ADSORPTION OF COPPER FROM AQUEOUS SOLUTION BY ELAIS GUINEENSIS KERNEL ACTIVATED CARBON

Journal of Enginring Scinc and Tchnology Vol. 3, No. 2 (2008) 180-189 School of Enginring, Taylor s Univrsity Collg ADSORPTION OF COPPER FROM AQUEOUS SOLUTION BY ELAIS GUINEENSIS KERNEL ACTIVATED CARBON NAJUA DELAILA TUMIN 1,*, A. LUQMAN CHUAH 2,3, Z. ZAWANI 2, SURAYA ABDUL RASHID 2 1 Dpartmnt of Chmical Enginring Tchnology, Malaysian Institut of Chmical and Bionginring Tchnology (MICET),Univrsity Kuala Lumpur 2 Dpartmnt of Chmical and Environmntal Enginring, Faculty of Enginring, Univrsiti Putra Malaysia 3 Institut of Tropical Forstry & Forst Product (INTROP), Univrsity Putra Malaysia *Corrsponding Author: najuadlaila@mict.unikl.du.my Abstract In this study, a sris of batch laboratory xprimnts wr conductd in ordr to invstigat th fasibility of Elais Guinnsis krnl or known as palm krnl shll (PKS)-basd activatd carbon for th rmoval of coppr from aquous solution by th adsorption procss. Invstigation was carrid out by studying th influnc of initial solution ph, adsorbnt dosag and initial concntration of coppr. Th particl siz of PKS usd was catgorizd as PKS M. All batch xprimnts wr carrid out at a constant tmpratur of 30 C (±2 C) using mchanical shakr that opratd at 100 rpm. Th singl componnt quilibrium data was analyzd using Langmuir, Frundlich, Rdlich-Ptrson, Tmkin and Toth adsorption isothrms. Kywords: Elais Guinnsis, coppr rmoval, adsorption and isothrms. 1. Introduction Pollution from havy mtals is a major concrn in dvloping countris. Th discharg of havy mtals into watr-courss is a srious pollution problm which may affct th quality of watr supply. Incrasing concntrations of ths mtals in th watr constitut a svr halth hazard mainly du to thir nondgradability and toxicity. Numrous mtals such as chromium Cr (III) and Cr (VI), coppr (Cu), lad (Pb), mangans (Mn), mrcury (Hg), cadmium (Cd), tc ar known to b significantly toxic. 180

Adsorption of Coppr from Aquous Solution 181 Cu, th mtal considrd in this projct, is a widly usd matrial. Coppr mtal contamination xists in aquous wast strams from many industris such as lctronic and lctrical, mtal plating, mining, manufactur of computr hat sinks, Cu plumbing, as wll as biostatic surfac, as a componnt in cramic glazing and glass colouring. Unfortunatly, Cu is a prsistnt, bioaccumulativ and toxic chmical that dos not radily brak down in th nvironmnt and is not asily mtabolizd. It may accumulat in th human or cological food chain through consumption or uptak and may b hazardous to human halth or th nvironmnt. Drinking watr that contains highr than normal lvls of Cu may caus vomiting, diarrha, stomach cramp and nausa. Th chronic ffcts of consumption of high lvls of coppr ar livr and kidny damag. Th suggstd saf lvl of Cu in drinking watr for humans varis dpnding on th sourcs, but tnds to b pggd at 1.5 to 2.0 mg/l. Hnc, rmoval of coppr from watr and wastwatr assums important. Tabl 1 shows th Environmntal Quality Act 1974, Environmntal Quality (Swag and Industrial Efflunts) Rgulations, 1979, in Malaysia with slctd paramtr limits of fflunt of havy mtals. a Tabl 1. Environmntal Quality Act 1974, Environmntal Quality (Swag and Industrial Efflunts) Rgulations, 1979, Malaysia: Slctd paramtr limits of fflunt of Standards A and B (Dpartmnt of Environmnt, DOE, Malaysia). Paramtr, mg/l A a Standard Mrcury 0.005 0.05 Cadmium 0.01 0.02 Arsnic 0.05 0.10 Lad 0.10 0.50 Chromium,trivalnt 0.20 1.0 Coppr 0.20 1.0 Nickl 0.20 1.0 Zinc 1.0 1.0 Iron 1.0 5.0 This standard applis to th industrial and dvlopmnt projcts which ar locatd within th catchmnts aras (aras upstram of surfac or abov subsurfac watr supply intaks, for th purpos of human consumption including drinking). Rspctivly, among th unit oprations in watr and wastwatr tratmnt, adsorption occupis an important position. It is rcommndd that th absorbnt is availabl in larg quantitis, of fr or vry low cost and asily rgnrabl. In th midst of a larg varity of adsorbnt availabl, activatd carbon is th most important and chapst adsorbnt usd in th currnt mthod of pollution control. In Malaysia, th palm oil industry gnrats hug amounts of palm shll. Som of this solid wast is usually usd as ful to produc procss stam and/or lctricity in palm oil mills. Howvr, a larg portion of it is ithr burnd in opn air or dumpd B Journal of Enginring Scinc and Tchnology AUGUST 2008, Vol. 3(2)

182 N. D. Tumin t al in ara adjacnt to th mill, which crats hug nvironmntal and disposal problms. Thrfor, application of palm shll activatd carbon as an adsorbnt offrs highly ffctiv tchnological mans in daling with th havy mtals pollution of th aqua-nvironmnt with th minimum invstmnt rquirmnt. 2. Matrials and Mthod 2.1. Instrumntations Thr quipmnts wr usd in this rsarch: An atomic absorption spctromtr (AAS) with coppr hallow cathod lamp and air actyln flam was usd to dtrmin th coppr concntrations. A ph mtr was usd for ph masurmnt. Th mtr was standardizd using buffr solutions with ph valus: 2 to 8. A mchanical shakr was usd for agitating th sampls. 2.2. Adsorbnts Palm krnl shll (PKS) basd activatd carbon usd as adsorbnt was that of granular form, and th msh siz is listd in Tabl 2. Activatd carbon was that of laboratory grad and was usd dirctly as rcivd from th supplir (KD Tchnology, Malaysia). PKS AC PKS M Particl siz (mm) Tabl 2. Proprtis of PKS Basd Activatd Carbon. S BET (m 2 /g) V micro (cm 3 /g) V mso (cm 3 /g) V total (cm 3 /g) D micro (Å) D mso (Å) Ash contnt 0.25 0.60 1146 0.43 0.12 0.582 5.3 26.1 <5% 2.3. Synthtic fflunt prparation An accurat wight of 1.000 g (±0.0005) CuSO 4 was dissolvd in 1 L of distilld watr to produc th stock solutions of synthtic fflunt. Ths stock solutions wr thn dilutd into th rquird concntrations using distilld watr whnvr ncssary. Evry tim th stock and standard solution hav bn prpard, th solution was shakn for about 2 hours using orbital incubator shakr at 30 C and 100rpm to nsur that ach solution was homognous. 2.4. Exprimntations Batch adsorption xprimnts wr carrid out in a sris of stopprd ragnt bottls. 30 ml of CuSO 4 solution with prdtrmind initial concntration of 10, 20, 30, 40 and 50 mg/l was put insid th 30 ml stopprd ragnt bottls, which containd 0.5 g of activatd carbon. Prior to that, th ph solution was adjustd to th dsird valus by adding HNO 3 or NaOH. Th ragnt bottls with activatd Journal of Enginring Scinc and Tchnology AUGUST 2008, Vol. 3(2)

Adsorption of Coppr from Aquous Solution 183 carbon CuSO 4 mixtur wr shakn using an orbital incubator shakr, which opratd at 100 rpm and 30 o C (±2 o C) for 6 hours to attain th quilibrium condition. Blank solutions wr tratd similarly without th adsorbnt, and th rcordd concntrations at th nd of ach opration wr takn as th initial. Th final concntrations of th solution wr thn dtrmind from a calibration curv. 3. Rsults and Discussion 3.1. Effct of initial ph Th acidity of solution ph is on of th most important paramtrs controlling th uptak of havy mtals from wastwatr and aquous solutions. Th uptak and prcntag rmoval of coppr from th aquous solution ar strongly affctd by th ph of th solution as illustratd in Fig. 1. Th uptak of coppr incrass from 0.11 mg/g to 1.20 mg/g whn th ph incrass from ph 2 to ph 6. Coppr sorption is notd to incras significantly at ph 4 with 0.96 mg/g and 1.07 mg/g adsorption capacity at ph 5 rspctivly. Aftr that th capacity of adsorption dcrass slightly in ph rang of 6 to 9. Th minimum adsorption obsrvd at low ph (ph 2) may b du to th fact that th highr concntration and highr mobility of H + ions prsnt favourd th prfrntial adsorption of hydrogn ions compard to Cu (II) ions [1]. It would b plausibl to suggst that at lowr ph valu, th surfac of th adsorbnt is surroundd by hydronium ions (H + ), thrby prvnting th mtal ions from approaching th binding sits of th sorbnt [2]. This mans that at highr H + concntration, th biosorbnt surfac bcoms mor positivly chargd such that th attraction btwn biomass and mtal cationsis rducd [3]. In contrast, as th ph incrass, mor ngativly chargd surfac bcoms availabl thus facilitating gratr coppr rmoval. It is commonly agrd that th sorption of mtal cations incrass with incrasing ph as th mtal ionic spcis bcom lss stabl in th solution. Q (mg/g) 1.2 1.0 0.8 0.6 0.4 0.2 0 0 2 4 ph 6 8 Fig. 1. Effct of ph on Coppr Adsorption Capacity, Q (mg/g) by 1 g Adsorbnt Mixd in 30 ml of Initial Concntration 50 mg/l, Orbital Shaking of 2 Hours at 100 rpm, Incubatd at 30 ± 2 C. Howvr, at highr ph valus (ph 6, ph 7, ph 8 and ph 9) thr is a dcras in th adsorption capacity. This is du to th occurrnc of coppr prcipitation. At ph 6 thr ar thr spcis prsnt in solution as suggstd by Elliot and Huang. [4], Cu 2+ in vry small quantitis and Cu(OH) + and Cu(OH) 2 in larg quantitis. Thr spcis ar adsorbd at th surfac of adsorbnt by ion xchang mchanism with th functional groups prsnt in adsorbnt or by hydrogn bonding. 10 Journal of Enginring Scinc and Tchnology AUGUST 2008, Vol. 3(2)

184 N. D. Tumin t al 3.2. Effct of adsorbnt dosag Th adsorbnt dosag is anothr important paramtr, which influncs th xtnt of mtal uptak from th solution and thus th ffct as shown in Fig. 2. It was vidnt that th amount of mtal uptak incrass from 0.86 mg/g with 0.5 g adsorbnt up to 1.08 mg/g with 1.0 g adsorbnt. 1.2 1 Q (mg/g) 0.8 0.6 0.4 0.2 0 0 0.5 1 1.5 2 2.5 3 Adsorbnt Dosag (g) Fig. 2. Effct of adsorbnt dosag (g) on coppr adsorption capacity, Q (mg/g) in 30 ml of initial concntration 50 mg/l at ph 5, orbital shaking of 2 hours at 100rpm, incubatd at 30 ± 2 C. Prior to that, it is apparnt that th prcnt rmoval of coppr incrass as th adsorbnt dosag incrass from 0.5 g up to 1.0 g du to th limitd availability of th numbr of adsorbing spcis for a rlativly largr numbr of surfac sits on th adsorbnt at highr dosag of adsorbnt. It is plausibl that with highr dosag of adsorbnt thr would b gratr availability of xchangabl sits from mtal ions [5]. Bsids, Fourst and Roux [6] suggstd that th rduction in adsorbnt dosag in th suspnsion at a givn mtal concntration nhancs th mtal/adsorbnt ratio, and thus incrass th mtal uptak pr unit adsorbnt, as long as th lattr is not saturatd. Similar obsrvation has bn rportd by Mashitah t al [7] for th adsorption of coppr ions onto Pycnoporous sanguinus biomass. Howvr, th adsorption capacity dcrasd sharply with th incrasing of adsorbnt dosag at valu 1.5 g. Th coppr adsorption capacity dcrass gradually at adsorbnt dosag 2.0 g with 0.41mg/g adsorption capacity and at 2.5 g with 0.34 mg/g. Ths rsults may du to th ovrlapping of th adsorption sits as a rsult of ovrcrowding of adsorbnt particls [8]. Morovr, th high adsorbnt dosag could impos a scrning ffct of th dns outr layr of th clls, thrby shilding th binding sits from mtal [9]. Journal of Enginring Scinc and Tchnology AUGUST 2008, Vol. 3(2)

Adsorption of Coppr from Aquous Solution 185 3.3. Effct of initial adsorbat concntration Figur 3 shows that adsorption capacity incrasing from 0.23 to 1.09 mg/g as th mtal concntration incrass from 10 to 50 mg/l. Th trnd is that of th rsult of th progrssiv incras in th lctrostatic intraction btwn th coppr ions and th absorbnt activ sits. Morovr, this can b xplaind by th fact that mor adsorption sits wr bing covrd as th mtal ions concntration incrass [10]. Bsids, highr initial concntrations lad to an incras in th affinity of th coppr ions towards th activ sits [11]. Th dclin in th adsorption capacity is du to th availability of smallr numbr of surfac sits on th adsorbnt for a rlativly largr numbr of adsorbing spcis at highr concntrations [12]. Similar rsults wr obsrvd by Han t al. [13] for th adsorption of coppr (II) and lad (II) on chaff. Q (mg/g) 3.4. Adsorption isothrm Th capacity of th adsorption isothrm is fundamntal, and plays an important rol in th dtrmination of th maximum capacity of adsorption. It also provids a panorama of th cours takn by th systm undr study in a concis form, indicating how fficintly a carbon will adsorb and allows an stimat of th conomic viability of th carbons commrcial applications for th spcifid solut. In ordr to adapt for th considrd systm, an adquat modl that can rproduc th xprimntal rsults obtaind, quations of Langmuir, Frundlich, Rdlich-Ptrson, Toth and Tmkin hav bn considrd. Langmuir modl is th most widly usd isothrm quation, as follows, Q 1.2 1 0.8 0.6 0.4 0.2 0 0 10 20 30 40 50 60 x m K L C ( 1+ ac ) Initial concntration (mg/l) Fig. 3. Effct of Initial Concntration (mg/l) on Coppr Adsorption Capacity, Q (mg/g) by 1 g Adsorbnt Mixd in 30 ml Solution at ph 5, Orbital Shaking of 2 Hours at 100 rpm, Incubatd at 30 ± 2 C. (1) Journal of Enginring Scinc and Tchnology AUGUST 2008, Vol. 3(2)

186 N. D. Tumin t al Frundlich isothrm quation is givn as: Q K C (2) F 1/ n Th Rdlich-Ptrson isothrm is a combination of Langmur-Frundlich modl. It approachs th Frundlich modl at high concntration and is in accord with th low concntration limit of th Langmuir quation. Th quation is givn as: Q k C j (3) 1 β + α L C Th quation of Toth combins th charactristics of Langmuir and Frundlich modl, which can b prsntd as: ac (4) Q / d 1 [ b+ ( C ) ] d Bsids that, th Tmkin isothrm also usd in this study to fit with th xprimntal data, and it can b rprsntd as, Q K ln C K 1 + (5) 2 Th xprimntal data on th ffct of an initial concntration of mtal on th carbon of th tst mdium wr fittd to th isothrm modls and graphical rprsntations of ths modls ar prsntd in Fig. 4. All of th constants ar prsntd in Tabl 3. Q, mg/g 4.5 4 3.5 3 2.5 2 1.5 1 0.5 0 0 0.5 1 1.5 C, mg/l xprimnt Langmuir modl Frundlich modl Rdlich-Ptrson modl Toth modl Tmkin modl Fig. 4. Langmuir Isothrm for Adsorption Procss. Journal of Enginring Scinc and Tchnology AUGUST 2008, Vol. 3(2)

Adsorption of Coppr from Aquous Solution 187 Tabl 3. Th Valu of Paramtrs for Each Isothrm Modl Usd in Th Studis. Isothrm Modl Paramtr R 2 Langmuir Frundlich Rdlich-Ptrson Toth Tmkin K L 14.6454 α3.1192 K f 3.5129 1/n0.4089 k j 15.1699 β0.9757 α L 3.2688 a4.5488 b0.3025 d1.0725 K 1 1.0871 K 2 3.557 0.9371 0.9019 0.9373 0.9373 0.9432 Sinc th valu of R 2 (non linar corrlation cofficint) narr to on indicats that th rspctiv quation bttr fits th xprimntal data. Th rprsntations of th xprimntal data by all modls quation rsults in non-linar curv with R 2 valus of a last 0.9 as tabulatd in Tabl 4. Tmkin isothrm was concludd to b prfrrd modl for th adsorption procss. Th obsrvations confirm th capacity of PKS to adsorb coppr fit: th Tmkin modl fits wll with R 2 valu of 0.9432. Th maximum adsorption capacity obtaind from th tst is 3.9293 mg/g. Th plottd quations obtaind from th graph ar prsntd in Tabl 4 blow. Tabl 4. Th Adsorption Isothrm Equations Usd in th Studis. Isothrm modl Equation Langmuir Frundlich q q q 14.6454C 1+ 3.1192C 0.4089 3.5129C 15.1699C Rdlich-Ptrson 0. 9757 1+ 3.2688C Tmkin q K ln C K 1 + 2 q 4.5488 Toth 1.0725 0. 9324 (0.3025+ C ) 4. Conclusion Th study indicats that activatd carbon prpard from Elais Guinnsis krnl or known as palm krnl shll could b usd as an ffctiv adsorbnt matrial for th tratmnt of coppr aquous wastwatr. Th adsorption of coppr on activatd carbon is found to b ph, initial concntration and dos dpndnt. Th optimum conditions of coppr uptak obtaind from this study ar: ph 5.0, initial Journal of Enginring Scinc and Tchnology AUGUST 2008, Vol. 3(2)

188 N. D. Tumin t al concntration 50 mg/l and biomass loading of 1.0 g. In addition, th corrlation of Tmkin adsorption isothrm fits th xprimntal data most accuratly. It was dtrmind that th maximum adsorption capacity is 3.9293 mg/g. Th matrial (Elais Guinnsis krnl) is not only conomical, but also is an agricultural wast product. Hnc activatd carbon drivd from Elais Guinnsis krnl would b usful for th conomic tratmnt of wastwatr containing coppr mtal. Acknowldgmnt W would lik to thank th Dpartmnt of Chmical Enginring Tchnology, UniKL MICET and th Dpartmnt of Chmical and Environmntal Enginring, Univrsiti Putra Malaysia for providing th rsarch facilitis and constant ncouragmnt; and K.D. Tchnology, Malaysia for th gnrous provision of palm shll activatd carbon for our rsarch. Rfrncs 1. Ajmal, M. Rao, R. A. K. Ahmad, and R. Ahmad (2000). Adsorption studis on Citrus rticulat (fruit pl of orang): rmoval and rcovry of Ni (II) from lctroplating wastwatr. Hazardous Matrials, 79, 117-131. 2. Wong, K. K., L, C. K., Low, K. S. and Haron, M. J. (2003). Rmoval of Cu and Pb by tartaric acid modifid ric husk from aquous Solutions. Chmosphr, 50, 23-28. 3. A. Sad, Muhammd Iqbal, and M. Wahd Akhtar (2004). Rmoval and rcovry of lad (II) from singl and multimtal (Cd, Cu, Ni, Zn) solutions by crop milling wast(black gram husk). Hazardous Matrials, 117, 65-73. 4. H. A. Elliot and C. P. Huang (1981). Watr Rsourcs, 15, 849. 5. Babl, S. and Kurniawan, T. A. (2004). Cr (VI) rmoval from synthtic wastwatr using coconut shll charcoal and commrcial activatd carbon modifid with oxidizing agnts and/or chitosan. Chmosphr. 54, 951-967. 6. Fourst, E. and Roux, J. C. (1992). Havy mtal biosorption by Fungal myclial by-products: Mchanism and Influnc of ph. Applid Microbiology Biotchnology.37, 399-403. 7. Mashitah, M. D., Zulfadhly, Z. and Bhatia, S. (1999). Ability of Pycnoporous sanguinus to rmov coppr ions from aquous solution. Artificial Clls, Blood Substitus and Immobilizd Biotchnology, 27 (5&6), 429-433. 8. Garg, V. K., Gupta, R., Yadav, A. B. and Kumar, R. (2003). Dy rmoval from aquous solution by adsorption on tratd sawdust. Biorsourc Tchnology, 89, 121-124. 9. Pons, M. P. and Fust, C. M. (1993). Uranium uptak by immobilizd clls of Psudomonas strain EPS 5028. Applid Microbiology Biotchnology, 39, 661-665. 10. S. Laraous, A. H. Mniai, and M. Bnchikh Lhocin (2005). Exprimntal study of th rmoval of coppr from aquous solutions by adsorption using sawdust. Dsalination, 185, 483-490. Journal of Enginring Scinc and Tchnology AUGUST 2008, Vol. 3(2)

Adsorption of Coppr from Aquous Solution 189 11. Al-Ashh, R. Banat, Z. Al-Omari, and Duvnjak (2003). Bnficial rus of chickn fathrs in rmoval of havy mtals from wastwatr. Clanr Production. 11, 321-326. 12. Khalid, N., Ahmad, S., Tohd, A. and Ahmd, J. (2000). Potntial of ric husks for antimony rmoval. Applid Radiation and Isotops, 52, 31-38. 13. R. Han, J. Zhang, W. Zou, H. Xiao, J. Shi, and H. Liu (2005). Biosorption of coppr (II) and lad (II) from aquous solution by chaff in a fixd-bd column. Hazardous Matrials, 133, 262-268. Journal of Enginring Scinc and Tchnology AUGUST 2008, Vol. 3(2)