Bioreduction of Thallium and Cadmium Toxicity from Industrial Wastewater using Microalgae

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1 A publicaion of CHEMICAL ENGINEERING TRANSACTIONS VOL. 57, 7 Gus Ediors: Sauro Pirucci, Jiří Jaromír Klmš, Laura Piazza, Srafim Bakalis Copyrigh 7, AIDIC Srvizi S.r.l. ISBN ; ISSN Th Ialian Associaion of Chmical Enginring Onlin a Biorducion of Thallium and Cadmium Toxiciy from Indusrial Waswar using Microalga Zainab S. Birungi*, Evans M.N. Chirwa War Uilisaion and Environmnal Enginring Division, Dparmn of Chmical Enginring, Univrsiy of Proria, Proria, Souh Africa zdbirungi@gmail.com Thallium (Tl) and Cadmium (Cd) ar lisd among prioriy mallic polluans known o caus irrvrsibl halh ffcs and asily magnify in h highr rophic lvls of h food chain. Micro alga has a divrsiy of spcis found in frshwar bodis bu only a fw hav bn xplord for hir biosorpion ponial as compard o macro alga. Th sudy sourcd microalga from urophic frshwar body (Harbspoor dam) in Souh Africa and isolad using srak plaing chniqu. Th pur srains wr idnifid using molcular mhods of 8S ribosomal RNA gn (rrna) as and. Th pur srains wr hn culurd in h laboraory and usd o drmin h adsorpion ponial and rcovry of Tl and Cd. Equilibrium and kinic xprimns wr usd o sima sorpion capaciy and ra of racion rspcivly. Th ffc of iniial concnraion on Cd and Tl adsorpion was also sudid. Th alga was characrizd o drmin h aciv funcional groups on h algal surfac wall using Fourir Transform Infra-rd spcroscopy (FTIR). From h sudy, rmoval fficincy was achivd a % for lowr concnraions of 5 mg/l of Tl. A highr concnraions in a rang of 5-5 mg/l Tl, h prformanc of and was sill high wih sorpion capaciy ( q ) of and mg/g rspcivly. Cd rmoval was highs for a q of mg/g and affiniy ( b ) of. L/g. Whn compard o ohr sudis on Tl and Cd adsorpion, h sd alga showd a rlaivly br q han mos adsorbns. Th kinic sudis showd br corrlaion co-fficin of.99 for Psudo-scond ordr modl () han h firs ordr modl. Rcovry of Tl was achivd highs for a 93.6% and Cd was highs for a 9.9% using niric acid. Th srongs funcional groups rsponsibl for Tl and Cd binding on h algal cll wall wr carboxyl and amins. Microalga from frshwar bodis showd significan ponial for Tl and Cd rmoval/rcovry from indusrial waswar.. Inroducion Toxic mals ar dircly or indircly rlasd ino h nvironmn mainly hrough anhropognic rlad aciviis. Mallic spcis ar non-biodgradabl and can only b rmovd physically or chmically from conaminad waswar (Ahluwalia and Goyal, 7). Cadmium is on of h criical mals wih a vry high dmand in indusrial applicaions. Cadmium is usually rlasd as a by-produc in waswar causing polluion vn a vry low concnraion along h food chain. Acu and Chronic ffcs of Cd poisoning includ bronchiis, pnumoniis, oxmia in h livr, vrigo, diarrhoa, abdominal pain, kidny damag. Thallium is anohr highly oxic lmn comparabl o mrcury, cadmium and lad bu wih limid informaion on disprsion in h nvironmn. Thallium asily rplacs poassium in h biological funcioning of h cll mmbran du o similar ionic charg and radii (Pr and Viraraghavan, 5). Th ngaiv ffcs of xposur includ ncphalopahy, achycardia, mild gasro insinal disurbancs, dgnraiv changs in kidny, livr, har, alraion of nrvous sysm and vnually dah. Convnional ramn chnologis hav bn usd for dcads for h rmoval of oxic havy mals bu hs chnologis sm o opra rlaivly wll for ffluns conaining highr mal concnraions mg/l (Aziz, al., 8). Th common failur of adsorpion procsss is h lack of slciviy for h arg mals and h high cos of

2 opraion du o high nrgy rquirmns. Th us of biological marial is an mrging and nvironmnally frindly chnology wih gra prospcs o ffcivly clan up oxic mals a low concnraions and possibl rcovry for r-us in indusry (Volsky, 7). Various living and dad organisms hav bn invsigad for mal rmoval. Th living biomass accumulas high lvls of mals bu possibl rcovry wihou cll disrupion sms almos impossibl. Biosorpion is a rm ofn usd o rfr o h ramn of waswar conaining havy mals using dad biomass. Th us of dad biomass has aracd mor anion as i offrs h possibiliy of rgnraion and rus of h biosorbn. Among h biosorbns sd, micro alga hav provn o b br sorbns in crain cass mainly du o h consiuns of hir cll wall wih a highr upak capaciy for mals compard o fungi, bacria and yas (Mha and Gaur, 5). A variy of microalga xis bu only a fw hav bn invsigad for hir sorpion capaciy. This sudy invsigad h ponial rmoval/rcovry of Cd and Tl from waswar using was micro alga.. Marials and Mhods. Algal Idnificaion and Culur Th plankonic alga wr collcd from a urophic dam in Harbspoor dam, Souh Africa and h pur srains isolad using srak plaing chniqu and idnifid using h Inrnal ranscribd spacr (ITS) and 8S ribosomal RNA gn (rrna). Phylognic analysis of squncs was chckd for similariy using a basic local alignmn sarch ool (BLAST). Th sampls idnifid as and Scndsmus acuminuus. Th pur srains wr culurd in AF6 mdium undr conrolld condiion using algal ligh (Osram L 36W/77 Flour a a mpraur of -3 C. Th alga was harvsd vry wo wks, cnrifugd and washd wic in dionisd war bfor drying in h ovn for 4 hours a 5 C.. Equilibrium and Kinic Exprimns A sandard sock soluion of mg/l of Cd + and Tl + was usd o prpar iniial mal concnraions. Th mal concnraions usd wr in h rang of 5-5 mg/l for Cd and 5-5 mg/l for Tl. Equilibrium xprimns wr carrid ou concurrnly wih kinic xprimns. Th sampls wr sirrd on a magnic sirrr a a consan spd of 35 rpm. Sampls wr wihdrawn a pr-drmind im inrvals for kinic xprimns and afr 6 hours for quilibrium xprimns. Th sampls wr cnrifugd for minus a 6 rpm and h filra analysd using h Inducivly Coupld Plasma (ICP, Spcro Arcos FHS, Boschsroiss, Grmany)..3 Characrisaion of Funcional Groups Th funcional groups on h algal cll wall wr idnifid using h Fourir Transform Infrard (FTIR) spcrum, (Prkin Elmr ). Th algal sampls bfor and afr adsorpion wr ach placd on h diamond sag o obain h spcrum. Daa was procssd wih diffrn paks aaind o rprsn h funcional groups..4 Adsorpion/Dsorpion Exprimns for R-us Th alga was sd for hir r-usabiliy for h rmoval and rcovry of sd mals using niric acid (HNO3). Th mal ladn biomass was rinsd wic in dionisd war o rmov rsidual soluion and wighd. Th wighd biomass was addd o 5ml of.m of lun (HNO3) and sirrd on a magnic sirrr for a priod of 4-6 hours. Th xprimn was carrid ou in duplicas. Th sampl was drawn a h nd of h xprimn, cnrifugd and h suprnaan analysd for mal analysis. 3. Rsuls and Discussion 3. Empirical Modls for Singl Mal Sysms Empirical modls for singl mal sysms ar usd o rprsn quilibrium daa from biosorpion xprimns. Ths modls drmin h ponial adsorpion fficincy of diffrn biosorbns (Mha and Gaur, 5; Korba, ). Th mos commonly usd modls ar h Langmuir isohrm which drmins h sorpion capaciy and affiniy, h ohr is h Frundlich modl which drmins h biosorpion quilibrium consan ( k ) and biosorpion innsiy ( n ). In his sudy, h Langmuir and Frundlich quaions (Eq) ar rprsnd in linarisd form as Eq( and ) rspcivly. C C q q bq ()

3 log q log k nlog C () Th rsuls from h sudy showd ha and had a br fi for Langmuir modl han Frundlich modl wih a corrlaion cofficin ( R ).9, Figur. showd a highr for boh Cd and Tl adsorpion of and mg/g rspcivly, Tabls &. Th q affiniy for binding mals o h algal sorbns was highs for in Tl adsorpion a.49 L/g. Som adsorbns from liraur wr compard wih sd algal spcis for sorpion capaciy, h lar showd a significanly highr q han formr for Tl adsorpion bu only showd highs q for Cd adsorpion, Tabl y=.57x R =.965. y= R =.96 C/q (g/l).8.7 C/q (g/l).5..6 Langmuir modl.5 Langmuir modl C (mg/l) C (mg/l) y=.x +.7 R = y=.x +.3 R = C/q (g/l)..5. C/q (g/l) Langmuir modl. Langmuir modl C (mg/l) C (mg/l) Figur : Graphical rprsnaion of h Langmuir modl for, Cd adsorpion, Tl adsorpion Tabl : Equilibrium modl consans for adsorpion of Cd using sd alga Algal spcis Langmuir consans Frundlich consans q (mg/g) b (L/g) R n K R Tabl : Equilibrium modl consans for adsorpion of Tl using sd alga Algal spcis Langmuir consans Frundlich consans q (mg/g) b (L/g) R n K R

4 Tabl 3: Comparison of sorpion capaciy wih ohr adsorbns Adsorbn Cd q (mg/g) Tl q (mg/g) Rfrncs Sargassum sp (Shng, al., 4) Odogonium sp (Gupa and Rasogi, 8) Lacic acid bacria (Halunn, al., 7) Modifid sugar b pulp (Zolgharnin, al., ) Acivad coal (Zolgharnin, al., ) Modifid ucalypus (Khavidaki, al., 3) Currn sudy Currn sudy 3. Effc of Iniial Concnraion Th ffc of iniial concnraion on h adsorpion of Cd and Tl was sd. A a known iniial concnraion of 5mg/L, Cd was high for h firs 5 minus wih.3 and. mg/l rmovd for and rspcivly, Figur a. An incras in im showd a rlaivly slow Cd rmoval of abou mg/l rmovd vry hours wih 9 mg/l lf afr 36 minus. Rmoval of Tl was significanly rmovd by boh s alga from iniial concnraion of 5 mg/l o 4.38 and 8.3 mg/l for Chlorlla vulgaris and rspcivly in h firs 5 minus. In h prcding minus, rmoval was slowr bu hn showd an incras o and.78 mg/l for and rspcivly, Figur b. 5 5 C(mg/L) C (mg/l) Figur : Effc of iniial concnraion on; Cd adsorpion and Tl adsorpion using slcd alga 3.3 Characrisaion of Funcional Groups for Adsorpion Th rsuls from FTIR indicad a rlaivly similar rnd for h ransmianc for boh h sd alga wih minimal diffrncs wavlngh. showd a highr shif from 358 o 33 cm - implying a mdium O-H srch of carboxylic bond and a lowr frquncy of 6cm - for amins. Scndsmus acuminuus also showd a highr frquncy of 3373 cm - indicaing primary and scondary amins Figur % ransmianc 6 8 % ransmianc 6 8 Bfor adsorpion Afr adsorpion Bfor adsorpion Afr adsorpion wavlngh (cm - ) wav lngh cm - Figur 3: FTIR ransmianc bfor and afr adsorpion for h sd alga

5 3.4 Kinic Modlling of Singl Mallic Sysms Kinic modls provid informaion ha can b uilisd in h dsign and opimisaion of opraion sysms. Th firs ordr modl and Psudo scond ordr modl () usd in his sudy wr linarizd as shown in Eq(3 and 4) rspcivly. Th gnrally showd a highr corrlaion cofficin.9 han firs ordr modl, Figur 4. log q q q logq k.33 q (4) k q (3) /q (mg.min/g) 4 3 /q(mg.min/g) /q (mg.min/g).6.4 /q(mg.min/g) Figur 4: Psudo scond ordr kinic modl for, Cd a mg/l and Tl a 5 mg/l 3.5 Adsorpion/Dsorpion fficincy for Tsd Alga Th ra of Cd rmoval a an iniial concnraion of 5 mg/l for and Scndsmus acuminuus was 63.9% and 58.6% rspcivly, Figur 5. Gnrally rcovry of Cd was highr han rmoval wih h highs ra aaind by a 9.9%. Th rmoval of Tl was highs for a 9.8% bu Tl rcovry highs for a 93.6%, Figur 5. 8 Rmoval of Tl Rcovry of Tl Rmoval of Cd Rcovry of Cd % % 4 4 Tl Cd Tl Cd Mals Mals Figur 5: Ra of Rmoval/Rcovry of Cd and Tl for, and

6 4. Conclusion showd h highs ponial for boh rmoval and rcovry of hallium and cadmium wih a highr sorpion capaciy and highr affiniy for mals. Boh spcis showd highs rmoval of hallium wih ovr % rmovd for lowr concnraions 5 mg/l. Th sudy indicad ha an incras in iniial concnraion lads o rducion in adsorpion du o sauraion of binding sis. Th mos common funcional groups influncing adsorpion wr carboxyl and amins. Th Langmuir modl prformd br han h Frundlich modl wih a highr corrlaion cofficin.9. Acknowldgmn Th auhors would lik o hank h Univrsiy of Proria (UP) Commonwalh and UP Posdocoral for h financial assisanc rndrd during his sudy. Rfrncs Ahluwalia S.S., Goyal D., 7, Microbial and plan drivd biomass for rmoval of havy mals from waswar.,biorsour. Tchnol. 98, Aziz H.A., Adlan M.N., Ariffin K.S., 8, Havy mals (Cd, Pb, Zn, Ni, Cu and Cr (III)) rmoval from war in malaysia: Pos ramn by high qualiy limson, Biorsour. Tchnol. 99, Gupa V., Rasogi A., 8, Equilibrium and kinic modlling of cadmium (II) biosorpion by nonliving algal biomass odogonium sp. from aquous phas.,j. Hazard. Mar. 53, Halunn T., Salminn S., Tahvonn R., 7, Rapid rmoval of lad and cadmium from war by spcific lacic acid bacria, In. J. Food Microbiol. 4, Khavidaki H.D., Aghai M., Shishhbor M., Aghai H., 3, Adsorpiv rmoval of hallium (III) ions from aquous soluions using ucalypus lavs powdrs, Indian J. Chm. Tchnol., Korba P.,, Microbial Biosorpion of mals Gnral Inroducion. Springr. Mha S., Gaur J., 5, Us of alga for rmoving havy mal ions from waswar: Progrss and prospcs, Cri. Rv. Biochnol. 5, 3-5. Pr A., Viraraghavan,T., 5, Thallium: A rviw of public halh and nvironmnal concrns, Environ. In. 3, Shng P.X., Ting Y., Chn J.P., Hong L., 4, Sorpion of lad, coppr, cadmium, zinc, and nickl by marin algal biomass: Characrizaion of biosorpiv capaciy and invsigaion of mchanisms, J. Colloid Inrfac Sci. 75, 3-4. Volsky B., 7, Biosorpion and m, War Rs. 4, Zolgharnin J., Asanjarani N., Shariamansh T.,, Rmoval of hallium (I) from aquous soluion using modifid sugar b pulp, Toxicological & Environmnal Chmisry 93, 7-4.