Chemistry and Materials Research ISSN (Print) ISSN (Online) Vol.7 No.5, 2015

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1 Chmisry and Marials Rsarch ISSN 4-34 (Prin) ISSN (Onlin) Vol.7 No.5, 5 Rmoval o Phnol rom Pain Waswar by Adsorpion ono Phosphoric Acid Acivad Carbon Producd rom Coconu Shll: Isohrmal and Kinic Modlling Sudis G. K. Lainwo and S. E. Agarry * Dparmn o Chmical Enginring, Biochmical Enginring and Chmical Enginring Biochnology Laboraory, Ladok Akinola Univrsiy o Tchnology, P. M. B. 4, Ogbomoso, Nigria. * Corrsponding auhor sam_agarry@yahoo.com Absrac Th asibiliy o using phosphoric acid acivad carbon producd rom coconu shll o rmov phnol rom pain waswar undr bach mod was invsigad. Th rsuls showd ha adsorpion o phnol was conac im, adsorbn paricl siz and adsorbn dosag dpndn. Th bach quilibrium adsorpion daa wr analyzd by wo-paramr adsorpion isohrm modls o Langmuir and Frundlich using h linar rgrssion mhod. Boh isohrm modls id vry wll o h quilibrium adsorpion daa, howvr, h Frundlich isohrm quaion providd h bs modl o dscrib h adsorpion o phnol ono coconu shll acivad carbon. Adsorpion capaciy ( K ) o. mg/g and adsorpion innsiy ( n ) o.7 was obaind or granular coconu shll acivad carbon and corrsponding 3.63 mg/g and.55 or powdrd coconu shll acivad carbon a 3 o C. Th adsorpion kinic daa wr id o hr adsorpion kinic modls (psudo irs-ordr, psudo scond-ordr and inra-paricl diusion) using h linar rgrssion mhod. Th hr kinic modls id wll o h adsorpion kinic daa; howvr, h psudo scond-ordr kinic modl gav h bs i and h adsorpion mchanism was conrolld by ilm diusion. Thus, phosphoric acid acivad carbon producd rom coconu shll has h ponial or applicaion as an civ adsorbn or phnol rmoval rom waswar. Kywords: Acivad carbon; Adsorpion isohrms; Adsorpion kinics; coconu shll; pain waswars.. Inroducion Th vr incrasing dmand or war has causd considrabl anion o b ocusd owards rcovry and r-us o was wars (Annadurai al., ). Mor han wo housand chmical conaminans hav bn ound in was wars and ovr 6 ar o organic origin (Annadurai al., ). Eluns o pain manuacuring company (PMW) conain highly oxic compounds and organic biorracory compounds such as phnol (Akyol, ). Phnol is a lisd prioriy polluan by h U.S. Environmnal Procion Agncy (EPA, 979) and is considrd o b a oxic compound by h Agncy or Toxic subsancs and Disas Rgisry (ATSDR, 3). Th advrs cs o phnol on halh ar wll documnd (Calabrs and Knyon, 99) and dah among aduls has bn rpord wih ingsion o phnol ranging rom o 3g (Prpich and Daugulis, 5). Th low volailiy o phnol and is ainiy or war mak oral consumpion o conaminad war h gras risk o humans (Prpich and Daugulis, 5). Gnrally, pain waswars hav advrs cs on human halh. I usd in closd aras, is chmical componns can irria ys, skin and lungs and causs hadachs and nausa. I can also conribu o rspiraory problms; muscl waknss, livr and kidny damag (Akyol, ). Thror, rmoving phnols rom waswars is imporan prior o discharging waswar ino h nvironmn. Consqunly, many ramn procsss hav bn applid or h rmoval o phnols rom was wars. Som o hs procsss includ: adsorpion (Tan al., 9; Hamad al., ), phoo-nn dgradaion (Poulopoulos al., 8), caalyic w oxidaion (Chaliha and Bhaacharyya, 8), phoocaalyic dgradaion (Laouiy al., 8; Dvipriya and Ysodharan, ), and biodgradaion (Agarry al., 8; ElKarmi al., 9). Liquid-phas adsorpion has bn shown o b an civ way or rmoving suspndd solids, odors, organic mar, and oil rom aquous soluions (Annadurai al., ). Acivad carbon is mos widly usd as adsorbn in h rmoval o havy mals, hydrocarbons and ohr hazardous chmicals (Hamd, 9) which may b ound in was wars bcaus o is high adsorpiv capaciy, bu is high cos and diiculy in rgnraion limis is commrcial applicaion in larg-scal was war ramn (Popuri al., 7). Mos o h aciv carbon is black powdr or granular amorphous carbon. In addiion o is main componn carbon, i also conains oxygn, hydrogn and ohr lmns. Acivad carbon has larg spciic surac ara and good adsorpion characrisics (Zhang al., ). Adsorpion on acivad carbon is on o 3

2 Chmisry and Marials Rsarch ISSN 4-34 (Prin) ISSN (Onlin) Vol.7 No.5, 5 h mos icin chniqus usd in war ramn procss or h rmoval o organics and micro polluans rom wass and drinking wars (Abassi and Sr, 999). Acivad carbon has bn rpord o hav high and as adsorpion capaciis (Chaiwaananon al., 998) du o is wll dvlopd porous srucur, high surac ara and high dgr o surac raciviy (Ozcan and Ozcan, 5). Howvr, bcaus o high cos o commrcial acivad carbon, is us in h ild is somims rsricd on conomical considraions spcially in dvloping counris lik Nigria. As such, amps hav bn mad by dirn rsarchrs in rcn yars o dvlop acivad carbons rom prrably low cos marials such as indusrial wass as wll as naural agriculural by-producs (baggas, palm da pis, palm shll, coconu husk, rubbr sd pricarp, acanhaca, priwinkl shll, bamboo) which ar ubiquious grn was in h nvironmn or h rmoval o polluans rom was wars (Siricho al., ; Vinod and Anirudhan, ; Mohammd al., 5; Badmus al., 7; Hamad al., ; Hussain al., ; Agarry and Owabor, ). Th characrisics o agriculural plan marials, such as polar and aromaic componns, impos a signiican inlunc on hir sorpiv bhavior (Chn and Schnoor, 9). Mor and mor inrss ar ocusd on dvloping hs agriculural wass as adsorbn or waswar ramn du o hir rlaiv high sorpion ainiy, ubiquious prsnc in h nvironmn, and h as o bing modiid o marials wih highr icincy (Li al., ; Chn al., ; Agarry and Armu, ). Thror, ors ar sill ndd o produc acivad carbon rom low cos adsorbns ha hav high adsorpion capaciy. Coconu palm (Cocos nucira) is a mmbr o h Arcaca amily (palm amily). Th coconu palm is grown hroughou h ropics. I susains h livlihood o millions o popl in coasal rgions o h ropical world (Hamd al., 8). I is on o h mos imporan crops in Nigria and hus, a larg amoun o coconu shlls ar gnrad annually which has no signiican indusrial and commrcial uss, bu bcoms an issu and conribus o srious nvironmnal problms. Thror, any amp o ruiliz his was will b usul as i will hlp in rducing nvironmnal wasag. Howvr, hr is a darh o inormaion on h us o coconu shll acivad carbon in h rmoval o phnol as organic polluan rom raw pain waswar using h adsorpion chnology. Mos o h inormaion in liraur rpord h rmoval o phnol rom simulad or synhic phnol aquous soluion (Namasivayam and Kaviha, 4; Sahishkumar al., 9; Ma al., ; Hamad al., ). Thus, his sudy was undrakn o prpar acivad carbon rom coconu shll using phosphoric acid as h acivaing agn o rmov phnol rom raw pain waswars. Th adsorpion isohrms and kinics o phnol rmoval uno h coconu shll-drivd acivad carbon was obaind.. Marials and Mhods. Sampl Collcion Pain waswars wr obaind rom wo dirn pain indusris locad in Lagos o Nigria. Coconu shlls wr obaind rom Ogbomoso mark in Nigria.. Carbonizaion o Coconu Shll and Is Chmical Acivaion Th saring raw marial, coconu shll (agriculural by-produc) was sun drid and crushd ino small chips (< mm and > mm paricl sizs) prior o carbonizaion procss. I was hn placd in a sainlss sl conainr wih a covr and pu in a urnac. Th sampl was had a 4 C or a priod o 3 h. Ar h pyrolysis, h pyrolysd sampl (rsidual char) was allowd o cool and washd wih dionizd war o rmov any l impuriis. Th washd rsidual char was drid in an ovn a C or h. Th nx sp was h chmical acivaion. This was don by mixing l g o h rsidual charcoal wih ml o phosphoric acid (H 3 PO 4 ) and l or 48 h. Ar dcanaion, h sampl was pyrolysd a 5 C or 3 h in a urnac. Th obaind acivad carbon was allowd o cool and hn washd wih poassium hydroxid (KOH) and dionizd war. I was hn drid in an ovn a C or 3 h. Chmical acivaion o h carbonizd coconu shll was rpad a acivaion mpraur o 6, 7, 8, 9 and o C, rspcivly. Th acivad carbons hus obaind wr inally smoohnd, sord in wll-id airigh corkd bols and proprly labld bor bing characrizd..3 Characrizaion o Coconu Shll-Drivd Acivad Carbon Th coconu shll-drivd acivad carbon was characrizd or spciic surac ara, iodin numbr and uncional groups. Th spciic surac ara o h adsorbn was drmind using mhyln blu (MB) sorpion mhod (Unnihan al., ; Agarry al., 3a). Mhyln blu aquous soluions, in h concnraion rang o o 5 mg/l, wr allowd o agia wih g o adsorbn ill h aainmn o quilibrium. Th concnraion o MB soluions was drmind a 664 nm. Th adsorpion isohrm daa ha wr obaind was usd o calcula spciic surac ara using Eq. (): 4

3 Chmisry and Marials Rsarch ISSN 4-34 (Prin) ISSN (Onlin) Vol.7 No.5, 5 N A S = ( M 5 ) Am () A is h spciic surac ara (m /g); Whr S M is h amoun o MB (in µmol) adsorbd pr g o h biosorbn whn h surac is complly covrd wih a monolayr o MB; N is h Avogadro numbr, and A m, is h cross-scional ara pr molcul on h surac (3 A ). Th valu o M was obaind by xrapolaing h isohrm o h q and hus akn as poin o monolayr covrag. Th coconu shll-drivd acivad carbon was characrizd or surac uncional groups by Fourir Transorm Inra Rd Spcroscopy (FT-IR) mhod using a Prkin Elmr inrard spcromr. Th spcrum o h biosorbn was rcordd in 4 4 cm. Th carbonacous adsorbns wr characrizd or iodin numbr in accordanc wih ASTM (995). Th iodin numbr givs an indicaion o h adsorpion capaciy o acivad carbon in microspors (ha is, an indicaion o porosiy) (Rngaraj al., ). For h drminaion o iodin numbr,. g o h sampl was akn ino a 5 ml conical lask. Abou ml.5 M iodin soluion in aquous poassium iodid was addd ino h lask. Ar h, h solid mass was sparad by cnriuging h mixur and h rsidual iodin in soluion was irad using. M sodium hiosulpha soluion. Th iodin numbr was calculad as mg o iodin adsorbd by on gram o acivad carbon. Th sampls o carbonacous adsorbn wr sd or ph by sirring wih dionizd war or h and l or 4 h ar which h ph o h war was akn..4 Bach Adsorpion Equilibrium Sudis Th bach adsorpion ss wr carrid ou in a glass-sopprd 5 ml Erlnmyr conical lask wih ml o working volum and an iniial phnol concnraion o 35 mg/l prsn in h pain waswar having a ph o 6. A wighd amoun (.5 g) o granular adsorbn was addd o h soluion. Th lasks wr agiad a a consan spd o 5 rpm or 8 min in a mpraur conrolld war bah shakr a 3 o C. Sampls wr collcd rom h lasks a prdrmind im inrvals or analyzing h rsidual phnol concnraion in h waswar. Prior o analysis, sampls wr cnriugd o spara adsorbn rom h adsorba and minimiz inrrncs. Th rsidual phnol concnraions wr drmind using UV-spcrophoomr a an absorbanc wavlngh o 34 nm. Th procdur was rpad or granular adsorbn dos o.,.5, 5., g and powdrd adsorbn dos o.5,.,.5, 5. and g, rspcivly. Th amoun o adsorpion a quilibrium, q (mg/g) was calculad according o Eq. () (Crisaully al., 8): Whr Co and ( Co C ) V q = () W C (mg/l) ar h iniial and inal (quilibrium) concnraions o phnol in was war. V (ml) is h volum o h was war and W (g) is h mass o dry adsorbn usd..5 Bach Kinic Sudis Th procdurs or kinic sudis wr basically idnical o hos o bach quilibrium sudis. Th amoun o phnol adsorbd a im, q was calculad according o Eq. (3) (Xun al., 7): Whr ( Co C ) V q = (3) W C is h concnraion o phnol in was war a im,. Whr h prcnag o phnol rmoval was calculad using Eq. (4) (Hamad al., ):.6 Adsorpion Isohrms C C o Rmoval (%) = C o An adsorpion isohrm rprsns h quilibrium rlaionship bwn h adsorba concnraion in h liquid phas and ha on h adsorbn surac a a givn condiion. A numbr o isohrms hav bn dvlopd o dscrib quilibrium rlaionships. In h prsn sudy, Langmuir and Frundlich modls wr usd o dscrib h quilibrium daa. (4) 5

4 Chmisry and Marials Rsarch ISSN 4-34 (Prin) ISSN (Onlin) Vol.7 No.5, 5 Whr Th Langmuir isohrm modl (Langmuir, 98) is givn in Eq. (5): q QmaxaC = + ac Qmaxand a ar isohrm consans. Langmuir consan ( Q max (5) ) is a masur o h amoun o adsorba sorbd pr uni wigh o adsorbn, whn sauraion is aaind. Langmuir consan ( a ) is rlad o nrgy o adsorpion (i.. ainiy o h binding sis). Whr Qmax and a can b drmind rom h linar plo o q vs. C. Langmuir quaion is valid or monolayr sorpion uno a surac wih a ini numbr o idnical sis which ar homognously disribud ovr h sorbn surac (Popuri al., 7). Th basic assumpion o Langmuir modl is ha sorpion aks plac a spciic sis wihin h adsorbn. Thorically, hror, a sauraion valu is rachd byond which no urhr sorpion can ak plac. Th Frundlich isohrm modl (Frundlich, 96) is givn in Eq. (6): q = K C (6) / n Whr K and n ar Frundlich consans. K is roughly an indicaor o h adsorpion capaciy (mg/g) and n is h adsorpion innsiy. Th Frundlich isohrm is usd or non-idal adsorpion on hrognous surac nrgy sysms (Annadurai al., ). I suggss ha binding sis ar no quivaln and/or indpndn. Whr, K and / n can b drmind rom h linar plo o logq vs. log C..7 Adsorpion Kinics Modlling In ordr o analyz h ra o adsorpion and possibl adsorpion mchanism o phnol ono granular and powdrd coconu shll-drivd acivad carbon, h Lagrgrn psudo irs- ordr (Lagrgrn, 898), psudo scond-ordr (Ho and Mckay, ) and inraparicl diusion (Wbr and Morris, 963) wr applid o adsorpion daa. Th Lagrgrn psudo irs-ordr kinic modl quaion (Lagrgrn, 898; Mckay and Ho, 999) is rprsnd in an ingral orm as givn in Eq. (7): ln( q q ) = ln q k (7) Whr, q is h calculad maximum quilibrium adsorpion capaciy (mg/g) and k is h adsorpion ra consan (min - ). Th valus o q and k wr calculad rom h slop and inrcp o h linar plos o ln( q q ) vs. Th psudo-scond- ordr kinic modl which is basd on h assumpion ha chmisorpion is h ra-drmining sp and can b xprssd as: q = k q + q Whr k is h ra consan o scond ordr biosorpion (g/mg/min). Th iniial adsorpion ra, h (mg g - min - ) is rprsnd as in Eq. (9) (Sari al., ): h = k ad q (9) vs. or granular and powdrd coconu shll- Valus o k and q wr calculad rom h plos o drivd acivad carbon. (): Whr q (8) Th Wbr and Morris (963) inra paricl diusion kinic modl can b wrin as prsnd in Eq. / q = K p + C K p is h inra paricl diusion ra consan (mg/g min -½ ) and C is h inrcp. () 6

5 Chmisry and Marials Rsarch ISSN 4-34 (Prin) ISSN (Onlin) Vol.7 No.5, 5 Th inrcp o h plo rlcs h boundary layr c. Largr h inrcp, grar is h conribuion o h surac sorpion in h ra conrolling sp. Inra paricl diusion is h sol ra-limiing sp i h rgrssion / o q vs. is linar and passs hrough h origin (Wbr and Morris, 963; Agarry al., 3a, 3b). 3. Rsuls 3. Characrizaion o Coconu Shll Acivad Carbon FT-IR spcrum o coconu shll acivad carbons wr obaind in ordr o idniy h uncional groups lik -OH, -CO, -CHO, N-H, - CONH, -C=C- and -COOH prsn in hm ha can b involvd in bonding wih phnol during adsorpion. Th FTIR Analysis rsul (Tabl ) shows h ransmianc spcra o h coconu shll, granular coconu shll acivad carbon, and powdrd coconu shll acivad carbon. Tabl. FTIR spcrum lucidaion o coconu shll (CS), granular coconu shll acivad carbon (GCSAC) and powdrd coconu shll acivad carbon (PCSAC) Wavlngh Rang (cm - ) Absorpion pak numbr (cm - ) or CS Absorpion pak numbr (cm - ) or Absorpion pak numbr (cm - ) or Suspcd uncional groups GCSAC PCSAC OH groups CH srching C=O srch COOH and C=C srch (alkns), NH dormaion, NH dormaion C-H bnd, C-O, C-N, and OH, COOH) and amid group (N-H bnding), CH dormaion C-O (alcohol), C- N srch (nirils), C-H bnding (alkans), PO 3-4 srching Th valus o h spciic surac ara, iodin numbr, bulk dnsiy, ash conn and moisur conn obaind or h granular and powdrd coconu shll acivad carbons ar prsnd in Tabl. Tabl : Characrizaion o coconu shll carbon acivad a 9 and o C Paricl siz Acivaion mpraur ( o C) Bulk dnsiy (g/cm 3 ) Ash conn (%) Granular coconu shll carbon Powdrd coconu shll carbon Granular coconu shll carbon Powdrd coconu shll carbon Iodin numbr (m /g) Spciic surac ara (m /g)

6 Chmisry and Marials Rsarch ISSN 4-34 (Prin) ISSN (Onlin) Vol.7 No.5, Ec o Tmpraur on Carbon Yild Fig. shows h c o acivaion mpraur on h yild o carbon rom coconu shll o dirn paricl siz (> mm and < mm) Yild o Carbon (g) Carbonizaion Tmpraur ( o C) Powdrd coconu shll (< mm) Granular coconu shll (> mm) Fig. : Ec o mpraur on h yild o carbon rom coconu shll 3.3 Ec o Adsorbn Paricl Siz Rsul or h c o adsorbn paricl siz on h adsorpion o phnol by coconu shll-drivd acivad carbon is as shown in Fig Adsorpion Capaciy (mg/g) % Phnol Rmoval 3.8 Powdrd Coconu Shll Carbon Granular Coconu Shll Carbon 94 Adsorpion Capaciy Phnol Rmoval Fig. : Ec o adsorbn paricl siz (granular and powdrd coconu shll acivad carbon) on phnol adsorpion 3.4 Ec o Adsorbn Dosag In his sudy, iv dirn adsorbn dosags wr slcd ranging rom.5 o g whil h phnol concnraions prsn in h pain waswar is 35 mg/l. Th rsuls ar prsnd in Fig. 3. 8

7 Chmisry and Marials Rsarch ISSN 4-34 (Prin) ISSN (Onlin) Vol.7 No.5, 5 Adsorpion Capaciy (mg/g) (a) Granular coconu shll acivad carbon % Phnol Rmoval Adsorpion Capaciy (mg/g) (b) Powdrd coconu shll acivad carbon % Phnol Rmoval Adsorbn Dosag (g) Adsorbn Dosag (g) Adsorpion Capaciy 88 Adsorpion Capaciy Phnol Rmoval Phnol Rmoval Fig. 3: Ec o adsorbn dosag on phnol adsorpion by (a) granular coconu shll acivad carbon, (b) powdrd coconu shll acivad carbon 3.5 Adsorpion Isohrms Th isohrm plos o Langmuir and Frundlich or granular and powdrd coconu shll acivad carbon ar prsnd in Fig. 4 and h simad isohrm consans rom h plo ar prsnd in Tabl 3. /q (a) Granular coconu shll acivad carbon /q 4 3 (b) Powdrd coconu shll acivad carbon 3 4 /C Exprimnal Daa /C Langmuir Isohrm Exprimnal Daa Langmuir Isohrm 9

8 Chmisry and Marials Rsarch ISSN 4-34 (Prin) ISSN (Onlin) Vol.7 No.5, 5 Log q (c) Granular coconu shll acivad carbon Log C Log q (d) Powdrd coconu shll acivad carbon Log C.5 - Exprimnal Daa Frundlich Isohrm Exprimnal Daa Frundlich Isohrm Fig. 4: Langmuir isohrm modl id o h phnol quilibrium adsorpion daa or (a) granular coconu shlldrivd acivad carbon, (b) powdrd coconu shll-drivd acivad carbon. Frundlich isohrm modl id o h phnol quilibrium adsorpion daa or (c) granular coconu shll acivad carbon, (d) powdrd coconu shll acivad carbon. Tabl 3. Adsorpion isohrm paramrs and corrlaion coicins obaind or phnol adsorpion by coconu shll acivad carbon Isohrm modls Granular coconu shll acivad carbon Langmuir q (mg/g) max a (L/mg) R Frundlich K (mg/g)(l/mg) n.7.55 R Adsorpion Kinics Modlling Powdrd coconu shll acivad carbon Th plos o id psudo irs-ordr, psudo scond-ordr and inra-paricl diusion kinic modls o h adsorpion kinic daa ar prsnd in Fig. 5 whil h simad consans o hs modls ar givn Tabl 4. ln (q - q ) 5-5 (a) Granular coconu shll acivad carbon 5 5 (min) Exprimnal Daa Psudo Firs-Ordr Kinics ln (q - q ) (b) Powdrd coconu shll acivad carbon (min) Exprimnal Daa Psudo Firs-Ordr Kinics 3

9 Chmisry and Marials Rsarch ISSN 4-34 (Prin) ISSN (Onlin) Vol.7 No.5, 5 /q 3 (c) Granular coconu shll acivad carbon 5 5 (min) /q 3 (d) Powdrd coconu shll acivad carbon 5 5 (min) Exprimnal Daa Psudo Scond-Ordr Kinics Exprimnal Daa Psudo Scond-Ordr Kinics () Granular coconu shll acivad carbon () Powdrd coconu shll acivad carbon.8 q (mg/g) q (mg/g) (min).5 (min) Exprimnal Daa Exprimnal Daa Inraparicl Diusion Inraparicl Diusion Fig. 5: Psudo irs-ordr kinics id o phnol adsorpion kinic daa o (a) granular coconu shll-drivd acivad carbon, (b) powdrd coconu shll-drivd acivad carbon. Psudo scond-ordr kinics id o phnol adsorpion kinic daa o (c) granular coconu shll-drivd acivad carbon, (d) powdrd coconu shll-drivd acivad carbon. Inra-paricl diusion modl id o phnol adsorpion kinic daa o () granular coconu shll-drivd acivad carbon; () powdrd coconu shll-drivd acivad carbon. 3

10 Chmisry and Marials Rsarch ISSN 4-34 (Prin) ISSN (Onlin) Vol.7 No.5, 5 Tabl 4. Psudo irs-ordr, psudo scond-ordr and inra-paricl diusion kinic consans and corrlaion coicins obaind or phnol adsorpion by coconu shll acivad carbon Kinic modls GCSAC PCSAC Psudo irs-ordr k (min - ) q (ho.) (mg/g)..3 q (xp) (mg/g) R Psudo scond-ordr k (g/(mg.min)) q (ho.) (mg/g) h (mg g - min - ) R Inra-paricl diusion K (mg/(g min.5 )) p C R Discussion From Tabl, coconu shll spcra s vibraions shows ha i may hav h prsnc o phnols or monomric alcohols du o h wav numbrs corrsponding o cm -. I also has paks around h rang o 6 cm - o cm -, which migh lad o h xisnc o alkns, alkans, amins and niro compounds. Srong srching vibraions a 739 cm - may corrspond o h C-H bonds o h Phnyl ring subsiuion ovrons. Th prsnc o N-H bonds o h amins and O-H bonds o h carboxylic acids ar also suspcd howvr rom Tabl, i can b obsrvd ha h spcra o h coconu shll and h acivad carbon vary by larg dviaions. Bu h granular and powdr acivad carbon spcra ar h sam. Th spcra s vibraion o h granular acivad carbon ar srchd rom 895 cm - o 358 cm - hus giving a clu or h prsnc o O-H bonds o carboxylic acids, monomric alcohols and phnols, along wih h prsnc o C-H bonds o aromaic rings and N-H o h amins. In addiion, i has paks a 8 cm - which may indica h xisnc o alcohols, hrs and nirils. Furhrmor, h spcra also imply a composiion o alkans, alkns and CN amins prsn in h acivad carbon. Bulk dnsiy is an imporan paramr o powdrd solids. Th Amrican War Work Associaion has s a lowr limi on bulk dnsiy a.5 g/ml or acivad carbon o b o pracical us. Th bulk dnsiy valus o h prpard coconu shll acivad carbon a dirn siz and mpraur as prsnd in Tabl saisis his condiion. Th bulk dnsiis valus ar in agrmn wih h valus rpord in liraur (Guu al., 3; Vna Dvi al., ). From Tabl, i can b sn ha h ash conn in h coconu shll acivad carbons (granular and powdrd orms) is low. Th low ash conn maks i an araciv candida or adsorpion sudis. Th ash conn o commrcial acivad carbon is around % (Vna Dvi al., ). I ash conn is high i will inrr wih por srucur dvlopmn and hnc adsorpion will b lss (Dvi al., ). Th rsul in Tabl shows ha h spciic surac ara incrasd wih incras in acivaion mpraur. A similar obsrvaion has bn rpord (Vna Dvi al., ). In addiion, h valus o spciic surac ara o granular and powdrd coconu shll acivad carbon producd a 9 o C o acivaion mpraur is wihin h valu o 5 o m /g rcommndd or commrcial acivad carbon (). Ths valus or coconu shll acivad carbon ar in agrmn wih ohr sudis (Vna Dvi al., ). Thus, h coconu shll acivad carbons producd a 9 o C wr usd or urhr sudis. Th powdrd coconu shll acivad carbon showd highr surac ara han h granular coconu shll acivad carbon (i.. surac ara incrasd wih dcrasd paricl siz). Th iodin numbrs o coconu shll acivad carbons prpard in his invsigaion lis bwn 48-7 m /g. Gnrally, highr h iodin numbr, grar is h sorpion capaciy. From Tabl, i can b sn ha h iodin numbr incrasd as h acivaion mpraur incrasd and paricl siz dcrasd. This suggss ha surac ara has incrasd in rms o microscopic pors. Th valu o iodin numbr or GCSAC and PCSAC rvald ha h adsorbns ar signiicanly porous and his porosiy impars a highr surac ara o h adsorbns which was conirmd by 3

11 Chmisry and Marials Rsarch ISSN 4-34 (Prin) ISSN (Onlin) Vol.7 No.5, 5 h high surac ara valu obaind. Th inracion o GCSAC and PCSAC wih dionizd war showd ha ph o h war was lowrd, which indicas ha h prpard carbonacous adsorbn coms undr 'L' yp carbon according o Snbrg Mason classiicaion (No.7). Th powdrd coconu shll acivad carbon showd highr iodin numbr han h granular coconu shll acivad carbon. As shown in Fig., i is sn ha or ach o h coconu shll paricl siz, h yild o carbon incrass wih incras in acivaion mpraur. Similar obsrvaions hav bn rpord (Lgrouri al., ). I is sn rom Fig. ha h adsorpion capaciy o powdrd coconu shll-drivd acivad carbon (< mm paricl siz) was rlaivly highr han ha o h granular coconu shll-drivd acivad carbon (> mm paricl siz). This is in agrmn wih h obsrvaion ha adsorpion capaciy incrasd wih dcras in paricl siz diamr (Annadurai al., ;) Prcnag phnol rmoval is rlaivly highr wih powdrd coconu shll-drivd acivad carbon han wih granular coconu shll-drivd acivad carbon and his may b du o incrasd surac ara (i.. smallr paricls hav highr surac ara pr uni mass) as wll as micro por volum (Agarry and Armu, b). Smallr paricl siz mans mor inrior surac and micro por volum and hnc mor will b h ara o aciv sis or adsorpion. Also or largr paricls h diusion rsisanc o mass ransr is highr and mos o h inrnal suracs o h paricl may no b uilizd or adsorpion and consqunly h amoun o phnol adsorbd is small (Lakshmi al., 994; Annadurai al.,, Dabhad al., 9). I was obsrvd ha prcnag o phnol rmoval incrasd wih incras in adsorbn dos (Fig. 3(a) and 3(b). This kind o a rnd is mosly aribud o an incras in h adsorpiv surac ara and h availabiliy o mor aciv binding sis on h surac o h adsorbn (Nasuha al., ; Das and Mondal, ). Howvr, h quilibrium adsorpion capaciy showd an opposi rnd. As h adsorbn dosag was incrasd rom.5 o g, h adsorpion capaciy rducd rom 6.34 o.35 mg/ using granular coconu shll-drivd acivad carbon g (Fig. 3(a)) and rom 6.44 o.38 mg/g or powdrd coconu shll-drivd acivad carbon (Fig. 3(b)), rspcivly. This may b du o h dcras in oal adsorpion surac ara availabl o phnol rsuling rom ovrlapping or aggrgaion o adsorpion sis (Crini al., 7; Akar al., 9; Agarry al., 3b). Thus, wih incras in h adsorbn mass, h amoun o phnol adsorbd ono uni mass o adsorbn gs rducd, hrby causing a dcras in q valu wih incrasing adsorbn mass concnraion. Furhrmor, maximum phnol rmoval (99%) lis bwn h us o.5 and 5 g o powdrd coconu shll-drivd acivad carbon and urhr incras in adsorbn dos did no signiicanly chang h adsorpion yild. This is du o h non-availabiliy o aciv sis on h adsorbn and sablishmn o quilibrium bwn h phnol on h adsorbn and in h waswar (Agarry al., 3b). Th simad consans o Langmuir isohrm rom h linar plo o ( q vs. C ) (Fig. 4(a) ar givn in Tabl 3. I can b xplaind apparnly ha whn a >, sorpion sysm is avorabl (Chn al., 8). In his sudy, a is.3376 L/mg and h maximum monolayr adsorpion capaciy ( max ) is 7.58 mg/g obaind or granular coconu shll-drivd acivad whil h corrsponding a and Q max valu o.5 L/mg and 4.3 mg/g was obaind or powdrd coconu shll-drivd acivad carbon. Sahishkumar al. (9) obaind 7.94 mg/g as h maximum monolayr adsorpion capaciy o maiz cob carbon or h adsorpion o,4-dichlorophnol whil 4.5 mg/g was obaind by Agarry al. (3b) as h maximum monolayr adsorpion capaciy o modiid planain pls or h adsorpion o,6-dichlorophnol. Th valuad consans o Frundlich isohrm rom h linar plo o logq vs. log C (Fig. 4(b)) as givn in Tabl 3 rvald ha K and n valus wr ound o b. mg/g(l/mg) /n and.5 or granular coconu shll-drivd acivad carbon whil corrsponding K and n valu o 3.63 mg/g(l/mg) /n and.55 was obaind or powdrd coconu shll-drivd acivad carbon, rspcivly. Namasivayam and Kaviha (4) obaind K and n valus o. and.7 or h adsorpion o, 4, 6-richlorophnol (TCP) ono coir pih carbon whil Radhika and Palanivlu (6) corrspondingly obaind a K and n valus o.5 and.5 or h adsorpion o, 4, 6-richlorophnol (TCP) ono coconu shll acivad carbon. Gnrally, Langmuir and Frundlich isohrm modls id wll o h quilibrium adsorpion xprimnal daa wih high corrlaion coicin. Howvr, or h granular and powdrd coconu shll-drivd acivad carbon, h Frundlich isohrm modl providd h bs i wih a highr corrlaion coicin ( R =.994 and.99) o dscrib h adsorpion procss. A similar obsrvaion has bn rpord or h adsorpion o, 4-DCP ono acivad bamboo charcoal (Ma al., ) and h adsorpion o, 4, 6- richlorophnol (TCP) ono coir pih carbon (Namasivayam and Kaviha, 4) and coconu shll carbon (Radhika and Palanivlu, 6). Q 33

12 Chmisry and Marials Rsarch ISSN 4-34 (Prin) ISSN (Onlin) Vol.7 No.5, 5 For Langrgrn psudo irs-ordr kinic modl, h paramr valus o q and k wr calculad rom h slop and inrcp o h linar plos o ln( q q ) vs (Fig. 5(a) and 5(b)). Th rspciv valus as givn in Tabl 4 showd ha h adsorpion ra consan ( k ) is rlaivly highr or powdrd coconu shlldrivd acivad carbon han h granular coconu shll-drivd acivad carbon. Also, h paramr valus o k and q or psudo scond-ordr kinic modl wr calculad rom h plos o q vs. (Fig. 5(c) and 5(d) or granular and powdrd coconu shll-drivd acivad carbon. Th rspciv consan valus as givn in Tabl 4 rvald ha h ra consan k o 35 mg/l phnol adsorpion is rlaivly highr or powdrd coconu shll-drivd acivad carbon han ha or granular coconu shll-drivd acivad carbon. As shown in Fig. 5() and 5() or inra paricl diusion modl, h linar plo o q vs. / did no pass hrough h origin. This dviaion rom h origin is du o dirnc in h ra o mass ransr in h iniial and inal sags o h adsorpion (Agarry al., 3b). This indicad h xisnc o som boundary layr c and urhr showd ha inra paricl diusion was no h only ra limiing sp. Th calculad diusion coicin K valus ar lisd in Tabl 4. Th K valu is highr or granular coconu shll-drivd p acivad carbon han or powdrd coconu shll-drivd acivad carbon. Gnrally, all h sd adsorpion kinic modls id wll o h adsorpion kinic daa wih high corrlaion coicin or granular and powdrd coconu shll-drivd acivad carbon; howvr, h psudo scond-ordr kinic modl gav h bs i wih a highr corrlaion coicin o dscrib h adsorpion bhaviour o phnol ono granular and powdrd coconu shll-drivd acivad carbon. Similar obsrvaions hav bn rpord or h adsorpion o chlorophnols ono ohr agriculural by-produc drivd carbon adsorbns (Sahishkumar al., 9; Ma al., ; Sharaani and Hamd, ; Hamad al., ; Wang al., ). p Conclusion In his sudy, phosphoric acid acivad carbon was producd rom coconu shll. I was sd and valuad as a possibl adsorbn or rmoval o phnol rom pain waswar using bach adsorpion chniqu. Th adsorpion procss is also dpndn on som acors such as h conac im, adsorbn paricl siz (granular and powdrd orm) and adsorbn dosag. Th prcnag rmoval o phnol rom pain waswar incrasd wih incras in conac im and adsorbn dos up o a crain lvl and rlaivly highr or adsorbn wih small paricl siz (powdrd orm). Adsorpion quilibrium daa id vry wll o boh Langmuir and Frundlich isohrm modls, howvr, h Frundlich isohrm quaion gav h bs iing, conirming h non-idal hrognous adsorpion capaciy o phnol ono coconu shll-drivd acivad carbon wih an adsorpion capaciy ( K ) o. mg/g and adsorpion innsiy ( n ) o.7 or granular coconu shll acivad carbon and corrsponding 3.63 mg/g and.55 or powdrd coconu shll acivad carbon a 3 o C. Th adsorpion kinics ollowd psudo scond-ordr kinic modl wih a vry good corrlaion coicin suggsing ha h biosorpion procss is prsumably chmisorpion. Inra-paricl diusion was no h sol ra conrolling acor. Acknowldgmn Th auhors wish o hank h sa o Cnral Rsarch Laboraory and Mr. Wahd Azz o Ladok Akinola Univrsiy o Tchnology, Ogbomoso, Nigria or hir chnical suppor. Rrncs Abbasi, W.A. and Sr, M. (999). Adsorpion o uranium rom aquous soluion using acivad carbon. Sp. Sci. and Tchnol., 9 (9): 7-3. Agarry, S. E., Durojaiy, A. O., Yusu, R. O., Armu, M. O., Solomon, B. O. and Mojd, O. (8). Biodgradaion o phnol in rinry was luns by pur culurs o Psudomonas aruginosa NCIB 95 and Psudomonas luorscnc NCIB In. J. Environ. Pollu., 3 (): 3. Agarry, S. E. and Owabor, C. N. (). Evaluaion o h adsorpion ponial o rubbr (hva brasilinsis) sd pricarp-acivad carbon in abaoir waswar ramn and in h rmoval o iron (iii) ions rom aquous a soluion. Nigrian J. Tchnol., 3 (3):

13 Chmisry and Marials Rsarch ISSN 4-34 (Prin) ISSN (Onlin) Vol.7 No.5, 5 Agarry, S. E. and Armu, M. O. (). Bach quilibrium and kinic sudis o simulanous adsorpion and biodgradaion o phnol by pinappl pls immobilizd Psudomonas aruginosa NCIB 95. Briish Biochnol. J., (): Agarry, S. E., Ogunly, O. O. and Aworani, O. A. (3a). Biosorpion quilibrium, kinic and hrmodynamic modlling o naphhaln rmoval rom aquous soluion ono modiid spn a lavs. Environ. Tchnol., 34 (7): Agarry, S. E., Owabor, C. N. and Ajani, A. O. (3b). Modiid planain pl as cllulos-basd low-cos adsorbn or h rmoval o, 6 dichlorophnol rom aquous soluion: adsorpion isohrms, kinic modlling and hrmodynamic sudis. Chm. Eng. Comm., (8): -47. Akar, S.T., Ozcan, A.S., Akar, T., Ozcan, A. and Kaynak, Z. (9). Biosorpion o a raciv xil dy rom aquous soluions uilizing an agro-was. Dsalinaion, 49 (): Akyol, A. () Tramn o pain manuacuring waswar by lcrocoagulaion. Dsalinaion 85: Annadurai, A., Babu, S.R., Mahsh, K.P.O. and Murugsan, T. (). Adsorpion and biodgradaion o phnol by chiosan-immobilizd Psudomonas puida (NICM 74). Bioprocss Eng., : Annadurai, G., Juang, R.S and L, D.J. (). Adsorpion o havy mal rom war using banana and orang pls. War Sci. Tchnol., 47:85-9. ASTM-D (995) Sandard Ts Mhod or Drminaion o Iodin Numbr o Acivad Carbon, Philadlphia. ATSDR (999). Agncy or oxic subsanc and disas rgisry.toxicological proil or chlorophnols. Alana, GA: US Dparmn o Halh and Human Srvics, Public Halh Srvic. Badmus, M. A. O., Audu, T. O. K. and Anyaa, B.U. (7): Rmoval o lad ion rom indusrial waswars by acivad carbon prpard rom priwinkl Shlls (Typanoonususcaus).Turkish J. Eng. Env. Sci., 3 (4): 5 63 Calabrs, E. J. and Knyon, E. M. (99). Air oxics and Risk Assssmn. Lwis publishrs, Chlsa, MI. Chaiwaananon, R., Niyomwan, N. and Noda, Y. (998) Opimum condiion or high qualiy acivad carbon producion rom Thai raw marials. Rpor No 6. Thailand Insiu o Sciniic and Tchnological Rsarch. Chaliha, S. and Bhaacharyya, K. G. (8). Caalyic w oxidaion o chlorophnol,,4-dichlorophnol and,4,6-richlorophnol in war wih Mn(II)-MCM4. Chm. Eng. J., 39, Chn, B. and Schnoor, J.L. (9). Rol o subrin, subran, and hmicllulos in phnanhrnn sorpion by roo issu racions o swichgrass (Panicum virhaum). Environ. Sci.Tchnol., 43: Chn, B., Yuana, M., and Liu, H. (). Rmoval o polycyclic aromaic hydrocarbons rom aquous soluion using plan rsidu marials as a biosorbn. J. Hazard Mar., 88: Chn, Z., Ma, W. and Han, M. (8):Biosorpion o nickl and coppr ono rad alga(undariapinnarliida): Applicaion o isohrm and kinic modls. J. Hazard. Mar.,55 (-): Crini, G., Pindy, H. N. Gimbr, F. and Robr, C. (7): Rmoval o C.I. Basic Grn 4 (Malachi Grn) rom aquous soluions by adsorpion using cyclodxrin basd adsorbn: kinic and quilibrium sudis. Sp. Puri. Tchnol., 53 (): 97. Crisaully, R., Milhom, M.A., Cavalcan, R.M, Silvira, E.R., Kuklir, D and Nascimno, F. (8). Rmoval o som polycyclic aromaic hydrocarbons rom prochmical was war using low-cos adsorbns o naural origin. Biorsour. Tchnol. 99: Dabhad, M.A., Saidua, M.B. and Murhy, D.V.R. (9). Adsorpion o phnol on granular acivad carbon rom nurin mdium: quilibrium and kinic sudy. In. J. Environ.Rs., 3(4), Das, B. and Mondal, N.K. (). Calcarous soil as a nw adsorbn o rmov lad rom aquous soluion: quilibrium, kinic and hrmodynamic sudy. Univrsal J. Environ. Rs. Tchnol., (4): Dvipriya, S.P. and Ysodharan, S. (). Phoo caalyic dgradaion o phnol in war using TiO and ZnO. J. Environ. Biol., 3, Elkarmi, A.Z., Abu-Eln, K.H., Aa, A.A. and Abu-Sbian, N.A. (9). Biodgradaion o,4- dichlorophnol originaing rom pharmacuical indusris. Ari. J. Biochnol., 8 ():

14 Chmisry and Marials Rsarch ISSN 4-34 (Prin) ISSN (Onlin) Vol.7 No.5, 5 Environmnal Procion Agncy (EPA) 979: Phnol ambin war qualiy criria. Oic o planning and sandards. Washingon, D. C. BB Frundlich, H. M. F. (96): Ovr h adsorpion in soluion. J. Phys. Chm., 57: Guu, Yao, B., Adouby, K., and Ado, G. (3) Havy Mals rmoval in aquous soluion by acivad carbons prpard rom coconu shll and sd shll o h palm r. J. Appl. Sci. 6(3): Hamad, B.K., Noor, A-Md., Rahim, A.A. (). Rmoval o 4-chloro--mhoxyphnol rom aquous soluion by adsorpion o oil palm shll acivad carbon acivad wih K CO 3. J. Phys. Sci., (), Hamd, B. H., Mahmoud, D. K. and Ahmad, A. L. (8). Equilibrium modling and kinic sudis on h adsorpion o basic dy by a low-cos adsorbn: Coconu (Cocos nucira) bunch was, J. Hazard. Mar Hamd, B.H. (9). Spn a lavs: A nw non-convnional and low-cos adsorbn or rmoval o basic dy rom aquous soluion. J. Hazard. Mar. 6: Ho, Y. S. and Mckay, G. (): Th kinics o sorpion o divaln mal ions ono sphagnum moss pa. War Rs., 34 (3): Hussain, A. A., Mohammd, S. R., Nallu, M. and Arivoli, S. () Adsorpion o F (III) rom aquous soluion by acanhaca acivad carbon. J. Chm. Pharm. Rs., 4 (4): Lagrgrn, S. (898). Zur hori dr sognann, adsorpion glosr so, Kungliga Svnska vnskapsakadmins, HAndlingar 4:-39. Lakshimi, Narayana Rao, K. C., Krishbaiah, K., Ashuosh, A. (994). Colour rmoval rom a dy su indusry lun using acivad carbon. Indian J. Chm. Tchnol. :3-9. Langmuir, I. (98): Th adsorpion o gass on plan suracs o glass, mica and plainum. J.Am. Chm. Soc., 4: Laouiy, N.A., Tassali, D., Bnahar, F. (8). Th dgradaion o phnol in war soluion by TiO phoo caalysis in a hlical racor. Global Ns J.,, Lgrouri, K., El Hari, M., Oumam, M., Khouya, E., Wahbi, R., Hannach, H., Zarrouk, A. () Characrizaion and valuaion prormanc o acivad carbon prpard rom coconu shll argan. J. Chm. Pharmacuical Rs., 4 (): Li, Y., Chn, B., and Zhu, L. (). Enhancd sorpion o polycyclic aromaic hydrocarbons rom aquous soluion by modiid pin bark, Biorsour. Tchnol. : Ma, J-W., Wang, H., Wang, F-Y., and Huang, Z-H. (). Adsorpion o, 4-dichlorophnol rom aquous soluions by a nw low cos adsorbn-acivad bamboo charcoal. Sp. Sci. Tchnol. 45: McKay, G. and Ho, Y. S. (999). Sorpion o lad (II) ions on pa. War Rs., 33: Mohammd, A, Nsaranam, S. and Mohammd, H. (5) Prparaion o phosphoric acid-acivad carbon using palm da pis: physico-chmcial and adsorpiv propris, J. Chm. Tchnol., 5 Availabl: [s Augus 8] Namasivayam C. and Kaviha, D. (4). Rmoval o phnol and chlorophnols rom war by coir pih carbon: Equilibrium and ra sudis. J. Environ. Eng. Sci., 46(3): 7-3. Nasuha, N., Hamd, B. H. and Din, A. T. M. (): Rjcd a as a ponial low cos adsorbn or h rmoval o mhyln blu. J. Hazard. Mar., 75 (-3):6-3. Ozcan, A. and Ozcan, A. S. (5) Adsorpion o Acid Rd 57 rom Aquous Soluions ono suracan modiid Spioli. J. Hazard. Mar., 5: 5-59 Popuri, S.R., Jammala, A., Rddy, K.V.N. and Abburi, K. (7). Biosorpion o hxavaln chromium using amarind (Tamarinddus indica) rui shll - a comparaiv sudy. Elcronic J. Biochnol. 3: Poulopoulos, S. G., Nikolaki, M., Karampsos, D. & Philippopoulos, C. J. (8). Phoochmical ramn o -chlorophnol in aquous soluion using ulraviol radiaion, hydrogn proxid and phoo-fnon racion. J. Hazar. Mar., 53, Prpich, G. P. and Daugulis, A. J. (5). Enhancd biodgradaion o phnol by a microbial consorium in a solid-liquid wo-phas pariioning bioracor. Biodgradaion 6: Radhika, M. and Palanivlu, K. (6). Adsorpiv rmoval o chlorophnols rom aquous soluion by low cos adsorbn- Kinics and isohrm analysis. J. Hazard. Mar., 38(), 6-4. Rngaraj, S., Moon, S. H., Sivabalan, R., Arabindoo, B. and Murugsan, V. () Rmoval o phnol 36

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