Kinetics of Batch Adsorption of Iron II Ions from Aqueous Solution using Activated Carbon from Nigerian Bamboo

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1 Intrnational Journal of Enginring and Tchnology Volum 3 No. 6, Jun, 2013 Kintics of Batch Adsorption of Iron II Ions from Aquous Solution using Activatd Carbon from Nigrian Bamboo Admiluyi F. T, Ujil A.A Dpartmnt of Chmical/Ptrochmical Enginring. Faculty of Enginring, Rivrs Stat Univrsity of Scinc and Tchnology, Nkpolu, Port Harcourt, Nigria ABSTRACT Kintics of batch adsorption of iron II ions from aquous solution using activatd carbon from wast Nigrian basd Nigrian bamboo was studid. Th bamboo was cut into sizs, washing and drying was carbonizd at 400 o C-500 o C and activatd at 800 o C using nitric acid. Th ffct of procss paramtrs such as particl siz, carbon dosag, initial concntration of adsorbat and contact tim wr also invstigatd and wr found to significantly affct th adsorption capacity. Th adsorption procss obyd th Frundlich, Tmkin and angmuir isothrm modl indicating a monolayr formation ovr th surfac of th matrial. angmuir isothrm had a bttr fit than Frundlich and Tmkin modls with maximum monolayr saturation capacity of mg of iron II ions adsorbd pr g of bamboo activatd carbon. In ordr to dtrmin th mchanism of sorption, kintic data wr modld using th psudo first ordr, psudo scond ordr kintic quations, and intra-particl diffusion modl. Th psudo scond ordr quation was th bst applicabl modl to dscrib th sorption procss. Hnc th psudo scond ordr kintic raction is th rat controlling stp with som intra particl diffusion taking plac. Kywords: Nigrian Bamboo, Activatd Carbon, Iron II ions, Adsorption Isothrm, Kintics. 1. INTRODUCTION Industrial activitis such as tanning, mining, lctroplating, rfining, mtallurgical opration and manufacturing hav ld to th rlas of toxic mtal ions into th nvironmnt. Ths rsultd in havy mtal pollution problms in th co-systm. Toxic mtallic compounds do not only contaminat th watr bodis lik sas, laks rsrvoirs and ponds but can also ntr th undrground watr in tracabl amounts. Unlik th organic pollutants which ar biodgradabl, havy mtals F, Zn, Ni ar not biodgradabl, thus making a sourc of grat concrn. Human halth, agricultural dvlopmnt and th co-systms ar all at risk unlss watr and land systm ar ffctivly managd. Iron xists in two forms which ar th iron (II) and iron (III) stats. As a rsult of th toxicological ffcts of ths mtals, intrst in havy mtal rmoval from wast watr has bn on th ris. Mtals rmoval at low concntration is mor ffctiv via adsorption bcaus of its conomic fasibility [1]. This principl is mainly applicabl for th rmoval of pollutants such as mtal ions, dys and othr organic compounds from wast watrs [2-3]. Admiluyi and David Wst [4] compard th ffctivnss of thr wast matrials (wast Nigrian basd bamboo, coconut shll and palm krnl shll) activatd with diffrnt activating agnts on th rmoval of havy mtals and rportd that bamboo activatd with nitric acid ffctivly rmov zinc ions mor than activatd carbon producd from coconut shll and palm krnl shll. Thr was no invstigation on th ffct of som physio- chmical paramtrs such as particl siz, carbon dosag, initial concntration and contact tim on th adsorption of ths mtal ions on activatd carbon from bamboo. Hnc thr is nd to optimiz and study th kintics of th iron ions rmoval from aquous solution using activatd carbon from bamboo in a batch systm. Thrfor, th objctiv of this work is to study th kintics of th batch adsorption of iron II ions in aquous solution using activatd carbon from Nigrian bamboo. Th ffct of procss paramtrs on th adsorption is also prsntd. 2. MATERIAS AND METHODS 2.1 Matrials Th following matrials and apparatus wr usd for this work: wast Nigria basd bamboo, Nitric acid was usd as activating agnts, A pyrolytic ractor was usd for carbonization of th bamboo with condnsr to condns othr by products of th pyrolysis procss. Othr matrials usd ar dsiccators, crucibls, funnls, and filtr paprs. Two lctronic wighing balanc, Ohaus top loading balanc (+0.01) was usd to wigh th bamboo bfor 623

2 pyrolysis, whil a mor snsitiv lctronic analytical wighing balanc (+0.001, Adams AFP 360) was usd for othr analysis, rtort stand, thrmocoupl with tmpratur snsor, spatula, crushr, sivs, masuring cylindrs, and ptri dishs tc. 2.2 Carbonization Known wights of wast bamboo wr cut into small sizs, washd, and drid as shown in Fig 1. Thy wr carbonizd diffrntly in a pyrolysis ractor at about C for about two hours aftr which th charrd products wr allowd to cool to room tmpratur. Th charrd matrial was crushd and sivd. 2.3 Chmical Activation Th carbonizd wast bamboo, was wighd sparatly and pourd in diffrnt bakrs containing known quantity of trioxonitrat (v) acid. Th bst concntrations of th acid usd for activation wr alrady dtrmind bfor this study. Th contnt of th bakrs was thoroughly mixd until a past was formd. Th past of th sampls wr thn transfrrd to crucibls and wr placd in a Muffl furnac and hatd at 800 C for two hours. Th activatd sampl wr thn coold at room tmpratur, washd with distilld watr to a ph of 6-7, and drid in an ovn at 105 C for thr hours. Th final products wr sivd to diffrnt particl sizs and kpt in an air tight polythyln bags, rady for us. 1g of activatd carbon was masurd and pourd into known amount of th stock iron II salt solution insid th flask. Th adsorption was carrid out for 15mins and filtrd. Th abov procdur was don for 30 minuts, 45 minuts, 60 minuts, 90 minuts, 120 minut till quilibrium was rachd. Th adsorption of iron in aquous solution on bamboo activatd carbon was carrid out by optimizing various physicochmical paramtrs such as particl siz, carbon dosag, initial concntration, contact tim Th amount of iron ions in solution (i.., F 2+ ) was dtrmind using conductomtric mthod from th filtrat aftr adsorption using wast Nigrian basd bamboo. Th work of Tanokkorn t al., rvald that at low concntrations, conductivity is linarly rlatd to th diffrnt mtal ion concntrations so that if just on mtal is prsnt its concntration is radily stablishd through calibration. Hnc a calibration curv of concntration vrsus conductivity was first prpard for iron ions in solution. bfor adsorption. Th amount of iron II ions adsorbd at quilibrium, Q (mg/g) was dtrmind using quation. Q ( Co C m ) V (1) and th prcnt adsorption (%) iron adsorbd computd as follows [7 ]: was Prcnt adsorption (%) = ( C o C) C o x 100 (2) whr C o and C ar th initial and quilibrium concntrations (mg/), V volum of solution (), m th wight of activatd carbon (g) and C th solution concntration at th nd of adsorption 2.6 Isothrms Modling Fig 1. Wast bamboo bfor and aftr carbonization and activation 2.4 Charactrization of Activatd Carbons Th wast Nigrian basd bamboo, wast coconut shll, and wast palm krnl shll usd in this work wr charactrizd (iodin numbr, Mthyln blu numbr, dnsity, tc.), using th ASTM mthods as dscribd in th work of Admiluyi t al. [4]. 2.5 Adsorption iron II ions (F 2+ ) in Aquous Solution on Activatd Carbons from Bamboo Stock solution of iron II solution was prpard by dissolving 1g of iron II salt into 1 litr of distilld watr. Th most commonly usd isothrms in adsorption studis to fit th xprimntal adsorption data wr usd namly: angmuir, Frundlich and Tmkin C Q angmuir isothrms ar usd for dtrmining th isothrmal bhaviours of th adsorption procsss. Th angmuir isothrm is xprssd as [8] 1 (3) K a C K whr Q is th amount of iron ions adsorbd pr unit mass of adsorbnt (mg/g) at quilibrium, C = th quilibrium concntration of th adsorbat (mg/) K = A constant rlatd to th affinity btwn th adsorbnt and th adsorbat 624

3 K / a = Th thortical monolayr saturation capacity Q o Th valus of Q o and K can b dtrmind by plotting C / Q vrsus C On of th most important paramtr of th angmuir isothrm modl is th sparation factor R which is a dimnsionlss factor dfind as [9] R 1 1 a C o whr: C o is th initial adsorbat concntration and a is th angmuir constant rlatd to th nrgy of adsorption. Th valus of R shows th shap of th isothrm to b ithr unfavorabl (R > 1), favorabl (0 < R < 1), linar (R = 1), or irrvrsibl (R = 0). og (4) Th linar form of th Frundlich isothrm is th arlist known rlationship dscribing th adsorption quation and is oftn xprssd as Q 1 og Kf og C (5) n K f = Th Frundlich constant rlatd to th adsorption capacity 1/n= Th Frundlich constant rlatd to th adsorption intnsity whr, Th Tmkin isothrm is also oftn usd to rprsnt th quilibrium adsorptiv bhavior btwn two phass composing th adsorption systm. Th Tmkin isothrm is xprssd as [7]: Q = a + b ln C (6) a, b = Constant rlatd to nrgy and capacity of adsorption 3. KINETIC STUDY Thr kintic modls wr usd in this study to modl th adsorption of iron II ion on bamboo activatd carbon namly: psudo first ordr, psudo scond ordr and th intra particl diffusion modls. Th psudo first ordr considrs th rat of occupation of adsorption sits to b proportional to th numbr of unoccupid sits. ln (Q -Q t ) = ln Q - K t (7) whr, Q is th mass of mtal adsorbd at quilibrium (mg/g), Q t (mg/g) is th mass of mtal adsorbd at tim t and K is th first ordr raction rat constant (/min). A straight lin of ln (Q - Q t) vrss t indicats th application of th first ordr kintic modl. t Q t Th Psudo Scond ordr kintic modl for adsorption of iron is xprssd as [10]: 1 2 k2q t Q Intra -particl diffusion may b th rat dtrmining stp in batch adsorption procss th uptak of adsorbat varis with th squar root of th adsorption tim [9]. so that (8) Q t = k 2 t 0.5 +C (9) A linar plot of Q t vrsus t 0.5 shows that th adsorption mchanism follows intra -particl diffusion and if th intra -particl diffusion is th rat controlling stp if th lin passs through th origin. 4. RESUTS AND DISCUSSION 4.1 Charactrization of activatd Carbon from Bamboo Tabl 1 shows th charactrization of activatd Carbon from Bamboo usd for th adsorption of iron II ions th bulk dnsity, mthyln blu adsorptiv capacity, iodin numbr ( a masur of activity lvl and th micro por contnt of th activatd carbon; highr numbr indicats highr dgr of activation ) ash contnt, compars favorably with rfrncs commrcial activatd carbons. Th work of Admiluyi and David-Wst [2] on ffct of chmical activation on th adsorption of havy mtals using activatd carbons from wast matrials rvald that wast bamboo activatd with HNO 3 can ffctivly b usd to rmov mtal ions from wast strams and in diffrnt mtal rcovry procsss than activatd carbon from coconut shll and palm krnl shlls. 4.2 Effct of Particl Siz on th Batch Adsorption of Iron II ions in Aquous Solution using Activatd Bamboo Carbon Effct of particl siz of activatd carbon producd from wast bamboo on th batch adsorption of iron II ions in aquous solution is prsntd in Fig. 2. Th adsorption of iron II ions incrasd with rduction in particl siz. Th shap rduction also rvald that particl siz of activatd bamboo carbon has significant ffct on th adsorption of iron II ions in aquous solution for batch procss. Fig 2 also shows that smallr particl siz ( 150 m) adsorbd th highst amount of iron II ions within 30 mins of adsorption, hnc for ffctiv adsorption of iron II ions in aquous solution using bamboo activatd 625

4 carbon, th particl siz of th carbon should th within m for ffctiv adsorption for batch procsss. Tabl 1 Charactrization of activatd Carbon from Bamboo S/N Paramtrs Unit ocally Mad GAC Rfrncs activatd Bamboo carbon 1 Bulk Dnsity g/cm ong and Criscion [11] 2 Mthyln Blu adsorptiv capacity mg/g [12] 3 Iodin numbr g of iodin /kg 1, ong and of C. Criscion [11] 4 Ash contnt % <8 Mlcalf and Eddy [13] 4.3 Effct of Carbon Dosag on th Batch Adsorption of Iron II Ions in Aquous Solution Iron II ions in aquous solution of known concntration. was adsorbd using diffrnt carbon dosag of activatd bamboo ranging from 0.1g 1g in 100 ml of stock solution of iron II ions. Th ffct of carbon dosag on th adsorption of iron II ions using activatd carbon from wast bamboo is prsntd in Fig 3 Thr was significant incras in th adsorption of iron II ions in solution) as carbon dosag incrasd within adsorption tim of 30min. Mhmt [14] rportd similar findings during th rmoval of havy mtal adsorption by modifid oak sawdust. This is du to th incrasd availability of activ adsorption sits arising du to th incras in ffctiv surfac ara rsulting from th incrass in dos of adsorbnt or du to conglomration of th adsorbnt. Incrasing th adsorbnt dosag furthr, it was found that th optimum uptak of iron ll ions rquirs about 4g of activatd carbon from bamboo to adsorb 100% iron II ions in aquous stock iron II solution. Fig 3 Effct of carbon dosag on th batch adsorption of Iron(ii) ion using activatd Bamboo Carbon 4.4 Effct of Initial Concntration on th Adsorption of Iron II Ion using Bamboo Activatd Carbon Th ffct of initial concntration of iron II ions on adsorption of iron II ions using bamboo activatd carbon is prsntd in Fig. 4. Adsorption of irons II ions in solution incras significantly with rduction in th initial concntration of iron II ions in solution. Th initial concntration of adsorbat varid from 25mg/ to 200mg/. Th rat of adsorption dcrasd from 98% - 37% as th concntration of iron II ions incrasd from 25mg/ to 200mg/ within 30 mins of adsorption. This was xpctd and shows that thr mor ractiv sits on th por of bamboo activatd carbon. 4.5 Effct of Contact Tim on batch Adsorption of Iron II ions in Aquous Solution Fig 2 Effct of Particl siz on th batch adsorption of Iron (II) ions in aquous using activatd Bamboo Carbon Figur 5 shows th ffct of contact tim on th adsorption of Iron II ions solution using activatd carbon from bamboo. Th concntrations of iron II ions in solution was varid from 25mg/ to 200mg/ and batch adsorption was carrid out with 1g of activatd bamboo. Th prcntag of iron II ions adsorbd incrasd with tim until quilibrium was rachd for ach 626

5 concntrations. It is thrfor vidnt from Fig 5 that at low concntration rangs th prcnt adsorption is high bcaus of th availability of mor ractiv sits. At highr concntration of mtal ion mor and mor surfac sits ar covrd, th capacity of th adsorbnt gt xhaustd du to non-availability of activ surfac sits. This lads to a fall in th prcntag of mtal ion adsorbd at highr concntration. It was obsrvd that th prcntag adsorption of iron (II) ion rapidly rachd quilibrium at 30 minuts of contact for 25mg/ concntration, it incrasd to 100% implid that iron II (F 2+ ) ion was compltly rmovd from aquous solution at this concntration. Fig 4 Effct of initial concntration on th batch adsorption of Iron(ii) ion using activatd Bamboo Carbon Fig 6. Th ratio of th quilibrium concntration to th ratio of th amount of iron adsorbd (C /Q ) was plottd against th quilibrium concntration of iron (C ). Th linarity of th plot shows that angmuir isothrm modl can b usd to prdict th sorption of iron II ions on bamboo activatd carbon Th angmuir plots shows that thr is incras in th rat of adsorption at diffrnt concntrations. This mans that th lssr th concntration of th iron, th highr th adsorption of mtal by th activatd carbon. Th angmuir modl assums that th uptak of mtal ions occurs on a homognous surfac by monolayr adsorption without any intractions btwn adsorbd ions [15]. Th angmuir modl paramtrs and th statistical fits of th adsorption data is prsntd in Tabl 2 and th corrlation cofficint is gratr than 0.89 which rvals' that th isothrm is consistnt with angmuir modl. Th thortical monolayr saturation capacity Q o for iron II adsorption on activatd carbon from bamboo obtaind from th slop of Fig 6 was mg/g of carbon. Similar rsults was obtaind during adsorption of Iron II on Thspsia populna bark activatd carbon by. Prabakaran and Arivoli [15] but with a lowr adsorption capacity Q o of mg/g as shown in Tabl 2. Th sparation factor (R ) was dtrmind from quation 4, th valus wr btwn 0.02 to 0.1 for adsorbat concntrations btwn 200mg/ to 50mg/. Sinc R is lss than 1 for all th concntrations it mans that adsorption procss is favorabl. Prabakaran and Arivoli [15] obtaind sparation factor (R ) of during adsorption of Iron II on Thspsia populna bark activatd carbon for adsorbat concntration btwn 125mg/ to 25mg/. Comparing th adsorption capacity (Q o) of iron II ions on bamboo activatd carbon and with othr rfrnc carbons in Tabl 2 shows that bamboo activatd carbon has vry high affinity for iron II ions Frundlich Adsorption Isothrm for Iron Fig 5 Effct of contact tim on th batch adsorption of Iron (ii) ions using activatd carbon from Bamboo 4.6 Adsorption Isothrm Equilibria angmuir Adsorption Isothrm for Iron Th angmuir adsorption isothrm for th adsorption of iron II ions on bamboo activatd carbon is prsntd in Fig 7 shows th batch adsorption isothrm of iron ions on bamboo activatd carbon at 30 o C. Th log of Q amount of iron adsorbd at quilibrium was plottd against th log of th quilibrium concntration C of th mtal ion adsorbd. Th adsorption capacity K f and th adsorption intnsity 1/n ar obtaind dirctly from th slops and intrcpts of th linar plot. Th linarity of th plot and high corrlation cofficint obtaind (0.992) which is also gratr than 0.89 rvals that th isothrm is consistnt with Frundlich modl. Atf [8] rportd that gratr than 0.89 shows that th adsorption data conforms with th modl. Th valu of adsorption intnsity (n = 2.3) is mor than on for bamboo activatd carbon, indicating th adsorption iron ion using 627

6 bamboo activatd carbon. is mor of chmisorptions than physical adsorption [16] 4.7 Adsorption Kintic Modls Figurs 9, 10 and 11 shows th kintic plots for th adsorption of iron II ions on activatd carbon from Bamboo using th psudo first ordr, psudo scond ordr and th intra particl diffusion modls at diffrnt concntrations. Th linarity of th thr plot shows that th adsorption mchanism is not only takn plac at surfac but combind with diffusion and chmisorption. Fig 6. angmuir adsorption isothrm for batch adsorption of iron II ions on bamboo activatd carbon at 30 o C Fig 8 Tmkin adsorption isothrm for batch adsorption of iron ions on bamboo activatd carbon at 30 o C Fig 7 Frundlich adsorption isothrm for batch adsorption of iron ions on bamboo activatd carbon at 30 o C Tmkin Adsorption Isothrm Modl for Iron Ions A linar rlationship was also xhibitd from th plot of amount of iron adsorbd (Q ) at quilibrium against th natural logarithm of quilibrium concntration of iron (In C ). Similarly th corrlation cofficint (0.966) obtaind for Tmkin adsorption isothrm modl for iron ions in Fig 8 and Tabl 2 shows that th Tmkin modl can also b usd to prdict th sorption of iron II ions using bamboo activatd carbon. Fig 9 Psudo first ordr kintic plot for th batch adsorption of iron ions at diffrnt concntrations of adsorbat at 30 o C Figurs 9, 10 and 11 also rvald th concntration of adsorbat affctd th adsorption and diffusion procss gratly sinc th slop and intrcpt ar not th sam at th diffrnt concntrations. Th psudo scond ordr kintic modl gav a highr corrlation cofficint than th psudo first ordr and th intra particl diffusion modls as shown in Tabl

7 Though a linar plot of Q t vrsus t 0.5 in Fig 11 shows that th adsorption mchanism follows intra -particl diffusion and if th intra -particl diffusion is th rat controlling stp, th lin of th plot in Fig 11 will pass through th origin. Th valus obtaind from th intrcpt (-5.855, , and 0.499) of th intra particl diffusion kintic modl at diffrnt adsorbat concntrations ar not th sam as shown in Fig 11 and did not pass through th origin which indicatd intra -particl diffusion is not th rat controlling stp. Thus psudo scond ordr kintic is th rat controlling stp. Also th valus of th intrcpt of Fig 11 at th diffrnt concntrations givs an ida of th thicknss of th boundary layr, th largr th intrcpt th thickr th boundary layr ffct [18]. Th valus obtaind from th intrcpt from Fig 11 at low adsorbat concntration (< 150mg/) was , and ar insignificant. At highr adsorbat concntration 200mg/ th intrcpt was small (0.499), which rvald that th boundary latr will not b thick. Hnc th psudo scond ordr kintic raction is th rat controlling stp with som intra particl diffusion taking plac. Fig 10 Psudo scond ordr kintic plot for th batch adsorption of iron ions at diffrnt concntrations of adsorbat at 30 o C Fig 11 Intra particl diffusion kintic modl plot for th batch adsorption of iron ions at diffrnt concntrations of adsorbat at 30 o C 5. CONCUSION Kintics of batch adsorption of iron II ions from aquous solution using activatd carbon from wast Nigrian basd bamboo has bn invstigatd. Th amount of iron II ions adsorbd was found to vary significantly with procss paramtrs such as particl siz, carbon dosag, initial concntration of adsorbat and contact tim. Th adsorption procss follows angmuir, Frundlich and Tmkin isothrms but a bttr sorption fit using angmuir isothrm modl was obtaind indicating a monolayr formation ovr a surfac of th matrial. Th monolayr saturation capacity of mg of iron II ions adsorbd pr g of bamboo activatd carbon was obtaind and found to b highr than monolayr saturation capacity of othr adsorbnt usd for iron II ions adsorption. Adsorption kintics was modlld using th psudo first ordr, psudo scond ordr kintic quations, and intra-particl diffusion modls. sorption kintics showd good agrmnt of th xprimntal data Th psudo scond ordr kintic raction is th rat controlling stp with som intra particl diffusion taking plac. Th high adsorption intnsity of bamboo activatd carbon and its affinity for Iron II ions can hlp solv many adsorption challngs in th industry and in watr purification procsss. Tabl 2 Isothrm modls and thir constant valus for adsorption of Iron from aquous solution using activatd carbons from bamboo Isothrms/Constants Activatd carbon from Prsnt study Bamboo Thspsia bark [15] Rfrnc activatd carbon Wild Jack bark [17 ] Jambul bark [17] 629

8 angmuir q max (mg/g) K (/mg) Frundlich n K f tmkin b a , N A N A N A N A N A Tabl 3 Kintic paramtrs for th batch adsorption of iron ions at diffrnt concntrations of adsorbat at 30 o C psudo first ordr Q (mg/g) K 2 Kintic Modl 100mg/ 150mg/ 200mg/ Psudo scond ordr Q K 2 Intra particl diffusion K 2 C , REFERENCES [1] Sursh Guptaa, and B. V. Babu Economic fasibility analysis of low cost adsorbnts for th rmoval of Cr(VI) from wastwatr Availabl: is [Accssd 17th April 2013] [2] Ngah W.S.W, Endud C.S, Mayanar R. (2002) Rmoval of coppr(ii) ions from aquous solution onto chitosan and cross-linkd chitosan bads Ract. Funct. Polym. 50, [3] Kith K.H.C, Gordon M. (2005) Sorption of cadmium, coppr, and zinc ions onto bonc char using Crank diffusion modl Chmosphr 60, [4] Admiluyi F.T, David Wst E.O (2012) Effct of Chmical activation on th adsorption of havy mtals using activatd carbons from wast matrials ISRN Chmical Enginring, DOI: /2012/ [5] Admiluyi F.T; Rhoda Gumus; Adniji S.M; & Jasm, O I (2009) Effct of Procss Conditions on th Charactrization of Activatd Carbon from Wast Nigrian Bamboo. Journal of Nigrian Socity of Chmical Enginrs 24, 1 & 2, [6] Banjonglaiad, Eric Croist, Ptr Silvston, Ptr. Douglas, Supaporn Douglas, Wittaya Tppaitoon and Suwassa Pongampha (2008) Dynamic Masurmnt of Coppr (II) Ion Adsorption in Activatd Carbon Fixd Bd Columns, Amrican Journal of Environmntal Scincs 4 (4): , [7] Surya Narayan Dash, Ramachandra Murthy.(2010) Prparation of Carbonacous Havy Mtal Adsorbnt from Shora Robusta af ittr Using Phosphoric Acid Imprgnation Intrnational journal of nvironmntal scincs 1, (3) [8] Atf Alzaydin (2009) Adsorption of Mthyln blu from aquous solution onto a low cost Natural Jordanian Tripoli Amrican journal of Environmntal Scincs 5 (3) [9] Wbr T. W and Chatravorti R.K (1974) Por and solid diffusion modls for fixd bd adsorbrs journal of Amrican Institut of Chmical Enginring 20 :

9 [10] Ho Y,S and Mckay G (1999) Psudo scond ordr modl for sorption procss rocss Biochmistry 34, [11] ong J. C,;Criscion J. M. (2003) Carbon Survy. Publishd Onlin: DOI: / [12] Activatd carbon (2012) Availabl : Accssd: Sptmbr 27th 2012 [13] Mtcalf and Eddy (2003). Wastwatr Enginring, Tratmnt and R-us. John Wily 6th Ed [14] Mhmt. E. A (2007). Havy mtal adsorption by modifid oak sawdust: Thrmodynamics and kintics. Journal of Hazardous Matrials [15] Prabakaran R. and S. Arivoli (2011) Biosorption of Frrous Ion from Aquous Solutions by using Activatd carbon prpard from Thspsia Populna Bark Archivs of Applid Scinc Rsarch,, 3 (6): [16] Arivoli S, Vnkatraman B. R, Rajachandraskar T, Hma M (2007). Rs J Chm Environ.17, [17] Priya Ros. E and Shamla Rajam (2012) Equilibrium study of th adsorption of iron (II) ions from aquous solution on carbons from wild jack and jambul Advancs in Applid Scinc Rsarch,, 3 (2): [18] Kannan N, and M, Sundaram (2001) kintic mchanism of rmoval of mthyln blu by adsorption on various carbons Dy pigmnts 51: