Biosorption of Azure Dye with Sunflower Seed Hull: Estimation of Equilibrium, Thermodynamic and Kinetic Parameters

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1 Inrnaional Journal of Enginring Rsarch and Dvlopmn -ISSN: X, p-issn: X, Volum, Issu 6 (Jun 24), PP.26-4 Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic and Kinic Paramrs Gbkloluwa Ogunimin, Jams Hunr 2 and Dong H Kang 3 Dparmn of Civil Enginring, Morgan Sa Univrsiy,52 Prring Parkway Balimor MD 225,USA Absrac:-Biosorpion ponial of sunflowr sd hull o rmov raciv xil dy conaminad soluions was h purpos of his invsigaion. Azur A chlorid dy was chosn as a modl for his invsigaion. Prramn, iniial ph, biomass dosag, conac im, iniial dy concnraion and mpraur wr valuad in bach mod sudis. Prliminary rsuls indica ha acid and bas prramn affcd h dy biosorpion propris of h milld hull. Paricls raind on h ASTM sivs 25 µm and 425 µm had h highs biosorpion capaciy. Th opimum ph for azur dy biosorpion was 6., and h valus of prcn dy biosorbd and biosorpion capaciy incrasd wih conac im and dosag of drid sunflowr sd hull (DSSH). Bach quilibrium daa obaind a diffrn mpraurs (22.5, 25, 3, 35, 35, 4 and 45 o C) wr modld by Frundlich, Langmuir and Dubinin Radushkvich (D R) isohrms. Langmuir and Frudlich isohrms modl fid h quilibrium daa, a all sudid mpraurs. Th highs monolayr biosorpion capaciy was found o b 22.27mg g - dry biomass a 4 o C. Th changs in Gibbs fr nrgy (ΔG * ), nhalpy (ΔH * ) and nropy (ΔS * ) of biosorpion wr also valuad for h biosorpion of Azur dy ono DSSH. Th rsuls indica ha h biosorpion was sponanous and xohrmic. Th kinic propris wr sudid; h daa fid h firs and psudo scond ordr modl a room mpraur (22.5 o C). Th psudo-scond-ordr kinic modl was obsrvd o provid h bs corrlaion of h xprimnal daa among h kinic modls sudid. Th biosorbn dy inracion mchanisms wr invsigad using Fourir ransform infrard spcroscopy. Kywords:- Biosorpion, Azur dy, psudo-scond ordr kinics, Isohrms, drid sunflowr sd hull I. INTRODUCTION Th conaminaion of h indusrial wars wih h organic basd chmicals has crad a srious nvironmnal problm. Synhic dys, on group of organic polluans, ar xnsivly usd in svral indusris such as xil, papr, prining and dy houss. Th ffluns from hs indusris ar highly colord and discharg of dy conaining ffluns ino h naural war bodis can pos hazardous ffcs on h living sysms bcaus of carcinognic, muagnic, allrgnic and oxic naur of dys. Th prsnc of vry small amouns of dys in war (lss han mg dm 3 for som dys) is highly visibl and undsirabl. Th convnional dcolorizaion mhods of dy baring waswars involv h combinaion of physical and chmical procsss such as prcipiaion, sdimnaion, ulrafilraion, floaion, color irradiaion, ozonaion and coagulaion. Howvr h applicaion of h abov mniond chnologis is somims rsricd du o chnical and conomic consrains. Also synhic dys hav a complx aromaic molcular srucur, which maks hm sabl and rsisan o biological dgradaion.adsorpion is an ffciv alrnaiv procss for h ramn of conaminad waswar. Currnly, acivad carbon is h mos popular and xnsivly usd commrcial biosorbn marial du o is high adsorpion capaciy, surfac ara and dgr of surfac raciviy as wll as micro porous srucurs. Bu i shows som disadvanags such as high opraing coss and rgnraion problms []. Thrfor, in h rcn yars considrabl amoun of rsarchs hav bn don on h dvlopmn of ffciv, low cos and asily availabl alrnaiv biosorbns. Diffrn agriculural biomasss such as r frn [2], pa and ric husk [3,4], panu hull [5,6], sugarcan dus [7], appl pomac and wha sraw [8,9], bark [], palm krnl fibr [], banana pl and orang pl [2,3], coir pih [4], linsd cak [5] and sawdus [6-8] hav bn prviously rid for h rmoval of diffrn yps of dys, bu high ffciv and mor conomical biosorbn marials ar sill ndd. Th sunflowr plan is a naiv of Norh Amrica. I was grown by h Indians for food in Norh Carolina bfor 6 and by Nw England coloniss for hair oil as arly as 65 [9]. Th rising prominnc of sunflowr oil in world dibl oil marks has simulad incrasd inrs in xpandd U.S producion for las dcads. U.S acrag of sunflowr planing has xpandd rapidly in h 97's, raching a pak a 5.5 million acrs. Th U.S sunflowr producion has dclind in rcn yars. Currnly U.S pland sunflowr ovr.8 million arcrs in 22 and approximaly million mric ons of sunflowr sd wr producd in 2. 4% and 32.7 % of oal sunflowr pland acrs wr grown in h Norh Dakoa and Souh Dakoa in 22, 26

2 Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic rspcivly [2]. Compard wih soyban oil which currnly dominas h US dibl oils mark, sunflowr sd oil has a highr conn of polyunsaurad fay acids [9]. Th world producion of sunflowr sd is 3. MT wih h USSR bing h largs producr producing 6.3MT, Ukrain 4.7MT, Argnina 3.7MT, China.9MT, India.9MT, USA.8MT [2]. Th U.S producd around 6% of h world's sunflowr producion and 85. % of oal U.S sunflowr producion is for vgabl oils. In rcn yars, approximaly 2 million acrs of sunflowrs hav bn grown in h world annually [22]. Th hull accouns for 22 o 28% of h wigh of sunflowr sd and bcoms a byproduc of h sd crushing opraion. Larg-sd variis hav highr proporion of hull han small-sd variis. Th mos promising us for sunflowr sd hulls appars o b as roughag ingrdin for livsock fd. Sunflowr hulls mak coars roughag, high in fibr bu suiabl for us in ruminan raions. Sunflowr hull conains.5% moisur, 3.5% proin 3.4% fa, and 22. % fibr [9]. Th objcivs of his sudy wr o invsiga h ponial us of sunflowr sd hull, as an ffciv biosorbn for h rmoval of dy from aquous soluions and sudy is hrmodynamic and kinic propris. Thr has bn no rpord sudy o da in his fild on h us of sunflowr sd hull as a biosorbn. II. MATERIAL and METHODS II. Prparaion of Sunflowr sd Hull (SSH) A 2g pack of Sunflowr sds purchasd from a local grocry was dhulld and h hull was milld in a coff grindr. Th milld hull was hn sparad ino diffrn paricl sizs using wih ASTM sandard sivs wih msh sizs 6 (25µm aprur), 4 (425µm aprur) and 2 (85µm aprur). Th fracion of h sunflowr sd which is hull was drmind by dhulling a known wigh of sd and wighing h hull sparad. Th ffc of acid and bas ramn was sudid using h fracion raind on h 4 msh siv. Thr grams ach of milld hull was soakd ovrnigh in ihr 25 ml of.5m hydrochloric acid (HCl) or 25mL of.5m sodium hydroxid (NaOH). Th phs of h suprnaans wr.4 and 2.7 rspcivly. Th suprnaan was rmovd and ach fracion was washd hric wih 25 ml disilld war (dh 2 O). Th ph of h acid rad sunflowr sd hull (SSH) was hn adjusd o ph 5. wih drops of M NaOH whil h bas rad SSH was adjusd o ph 5.5 wih drops of M HCl. Th w SSH was drid ovrnigh a 7 o C in a forcd air drying ovn o consan wigh. Th drid sunflowr sd hull (DSSH) was usd in h adsorpion characrisics sudis. II.2 Prparaion of Azur Dy soluion Azur dy (C 4 H 4 N 3 SCl; MW 29.5 g mol - ) shown in figur was obaind from Sigma Co., S Louis, MO. Th dy showd a maximum absorbanc a wavlngh 6 nm. Sock dy soluion ( mm) was prpard by dissolving 29.5mg of Azur dy in dh 2 O and ohr concnraions wr prpard by diluion of h sock soluion. All h chmicals usd in his sudy wr in analyical grad. II.3 Dy biosorpion xprimns Bach biosorpion xprimns wr prformd in 5 ml plasic ubs conaining 2 mldy soluion wih vorx mixing. Aliquo of ml wr wihdrawn vry 5min for absorbanc masurmn a 6nm using a GENESYS 5 Scanning Spcrophoomr (Thrmo Scinific, Madison, WI, USA) o drmin h concnraion of dy. Th concnraion of azur dy was drmind from a calibraion plo of absorbanc a 6nm vrsus concnraion. Th calibraion plo was linar up o an Azur dy concnraion of mm. In ordr o drmin h ffciv biosorpion condiions, xprimns wr conducd wih boh acid and basd rad SSH, diffrn paricl sizs SSH, a diffrn ph valus, and iniial dy concnraions. To drmin h ffc of concnraion of azur dy on adsorpion capaciy,.2g of DSSH was wighd ino h 5mL plasic ubs and ml soluion of.5 M aca buffr ph 6. o ach ub followd by ml of diffrn concnraions (.5-.mM) of Azur dy sock soluions. To drmin h ffc of iniial ph on biosorpion characrisics of DSSH,.2 g of DSSH was wighd ino 5 ml plasic ubs and 2 ml of.mm soluion of Azur dy soluion whos ph had bn adjusd wih diffrn concnraions of HCL and NaOH. To drmin h ffc of paricl siz of DSSH on adsorpion of azur dy,.5 g of DSSH of diffrn paricl sizs (<25µm, 25 µm -425 µm, 425 µm -85 µm,>85 µm ) was wighd ino 5 ml plasic ubs and o ach ub was addd 2 ml of.5 mm soluion of Azur dy and vorx mixd vry n minus. All xprimns wr conducd a room mpraur 22.5 o C in riplicas. Th amoun of Azur dy biosorbd pr gram of DSSH was calculad using h following quaion (): V q C o C () M 27

3 Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic Whr q is h biosorpion of Azur dy pr gram of DSSH(mg g - ); C o is h iniial concnraion of Azur dy (mg L - ) and C is h concnraion a im (mg L - ); V is h oal volum of h suspnsion (L); M is h dry wigh (mass) of DSSH (g). Th prcn dy biosorbd (PDB) from aquous soluion by DSSH was calculad using quaion (2) : C o PDB %. (2) C Whr C is h Azur dy concnraion (mg L - ) a im and C o is h iniial dy concnraion (mg L - ) II.3. Kinic modling Th kinics of Azur dy biosorpion on DSSH was analyzd using hr kinic modls: h psudofirs ordr and psudo scond ordr and inraparicl diffusion modl [6,23]. Th psudo firs ordr kinics quaion is gnrally xprssd as: dq d k q q. (3) whr q is h biosorpion capaciy of Azur dy on DSSH a quilibrium drmind from xprimnal daa (mg g - ); q is h biosorpion capaciy of Azur dy by DSSH a a paricular im (mg g - ); k is h psudo-firs ordr ra consan (g mg - min - ). Afr ingraion and applying boundary condiions = and =, h ingrad form of quaion (3) bcoms Ln q q Lnq k.. (4) From h plo of Ln(q - q ) vrsus im (), k and q can b drmind from h slop and inrcp rspcivly. Th psudo scond-ordr kinics quaion is xprssd as dq d q q 2 k (5) 2 whr q is h biosorpion capaciy of Azur dy by DSSH a quilibrium drmind from xprimnal daa (mg g - ); q is h biosorpion capaciy of Azur dy by DSSH a a paricular im (mg g - ); k 2 is h psudoscond ordr ra consan (mg g - min - ). Afr ingraion and applying boundary condiions = and =, h ingrad form of quaion (5) bcoms q q q k (6) Equaion (6) can b rarrangd o obain a linar form q 2 k2q q (7) whr h (mg g - min - ) can b rgardd as h iniial sorpion ra as q -, hnc 2 h k q... (8) 2 Equaion. (7) hn bcoms q (9) h q If h psudo-scond ordr kinics is applicabl o h xprimnal daa, h plo of q - vrsus of quaion (9) should giv a sraigh lin, from which q and k 2 (h ra consan) can b drmind from h slop and inrcp of h plo. Th rsuls ar also analyzd in rms of inraparicl diffusion modl o invsiga whhr h inraparicl diffusion is h ra conrolling sp in biosorpion of Azur dy ono DSSH biomass. Th inraparicl diffusion quaion is xprssd as:.5 q K c. () id whr K id is h inraparicl diffusion ra consan (mg g - min -.5 ) and C is h inrcp. Saisical analyss (rgrssion rlaionship, -s for significanc of slop and inrcp valus, and -s for avrag valus) wr prformd using Microsof Excl 27. III. RESULT and DISCUSSION III. Effc of ramn on biosorpion capaciy of DSSH Figur 2 shows a plo of h biosorpion capaciy of DSSH afr 2 minu incubaion. Boh h acid and bas rad DSSH had a highr biosorpion capaciy han h non-rad DSSH. Boh h acid and bas rad DSSH wr saisically diffrn(p<.5) from h non-rad DSSH. Though, h bas rad DSSH 28

4 Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic (P=.8) was no significanly diffrn (P>.5) from h acid rad DSSH, h bas rad DSSH had a slighly highr biosorpion capaciy han h acid rad DSSH. Similar rsuls wr obaind wih wha sraw by Wang al. 22. According o hs auhors [9], bcaus in h surfac of wha sraw, hr is larg amoun of SiO 2 and non-aromaic srs. Howvr, h aquous NaOH ramn may mak srs and SiO 2 dissolvd ou and hn h cllulos, hmiclluloss, and lignin wr xposd. Thrfor, h mor aciv sis wr providd and biosorpion spcific surfac was incrasd, making for h incras of dy biosorpion ra. III.2 Effc of paricl siz Th paricl siz of h biosorbn has a significan influnc on h kinics of adsorpion. I furnishs imporan informaion of achiving opimum uilizaion of adsorbn and on h naur of brakhrough curvs. Ras of adsorpion on a solid surfac ar xpcd o vary wih availabl surfac ara for a conac adsorbn mass wih h paricl siz. Th adsorpion capaciy is dircly proporional o h paricl diamr for nonporous adsorbns. Th prsnc of a larg numbr of smallr paricls provids h adsorpion sysm wih a grar surfac ara availabl for dy rmoval [24]. Th bas rad DSSH was fracionad ino diffrn paricl sizs and h biosorpion capaciy of h diffrn sizs wr drmind. Figur 3 shows h plo of h biosorpion capaciy afr 2 minu incubaion. Th fracion raind by h 6 msh siz wih paricl siz grar han 25µm bu lss han 425 µm had h highs biosorpion capaciy and was usd in subsqun xprimns. Th paricl siz lss han 25µm was powdry. Prvious sudis hav also shown ha as h paricl siz dcrass h biosorpion capaciy incrass [24,25]. III.3 Effc of im on biosorpion Th ra of biosorpion is imporan for dsigning bach biosorpion xprimns. Thrfor, h ffc of conac im on h biosorpion of Cu(II) was invsigad. In addiion h ffc of im on adsorpion of dy on biomass has bn rpord in liraur [26]. Figur 4 shows h ffc of im on PDB which incrasd considrably unil h conac im rachd 2 minus. Furhr incras in conac im did no nhanc h biosorpion, so, h opimum conac im was slcd as 2 min for furhr xprimns. III.4. Effc of ph Prvious sudis in h liraur hav shown ha soluion ph is an imporan paramr affcing h biosorpion procss [,5,27]. Furhr, ph influncs surfac propris of h biosorbn by way of funcional group dissociaion and also surfac chargs [28]. Figur 5 shows h variaion of h biosorpion capaciy afr 2 minus wih diffrn ph valus. As h ph incrasd from 3.5 o 6. h biosorpion capaciy incrasd afr which i dcrasd a ph 6.5. Th PDB on h ohr hand incrasd as h ph incrasd for all ph valus. Th ph opimum for biosorpion of Azur dy by DSSH was around ph 6.. Th maximum dy upak capaciy of DSSH was found o b 2.5mg g a a ph valu of 6.3. Th biosorbn surfac has many diffrn funcional groups and h n charg on h biosorbn surfac is ph-dpndn. Thrfor, h ph of h mdium is an imporan nvironmnal paramr for dy rmoval from h aquous mdium []. I is wllknown ha ph can affc proonaion of funcional groups (i.. carboxyl, phospha and amino groups) in h biomass, as wll as h chmisry of h dy (i.. is solubiliy) [6]. III.4 Effc of Dy concnraion Figur 6 shows h ffc of dy concnraion on PDB and biosorpion capaciy a ph 6.. Th maximum PDB occurs a a dy concnraion of 2mg L - whil h biosorpion capaciy (BC) incrasd linarly wih concnraion. This was probably du o h incrasing driving forc in h concnraion gradin and incrasing lcrosaic inracions bwn surfac sis and dy [29]. Th linar rlaionship was fid o a sraigh lin BC =.9C o wih a corrlaion cofficin of.99, whr C o is h iniial dy concnraion in mg L -. III.5 Effc of biomass dosag Th numbr of sis availabl for biosorpion dpnds upon h amoun of h adsorbn. Th incras in h biosorpion prcnag wih incras in biomass dosag is du o incras in aciv sis on h adsorbn and hus making asir pnraion of h dy o h sorpion sis [28]. Figur 7 shows h plo of h PDB vrsus biomass dosag. As i can b sn from his figur, an incras in h biomass concnraion from 2.76 o 25. g L - h PDB incrasd from 47. % o 86. % afr 2 minus incubaion which is h maximum valu, whras h biosorpion capaciy of h DSSH dcrasd from.27 mg g - o.24 mg g -. A dcras in h biosorpion capaciy a highr biomass concnraion may b aribud o ovrlapping or parial aggrgaion of biosorpion sis on h biosorbn surfac. This fac rsuls in a dcras in ffciv surfac ara of h biosorbn availabl o h dy[,27,3]. Furhr incras in h biosorbn concnraion up o 3. g L did no significanly chang h PDB. This is du o h binding of almos all dy ions o biosorbn surfac and h 29

5 Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic sablishmn of quilibrium bwn h dy molculs on h biosorbn and in h soluion [27,3, 32]. Incrasing h biosorbn dosag causd an incras in h biomass surfac ara and in h numbr of ponial binding sis [6]. III.8 Biosorpion isohrms Th daa obaind from biosorpion xprimns ar gnrally rprsnd by quilibrium isohrms. Ths provid mor imporan paramrs for dsigning and opimizing of h biosorpion sysms. Diffrn isohrm modls can b usd o drmin h biosorpion characrisics of a biosorbn. In h prsn sudy h Azur dy biosorpion was analyzd by hr diffrn modls Langmuir, Frundlich and Dubinin Radushkvich (D R). Th daa wr fid and h calculad isohrm consans ar prsnd in Tabl. Th fundamnal assumpion of h Langmuir isohrm modl is ha biosorpion aks plac a spcific sis wihin h biosorbn. Onc a biosorba occupis a binding si, no furhr biosorpion occurs a his si. In h ohr words Langmuir modl assums ha biosorbd layr is on molcul hicknss (monolayr biosorpion) [33]. q qmaxkc K C L () whr q is h quilibrium biosorpion capaciy of Azur dy (mg g - ), C is h quilibrium Azur dy concnraion in h soluion (mg L - ), q max is h monolayr biosorpion capaciy of h biosorbn (mg L - ), and K L is h Langmuir consan (L mg - ) and is rlad o h fr nrgy of biosorpion. Th linarizd form of h Langmuir quaion is givn blow:.... (2) q qmax qmaxk L C Th ffc of isohrm shap has bn discussd [34]wih a viw o prdic whhr a biosorpion sysm is favorabl or unfavorabl. Th ssnial faur of h Langmuir isohrm can b xprssd by mans of R L, a dimnsionlss consan rfrrd o as sparaion facor or quilibrium paramr. R L is calculad by using quaion (3). R L K L C o (3) whr C o is h iniial Azur dy concnraion (mg L - ). Th valu of R L calculad using h abov quaion is incorporad in Tabl. If h R L valus li bwn and, h biosorpion procss is considrd o b favorabl [34]. Valus of K L and q max ar obaind from h inrcp and slop of h linar plos a various mpraur in Figur 8 and ar rprsnd in Tabl. Th R L valus obaind in his sudy wr in h rang , indicaing ha h biosorpion procss is favorabl. Th Frundlich isohrm is an mpirical quaion assuming ha h adsorpion procss bcoms on hrognous surfacs and adsorpion capaciy is rlad o h concnraion of Azur dy a quilibrium. Th Frundlich isohrm quaion is gnrally xprssd as follows[35] : q K F C n Th linarizd form is: (4) Lnq LnKF LnC (5) n whr q is h quilibrium Azur dy concnraion on h biomass (mg g - ); C is h quilibrium dy concnraion in h soluion (mg L - ); K F (L mg - ) and n (dimnsionlss Frundlich isohrm consan bing indicaiv of h xn of h biosorpion and h dgr of nonlinariy bwn soluion concnraion and biosorpion, rspcivly. Valus of K F and n ar obaind from h inrcp and slop of h linar plos a various mpraur in Figur 9 and ar rprsnd in Tabl.Th numrical valus of Frundlich consan of n wr bwn.667 and.678, which ar a masur of h dviaion from linariy of h biosorpion [3]. Thy wr grar han uniy, a 3 and 35 o C indicaing ha Azur dy is favorably adsorbd by DSSH a all hs mpraurs. Th Dubinin Radushkvich (D R) isohrm is mor gnral han h Langmuir isohrm sinc i dos no assum a homognous surfac or consan biosorpion ponial [36]. Th D R isohrm modl dscribs h biosorpion naur of h sorba on h biosorbn and i is usd o calcula h man fr nrgy of biosorpion. Th characrisic biosorpion curv is rlad o h porous srucur of h biosorbn according o his modl. Th linarizd form of (D R) quaion can b wrin as: 2 Lnq Lnq (6) m 3

6 Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic whr q m is h biosorpion capaciy of h biosorbn (mg g - ), β is a consan rlad o h biosorpion nrgy, ε is Polanyi ponial which can b prsnd as: RTLn * C.....(7) whr R is h univrsal gas consan (8.34 J mol - K - ) and T is h mpraur (K). Th valus of D R isohrm consans, β and q m wr obaind from h slop and inrcp of h linar plo prsnd in Figur. Th consan β givs an ida abou h man fr nrgy of biosorpion and E valu can b compud using h following rlaionship. E ˇ (8) Th magniud of E valu characriz h yp of h biosorpion as chmical ion xchang (E = 8 6 kj mol - ) [37], or physical sorpion (E<8kJ mol - ) [38]. Th man fr nrgy of biosorpion (E) is found bwn.55 and kj mol - a diffrn mpraurs, which implis ha, h biosorpion of Azur dy on DSSH may b considrd as physical biosorpion and q m h horical sauraion capaciy varid bwn.979 and 6.55 mg g -. According o h corrlaion cofficin r 2 valus in Tabl I boh h Langmuir and Frundlich isohrms modl fi h Azur dy biosorpion daa br han h D-R isohrm modl a all sudid mpraurs. III.9 Thrmodynamic analysis of dy rmoval procss Th quilibrium biosorpion capaciy of Azur dy ono DSSH was favord a lowr mpraurs. Th hrmodynamics consans ar prsnd in Tabl II. Th quilibrium consan incrasd from 23 o 35 o C hn dcrasd as h mpraur was incrasd o 45 o C indicaing a dcras in h biosorpion capaciy. In ordr o drmin h mpraur dpndnc of h dy rmoval procss by DSSH, h changs in h hrmodynamic paramrs (fr nrgy (ΔG * ), nhalpy (ΔH * ) and nropy (ΔS * )) wr analyzd using h Langmuir quilibrium (K L ). Th following quaions wr usd o calcula h hrmodynamic paramrs. ΔG *= - RT Ln K L.... (9) ΔG* ΔH* ΔS* ln KL = - = (2) RT RT R Th Van Hoff plo of Ln K L as funcion of * T - from 23 o 35 o C is shown in Figur yilds a sraigh lin wih a corrlaion cofficin of.96 from which ΔH * and ΔS * wr calculad from h slop and inrcp rspcivly. Th ngaiv valus of ΔG * indica ha h biosorpion procss was sponanous in naur and confirm h affiniy of h biosorbn owards h dy molculs. Th ngaiv valu of ΔH * (-28.5 kj mol - ) suggss h xohrmic naur of h biosorpion procss. Th posiiv nropy valu of (59.78 J mol - ) indicas incrasd randomnss a h solid/liquid inrfac during h biosorpion procss whil low valu of ΔS indicas ha no rmarkabl chang on nropy occurs [39-4] III. Biosorpion kinics Biosorpion kinics dpnds on h sorba sorbn inracions and opraing condiions. Svral kinic modls ar availabl o undrsand h bhavior of h adsorbn and also o xamin h conrolling mchanism [28]. In his sudy, h biosorpion quilibrium daa wr analyzd using hr kinic modls, psudo-firs-ordr, psudo-scond-ordr and inraparicl diffusion modl. Th kinic sudis wr carrid ou o drmin h fficincy of Azur dy adsorpion ono DSSH. Th biosorpion capaciy incrasd wih h iniial dy concnraions whil h PDB had a maximum a a dy concnraion of 2 mg L - Figur 6. From h firs psudo-firs ordr quaion (4) [23] valus of k calculad from h slop of h plos of from h plo of Ln(q -q ) vrsus im () ar givn in Tabl III. I was found ha h corrlaion cofficins for h firsordr modl ar lowr han ha for h psudo-scond-ordr modl. This implis ha h biosorpion procss dos no follow firs-ordr kinics. For h psudo-scond-ordr kinic modl quaion (7) [23,27], a plo of * q - vrsus (Figur 2), valus of k 2 and q 2 wr calculad. Ths paramrs ar summarizd in Tabl 3. Th calculad q valus agr wih xprimnal q valus and h corrlaion cofficins for h psudo-scond ordr kinic plos wr vry high. Ths rsuls suggsd ha h biosorpion sysm sudid follows h psudo-scond ordr kinic modl. Similar rsuls hav bn obsrvd wih panu hull [6]. Th psudoscond-ordr ra consans for h biosorpion of Azur dy ono DSSH show a sady incras wih DSSH dosag. Th valus of ra consans wr found o dcras from o gm g - min - wih an incras in biomass dosag from.7 o 3. mg L - (Tabl 3).Th valus of k 2 h scond ordr ra consan and h h iniial biosorpion ra wr corrlad o h iniial concnraion by h following rlaionships K C o 3

7 Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic.49C H.459 o Th corrlaion cofficin for hs rlaionships wr.98 and. 93 rspcivly. Similar rlaionships wr obaind for h biosorpion of mhyln blu ono palm krnl fibr [42]. Figur 3 shows h plo of q vrsus h squar roo of im ( /2 ). I was obsrvd ha all h plos hav an iniial curvd porion, followd by a linar porion and a plaau rgion. This kind of muli-linariy in h shap of h inraparicl diffusion plo has also bn obsrvd in h biosorpion of mhyln blu by palm krnrnl fibr [42]. Th hr phass in h inraparicl diffusion plo suggs ha h sorpion procss procds by surfac sorpion, inraparicl diffusion and a likly chmical racion sag. Th iniial curvd porion of h plo indicas a boundary layr ffc; h scond porion is du o inraparicl diffusion whil h hird linar porion is likly du o chmical racion. Th iniial curv of h plo is du o h diffusion of dy molcul hrough h soluion o h xrnal surfac of DSSH biomass. Th linar porion of curvs dscribs h gradual biosorpion sag, whr inraparicl diffusion of dy molcul on DSSH aks plac and final plaau rgion indicas quilibrium upak. Th slop of h scond porion of h plo is dfind as h inraparicl diffusion paramr K id (mg g - min -.5 ). On h ohr hand, h inrcp of h plo rflcs h boundary layr ffc. Th lagr h inrcp, h grar h conribuion of h surfac sorpion in h ra limiing sp. Th ra consans of inraparicl diffusion modl K id ar shown in Tabl 3. Th valus incrasd from.6 o.24 (mg g - min -.5 ) as h concnraion incrasd from.73 mg L - o 28.5 mg L - hn dcrasd o.6(mg g - min -.5 ) a 3. mg L -. Basd on h rsuls i may b concludd ha inraparicl diffusion is no only h ra drmining facor [28]. III. FTIR analysis In ordr o confirm h prsnc and naur of h binding sis on DSSH and hir involvmn during biosorpion of Azur dy, FTIR sudis wr carrid ou. Lignin and cllulos ar h main componns of agriculural and plan marials. Thy also includ hmiclluloss, xracivs, lipids, proins, simpl sugars, sarchs, war, hydrocarbons, ash and many mor compounds. Ths componns hav many diffrn funcional groups rsponsibl for biosorpion procsss. Th funcional groups on h biosorbn surfac ar h vidnc of h prsnc of som of hs componns and of rsponsibiliy for h biosorpion of Azur dy. Th FTIR spcra wr rcordd in h rgion from 7 o 4 cm - for boh DSSH ((Fig. 4a) and dyloadd DSSH biomass (Fig. 4b ). Thr wr significan similariis in h spcra bfor and afr biosorpion, suggsing ha h componns and srucur of DSSH rmaind inac. Pak posiions wr noicd a , , , , and 3.72 cm. Th bands a ar du o O-H and N-H srching. Whil h bands a rprsns h CH 2 asymric srching vibraion. Th band a rflc N-H bnding [43]. Band a corrspond o N-H ppid amid II [44] and band a 3.72 cm - corrspond o C-O srching. Compard wih h FTIR spcra of h dy loadd DSSH (Fig.4b), h band innsiy a , , , , and 3.72 cm shifd o , , 735.9, , and 28.7 cm - rspcivly. Addiional bands wr obsrvd a 57, and cm -. Corrsponding o N=N groups bnding and C-N srching rspcivly [43]. Th innsiy of h bands incrasd afr Azur dy biosorpion dmonsraing ha hr was racions of Azur dy wih hydroxyl, amin, N=N groups. Th innsiis of h paks a abou cm - on h FTIR spcrum of h dy loadd DSSH biomass, ascribd o CH 2 srching vibraions wr srongr. Ths findings show possibly involvmn of h funcional groups on h biosorbn surfac in biosorpion procss. IV. CONCLUSION Biosorpion of Azur A chlorid dy from aquous soluion by drid milld sunflowr sd hull was sudid as a funcion of paricl siz, iniial ph, iniial biomass concnraion and acid bas ramn. Acid and bas ramn affcd h dy adsorpion propris of h milld hull. Paricls raind by siv >25 µm and < 425 µm had h highs adsorpion capaciy. Th opimum ph for azur dy adsorpion was around 6.. Th valus of pr cn dy biosorbd (PDB) and biosorpion capaciy (BC) incrasd wih im of conac, dosag of drid sunflowr sd hull. Th xprimnal daa fid wll o Langmuir and Frundlich isohrms modl. Th ngaiv valus of ΔG * confirmd a favorabl biosorpion procss a all sudid mpraurs. Th biosorpion procss is also xohrmic in naur. Exprimnal daa wr analyzd in rms of psudo-firs ordr, psudo-scond ordr and inraparicl diffusion kinic modls. Th psudo-scond-ordr kinic modl was obsrvd o provid h bs corrlaion of h xprimnal daa among h kinic modls sudid. To sum up, sunflowr sd hull, has a ponial o b usd as a biosorbn marial for h rmoval of Azur A chlorid dy from aquous soluions bcaus of a by produc of sunflowr oil producion, is low cos, high biosorpion capaciy and rasonabl rapid ra of biosorpion. 32

8 Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic REFERENCES []. S. T. Akar,A. Safa Özcan,T. Akara,A. Özcan and Z. KaynakBiosorpion of a raciv xil dy from aquous soluions uilizing an agro-was. Dsalinaion, 249: [2]. Y. S. Ho, T. H. Chiang, and Y. M. Hsuh, Rmoval of basic dy from aquous soluion using r frn as a biosorbn. Procss Biochm., 4: [3]. G. McKay, S. J. Alln, I. F. McConvy and M. S. Orburn. Transpor procsss in h sorpion of colord ions by pa paricls. J. Colloid Inrfac Sci., 8: [4]. S. S. Nawar, and H. S. Doma..Rmoval of dys from ffluns using low-cos agriculural by-producs, Sci. Toal Environ., 79: [5]. R. Gong, Y. Ding, M..Li, C. Yang, H. Liu and Y. Sun, Y. Uilizaion of powdrd panu hull as biosorbn for rmoval of anionic dys from aquous soluion. Dys and Pigmns, 64: [6]. A. Wik-Krowiak, R. G. Szafran and S. Modlski. Biosorpion of havy mals from aquous soluions ono panu shll as a low-cos biosorbn. Dsalinaion, 265: [7]. Y. S. Ho, W. T. Chiu and C. C. Wang, Rgrssion analysis for h sorpion isohrms of basic dys on sugarcan dus. Biorsourc Tchnol., 96: [8]. T. Robinson, B. Chandran, and P. Nigam, Rmoval of dys from a synhic xil dy fflun by biosorpion on appl pomac and wha sraw, War Rs., 36: [9]. X. Wang, L. Xia, K. Tan and W. Zhng. Sudis on Adsorpion of Uranium (VI) from aquous soluion by wha sraw. Environ. Prog. and Susain. Enrgy, 3: []. G. McKay, J, F. Porr and G. R. Prasad, Th rmoval of dy colors from aquous soluions by adsorpion on low-cos marials. War Air Soil Pollu., 4 : []. A. E. Ofomaja, and Y.S. Ho. Equilibrium sorpion of anionic dy from aquous soluion by palm krnl fibr as sorbn. Dys and Pigmns, 74: [2]. G. Annadurai, R.S. Juang and D.J. L Us of cllulos-basd wass for adsorpion of dys from aquous soluions, J. Hazard. Mar., B92: [3]. A. Chaparadza and J.M. Hossnlopp. Adsorpion kinics, Isohrms and hrmodynamics of arazin rmoval using a banana pl basd sorbn. War Scinc and Tchnology, 65: [4]. C. Namasivayam, R, Radhika and S. Suba Upak of dys by a promising locally availabl agriculural solid was: coir pih. Was Managmn., 2 : [5]. R. M. Livrsidg, G.J. Lloyd, D.A.J. Was, and C.F. Forsr. Rmoval of Basic Blu 4 dy from aquous soluion by linsd cak. Procss Biochm., 32: [6]. M. Özacar, and I. A. Şngil, A kinic sudy of mal complx dy sorpion ono pin sawdus, Procss Biochm., 4: [7]. S.P. Raghuvanshi, R, Singh,C. P. Kaushik and A.K. Raghav Rmoval of xil basic dy from aquous soluions using sawdus as bio-adsorbn. In. J. Environ. Sud., 62: [8]. M.N. Sahmoun, and N. Ouazn. Mass-ransfr procsss I h adsorpion of caionic dy by sawdus. Environ. Prog. and susain nrgy, 3: [9]. W. K. Tror, H, O. Doy, Jr. W, D. Givan and J. V. Lawlr, Ponial for Oilsd sunflowrs in h Unid Sas. US Dparmn of Agriculur Economic Rsarch Srvic AER [2]. Naional Agriculural Saisics Srvic (NASS), Acrag rpor. Agriculural Saisics Board, Unid Sas Dparmn of Agriculur (USDA), hp://usda.library.cornll.du/usda/currn/acr/acr pdf 22. [2]. FAO Unid Naion Food and Agriculural Organizaion. Major food and Agriculural commodiis and producrs. FAO [22]. Norh Dakoa Agriculural Exprimn Saion and Norh Dakoa Sa Univrsiy Exnsion Srvic, Sunflowr Producion. Exnsion Publicaion A- 33,hp:// ok.pdf.27. [23]. S. Xu,S, Zhang, K, Chn, J. Han, H, Liu, H. and K. Wu, K. Biosorpion of La 3+ and C 3+ by Agrobacrium sp. HN. J. Rar Earhs, 29: [24]. S.D. Khari, and M.K. Singh, Us of Sagun sawdus as an adsorbn for h rmoval of crysal viol dy from simulad waswar. Environ. Prog, and Susain. Enrgy, 3: [25]. M. S. El-Gundi 997. Adsorbn for indusrial polluion conrol, Adsorpion Scinc and Tchnology, 5: [26]. R. G. Sanchz-Duar, D. I. Sanchz-Machado, J. Lopz-Crvans, and M.A. Corra-Murria, Adsorpion of Azur dy by cross-linkd chiosan from shrimp was. War Scinc and Tchnology, 65:

9 Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic [27]. I. Kiran, T, Akara, A, Safa Ozcanb, A., Ozcanb, and S. Tunali. Biosorpion kinics and isohrm sudis of Acid Rd 57 by drid Cphalosporium aphidicola clls from aquous soluions. Biochmical Enginring Journal, 3: [28]. M.V. Subbaiah, Y, Vijaya, A, Subba Rddy, G. Yuvaraja, and A. Krishnaiah, Equilibrium, kinic and hrmodynamic sudis on h biosorpion of Cu(II) ono Trams vrsicolor biomass. Dsalinaion, 276: [29]. S. Ozdmir, F.M. Bklr, V, Okumus, A, Dundar, and E. Kilinc, Bisorpion of 2,4-D, 2,4-DP, and 2,4-DB from aquous soluion by using Thrmophilic Anoxybacillus flavihrmus and analysis by high prformanc hin layr chromaography: Equilibrium and kinic sudis. Environ. Prog. Susain. Enrgy, 3: [3]. Malik, P.K., 24. Dy rmoval from waswar using acivad carbon dvlopd from sawdus adsorpion quilibrium and kinics. J. Hazard. Mar., 3: [3]. N. Kannan, and M.M. Sundaram. Kinics and mchanism of rmoval of mhyln blu by adsorpion on various carbons a comparaiv sudy, Dys and Pigmns, 5: [32]. Y. S. Ho, and G. McKay, Sorpion of dy from aquous soluion by pa. Chm. Eng., J. 7: [33]. I. Langmuir, Th adsorpion of gass on plan surfacs of glass, mica and plainum, J. Am. Chm. Soc., 4: [34]. K. R. Hall, L.C. Eaglon, A, Acrivos and T. Vrmuln, Por- and solid-diffusion kinics in fixdbd adsorpion undr consan-parn condiions. Ind. Eng. Chm. Fundam., 5: [35]. H.M.F. Frundlich. Ubr di adsorpion in losungn, Z. Phys. Chm. 57: [36]. M.M. Dubinin, and L.V. Raduskhvich, Th quaion of h characrisic curv of h acivad charcoal. Proc.Acad.Sci.U.S.S.R Phys.Chm. Sc., 55 : [37]. F. Hlffrich. Ion Exchang, McGrawHill, Nw York. 962 [38]. M. S. Onyango,Y, Kojima, O, Aoyi, E,C. Brnardo and H. Masuda Adsorpion quilibrium modling and soluion chmisry dpndnc of fluorid rmoval from war by rivaln-caionxchangd zoli F-9. J. Colloids Inrfac Sci., 279: [39]. K. V. Kumar, S. Sivansan and V. Ramamurhi Adsorpion of malachi grn ono Pihophora p., a frsh war alga: Equilibrium and kinic modling. Procss Biochm., 4: [4]. Wang, B., Hu, Y., Xi, L,.and Png, K., 28. Biosorpion bhavior of azo dy by inaciv CMC immobilizd Asprgillus fumigaus bads. Biorsourc Tchnol., 99: [4]. T. Akar,A, Safa Ozcan, S, Tunali, and A. Ozcan Biosorpion of a xil dy (Acid Blu 4) by con biomass of Thuja orinalis: Esimaion of quilibrium, hrmodynamic and kinic paramrs. Biorsourc Tchnology, 99: [42]. A. E. Ofomaja, Kinics and mchanism of mhyln blu sorpion ono palm krnl fibr. Procss Biochmisry, 42: [43]. M. Aramia,N, Y. Limaa, N. M. Mahmoodia and N.S. Tabrizia.. Equilibrium and kinics sudis for h adsorpion of dirc and acid dys from aquous soluion by soy mal hull. J. of Hazard. Mar., B35: [44]. J. Gao. J. Wang, C., Yang, S., Wang, and Y. Png, Binary biosorpion of Acid Rd 4 and Raciv Rd 5 ono acid rad okara: Simulanous spcrophoomric drminaion of wo dys using parial las squars rgrssion. Chmical Enginring Journal, 7: Tabl I. Biosorpion Isohrm consans a various mpraurs Tmp.( o C) Frundlich Langmuir Dubinin-Radushkvich (D-R) K F * n R 2 K L ** q m * R L R 2 q m β *** E **** R *Uni of K f and qm: mg g - ** Uni of K L : L mg - *** Uni of β : mol 2 kj -2 **** Uni of E : kj mol - 34

10 Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic Tabl II. Thrmodynamic paramrs calculad from h Langmuir consan (K L ) for h Biosorpion of Azur dy ono DSSH a various mpraurs. Tmp. ( O C) K L ΔG * (kj mol - ) ΔH * (kj mol - ) ΔS * (J/K mol) Tabl III. Kinic paramrs for h biosorpion of Azur Dy ono DSSH a various dy concnraions Concnraio n (mg L - ) k (min - ) q (mg g-) q 2 (mg g - ) R 2 R 2 R 2 k 2 (g mg min ) K id (mg g m in.5).7.8± ± ±..± ±.9.4± ±.2.46± ±.7.24± ±.4.7± ±.8.8±.4.9.3±. 2.26± ±.9.47± ±. 2.7± ±.3.3± ±. 2.88± N Cl - HN S + N CH 3 CH 3 CH 3 Fig. : Chmical srucur of Azur Chlorid A dy 35

11 Biosorpion Capaciy q(mg g - ) Biosorpion Capaciy q (mg g - ) Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic Acid Trad DSSS Bas Trad DSSS No Tramn DSSS DSSS Tramn Fig.2: Effc of prramn on biosorpion capaciy of DSSH <25µm >25µm <425µm >425µm < 85µm >85µm Paricl siz Fig. 3: Effc of paricl siz on biosorpion capaciy of DSSH 36

12 % Dy Biosorbd (PDB) Biosorpion Capaciy q (mg g - ) % Dy Biosorbd (PDB) Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic Tim (min) Fig 4: Effc of im on bisorpion of Azur Dy on DSSH ph 37

13 % Dy Biosorbd (PDB) Biosorpion Capaciy q (mg g - ) % Dy Biosorbd (PDB) Biosorpion Capaciy q (mg g - ) Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic Fig. 5: Effc of ph on % dy biosorbd (PDB) ( ) and biosorpion capaciy ( ) of DSSH Azur Dy concnraion (mg L - ) Fig. 6: Effc of dy concnraion on prcn dy biosorbd PDB ( ) and biosorpion capaciy ( ) PDB vs DSSH BC vs DSSH Concnraion of DSSH (g L - ) 38

14 log q q- Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic Fig. 7: Effc of biosorbn dosag on h PDB( )and biosorpion capaciy ( ) a room mpraur C - Fig. 8: Langmuir isohrm plos for h biosorpion of Azur dy by DSSH a diffrn mpraurs.. (җ) 23 o C ( ) 25 o C; ( ) 3 o C ; ( ) 35 o C;(X) 4 o C;; (O) 45 o C logc Fig. 9: Frundlich isohrm plos for h biosorpion of Azur dy by DSSH a diffrn mpraurs. (җ) 23 o C ( ) 25 o C; ( ) 3 o C ; ( ) 35 o C;(X) 4 o C;; (O) 45 o C 39

15 Ln q Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic ɛ 2 Fig. : D R isohrm plos for h biosorpion of Azur dy by DSSH a diffrn mpraurs. (*) 23 o C ( ) 25 o C; ( ) 3 o C ; ( ) 35 o C;(X) 4 o C;; (O) 45 o C T - (K - ) Ln K L y = -5456x R² =.963 Fig. : Plo of Ln K L vrsus T - for simaion of hrmodynamic paramrs 4

16 q (mg g - ) q - (min g mg - ) Biosorpion of Azur Dy wih Sunflowr Sd Hull: Esimaion of Equilibrium, Thrmodynamic 4 for h biosorpion of Azur dy ono DSSH Tim (min) Fig.2: Psudo-scond-ordr kinic plos for h biosorpion of various Azur dy concnraions (+).7 mg L - ; ( ) 5. 2 g ml - ; ( ) 7.85 mg L - ;( ) 23.5 mg L - ; ( X ) 28.5 mg L - ; ( O )3.75mg L - ono DSSH Tim -.5 Fug. 3: Inraparicl diffusion kinic modl plos for h biosorpion of various Azur dy concnraions (*).7 mg/l; ( ) 5. 2 g/l; ( ) 7.85 mg/l;( ) 23.5 mg/l; ( X ) 28.5 mg/l ; ( O )3.75mg/L ono DSSH 4