Isotherm, Kinetic and Thermodynamic Studies on the Adsorption of Cd (II) and Zn (II) ions from Aqueous Solutions onto Bottom Ash

Transcription

1 Intrnational Journal of Environmntal Scinc and Dvlopmnt, Vol. 5, No. 2, April 14 Isothrm, Kintic and Thrmodynamic Studis on th Adsorption of Cd (II) and Zn (II) ions from Aquous Solutions onto Bottom Ash Hatairat Sukprabprom, Orn-Anong Arquro, Wimol Naksata, Ponlayuth Sooksamiti, and Sorapong Janhom Th convntional mthods for rmoval of havy mtal ions from industrial fflunts includ chmical prcipitation, coagulation, solvnt xtraction, lctrodialysis, rvrs osmosis, ion xchang, vaporation and filtration. Howvr, th application of ths mthods is rstrictd du to tchnical complxity and conomical constraint. Adsorption procss is on of th most common mthods usd in wastwatr tratmnt bcaus of its low cost, simplicity and high fficincy [5]-[7]. Th important charactristics of adsorbnt ar th adsorption capacity, slctivity, possibility of rgnration, raction vlocity, compatibility and pric. Adsorption capacity dpnds on surfac ara, por siz, diamtr and chmical composition of th adsorbnt. Activatd carbon has bn widly usd in adsorption procss bcaus it has high spcific surfac ara and por volum. Activatd carbon is rgardd as an ffctiv adsorbnt but th rmoval of havy mtal ions by adsorption with activatd carbon is rlativly xpnsiv. At prsnt, attntions hav bn focusd on th dvlopmnt of low cost adsorbnt for wastwatr tratmnt application. Th matrials considrd to produc adsorbnt ar industrial and agricultural wasts such as clay, pat, ric husk, fly ash, sawdust, rd mud, mangans nodul rsidu and oxid-coatd sands tc. [8], [9]. Th Ma Moh powr plant is th largst lignit coal-burning powr plant in Thailand. Th gnration of lctricity through combustion producs a hug amount of wast such as fly ash, bottom ash and boilr slag. Th wasts from coal-burning powr plant can b th sourc of pollution. Thrfor, th utilization of ths wasts has bn dvlopd. From th coal-burning procss, th amount of bottom ash is approximatly % by wight of th total ash. It is mad from agglomratd ash particls that ar too larg to b carrid in th flu gass and fall through opn grats to an ash hoppr at th bottom of th furnac. Bottom ash, which is porous, coars, glassy and granular matrial, has alrady bn usd as aggrgat in concrt and road bas matrial. Rcntly, svral studis hav rportd th us of bottom ash as adsorbnt for th rmoval of various havy mtals. Th physical charactristics of bottom ash ar small particl siz, high porosity and larg surfac ara. Du to ths proprtis, it is a good choic for us as a potntial adsorbnt []-[12]. Th objctiv of this rsarch is to invstigat th possibility of using bottom ash as an adsorbnt for rmoval of Cd (II) and Zn (II) ions from aquous solutions. Th ffct of ph, contact tim and tmpratur wr studid by batch xprimnts. Th quilibrium data would b analyzd using Langmuir and Frundlich isothrm modls. Furthrmor, th adsorption kintics and thrmodynamic paramtrs for adsorption procss of havy mtal ions onto bottom ash wr also valuatd. Abstract Bottom ash is a wast matrial obtaind from lctricity gnration through combustion of coal at th Ma Moh powr plant in Thailand. Th adsorption of Cd (II) and Zn (II) ions from aquous solutions onto bottom ash was studid using batch xprimnts. Th ffct of ph, contact tim and tmpratur wr invstigatd. Adsorption isothrm data for mtal ions was analyzd by th Langmuir and Frundlich isothrms. Th Frundlich isothrm proprly dscribd th adsorption data for all studid tmpraturs. Th rsults rvald that th adsorption kintics followd psudo-scond-ordr kintic modl. Thrmodynamic paramtrs such as Gibbs fr nrgy chang ( G ), nthalpy chang ( H ) and ntropy chang ( S ) wr invstigatd. Th calculatd valus showd that th adsorption procss for both Cd (II) and Zn (II) ions was ndothrmic. Indx Trms Bottom ash, adsorption, isothrm, kintic, thrmodynamic. I. INTRODUCTION A srious nvironmntal problm is toxic havy mtals contamination of wastwatr. Havy mtal ions ar rlasd into watr from many industris such as mining, chmical manufacturing, battry manufacturing, lctroplating, coating and pigmnt [1], [2]. Cadmium (Cd (II)) and Zinc (Zn (II)) ar common pollutants widly found in industrial wastwatr. Cd (II) has bn wll rcognizd for its ngativ ffct on th nvironmnt. It is a non-ssntial and non-biodgradabl componnt which radily accumulats in living systms. A numbr of acut and chronic disordrs, such as itai-itai disas, rnal damag, mphysma, hyprtnsion, and tsticular atrophy ar harmful ffcts of Cd (II) [3]. Zn (II) is an ssntial trac lmnt for humans in nzymatic ractions. Howvr, xcssiv intak of Zn (II) may caus toxic ffcts such as carcinognsis, mutagnsis and tratognsis as a rsult of its bioaccumulation [4]. Thrfor, from an nvironmntal point of viw, a study on th rmoval of Cd (II) and Zn (II) ions is on of considrabl significanc. Manuscript rcivd August 15, 13; rvisd Sptmbr 27, 13. This work was supportd in part by th Graduat School of Chiang Mai Univrsity, Thailand. Hatairat Sukprabprom, Orn-Anong Arquro, Wimol Naksata, and Sorapong Janhom ar with th Dpartmnt of Chmistry, Faculty of Scinc, Chiang Mai Univrsity, Chiang Mai, Thailand (-mail: hatairat278@gmail.com, orn.arquro@gmail.com, scchi021@chiangmai.ac.th, sorapongj@gmail.com). Ponlayuth Sooksamiti is with th Dpartmnt of Primary Industry and Min Offic Rgion 3, Chiang Mai, Thailand (-mail: sooksamiti@hotmail.com). DOI:.7763/IJESD.14.V

2 Intrnational Journal of Environmntal Scinc and Dvlopmnt, Vol. 5, No. 2, April 14 II. MATERIALS AND METHODS A. Prparation of Adsorbnt Bottom ash usd as adsorbnt in this study was obtaind from Ma Moh powr plant in Thailand. It was drid at 1 C for 24 hours in ordr to rach constant wight. Th drid bottom ash was crushd and sivd to 80 msh (0.177 mm). Th prpard matrial was stord in dsiccators for furthr us. B. Chmicals All th chmicals usd wr analytical ragnt (AR) grad. Cadmium nitrat ttrahydrat (Cd(NO 3 ) 2.4H 2 O) was procurd from Fluka, Switzrland. Zinc nitrat hxahydrat (Zn(NO 3 ) 2.6H 2 O) was procurd from Carlo Erba, Italy. Nitric acid (HNO 3 ) was purchasd from RCI Labscan, Thailand. Sodium hydroxid (NaOH) was purchasd from Mrck, Grmany. Stock solutions of Cd (II) and Zn (II) (00 mg/l) wr prpard by dissolving xact amount of Cd(NO 3 ) 2.4H 2 O and Zn(NO 3 ) 2.6H 2 O in dionizd watr, rspctivly. Solutions of 1 M HNO 3 and 1 M NaOH wr usd for ph adjustmnt. C. Charactrization of Adsorbnt Th physical and chmical charactristics of bottom ash wr prformd by convntional mthods. Th ph of bottom ash was masurd using ph mtr (Modl phtstr, Eutch instrumnts, Singapor). A spcific gravity bottl was usd to dtrmin th dnsity of th adsorbnt. Th moistur contnt was carrid out according to ASTM D Th cation xchang capacity (CEC) was masurd to valuat th adsorption capacity using Kjldahl microstam apparatus aftr saturation with ammonium actat. Th particl siz of bottom ash was dtrmind using particl siz distribution analyzr (Modl Mastrsiz 00, Malvrn instrumnts, UK). Th spcific surfac ara was dtrmind by th Brunaur-Emmtt-Tllr (BET) mthod using Quantachrom Autosorb automat with nitrogn gas (vrsion 2.46). Th Phillips MagiX PRO PW Squntial X-ray fluorscnc (XRF) Spctromtr using Rhodium (Rh) tub was usd for chmical compositions dtrmination of bottom ash. D. Batch Adsorption Studis For ach xprimnt, th 0 ml of 50 mg/l mtal solutions was addd to rlnmyr flask containing 0.1 g of bottom ash. All Batch xprimnts wr carrid out in watr bath shakr (Modl WSB-45, Daihan scintific, Kora) with a 150 rpm shaking rat at C. Th ffct of solution ph was studid in th ph rang of 4-6. Th initial ph of solution was adjustd with 1 M HNO 3 or 1 M NaOH solution. Aftr 5 hours of contact tim, th suprnatant was sparatd by filtration and analyzd for th rsidual concntrations of Cd (II) and Zn (II) by atomic absorption spctrophotomtr (AAS) (Modl 31, Prkin Elmr, USA). Th amount of mtal ion adsorbd, q (mg/g), was calculatd using th following quation: q= 0 C -C V whr C 0 is th initial mtal ion concntration (mg/l), C is th quilibrium mtal ion concntration (mg/l), V is th volum of solution (L) and m is th mass of th adsorbnt (g). m (1) E. Adsorption Kintics Th kintic studis wr also prformd using batch xprimnts. In ach flask containd 0.1 g of bottom ash and 0 ml of aquous solutions was usd. Th xprimnts wr carrid out with initial concntration of 50 mg/l for all mtal solutions at C and ph 6. This ph was found to b th optimum on th basis of th ffct of ph tst. Th adsorption of mtal ions on bottom ash at various tims (,,, 60, 90, 1, 180, 2 and 0 minuts) was masurd to dtrmin th ffct of contact tim. Sorption kintics can b usd to dscrib th controlling mchanism of adsorption procss. Th two kintic modls, psudo-first-ordr and psudo-scond-ordr, wr usd to invstigat th fit xprimntal data from th adsorption of Cd (II) and Zn (II) ions 1) Psudo-first-ordr modl Th adsorption kintic data is valuatd using th psudo-first-ordr quation (Lagrgrn s quation), which can dscrib th adsorption rat basd on th sorption capacity of solids. Th linar form of psudo-first-ordr modl can b xprssd as: k1 logq qt logq t (2) 2.3 whr q and q t ar th amount of mtal ion adsorbd at quilibrium and at tim t (min), rspctivly (mg/g) and k 1 is th rat constant of psudo-first-ordr adsorption (min -1 ). 2) Psudo-scond-ordr modl Th adsorption kintic may also b dscribd by th psudo-scond-ordr modl. Th quation for linar form is: t q t 1 1 t 2 (3) k q q 2 whr k 2 is th rat constant of psudo-scond-ordr adsorption (g/mg.min) and k 2 q 2 or h is th initial adsorption rat (mg/g.min) [13], [14]. F. Adsorption Isothrms Adsorption isothrms wr obtaind by varying th initial concntration of mtal ions from 5 to 50 mg/l (5,, 15,, 25,, and 50 mg/l) at diffrnt tmpraturs (,, and C). Th adsorption conditions wr controlld th sam as in adsorption kintic studis and 60 min was slctd as contact tim. In prvious kintic xprimnts, 60 min was provd to b sufficint for adsorption of Cd (II) and Zn (II) ions onto bottom ash to rach quilibrium. Adsorption isothrm can xplain th quilibrium rlationship btwn adsorbnt and adsorbat, and dtrmin th maximum capacity of adsorption. Th common usd isothrm modls ar th Langmuir and Frundlich isothrms. 1) Langmuir isothrm Th Langmuir isothrm is th simplst thortical modl for monolayr adsorption, basd on th assumption that molculs ar adsorbd at a fixd adsorption sit and ach sit can hold on adsorbat molcul. It also suggsts that all sits ar nrgtically quivalnt and thr is no intraction btwn th adsorbat molculs. Th Langmuir isothrm is xprssd as follows: 166

3 Intrnational Journal of Environmntal Scinc and Dvlopmnt, Vol. 5, No. 2, April 14 C q 1 (4) bq whr q m is th maximum adsorption capacity (mg/g) and b is th Langmuir constant rlatd to th nrgy of adsorption (L/mg). 2) Frundlich isothrm Th Frundlich isothrm is basd on th assumption that th adsorption occurs on htrognous surfac of an adsorbnt with intraction btwn th adsorbat molculs. Th adsorption nrgy is non-uniform distribution ovr th surfac. Th linar form of Frundlich quation is xprssd as: 1 logq logkf logc (5) n whr K F and n ar th Frundlich constant rlatd to adsorption capacity and adsorption intnsity, rspctivly [9], [13]. G. Thrmodynamic Paramtrs Th ffct of tmpratur on th adsorption of Cd (II) and Zn (II) ions onto bottom ash was studid at four tmpraturs (,, and C) in 50 mg/l mtal solution. Ths studis wr carrid out at th optimum ph valu obtaind from th prvious batch adsorption studis. Th thrmodynamic paramtrs of th adsorption such as th Gibbs fr nrgy chang G (kj/mol), th standard nthalpy chang H (kj/mol) and th standard ntropy chang S (J/mol.K) wr calculatd using th following quations: m K C q m G RT ln (6) S H ln K (7) R RT G H TS (8) whr K is th quilibrium constant, T is th absolut tmpratur (K) and R is th univrsal gas constant (8.314 J/mol.K) [13], [15]. III. RESULTS AND DISCUSSION A. Proprtis of Adsorbnt contnt wr 2.43 g/cm 3, µm and 2.%, rspctivly. Th CEC valu of bottom ash was.56 cmol/kg. Th spcific surfac ara, which masurd using BET mthod, was 5.14 m 2 /g. Th chmical compositions of bottom ash wr dtrmind by XRF as shown in Tabl I. Th major chmical componnts wr SiO %, CaO 18.0%, Al 2 O % and F 2 O %. B. Effct of PH Th ph of solution is th most significant paramtrs for adsorption of mtal ions. Th chang of ph affcts th surfac charg of th adsorbnt, th dgr of ionization of adsorbat and th chmical spciation of mtal ions. Th adsorption of Cd (II) and Zn (II) ions onto bottom ash at diffrnt valus of ph (4, 5 and 6) was shown in Fig. 1. Th rmoval of Cd (II) and Zn (II) ions significantly incrasd whn ph valu incrasd from 4 to 6. At low ph valus, th rmoval of mtal ions dcrasd bcaus of th fact that th surfac charg is not suitabl for adsorption. Th incras in positivly chargd surfac sits whn ph dcras lads to lctrostatic rpulsion btwn th surfac positiv chargs and th cationic mtal ions. In addition, a highr concntration of H + ions in solution can compt with mtal ions for th adsorption sits, rsulting in th dcrasd adsorption of mtal ions. Th positiv charg dvlops on th oxid surfac of adsorbnt in an acidic solution. Th raction can b rprsntd as: MO H OH H 2 M OH OH According to th simpl spciation diagrams for Cd (II) and Zn (II) ions, all th spcis occurring at ph 7 contain positiv chargs as Cd 2+, Cd(OH) +, Zn 2+ and Zn(OH) +. As th ph incrasing, th positivly chargd surfac sits dcras and th ngativly chargd surfac sits of adsorbnt incras as shown blow: MOH OH MO H 2O (9) () MO Cd M O Cd (11) Th abov ph 6, th surfac of th adsorbnt is ngativ and th mtal ions, Cd (II) and Zn (II) ions ar still prsnt as Cd(OH) + and Zn(OH) + ions. Th adsorption of ths mtals undr this condition is lctrostatic attraction [15], [16]. Thrfor, ph 6 was chosn as th optimum ph for adsorption of Cd (II) and Zn (II) ions TABLE I: CHEMICAL COMPOSITIONS OF BOTTOM ASH Chmical compositions Wight prcnt (%) SiO CaO 18.0 Al 2 O F 2 O SO MgO 2.46 K 2 O 2.15 TiO Mn 2 O Study on th physical and chmical proprtis of bottom ash showd that bottom ash was slightly alkalin at ph of Th dnsity, particl siz distribution and moistur Fig. 1. Effct of ph on th adsorption of Cd (II) and Zn (II) ions 167

4 Intrnational Journal of Environmntal Scinc and Dvlopmnt, Vol. 5, No. 2, April 14 Fig. 2. Effct of contact tim on th adsorption of Cd (II) and Zn (II) ions C. Kintic Studis Th ffct of contact tim on Cd (II) and Zn (II) ions rmoval by bottom ash was shown in Fig. 2. All th batch xprimnts indicatd that th adsorption rat incrasd rapidly at th bginning, aftr that th chang of rat bcam constant. Th adsorption rat is high in th initial stags of adsorption bcaus a larg numbr of adsorption sits ar availabl for th adsorption of mtal ions. Th adsorption of Cd (II) and Zn (II) ions incrasd with incrasing contact tim and bcam almost constant aftr 60 min for bottom ash. According to ths rsults, a 60 min was usd as contact tim in ordr to nsur that quilibrium conditions wr attaind. To xplain th adsorption kintics, psudo-first-ordr and psudo-scond-ordr modls wr tstd to fit th xprimntal data obtaind from th adsorption of Cd (II) and Zn (II) ions xprimnts. For psudo-first-ordr modl, th valus of k 1 and q wr obtaind from th slop and intrcpt by plotting log (q -q t ) vrsus t, rspctivly (Fig. 3). Psudo-scond-ordr paramtrs, q, k 2 and h, wr calculatd from th linar plots of t/q t vrsus t (Fig. 4). All th paramtrs of psudo-first-ordr and psudo-scond-ordr modls wr dtrmind and listd in Tabl II. Th quilibrium amount adsorbd (q ) from th xprimnt (q,xp) and th calculation (q,cal) wr also shown in Tabl II. In cas of psudo-scond-ordr modl, th calculatd q valus agrd wll with th xprimntal q valus. Furthrmor, th corrlation cofficint (R 2 ) for psudo-scond-ordr modl was much closr to than th corrlation cofficint for psudo-first-ordr modl. Thrfor, ths rsults confirmd that th adsorption of Cd (II) and Zn (II) ions onto bottom ash can b rprsntd by psudo-scond-ordr kintic modl. Fig. 3. Psudo-first-ordr kintic of Cd (II) and Zn (II) ions adsorption onto bottom ash. Fig. 4. Psudo-scond-ordr kintic of Cd (II) and Zn (II) ions adsorption TABLE II: ADSORPTION KINETIC PARAMETERS FOR THE ADSORPTION OF CD (II) AND ZN (II) IONS BY BOTTOM ASH. Kintic modls Cadmium Zinc q,xp (mg/g) psudo-first-ordr q,cal (mg/g) k 1 (min -1 ) R psudo-scond-ordr q,cal (mg/g) k 2 (g/mg.min) h (mg/g.min) R TABLE III: LANGMUIR AND FREUNDLICH CONSTANTS FOR THE ADSORPTION OF CD (II) AND ZN (II) IONS BY BOTTOM ASH AT DIFFERENT TEMPERATURES. Tmpratur ( C) Langmuir Frundlich Cadmium q m (mg/g) b (L/mg) R 2 K F (mg/g) n R Zinc

5 Intrnational Journal of Environmntal Scinc and Dvlopmnt, Vol. 5, No. 2, April 14 (a) (a) (b) Fig. 5. Langmuir isothrms for Cd (II) (a) and Zn (II) (b) ions adsorption onto bottom ash at diffrnt tmpraturs. D. Adsorption Isothrm Studis Th Langmuir and Frundlich isothrms wr usd to tst th quilibrium rlationship btwn th amount of Cd (II) and Zn (II) ions adsorbd on bottom ash, th quilibrium concntration of mtal ions and th maximum adsorption capacity of bottom ash. Both isothrms, at ph 6 and diffrnt tmpraturs (,, and C), wr usd to dtrmin th adsorption data at various initial concntrations of mtal ions (5 to 50 mg/l). Th Langmuir constants, q m and b, can b obtaind from slop and intrcpt of th plot C /q against C, rspctivly (Fig. 5). Th slop and intrcpt of a plot of log q against log C wr usd to calculat th Frundlich constants, n and K F, rspctivly (Fig. 6). Th Langmuir and Frundlich paramtrs for Cd (II) and Zn (II) ions adsorption onto bottom ash at diffrnt tmpraturs wr givn in Tabl III. It can b obsrvd that th corrlation cofficint (R 2 ) of Frundlich isothrm was closr to unity whn compard with that of Langmuir isothrm. Thrfor, th Frundlich isothrm was mor satisfying to fit th quilibrium adsorption data of Cd (II) and Zn (II) ions for all tmpraturs than th Langmuir isothrm. This can b proposd that th adsorption occurrd on htrognous surfac of bottom ash. Th Frundlich paramtr, n, should hav valus lying in th rang of 1 to for classification as favorabl adsorption. In this study, n valu was found to b gratr than unity, so both Cd (II) and Zn (II) ions wr favourably adsorbd by bottom ash. Morovr, th adsorption capacity (K F ), which is th Frundlich constant, incrasd with an incrasd tmpratur. It indicatd that th adsorption procss of Cd (II) and Zn (II) ions was ndothrmic. (b) Fig. 6. Frundlich isothrms for Cd (II) (a) and Zn (II) (b) ions adsorption onto bottom ash at diffrnt tmpraturs. E. Thrmodynamic Studis Th plot of ln K vrsus 1/T was usd to calculat H and S from slop and intrcpt, rspctivly. Th rlationship btwn ln K and 1/T was shown in Fig. 7. Th thrmodynamic paramtrs for th adsorption of Cd (II) and Zn (II) ions wr indicatd in Tabl IV. Fig. 7. Thrmodynamic study for Cd (II) and Zn (II) ions adsorption TABLE IV: THERMODYNAMIC PARAMETERS FOR THE ADSORPTION OF CD (II) AND ZN (II) IONS BY BOTTOM ASH. Tmpratur ( C) G (kj/mol) H (kj/mol) S (J/mol.K) Cadmium Zinc

6 Intrnational Journal of Environmntal Scinc and Dvlopmnt, Vol. 5, No. 2, April 14 Th positiv valu of H confirmd that th adsorption procss was ndothrmic, which was supportd by th incras of adsorption capacity whn th tmpratur incrasd. Th positiv valus of S considrd th good affinity of th bottom ash towards mtal ions and th incrasd randomnss at th solid-liquid intrfac during th adsorption of mtal ions Th positiv valus of G rsultd from th Langmuir constant (b) lss than on. IV. CONCLUSION Bottom ash can b usd as an adsorbnt for th rmoval of Cd (II) and Zn (II) ions from aquous solutions. Th quilibrium contact tim in th rmoval of mtal ions by bottom ash was around 60 min. Th adsorption capacity incrasd with incrasing tmpratur. Th adsorption quilibrium data fittd to th Frundlich isothrm modl in comparison to Langmuir isothrm modl at th studid tmpratur. Th suitabl kintic modl for adsorption of Cd (II) and Zn (II) ions onto bottom ash was psudo-scond-ordr kintic modl. Th thrmodynamic paramtrs indicatd that th adsorption procss of mtal ions was ndothrmic in natur. Bottom ash is not only utilizabl wast, but also low cost. Thrfor, adsorbnt drivd from bottom ash would b usful for th conomical tratmnt of wastwatr containing mtal ions. ACKNOWLEDGMENT This work was supportd by th Highr Education Rsarch Promotion and National Rsarch Univrsity Projct of Thailand, Offic of th Highr Education Commission. Th authors want to ddicat spcial thanks to lctric powr plant in Ma Moh district, Lampang Provinc, Thailand for bottom ash. REFERENCES [1] V. C. Srivastava, I. D. Mall, and I. M. Mishra, Rmoval of cadmium (II) and zinc (II) mtal ions from binary aquous solution by ric husk ash, Colloids Surf. A, vol. 312, pp , January 08. [2] S. Gun, B. Yao, K. Adouby, and G. Ado, Kintics and thrmodynamics study of lad adsorption on to activatd carbons from coconut and sd hull of th palm tr, Int. J. Environ. Sci. Tch., vol. 4, pp , Wintr 07. [3] R. A. D. Tilaki and S. Mahmood, Study on rmoval of cadmium from watr by adsorption on GAC, BAC and biofiltr, Pak. J. Biol. Sci., vol. 7, pp , May 04. [4] D. Tirumalaraju and S. Mishra, Rmoval of zinc from aquous solution on HCl imprgnatd spong iron plant wast: optimization by DOE, Int. J. Environ. Sci. Dv., vol. 2, pp , August 11. [5] C. G. Ruiz, V. Rodriguz, and B. G. Gil, Cadmium and zinc rmoval from aquous solutions by Bacillus jotgali: ph, salinity and tmpratur ffcts, Biorsour. Tchnol., vol. 99, pp , Jun 08. [6] V. K. Gupta, C. K. Jain, I. Ali, M. Sharma, and V. K. Saini, Rmoval of cadmium and nickl from wastwatr using bagass fly ash-a sugar industry wast, Watr Rs., vol. 37, pp , Sptmbr 03. [7] D. Pntari, V. Prdikatsis, D. Katsimicha, and A. Kanaki, Sorption proprtis of low calorific valu Grk lignits: Rmoval of lad, cadmium, zinc and coppr ions from aquous solutions, J. Hazard. Matr., vol. 168, pp , Sptmbr 09. [8] R. Baccar, J. Bouzid, M. Fki, and A. Montil, Prparation of activatd carbon from Tunisian oliv-wast caks and its application for adsorption of havy mtal ions, J. Hazard. Matr., vol. 162, pp , March 09. [9] J. X. Zhang and L. L. Ou, Kintic, isothrm and thrmodynamic studis of th adsorption of crystal violt by activatd carbon from panut shlls, Watr Sci. Tchnol., vol. 67, pp , Fbruary 13. [] R. Kasmchaisiri and S. Tangtrmsirikul, Proprtis of slf-compacting concrt in corporating bottom ash as a partial rplacmnt of fin aggrgat, Scinc Asia., vol. 34, pp , March 08. [11] J. B. Gorm, M. C. Maniquiz, S. S. Kim, Y. G. Son and Y. T. Kim, Charactrization of bottom ash as an adsorbnt of lad from aquous solution, Environ. Eng. Rs., vol. 15, pp , Dcmbr. [12] A. R. Dinçr, Y. Günş, N. Karakaya and E. Günş, Comparison of activatd carbon and bottom ash for rmoval of ractiv dy from aquous solution, Biorsour. Tchnol., vol. 98, pp , March 07. [13] H. K. Boparai, M. Josph, and D. M. O Carroll, Kintics and thrmodynamics of cadmium ion rmoval by adsorption onto nano zrovalnt iron particls, J. Hazard. Matr., vol. 186, pp , Fbruary 11. [14] V. C. Srivastava, I. D. Mall, and I. M. Mishra, Charactrization of msoporous ric husk ash (RHA) and adsorption kintics of mtal ions from aquous solution onto RHA, J. Hazard. Matr., vol. 134, pp , Jun 06. [15] T. S. Anirudhan and P. S. Suchithra, Equilibrium, kintic and thrmodynamic modling for th adsorption of havy mtals onto chmically modifid hydrotalcit, Indian J. Chm. Tchnol., vol. 17, pp , July. [16] V. C. Srivastava, I. D. Mall, and I. M. Mishra, Equilibrium modlling of singl and binary adsorption of cadmium and nickl onto bagass fly ash, Chm. Eng. J., vol. 117, pp , March 06. Hatairat Sukprabprom was born in Chiang Mai, Thailand on August 27, Sh rcivd th B. Sc. dgr in 06 and th M. Sc. dgr in 09 in th fild of chmistry from Chiang Mai Univrsity, Chiang Mai, Thailand. In 06 sh workd th rsarch about production of adsorbnt from bottom ash and flu gas dsulfurization gypsum for adsorption of cadmium from aquous solutions. Sh is now studying Ph. D. dgr at Chiang Mai Univrsity, Chiang Mai, Thailand. Hr rsarch intrst is th rmoval of havy mtal from wastwatr. Orn-Anong Arquro was born in Chiang Mai, Thailand in Sh rcivd th B. Sc. dgr in chmistry from Chiang Mai Univrsity, Chiang Mai, Thailand. From , sh arnd Ph.D. (Physical Chmistry) dgr from Bradford Univrsity, Bradford, UK. From , sh was a postdoctoral rsarch associat in th Karlsruh Rsarch Cntr, Karlsruh, Grmany. In 04, sh workd th rsarch at Mlbourn Univrsity, Mlbourn, Australia. Sh had workd as lcturr in th Dpartmnt of Chmistry, Chiang Mai Univrsity, Chiang Mai, Thailand until 13. Assist. Prof. Dr. Arquro s rsarch intrsts ar in adsorption study, nutron activation analysis and X-ray fluorscnc and nvironmntal study. Sh is an author of Surfac Chmistry (publishd in Faculty of Scinc, Chiang Mai Univrsity, 1994). 170