg gminus1 The adsorption of RB onto CEC is thermodynamicallyfavourable feasible and endothermic in nature

1 Introduction

Theuse of synthetic colouring agents in textile paper leatherand plastic industries leads to the growing concern of thedye wastewater Many synthetic dyes are chemically and ther-mally stable and are usually nonbiodegradable Dye wastew-ater must be treated before discharge to the environmentHowever such practices of direct discharge of dye wastewaterwere being observed in some low-income countries and thedamage is not limited to ecological damage but also to thehealth of those who consume the water [1]

There are many methods available for treating dye waste-water such as ozonation addition of reducing agents Fentonrsquosmethod membrane filtration ion-exchange and adsorp-tion methods where their advantages and disadvantages arewidely discussed in literature [2] Among these methodsadsorption is one of the simplest and most researchedmethods in the last decade [3] Adsorption is also widely usedfor the removal of pollutants that are not easily biodegradable[2] The cost of dye wastewater remediation by adsorptiondepends on the removal efficiency of the adsorbent as well asits sources Low-cost adsorbents may include materials thatcan be found in abundance such as weeds or agricultural

wastes while higher-cost adsorbents may include chemicallytreated materials

Casuarina equisetifolia is a multipurpose crop native inAustralia Bangladesh Brunei Darussalam Malaysia Thai-land and Philippines islands [4] which was introduced toIndia China Egypt Tanzania and North America for agro-forestry research [5]This plant is a nonleguminous plant andcapable of forming symbiosis relationship with phosphatemobilising mycorrhizae for its phosphatersquos need while thenitrogen source can be obtained through nitrogen-fixingFrankia in root nodules [5] thereby reducing the need ofinputs

In this study the Casuarina equisetifolia cone (CEC) wasinvestigated as a potential adsorbent for the removal ofrhodamine B (RB) In our previous studies we reported thepotential of Casuarina equisetifolia needle (CEN) as a goodadsorbent for the removal of RB [6] methyl violet [7] andmalachite green [8] CEC contributes to 2ndash10 of total plantlitter from a Casuarina equisetifolia tree [9] CEC has noeconomic importance and is not used for landscape purposesunlike the CEN The nutrient density of CEC is lower thanCEN [10] while upon decomposition the CEC releases lessnitrogen than CEN which makes CEC a less useful material

Hindawi Publishing CorporationAdvances in Physical ChemistryVolume 2016 Article ID 9497378 7 pageshttpdxdoiorg10115520169497378

2 Advances in Physical Chemistry

for composting or as biofertiliser [9] Another reason of usingCEC as an adsorbent is because of the brittleness featurewhich allows the biomass to be easily processed into powderCEC also contain lignocellulosic material which is one ofthe known materials used for remediation of pollutants [11]Currently there are no reports on the use of CEC as anadsorbent for removal of dyes however the cones of Pinusradiata tree unrelated to Casuarina species were reported tobe used for removal ofmethylene blue [12] and congo red [13]

The xanthine dye RB is chosen for this study because ofits importance in paint textile and paper industries [14]RB was reported to cause mutagenic effect and reproductivetoxicity in rats [15] and is also toxic to fish with a LC50 of839mg Lminus1 reported for Cyprinodon variegatus [16]

2 Materials and Methods

21 Preparation of Adsorbent and Adsorbate Casuarina equi-setifolia cone (CEC) was collected from the campus groundand was washed using water before drying it in the oven at70∘C for few days The dried CEC was then blended andsieved to obtain particle size of 355120583mThe sample was keptin sealed plastic bag until further use

Rhodamine B (RB) (C28H31ClN2O3119872119903 47901 gmolminus1)with purity of 95 dye content was purchased from Sigma-Aldrich RB stock solution (1000mg Lminus1) was prepared bydissolving an appropriate amount of RB in water and a serialdilutionwas used in order to prepare lowerRB concentrationsfrom the stock solution All reagents were used withoutfurther purification and distilled water was used throughoutthe experiments

22 Characterisation of CEC The point of zero charge(pHpzc) of CEC was determined using the salt additionmethod [17] Five solutions of 01mol Lminus1 KNO3(20mL) wereprepared and the pH of each solution was adjusted to pH 2 46 8 and 10 using 01mol Lminus1NaOHandHNO3 004 g of CECwas mixed with the salt solutions in conical flasks and themixtures were agitated using Stuart Orbital Shaker at a speedof 250 rpm for 24 h The pH of the solutions was measuredusing aThermo-Scientific digital pHmeter after the 24 h agi-tationThe pHpzc was determined from the plot of ΔpH (finalpH minus initial pH) versus initial pH

The identification of CEC and CEC-RBrsquos functionalgroups was done by Fourier transform infrared (FTIR)spectroscopy (Shimadzu Model IR Prestige-21 spectropho-tometer) using the KBr disc methodThe KBr was purchasedfromSigma-Aldrich andof spectroscopy grade It was dried at110∘C for 2 h prior to the analysis in order to remove themoisture

The surface morphology of the samples was done usingscanning electron microscope (SEM) (Tescan Vega XMU)The samples were placed on carbon tape andwere gold coatedusing SPI-MODULE Sputter Coater at plasma current of 8mA for 60 seconds

23 Experimental Procedures Batch experiment used in thisstudy was generally carried out by mixing CEC (005 g) with

RB solution (20mL) of specific concentration in conicalflasks and agitated at 250 rpm for a certain period of timeThe quantity of the dye after agitation was analysed usingUV-visible spectrophotometer (Shimadzu UV-1601PC) atwavelength of 555 nm

In this study parameters such as contact time(5minus240min) temperature (25ndash55∘C) dosage (001ndash006 g)ionic strength (01ndash08MKNO3) and pH (2ndash10) were carriedout in order to investigate their effects on the adsorption ofRB onto CEC The amount of RB adsorbed per gram of CECand percentage removal are determined by the followingequations respectively

Adsorption capacity 119902119890 (mg gminus1) = (119862119894 minus 119862119890) 119881119898 (1)

Percentage removal = (119862119894 minus 119862119890) times 100119862119894 (2)

where 119862119894 is the initial dye concentration (mg Lminus1) 119862119890 is thedye concentration after agitation (mg Lminus1)119881 is the volume ofdye solution used (L) and 119898 is the mass of adsorbent used(g)

24 Error Analyses In order to determine the best-fittingmodel for describing the experimental data in kinetics andisotherm studies two error functions were used namely thesum of absolute error (EABS) and chi-square test (1205942) Errorfunctions are useful as the conversion of nonlinear equationsinto linear forms can violate the error variance of the standardleast squares [18 19] therefore determining the best-fittingmodel based on the value of the coefficient of determination(1198772) alone is inadequate The lower the value of the errorfunctions the closer the agreement between the calculatedand experimental values and hence the better the fitting ofthe model into the experimental data [20] The equations ofthe two error functions are as follows

Sum of absolute error (EABS)119899

sum119894=1

10038161003816100381610038161003816119902119890exp minus 119902119890cal10038161003816100381610038161003816

Chi-square test (1205942)119899

sum119894=1

(119902119890exp minus 119902119890cal)2119902119890exp

(3)

where 119902119890exp is 119902119890 value obtained from the experiment while119902119890cal is the calculated value from the theoretical models andn is the number of data points in the experiment

25 Regeneration Study The regeneration study on CECrsquosadsorption capacity after the treatment with RB dye was doneby washing the spent CEC with water and 01M NaOH asregenerating solutions Full details of the regeneration exper-imental procedures are available in our previous study [21]Briefly the spent CEC was made by agitating with 50mg Lminus1RB and distilled water was used for washing the dye onthe adsorbent several times at 30min interval Spent CECusing base treatmentwas prepared by agitating the spent CECwith 01M NaOH for 30min followed by repeated distilled

Advances in Physical Chemistry 3

4000 3500 3000 2500 2000 1500 1000 500

Wavenumber (cmminus1)

Perc

enta

ge tr

ansm

issio

n (

)

(A)

(B)

339583 293096

163088 151901

144282

134251

124703

102425 57963

342283 292517

173697

162027 151419

145053

137048

132226

124414

111105

103775

Figure 1The FTIR spectra for (A) untreated CEC and (B) CEC-RB

100120583m

Figure 2 SEM image of CEC at 400x magnification

water washing until the washed solution is near neutral Theregenerated CEC was dried in an oven at 70∘C overnightbefore being subjected to fresh 50mg Lminus1 RB This is consid-ered as one cycle and the experiment was carried out until thethird cycle

3 Results and Discussions

31 Characterisation of CEC The functional groups identifi-cation of CEC and CEC-RB using FTIR is shown in Figures1(A) and 1(B) respectively InCECrsquos FTIR spectrumOHandor NH group (3422 cmminus1) CH (2925 cmminus1) amide NH2bending (1620 cmminus1) CN stretching (1514 cmminus1) and C-Ostretching vibration (1037 cmminus1) were observed In CEC-RBhowever these bands were shifted to 3395 2930 1630 1519and 1024 cmminus1 respectively suggesting that these functionalgroups could be involved in the interaction between CECrsquossurface and RBmoleculesThe surface morphology of CEC isdisplayed in Figure 2 and it can be seen that CEC has roughand irregular surface which suggests large surface area for theadsorption to occur

The pHpzc of CEC is determined as 422 According to theconcept of point of zero charge this value indicates the pH atwhich CECrsquos surface is neutral When CEC is subjected tohigher pH the surface would be predominately negativein charge due to the deprotonation of its functional group

such as carboxyl group While in lower pH the surface ispredominately negative in charge due to the protonation offunctional group such as amine group This parameter isuseful in the prediction at which pH the adsorbents caneffectively adsorb the adsorbate in solutions

32 Effect of Contact Time and Kinetics Study The amount oftime required for the adsorption process to be in equilibriumcan vary depending on the chemical and physical nature ofthe adsorbent as well as the adsorbateTherefore it is useful toinvestigate the effect of contact time in order to obtain theoptimal time to be used for the rest of the experimentsThe adsorption of 50100 and 200mg Lminus1 RB onto CEC isshown in Figure 3(a) where a rapid increase in 119902119890 values inthe first 30min of contact time was observed and this couldbe due to the availability of CECrsquos active sites Beyond 60minthe adsorption slowed down which was contributed by thediminishing number of active sites for RB molecules tointeract with

In this study the Lagergren 1st-order [22] and pseudo-2nd-order [23] models were used to describe the adsorp-tion mechanism while Weber-Morris intraparticle diffusionmodel [24] was used to investigate the diffusion mechanismof the adsorption process The linear equations for thesemodels are expressed as follows

Lagergren 1st-order log (119902119890 minus 119902119905)= log 119902119890cal minus 11990523031198961

Pseudo-2nd-order 119905119902119905 =1119902119890cal21198962 +

119905119902119890cal

Weber-Morris intraparticle diffusion 119902119905= 119896311990512 + 119862

(4)

where 119902119905 is the adsorption capacity at given time (mg gminus1) 119905is the time (min) 119902119890cal is the calculated adsorptioncapacity (mg gminus1) and 119862 is the intercept 1198961 (minminus1) 1198962(gmgminus1minminus1) and 1198963 (mg gminus1minminus12) are rate constants forthe Lagergren 1st-order pseudo-2nd-order and Weber-Morris intraparticle diffusion model respectively

Table 1 summarises the kinetics parameters calculatedfrom each of the modelsrsquo linear plots It can be seen thatthe pseudo-2nd-order has higher coefficient of determination(1198772) values compared to the Lagergren 1st-order This indi-cates that the pseudo-2nd-order ismore suitable in describingthe experimental data than the Lagergren 1st-order modelThis is supported by the smaller EABS and 1205942 values forpseudo-2nd-order as well as the close agreement of themodelrsquos 119902119890cal with that of the experimental 119902119890 In the Weber-Morris model a straight plot passing through the originindicates that intraparticle diffusionmodel is the rate limitingstep In some cases multilinear plots are also obtained wherein such plots there are usually three distinct regions thatcan be seen which represent the film diffusion (1st region)intraparticle diffusion (2nd region) and equilibrium phase


0

10

20

30

40

50

0 50 100 150 200

50mg Lminus1

100mg Lminus1200mg Lminus1

t (min)

qe

(mgg

minus1 )

(a)

0 2 4 6 8 10 12 14 16

50mg Lminus1


0

10

20

30

40

50

qe

(mgg

minus1 )

t12 (min12)

(b)

Figure 3 (a) Effect of contact time on the adsorption at dye concentrations of 50 100 and 200mg Lminus1 RB onto 004 g CEC and (b) Weber-Morris intraparticle diffusion plots

Table 1 The calculated parameters of the kinetics models

119862119894 (mg Lminus1) 50 100 200Lagergren 1st-order model

119902119890cal (mg gminus1) 8226 16484 23608119902119890exp (mg gminus1) 10667 22863 403291198961 0018 0021 00141198772 0919 0918 09951205942 11646 34150 109759EABS 24912 66826 166513

Pseudo-2nd-order model119902119890cal (mg gminus1) 11560 24245 41938119902119890exp (mg gminus1) 10667 22863 403291198962 0004 0002 00011198772 0985 0990 09931205942 7182 14619 24406EABS 18614 42424 72061

Weber-Morris intraparticle diffusion model1198963 0895 1555 2477119862 1234 5896 114931198772 0906 0954 0981

(3rd region) [25] However since film diffusion is a very fastprocess it is usually not seen in many cases In this studymultilinear Weber-Morris plots were obtained for all threeconcentrations (Figure 3(b)) From Table 2 it can be said thatthe y-intercept of each plot did not pass through the originand thus intraparticle diffusion is not the rate limiting step

33 Effect of pH and Ionic Strength The condition of dyeingprocesses varies depending on the nature of the dye that isacid dyes work best in acidic condition and reactive dyes needthe addition of salt As the dyeing process does not use upall the dyes in the bath they are often disposed and if not

Table 2Thermodynamics parameters for the adsorption of RB ontoCEC

Temperature(∘C)

ΔG∘(kJmolminus1)

ΔH∘(kJmolminus1)

ΔS∘(Jmolminus1 Kminus1) 119902119890 (mg gminus1)

25 minus1191419 5116

120835 minus147 127745 minus247 140955 minus284 1485

properly processed can affect the ecology of the water bodiespH and presence of salt can affect the adsorption capacityof an adsorbent and thus it is important to investigate theseparameters

Figure 4(a) shows the effect of pH on the adsorption of50mg Lminus1 RB onto CEC The highest removal was obtainedat pH 2 (75) while the other pH including the ambient pHyielded similar removal of around 66 RB dye moleculeexists in cationic form when pH lt 4 [26] and using theconcept of pHpzc the adsorption of RB molecules is lessfavourable in such low pH due to electrostatic repulsionHowever this was not observed in this study which may bedue to the possibility of other forces such as hydrogen bond-ing and hydrophobic interactions playing bigger roles thanelectrostatic interaction Similar observation was reported inthe removal of RB using Azolla pinnata [27]

The effect of ionic strength on the adsorption of 50mg Lminus1RB onto CEC is shown in Figure 4(b) It can be seen thatthe removal of RB only decreased when 004MNaCl andbeyond were introduced into the system The removal ofRB was initially 70 which decreased to 61 in 08MNaClsolutionThe reduction of removal capacity is contributed bythe competition between the dye molecules and Na+ ions forCECrsquos active sites Also the adsorbed Na+ can cause elec-trostatic repulsion due to increase in positive charge on theCECrsquos surface However the reduction was not severe as the


0

20

40

60

80

100

Amb (376) 206 43 584 833 1024

Perc

enta

ge re

mov

al (

)

pH

(a)

0

20

40

60

80

000 010 020 040 060 080

Perc

enta

ge re

mov

al (

)

[NaCl] (M)

(b)

Figure 4The effect of (a) pH and (b) ionic strength on the adsorption of 20mL of 50mg Lminus1 RB onto CEC using 004 g adsorbent at agitationspeed of 250 rpm

RBmolecule is likely to interact with CEC using hydrophobicinteraction and hydrogen bonding as mentioned aboveRemoval of RB using jackfruit seed reported a similarobservation [28]

34 Effect of Temperature and Thermodynamics StudyTable 2 shows 119902119890 values at various temperature as well asthe calculated Δ119878∘ and Δ119867∘ values obtained from linearplot presented by (9) and these two parameters are used tocalculate Δ119866∘ using (5) It can be seen that increasing thetemperature from 25∘C to 55∘C only increased 119902119890 values bytwo units which indicates that temperature has little effect onthe adsorption process Thermodynamically the adsorptionin this study is viewed as endothermic due to the increase in119902119890 values and the positive value of Δ119867∘ The negative valuesof Δ119866∘ indicate the spontaneous reaction while positive Δ119878∘value showed that the reaction is favourable

Van rsquot Hoff equation can be expressed as follows

Δ119866∘ = Δ119867∘ minus 119879Δ119878∘ (5)

Δ119866∘ = minus119877119879 ln 119896 (6)

119896 = 119862119904119862119890 (7)

119862119904 = 119862119894 minus 119862119890 (8)

By substituting (5) into (6)

ln 119896 = Δ119878∘119877 minusΔ119867∘119877119879 (9)

where T is the temperature in Kelvin (K) Δ119866∘ is Gibbsrsquo freeenergy Δ119878∘ is the change in entropy Δ119867∘ is the change inenthalpy 119896 is the distribution coefficient for adsorption 119862119904is the amount of RB adsorbed by the adsorbent after equilib-rium (mg Lminus1) and 119877 is the gas constant (8314 Jmolminus1 Kminus1)Δ119878∘ and Δ119867∘ were calculated from the linear plot of ln 119896

versus 111987935 Effect of Concentration and Isotherm Modelling As seenin Figure 5 119902119890 value increases as the concentration of

0

10

20

30

40

50

60

0 100 200 300 400 500 600

qe

(mgg

minus1 )

Ci (mg Lminus1)

Figure 5 The effect of various concentration of RB on the adsorp-tion process (004 g adsorbent unadjusted pH)

RB increased from 20mg Lminus1 (55mg gminus1) to 200mg Lminus1(411mg gminus1) This is contributed by the driving force pro-vided by the concentration gradient which forces moremolecules to be transferred from the bulk solution to theadsorbent [29] Beyond 200mg Lminus1 the adsorption sloweddown to a point where the uptake did not increase signifi-cantly that is 445mg gminus1 at 500mg Lminus1

Three theoretical isothermmodels namely the Langmuir[30] Freundlich [31] and Sips [32] were chosen in this studyin order to describe the adsorption process These adsorp-tion isotherm models are widely used in adsorption studyand their applications are discussed in literature [20] Thelinearised equations of the models are expressed as follows

Langmuir119862119890119902119890 =1119870119871119902119898 +

119862119890119902119898

Freundlich ln 119902119890 = 1119899119865 ln119862119890 + ln119870119865

Sips ln( 119902119890119902119898 minus 119902119890) = 119870119871119865 ln119862119890 + ln119870119878

(10)

where 119902119898 (mg gminus1) is the maximum monolayer adsorptioncapacity 119870119871 (Lmgminus1) is the Langmuir constant 119870119865 (mg gminus1

(Lmgminus1)1119899) is the adsorption capacity of the adsorbent


Table 3 Calculated parameters and error functions for the Langmuir Freundlich and Sips models

Langmuir Freundlich Sips119902119898 (mg gminus1) 49529 119870119865 [mg gminus1 (Lmgminus1)1n] 4087 119902119898 (mg gminus1) 60700119870119871 0033 119899119865 2212 119870119904 (Lmgminus1) 0038119877119871 0057 119870119871119865 12531198772 0993 1198772 0900 1198772 09511205942 1624 1205942 12741 1205942 2328EABS 18352 EABS 49706 EABS 21314

119899119865 value (between 1 and 10) indicates favourability of theadsorption process119870119878 (L gminus1) is Sips constant and119870119871119865 is theexponent

Separation factor (119877119871) can be calculated from Langmuirconstant and it is used to predict the favourability of theadsorption process [33]

119877119871 = 1(1 + 119870119871119862119894) (11)

where 119877119871 = 0 unfavourable when 119877119871 gt 1 linear when 119877119871 =1 and favourable when 0 lt 119877119871 lt 1 [34]The Langmuir Freundlich and Sips models were com-

pared using their 1198772 EABS and 1205942 values in order todetermine the best model to describe the adsorption processFrom Table 3 all three models displayed high 1198772 values(1198772 gt 09) with the Langmuir being the highest followed bySips and FreundlichmodelsThe Langmuirmodel also exhib-ited the lowest EABS and 1205942 values among the three modelsThis indicates that the Langmuir model is the best fittedmodel to the experimental data which assumes that the RBmolecules formed a single layer on the CECrsquos surfaceBoth 119877119871 and 119899119865 values indicate that the adsorption of RBonto CEC is a favourable process The maximum mono-layer adsorption capacity (119902119898) for CEC is determined as495mg gminus1 The performance of CEC in removing RB islower than Casuarina equisetifolia needle (823mg gminus1) [6]and Azolla pinnata (722mg gminus1) [27] and higher than jack-fruit seed (264mg gminus1) [28] acid treated Acacia nilotica leaf(224mg gminus1) [14] and microwave treated Acacia niloticaleave (243mg gminus1) [14]

36 Regeneration Study An alternative of disposing or incin-erating the used adsorbents the regeneration of the adsor-bentsrsquo removal capabilities using chemicals can be investi-gated as it can reduce disposal problem and save cost fromusing fresh adsorbents Distilled water and 01MNaOHwereused to regenerate CEC in this study and the result is shownin Figure 6 Fresh CEC yielded 689 RB removal whiledistilled water and base by the third cycle only yielded 426and 115 removal respectively Distilled water managed toregenerate around 40 of CECrsquos original removing capabilitywhich is considerably high for a simple washing solutionOur previous works on the removal of RB also showedsimilar result in the regeneration of the adsorbents wherebase washing tend to result in lower percentage removal onconsecutivewashing cycle and thismay be due to the removal

0

20

40

60

80

0 1 2 3Pe

rcen

tage

rem

oval

()

Number of cycles

Distilled waterBase

Figure 6 The regeneration of CEC using distilled water and 01MNaOH

of lignin and low molecular weight wax which may interactwith the RB dye molecules [6 28]

4 Conclusion

CEC has shown to have a good potential as an adsorbent inremovingRB fromaqueous solution It has several advantageswhere CECrsquos performance is not severely affected by thechange of pH ionic strength and temperature making it avery versatile adsorbent The pH and ionic strength experi-ments indicated that the adsorption of RB onto CEC does notdepend on electrostatic interactions The Langmuir modelcan be used to describe the process where CECrsquos 119902119898 value is495mg gminus1

Competing Interests

All authors declare no conflict of interests

References

[1] G De Aragao Umbuzeiro H S Freeman S H Warren et alldquoThe contribution of azo dyes to the mutagenic activity of theCristais Riverrdquo Chemosphere vol 60 no 1 pp 55ndash64 2005

[2] G Crini ldquoNon-conventional low-cost adsorbents for dyeremoval a reviewrdquo Bioresource Technology vol 97 no 9 pp1061ndash1085 2006


[3] M-H Wang J Li and Y-S Ho ldquoResearch articles published inwater resources journals a bibliometric analysisrdquo Desalinationand Water Treatment vol 28 no 1ndash3 pp 353ndash365 2011

[4] C Orwa A Mutua R Kindt R Jamnadass and S AnthonyldquoCasuarina equisetifoliardquo httpwwwworldagroforestryorgtreedb2AFTPDFSCasuarina equisetifoliaPDF

[5] N Subbarao and C Rodriguez-Barrueco Casuarinas SciencePublishers LaBombard Road North Lebanon 1995

[6] M R R Kooh M K Dahri and L B L Lim ldquoThe removal ofrhodamine B dye from aqueous solution using Casuarina equi-setifolia needles as adsorbentrdquo Cogent Environmental Science2016

[7] M K Dahri M R R Kooh and L B L Lim ldquoRemovalof methyl violet 2B from aqueous solution using Casuarinaequisetifolia needlerdquo ISRN Environmental Chemistry vol 2013Article ID 619819 8 pages 2013

[8] M K Dahri M R R Kooh and L B L Lim ldquoApplication ofCasuarina equisetifolianeedle for the removal ofmethylene blueand malachite green dyes from aqueous solutionrdquo AlexandriaEngineering Journal vol 54 no 4 pp 1253ndash1263 2015

[9] A K Srivastava and R S Ambasht ldquoLitterfall decompositionand nitrogen release in two age groups of trees in Casuarinaequisetifolia plantations in the dry tropical Vindhyan plateauIndiardquo Biology and Fertility of Soils vol 21 no 4 pp 277ndash2831996

[10] K Rajendran andPDevaraj ldquoBiomass andnutrient distributionand their return of Casuarina equisetifolia inoculated withbiofertilizers in farm landrdquo Biomass and Bioenergy vol 26 no3 pp 235ndash249 2004

[11] A Abdolali W S Guo H H Ngo S S Chen N C Nguyenand K L Tung ldquoTypical lignocellulosic wastes and by-productsfor biosorption process in water and wastewater treatment acritical reviewrdquoBioresource Technology vol 160 pp 57ndash66 2014

[12] T K Sen S Afroze and H M Ang ldquoEquilibrium kineticsand mechanism of removal of methylene blue from aqueoussolution by adsorption onto pine cone biomass ofPinus radiatardquoWater Air amp Soil Pollution vol 218 no 1ndash4 pp 499ndash515 2011

[13] S Dawood and T K Sen ldquoRemoval of anionic dye Congo redfrom aqueous solution by raw pine and acid-treated pine conepowder as adsorbent equilibrium thermodynamic kineticsmechanism and process designrdquoWater Research vol 46 no 6pp 1933ndash1946 2012

[14] T Santhi A L Prasad and S Manonmani ldquoA comparativestudy of microwave and chemically treated Acacia nilotica leafas an eco friendly adsorbent for the removal of rhodamine B dyefrom aqueous solutionrdquoArabian Journal of Chemistry vol 7 no4 pp 494ndash503 2014

[15] E R Nestmann G R Douglas T I Matula C E Grant andD J Kowbel ldquoMutagenic activity of rhodamine dyes and theirimpurities as detected bymutation induction in Salmonella andDNA damage in Chinese hamster ovary cellsrdquo Cancer Researchvol 39 no 11 pp 4412ndash4417 1979

[16] SIGMA-ALDRICH Rhodamine B [Material Safety Data Sheet]Version 54 2015 httpwwwsigmaaldrichcomMSDSMSDSDisplayMSDSPagedocountry=BNamplanguage=enampproductNumber=R4127ampbrand=SIGMAampPageToGoToURL=http3A2F2Fwwwsigmaaldrichcom2Fcatalog2Fproduct2Fsigma2Fr41273Flang3Den

[17] T Mahmood M T Saddique A Naeem P Westerhoff SMustafa and A Alum ldquoComparison of different methods forthe point of zero charge determination of NiOrdquo Industrial amp

Engineering Chemistry Research vol 50 no 17 pp 10017ndash100232011

[18] D A Ratkowsky Handbook of Nonlinear Regression ModelsMarcel Dekker 1990

[19] Y-S Ho ldquoSelection of optimum sorption isothermrdquo Carbonvol 42 no 10 pp 2115ndash2116 2004

[20] K Y Foo and B H Hameed ldquoInsights into the modeling ofadsorption isotherm systemsrdquo Chemical Engineering Journalvol 156 no 1 pp 2ndash10 2010

[21] M K Dahri M R R Kooh and L B L Lim ldquoWaterremediation using low cost adsorbent walnut shell for removalof malachite green equilibrium kinetics thermodynamic andregeneration studiesrdquo Journal of Environmental Chemical Engi-neering vol 2 no 3 pp 1434ndash1444 2014

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

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

[24] W J Weber and J C Morris ldquoKinetics of adsorption on carbonfrom solutionrdquo Journal of the Sanitary Engineering Division vol89 no 2 pp 31ndash60 1963

[25] B I Olu-Owolabi P N Diagboya and K O AdebowaleldquoEvaluation of pyrene sorption-desorption on tropical soilsrdquoJournal of Environmental Management vol 137 pp 1ndash9 2014

[26] H M H Gad and A A El-Sayed ldquoActivated carbon fromagricultural by-products for the removal of Rhodamine-B fromaqueous solutionrdquo Journal of Hazardous Materials vol 168 no2-3 pp 1070ndash1081 2009

[27] M R R Kooh L B L Lim L H Lim and M K DahrildquoSeparation of toxic rhodamine B from aqueous solution usingan efficient low-cost material Azolla pinnata by adsorptionmethodrdquo Environmental Monitoring and Assessment vol 188no 2 pp 1ndash15 2016

[28] M R R Kooh M K Dahri and L B Lim ldquoJackfruit seed asa sustainable adsorbent for the removal of Rhodamine B dyerdquoJournal of Environment amp Biotechnology Research vol 4 pp 7ndash16 2016

[29] M Saif Ur Rehman M Munir M Ashfaq et al ldquoAdsorptionof Brilliant Green dye from aqueous solution onto red clayrdquoChemical Engineering Journal vol 228 pp 54ndash62 2013

[30] I Langmuir ldquoThe adsorption of gases on plane surfaces ofglassmica and platinumrdquoThe Journal of the AmericanChemicalSociety vol 40 no 9 pp 1361ndash1403 1918

[31] H M F Freundlich ldquoOver the adsorption in solutionrdquo Journalof Physical Chemistry vol 57 pp 385ndash470 1906

[32] R Sips ldquoCombined form of Langmuir and Freundlich equa-tionsrdquo The Journal of Chemical Physics vol 16 pp 490ndash4951948

[33] T W Weber and R K Chakravorti ldquoPore and solid diffusionmodels for fixed-bed adsorbersrdquo AIChE Journal vol 20 no 2pp 228ndash238 1974

[34] G McKay H S Blair and J R Gardner ldquoAdsorption of dyeson chitin I Equilibrium studiesrdquo Journal of Applied PolymerScience vol 27 no 8 pp 3043ndash3057 1982

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


for composting or as biofertiliser [9] Another reason of usingCEC as an adsorbent is because of the brittleness featurewhich allows the biomass to be easily processed into powderCEC also contain lignocellulosic material which is one ofthe known materials used for remediation of pollutants [11]Currently there are no reports on the use of CEC as anadsorbent for removal of dyes however the cones of Pinusradiata tree unrelated to Casuarina species were reported tobe used for removal ofmethylene blue [12] and congo red [13]

The xanthine dye RB is chosen for this study because ofits importance in paint textile and paper industries [14]RB was reported to cause mutagenic effect and reproductivetoxicity in rats [15] and is also toxic to fish with a LC50 of839mg Lminus1 reported for Cyprinodon variegatus [16]

2 Materials and Methods

21 Preparation of Adsorbent and Adsorbate Casuarina equi-setifolia cone (CEC) was collected from the campus groundand was washed using water before drying it in the oven at70∘C for few days The dried CEC was then blended andsieved to obtain particle size of 355120583mThe sample was keptin sealed plastic bag until further use

Rhodamine B (RB) (C28H31ClN2O3119872119903 47901 gmolminus1)with purity of 95 dye content was purchased from Sigma-Aldrich RB stock solution (1000mg Lminus1) was prepared bydissolving an appropriate amount of RB in water and a serialdilutionwas used in order to prepare lowerRB concentrationsfrom the stock solution All reagents were used withoutfurther purification and distilled water was used throughoutthe experiments

22 Characterisation of CEC The point of zero charge(pHpzc) of CEC was determined using the salt additionmethod [17] Five solutions of 01mol Lminus1 KNO3(20mL) wereprepared and the pH of each solution was adjusted to pH 2 46 8 and 10 using 01mol Lminus1NaOHandHNO3 004 g of CECwas mixed with the salt solutions in conical flasks and themixtures were agitated using Stuart Orbital Shaker at a speedof 250 rpm for 24 h The pH of the solutions was measuredusing aThermo-Scientific digital pHmeter after the 24 h agi-tationThe pHpzc was determined from the plot of ΔpH (finalpH minus initial pH) versus initial pH

The identification of CEC and CEC-RBrsquos functionalgroups was done by Fourier transform infrared (FTIR)spectroscopy (Shimadzu Model IR Prestige-21 spectropho-tometer) using the KBr disc methodThe KBr was purchasedfromSigma-Aldrich andof spectroscopy grade It was dried at110∘C for 2 h prior to the analysis in order to remove themoisture

The surface morphology of the samples was done usingscanning electron microscope (SEM) (Tescan Vega XMU)The samples were placed on carbon tape andwere gold coatedusing SPI-MODULE Sputter Coater at plasma current of 8mA for 60 seconds

23 Experimental Procedures Batch experiment used in thisstudy was generally carried out by mixing CEC (005 g) with

RB solution (20mL) of specific concentration in conicalflasks and agitated at 250 rpm for a certain period of timeThe quantity of the dye after agitation was analysed usingUV-visible spectrophotometer (Shimadzu UV-1601PC) atwavelength of 555 nm

In this study parameters such as contact time(5minus240min) temperature (25ndash55∘C) dosage (001ndash006 g)ionic strength (01ndash08MKNO3) and pH (2ndash10) were carriedout in order to investigate their effects on the adsorption ofRB onto CEC The amount of RB adsorbed per gram of CECand percentage removal are determined by the followingequations respectively

Adsorption capacity 119902119890 (mg gminus1) = (119862119894 minus 119862119890) 119881119898 (1)

Percentage removal = (119862119894 minus 119862119890) times 100119862119894 (2)

where 119862119894 is the initial dye concentration (mg Lminus1) 119862119890 is thedye concentration after agitation (mg Lminus1)119881 is the volume ofdye solution used (L) and 119898 is the mass of adsorbent used(g)

24 Error Analyses In order to determine the best-fittingmodel for describing the experimental data in kinetics andisotherm studies two error functions were used namely thesum of absolute error (EABS) and chi-square test (1205942) Errorfunctions are useful as the conversion of nonlinear equationsinto linear forms can violate the error variance of the standardleast squares [18 19] therefore determining the best-fittingmodel based on the value of the coefficient of determination(1198772) alone is inadequate The lower the value of the errorfunctions the closer the agreement between the calculatedand experimental values and hence the better the fitting ofthe model into the experimental data [20] The equations ofthe two error functions are as follows

Sum of absolute error (EABS)119899

sum119894=1

10038161003816100381610038161003816119902119890exp minus 119902119890cal10038161003816100381610038161003816

Chi-square test (1205942)119899

sum119894=1

(119902119890exp minus 119902119890cal)2119902119890exp

(3)

where 119902119890exp is 119902119890 value obtained from the experiment while119902119890cal is the calculated value from the theoretical models andn is the number of data points in the experiment

25 Regeneration Study The regeneration study on CECrsquosadsorption capacity after the treatment with RB dye was doneby washing the spent CEC with water and 01M NaOH asregenerating solutions Full details of the regeneration exper-imental procedures are available in our previous study [21]Briefly the spent CEC was made by agitating with 50mg Lminus1RB and distilled water was used for washing the dye onthe adsorbent several times at 30min interval Spent CECusing base treatmentwas prepared by agitating the spent CECwith 01M NaOH for 30min followed by repeated distilled


4000 3500 3000 2500 2000 1500 1000 500


Perc

enta

ge tr

ansm

issio

n (

)

(A)

(B)

339583 293096

163088 151901

144282

134251

124703

102425 57963

342283 292517

173697

162027 151419

145053

137048

132226

124414

111105

103775


100120583m











119905119902119890cal


(4)




0

10

20

30

40

50

0 50 100 150 200

50mg Lminus1


t (min)

qe

(mgg

minus1 )

(a)

0 2 4 6 8 10 12 14 16

50mg Lminus1


0

10

20

30

40

50

qe

(mgg

minus1 )

t12 (min12)

(b)










Temperature(∘C)

ΔG∘(kJmolminus1)

ΔH∘(kJmolminus1)


25 minus1191419 5116






0

20

40

60

80

100

Amb (376) 206 43 584 833 1024

Perc

enta

ge re

mov

al (

)

pH

(a)

0

20

40

60

80

000 010 020 040 060 080

Perc

enta

ge re

mov

al (

)

[NaCl] (M)

(b)





Δ119866∘ = Δ119867∘ minus 119879Δ119878∘ (5)

Δ119866∘ = minus119877119879 ln 119896 (6)

119896 = 119862119904119862119890 (7)

119862119904 = 119862119894 minus 119862119890 (8)


ln 119896 = Δ119878∘119877 minusΔ119867∘119877119879 (9)



0

10

20

30

40

50

60

0 100 200 300 400 500 600

qe

(mgg

minus1 )

Ci (mg Lminus1)




Langmuir119862119890119902119890 =1119870119871119902119898 +

119862119890119902119898



(10)








119877119871 = 1(1 + 119870119871119862119894) (11)




0

20

40

60

80

0 1 2 3Pe

rcen

tage

rem

oval

()

Number of cycles

Distilled waterBase



4 Conclusion


Competing Interests


References














































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


4000 3500 3000 2500 2000 1500 1000 500


Perc

enta

ge tr

ansm

issio

n (

)

(A)

(B)

339583 293096

163088 151901

144282

134251

124703

102425 57963

342283 292517

173697

162027 151419

145053

137048

132226

124414

111105

103775


100120583m











119905119902119890cal


(4)




0

10

20

30

40

50

0 50 100 150 200

50mg Lminus1


t (min)

qe

(mgg

minus1 )

(a)

0 2 4 6 8 10 12 14 16

50mg Lminus1


0

10

20

30

40

50

qe

(mgg

minus1 )

t12 (min12)

(b)










Temperature(∘C)

ΔG∘(kJmolminus1)

ΔH∘(kJmolminus1)


25 minus1191419 5116






0

20

40

60

80

100

Amb (376) 206 43 584 833 1024

Perc

enta

ge re

mov

al (

)

pH

(a)

0

20

40

60

80

000 010 020 040 060 080

Perc

enta

ge re

mov

al (

)

[NaCl] (M)

(b)





Δ119866∘ = Δ119867∘ minus 119879Δ119878∘ (5)

Δ119866∘ = minus119877119879 ln 119896 (6)

119896 = 119862119904119862119890 (7)

119862119904 = 119862119894 minus 119862119890 (8)


ln 119896 = Δ119878∘119877 minusΔ119867∘119877119879 (9)



0

10

20

30

40

50

60

0 100 200 300 400 500 600

qe

(mgg

minus1 )

Ci (mg Lminus1)




Langmuir119862119890119902119890 =1119870119871119902119898 +

119862119890119902119898



(10)








119877119871 = 1(1 + 119870119871119862119894) (11)




0

20

40

60

80

0 1 2 3Pe

rcen

tage

rem

oval

()

Number of cycles

Distilled waterBase



4 Conclusion


Competing Interests


References














































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


0

10

20

30

40

50

0 50 100 150 200

50mg Lminus1


t (min)

qe

(mgg

minus1 )

(a)

0 2 4 6 8 10 12 14 16

50mg Lminus1


0

10

20

30

40

50

qe

(mgg

minus1 )

t12 (min12)

(b)










Temperature(∘C)

ΔG∘(kJmolminus1)

ΔH∘(kJmolminus1)


25 minus1191419 5116






0

20

40

60

80

100

Amb (376) 206 43 584 833 1024

Perc

enta

ge re

mov

al (

)

pH

(a)

0

20

40

60

80

000 010 020 040 060 080

Perc

enta

ge re

mov

al (

)

[NaCl] (M)

(b)





Δ119866∘ = Δ119867∘ minus 119879Δ119878∘ (5)

Δ119866∘ = minus119877119879 ln 119896 (6)

119896 = 119862119904119862119890 (7)

119862119904 = 119862119894 minus 119862119890 (8)


ln 119896 = Δ119878∘119877 minusΔ119867∘119877119879 (9)



0

10

20

30

40

50

60

0 100 200 300 400 500 600

qe

(mgg

minus1 )

Ci (mg Lminus1)




Langmuir119862119890119902119890 =1119870119871119902119898 +

119862119890119902119898



(10)








119877119871 = 1(1 + 119870119871119862119894) (11)




0

20

40

60

80

0 1 2 3Pe

rcen

tage

rem

oval

()

Number of cycles

Distilled waterBase



4 Conclusion


Competing Interests


References














































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


0

20

40

60

80

100

Amb (376) 206 43 584 833 1024

Perc

enta

ge re

mov

al (

)

pH

(a)

0

20

40

60

80

000 010 020 040 060 080

Perc

enta

ge re

mov

al (

)

[NaCl] (M)

(b)





Δ119866∘ = Δ119867∘ minus 119879Δ119878∘ (5)

Δ119866∘ = minus119877119879 ln 119896 (6)

119896 = 119862119904119862119890 (7)

119862119904 = 119862119894 minus 119862119890 (8)


ln 119896 = Δ119878∘119877 minusΔ119867∘119877119879 (9)



0

10

20

30

40

50

60

0 100 200 300 400 500 600

qe

(mgg

minus1 )

Ci (mg Lminus1)




Langmuir119862119890119902119890 =1119870119871119902119898 +

119862119890119902119898



(10)








119877119871 = 1(1 + 119870119871119862119894) (11)




0

20

40

60

80

0 1 2 3Pe

rcen

tage

rem

oval

()

Number of cycles

Distilled waterBase



4 Conclusion


Competing Interests


References














































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of






119877119871 = 1(1 + 119870119871119862119894) (11)




0

20

40

60

80

0 1 2 3Pe

rcen

tage

rem

oval

()

Number of cycles

Distilled waterBase



4 Conclusion


Competing Interests


References














































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of












































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

research article remediation of rhodamine b dye …downloads.hindawi.com/archive/2016/9497378.pdf(b)...

Documents