Copper (II) Uptake by Adsorption Using Palmyra Palm Nut

Transcription

1 Availabl onlin a Plagia Rsarch Library Advancs in Applid Scinc Rsarch, 0, (6):66-75 ISSN: CODEN (USA): AASRFC Coppr (II) Upak by Adsorpion Using Palmyra Palm Nu Josph T. Nwabann* and Philomna K. Igbokw Dparmn of Chmical Enginring, Nnamdi Azikiw Univrsiy, P.M.B. 505, Awka, Nigria _ ABSTRACT Th rmoval of coppr () from aquous soluion using palmyra palm nu (PPN) as ponial raw marial for h prparaion of acivad carbon was invsigad. Chmical acivaion using phosphoric acid (H 3 PO 4 ) was mployd for h prparaion of acivad carbon. Th ffc of various facors namly ph, adsorbn dosag, and adsorbn paricl siz was sudid o idnify h adsorpion capaciy of palmyra palm nu. Th prcnag of Cu + adsorbd was found o b dpndn on adsorbn dosag, ph and paricl siz. Adsorpion daa wr modld using Langmuir, Frundlich and Dubinin-Radushkvich quaions. Th quilibrium daa was bs dscribd by Frundlich modl. Th kinic daa wr also applid o h psudo firsordr, psudo scond-ordr and Bhaacharya-Vnkobachor modls. Th kinic daa followd all h hr kinic modls bu psudo scond-ordr modl bs dscribd kinics of h adsorpion procss. I is sn from h work ha palmyra palm nu, a low-cos adsorbn, can b usd for h rmoval of Cu + from aquous soluion. Ky words: Kinics, adsorpion, upak, coppr, palmyra palm nu. _ INTRODUCTION Th progrssiv incras of indusrializaion in Nigria has rsuld in coninuous incras of polluion of boh surfac and ground wars. Wih h rapid dvlopmn of chmical, polymr, procssing and prolum procssing indusris, hr is a rapid incras in h amoun and h variy of chmicals ha ar hrown ino h wars. Effor has bn dvod owards minimizing hs hazardous polluans so as o avoid hir dangrous ffcs on animals, plans and humans. Svral biological and chmical mhods such as filraion, coagulaion, oxidaion, and ionxchang hav bn usd for h ramn of was war, bu h coninuing incras in h variy and h amoun of hazardous chmicals prsn in our laks, rivrs and somims ground war rsrvs mak hs convnional mhods infficin and somims inffciv []. Consqunly, h dvlopmn of nw and mor ffciv chnologis bcoms ssnial. Acivad carbon adsorpion has bn givn anion in rcn im by many sciniss. Bu Plagia Rsarch Library 66

2 Josph T. Nwabann al Adv. Appl. Sci. Rs., 0, (6):66-75 commrcially availabl acivad carbons ar sill xpnsiv [,3,4]. As a rsul of his, many rsarchrs hav sudid chapr alrnaivs, which ar rlaivly inxpnsiv, and qually ndowd wih rasonabl adsorpiv capaciy. Among hs sudis ar h us of ric husk [5], almond shll [6] and palm krnl shll [7]. Havy mal ions ar classifid as prioriy polluans [8]. Ths havy mals ar no biodgradabl and hir prsnc in wars lads o bioaccumulaion in living organisms causing halh problms in animals, plans, and human bings [9]. Coppr is mal ha has a wid rang of applicaions du o is good propris. I is usd in lcronics, for producion of wirs, shs, ubs, and also o form alloys. Sinc coppr is a widly usd marial, hr ar many acual or ponial sourcs of coppr polluion. Coppr may b found as a conaminan in food, spcially shllfish, livr, mushrooms, nus, and chocola. Coppr is ssnial o lif and halh bu, lik all havy mals, is ponially oxic as wll. For xampl, coninud inhalaion of copprconaining spray is linkd wih an incras in lung cancr among xposd workrs. For drinking war, h maximum prmissibl limi of coppr is.5mg/l [0]. Th maximum concnraion allowd for discharg ino inland war is lss han mg/l []. This work was undrakn o sudy h rmoval of coppr (II) from aquous soluion by adsorpion using palmyra palm nu as a low cos raw marial for h prparaion of acivad carbon. MATERIALS AND METHODS Prparaion of acivad carbon Palmyra palm nus wr obaind from h prmiss of Nnamdi Azikiw Univrsiy, Awka, Nigria. Th palm nus wr washd wih dionizd war, drid in h sun, ground ino fin paricls and sivd o a paricl siz of 300µm. 00g of sampl was imprgnad wih concnrad orhophosphoric acid a h raio of : (w %). Th imprgnad sampl was drid in a Mmmr ovn a 0 0 C for 4hrs. Th drid sampl was carbonizd in a Muffl furnac a C for hours. Afr cooling o h ambin mpraur, h sampl was washd svral ims wih d-ionizd war unil ph 6-7, filrd wih Whaman No. filr papr and drid in h ovn a 0 0 C for 8hours. Th sampl was crushd and passd hrough diffrn siv sizs and hn sord in a igh bol rady for us. Characrizaion of acivad carbon Drminaion of ph of acivad carbon. Th ph of h carbon was drmind using sandard s of ASTM D []. Drminaion of moisur conn. Moisur conn of acivad carbon and raw marials was drmind using ASTM D [3]. Drminaion of bulk dnsiy of acivad carbon. Th bulk dnsiy of h acivad carbon was drmind according o h amping procdur by Ahmdna al [4]. Drminaion of volail conn..0g of sampl was wighd and placd in a parially closd crucibl of known wigh. I was had in a muffl furnac a C for 0mins. Plagia Rsarch Library 67

3 Josph T. Nwabann al Adv. Appl. Sci. Rs., 0, (6):66-75 Drminaion of prcnag fixd carbon. Th prcnag fixd carbon is givn by: 00 (Moisur conn + ash conn + volail mar) %. Drminaion of iodin numbr of acivad carbon. Th iodin numbr was drmind basd on ASTM D [5] by using h sodium hiosulpha volumric mhod. Drminaion of surfac ara: Th spcific surfac ara of h acivad carbon was simad using Sar s mhod [6, 7]. Adsorba prparaion and adsorpion sudy Th ragn usd was coppr sulpha (CuS0 4 ) and d-ionizd war. Th ragns wr of high grad. Th sampl (CuS0 4 ) was drid in an ovn for hrs a 05 0 C o rmov moisur..5g of CuS0 4 was dissolvd in 000ml of d-ionizd war o g h sock soluion of 000g/l. A prdrmind amoun of acivad carbon was addd o 00ml of h 00mg/l of adsorba in a conical flask and placd on a magnic sirrr. Th sirring was don a diffrn mpraur for diffrn ims. Afr adsorpion is compl, h soluion was filrd using Whaman no. filr papr. Th rsidual Cu + concnraion of h fflun was drmind spcrophoomically using aomic adsorpion spcrophoomr a 34.8nm wavlngh. Th adsorpion capaciy, q (mg/g) and prcnag adsorbd wr calculad from quaion () and quaion () rspcivly. q = [( C C ) V / m] o % Adsorbd = [( C C ) / C ] x 00 o Whr, C o and C ar h mal concnraions (mg/l) a iniial and any im, rspcivly, V h volum of h soluion (L), and m h mass of adsorbn usd (g).th ffcs of paricl siz, adsorbn dosag, ph wr sudid. RESULTS AND DISCUSSION Characrisics of acivad carbon drivd from palmyra palm nu: Th physico-chmical characrisics of acivad carbon ar shown in Tabl. Tabl : Physico-chmical characrisics of acivad carbon drivd from palmyra palm nu. Propris Valus ph 6.8 Bulk dnsiy, g/cm Iodin numbr, mg/g Moisur conn, % 4.0 Volail mar, % 8.4 Ash conn, % 3.40 Fixd carbon, % Surfac Ara, m /g Effc of adsorpion dosag on h adsorpion procss Adsorpion dosag drmins h capaciy of an adsorbn for a givn iniial concnraion of h adsorba. Th rsul showd ha as h adsorbn dosag incrasd, h prcnag of o Plagia Rsarch Library 68

4 Josph T. Nwabann al Adv. Appl. Sci. Rs., 0, (6):66-75 adsorpion also incrasd bu h amoun adsorbd pr uni mass of h adsorbn dcrasd considrably (Figur ). Th dcras in uni adsorpion wih incrasing dos of adsorbn is basically du o adsorpion sis rmaining unsaurad during h adsorpion racion [8]. Figur rvals a dfini incras in h adsorpion capaciy of h adsorbn wih dosag. This is aribud o h largr numbr of availabl adsorpion sis favouring h nhancd upak of h mal ions [9]. Fig. : Effc of adsorbn dosag on h adsorpion of Cu + on PPN Effc of paricl siz on h adsorpion procss Th rmoval of Cu + a diffrn paricl sizs showd ha h rmoval ra incrasd br wih a dcras in paricl siz (Figur ). This sam rnd was rpord by Dmirbas al [6].Th rlaivly highr adsorpion wih smallr adsorba paricl may b aribud o h fac ha smallr paricls yild larg surfac ara. Thr is a ndncy ha a smallr paricl producs shorr im o quilibrium. Fig. : Effc of paricl siz on h adsorpion of Cu + on PPN Effc of ph on h adsorpion procss ph is on of h mos imporan nvironmnal facors influncing no only si dissociaion, bu also h soluion chmisry of havy mal: hydrolysis, complxaion by organic and/or inorganic ligands, rdox racions, and prcipiaion ar srongly influncd by ph and on h ohr hand, i Plagia Rsarch Library 69

5 Josph T. Nwabann al Adv. Appl. Sci. Rs., 0, (6):66-75 srongly influncs h spciaion and adsorpion availabiliy of havy mals [0]. Figur 3 prsns h ffc of ph on h rmoval of Cu +. Th adsorpion of h Cu + incrasd wih incrasing ph. Th maximum Cu + adsorpion for all h adsorbns was obaind a ph 7. Cu + adsorpion dcrasd as ph ros byond h opimum ph. Fig. 3: Effc of ph on h adsorpion of Cu + on PPN Adsorpion Isohrm Langmuir isohrm modl Th Langmuir adsorpion modl is givn by: b C q = Q + b C 3 Th Langmuir quaion can b dscribd by h linarizd form [0, ]. C = + C q Qob Q 4 o Whr C is h quilibrium concnraion of h adsorba, q h amoun of adsorba pr uni mass of adsorbn (mg/g), and Q 0 and b ar Langmuir consans rlad o adsorpion capaciy and ra of adsorpion, rspcivly. Whn C /q is plod agains C, sraigh lin wih slop /Q 0 indicas ha adsorpion follows h Langmuir isohrm. Th Langmuir consans, Q 0 and b wr valuad from h inrcp and h slop of h linar plo of xprimnal daa of /q vrsus /c and prsnd in Tabl. Th ssnial characrisics of h Langmuir quaion can b xprssd in rms of a dimnsionlss sparaion facor, R L, dfind as []. R L = + bc O whr C o is h iniial ion concnraion. Th R L valu implis h adsorpion o b unfavourabl (R L > ), Linar (R L =), favourabl (O<R L <), or irrvrsibl (R L =0). R L valus for Cu + adsorpion wr lss han and grar han zro indicaing favourabl adsorpion undr 5 Plagia Rsarch Library 70

6 Josph T. Nwabann al Adv. Appl. Sci. Rs., 0, (6):66-75 condiions usd in his sudy (Tabl ). Th corrlaion cofficin showd ha adsorpion of Cu + on PPN did no followd Langmuir. Frundlich Isohrm Th Frundlich adsorpion isohrm [3] is / n q = K C 6 F A linar form of his xprssion is: log q = log K + / logc 7 F n Whr K F and n ar Frundlich consans, n giving an indicaion of how favourabl h adsorpion procss is and K F is h adsorpion capaciy of h adsorbn. K F and n ar drmind from h linar plo of log q vrsus log C. From h linar plos of log q vrsus log C, valus of Frundlich consans K F and n wr calculad from h inrcp and slop, rspcivly, and ar prsnd in Tabl. Th magniud of h xponn, n givs an indicaion of h favourabiliy and capaciy of h adsorbn/adsorba sysm. Karhikyan al [9] has rpord ha n valus bwn and 0 rprsn favourabl adsorpion condiions. In his work, h xponn rangd from.605 o.675 showing bnficial adsorpion for h sysm. Th corrlaion cofficins, R ranging from o indicad h Cu + adsorpion followd Frundlich isohrm modl. Similar rsuls wr obaind by Aksu and Tzr [4]. Dubinin-Radushrich isohrm modl Th Dubinin Radushkvich quaion has h following form: q = q βε m 8 A linar form of Dubnin Radushkvich quaion isohrm [] is: Inq = Inqm βε 9 q is h Dubinin Radushkvich monolayr capaciy ( ) β Whr m mmol / g, a consan rlad o sorpion nrgy, and ε is h Polanyi ponial which is rlad o h quilibrium concnraion as follows: ε = RT In + 0 C Whr, R is h gas consan ( 8.3J / mol K ) and T is h absolu mpraur. Th consan β givs h man fr nrgy, Ε, of sorpion pr molcul of h sorba whn i is ransfrrd o h surfac of h solid from infiniy in h soluion and can b compud using rlaionship [5]. E = β Plagia Rsarch Library 7

7 Josph T. Nwabann al Adv. Appl. Sci. Rs., 0, (6):66-75 Th Dubinin-Radushkrich consans wr valuad and givn in Tabl. Th corrlaion cofficins wr drmind as shown in Tabls. R indicad ha h adsorpion of Pb + did no follow h Dubinin-Radushkrich isohrm. If h man fr nrgy, E is <8KJ/mol, h adsorpion is physisorpion and if h nrgy of acivaion is 8-6KJ/mol, h adsorpion is chmisorpion in naur [6]. Rsuls of E obaind indicad ha adsorpion of Pb + on all h NPN is physisorpion. Tabl : Calculad isohrm paramrs for h adsorpion of Cu + on PPN Isohrm modl Tmpraur, K Langmuir Q (mg/g) b (L/mg) R L R Frundlich N K f (L/g) R Dubinin-Radushkvich q D (mg/g) β (mol /J ) 6x0-8 x0-7 3x0-7 E (KJ/mol) Adsorpion Kinics Psudo firs-ordr kinic modl Th Psudo firs-ordr kinic modl was proposd by Lagrgrn [7]. Th quaion is gnrally xprssd as dq = K I ( q q ) d Whr, q and q ar h adsorpion capaciy a quilibrium and a im, rspcivly (mgg - ), K is h ra consan of psudo firs -ordr adsorpion (L min - ). Afr ingraion and applying boundary condiions, = 0 o = and q = 0 o q = q, h ingrad form of quaion.6 bcoms: K log ( q q ) = log ( q ) Th valus of log (q q ) ar linarly corrlad wih. Th slop and inrcp of plos of log (q -q ) vrsus wr usd o drmin h psudo-firs ordr ra consans, K and q a diffrn mpraurs. Th rsuls of h q and K wr valuad and lisd in Tabl 3. Th corrlaion cofficins rangd from o indicaing ha Pb + adsorpion fid wll o psudo firsordr kinic quaion. Plagia Rsarch Library 7

8 Josph T. Nwabann al Adv. Appl. Sci. Rs., 0, (6):66-75 Psudo scond- ordr modl Th adsorpion kinics may also b dscribd by a psudo scond-ordr quaion [8, 9, 30]. dq d = K 4 ( q q ) Ingraing quaion.9 and applying h boundary condiion = 0 o = and q = 0 o q = q, givs q q = + K 0 q 5 Equaion (.0) can b rarrangd o obain a linar form: = + 6 q K q q Whr, K is h ra consan, of psudo scond-ordr adsorpion (gmg - min - ). Th slop and inrcp of plo of /q vrsus wr usd o calcula h psudo scond-ordr ra consan, a diffrn mpraurs. Tabl 3 liss h rsuls of h ra consan and q by psudo scondordr modls. Th corrlaion cofficin, R for h psudo scond-ordr adsorpion modl has high valu (> 0.984). Is calculad quilibrium adsorpion capaciy, q is consisn wih xprimnal daa. Ths facs suggs ha h psudo scond-ordr adsorpion mchanism is prdominan. Similar phnomna hav also bn obsrvd in h adsorpion of dirc dy on palm ash []. Bhaacharya Vnkobachor kinic modl Bhaacharya Vnkobachor modl [3] is xprssd as Ln U [ ] = U ( ) K B. 7 ( ) ( Co C ) ( Co C ) = / 8 Th ffciv diffusion cofficin D, is obaind from h quaion: KB. r D = 9 π Whr, r is paricl radius. From h plo of In [-U ()] vs, h ffciv diffusion cofficin D and ra consan, K B wr obaind and prsnd in Tabl 3. Th ffciv diffusion cofficins drmind ar in h rang of 4.55x0-0 o 3.36x0-0 m /s. Th kinic daa also followd Bhaacharya Vnkobachor modl. Plagia Rsarch Library 73

9 Josph T. Nwabann al Adv. Appl. Sci. Rs., 0, (6):66-75 Tabl 3: Calculad kinic paramrs for h adsorpion of Cu + on PPN Kinic modl Tmpraur, K Psudo firs-ordr K (min - ) q (mg/g) R Psudo scond-ordr K (g/mg min) q (mg/g) R Bhaacharya-Vnkobachor K B D (m /s) 3.36x x x CONCLUSION Th rmoval of coppr (II) from aquous soluion using acivad carbon prpard from palmyra palm nu has bn invsigad in his work. Th adsorpion procss showd ha palmyra palm nu was ffciv in h upak of coppr (II) from aquous soluion. Th amoun of Cu + adsorbd was found o vary wih ph, paricl siz and adsorbn dosag. Adsorpion daa wr fid o Langmuir, Frundlich and Dubinin-Radushkvich quaions. Th adsorpion daa conformd o Frundlich modls. Th adsorpion daa also fid Bhaacharya-Vnkobachor, psudo firs-ordr and psudo scond-ordr modls. Howvr, psudo scond-ordr bs dscribd h adsorpion procss. REFERENCES [] Bansal RC, Goyal M, Acivad Carbon Adsorpion, CRC Prss, USA, 005, -5. [] Chakrabory S, D S, DasGupa S, Basu JK, Chmosphr, 005, 58, [3] Ambdkar G, Muniyan M, Adv. Appl. Sci. Rs, 0, (4), 83 [4] Sivakumar P, Palanisamy N, Adv. Appl. Sci. Rs, 00, (), 58 [5] Malik PK, Dys Pigmns, 003, 56(3), [6] Zawani Z, Luqman CA, Choong TSY, Europan Journal of Scinific Rsarch, 009, 37(), [7] Dmirbas E, Kobya M, Snurk E, Ozkan T, War SA, 004, 30(4), [8] Volsky B, Holan ZR, Biochnology Progrss, 995, (3), [9] Ong S, Sng C, Lim P, EJEAFch. 007, 6 (), [0] World Halh Organizaion (WHO), Guidlins for drinking war, Gnva, 97, [] Fdral Environmnal Polluion Agncy (FEPA), Naural guidlins and sandards for indusrial ffluns, gasous missions and hazardous was managmn in Nigria, Lagos, Nigria, 99, [] Amrican Sociy for Tsing and Marials, Annual Book of ASTM Sandard, Volum 5.0, Rfracoris, Carbon and Graphic Producs; acivad Carbon, ASTM, Philadlphia, PA. 996 Plagia Rsarch Library 74

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