Removal of chlorinated volatile organic compounds by fixed bed adsorption technique: Adsorption equilibrium and breakthrough analyses

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1 Romanian Biotchnological Lttrs Vol., No., 15 Copyright 15 Univrsity of Bucharst Printd in Romania. All rights rsrvd ORIGINAL PAPER Rmoval of chlorinatd volatil organic compounds by fixd bd adsorption tchniqu: Adsorption quilibrium and brakthrough analyss Rcivd for publication, Octobr, 19, 14 Accptd, Fbruary,, 15 MEHMET KALENDER 1 AND CEVDET AKOSMAN 1 Dpartmnt of Bionginring, Fırat Univrsity, 3119, Elazığ, Turky Dpartmnt of Chmical Enginring, Fırat Univrsity, 3119, Elazığ, Turky * Corrsponding author: Mhmt Kalndr, mkalndr@firat.du.tr Abstract Th adsorption quilibrium and dynamic brakthrough bhaviour of chlorinatd volatil organic compounds (CVOCs), namly chloroform and carbon ttrachlorid, wr xprimntally invstigatd by using plltd activatd carbon in a fixd bd. Th xprimntal studis wr carrid out at atmosphric prssur, th tmpratur of 313 K, th gas flow rat of 3 L/min and various inlt gas phas concntration of CVOCs (5-15 ppmv). Th xprimntal adsorption quilibrium isothrms wr obtaind and compard with four modl quations (Frundlich, Langmuir, DRK and BET) xisting in litratur. It was obsrvd that th Frundlich and Langmuir isothrm modls wr in agrmnt with th xprimntal data obtaind. It was also obsrvd that K F andq m valus of chloroform on th activatd carbon usd wr gratr than thos valus of carbon ttrachlorid. Th Yoon Nlson and dactivation modls wr usd to dscrib th brakthrough curvs of th CVOCs studid on th activatd carbon by using th xprimntal data. It was found that th modl rsults wr in agrmnt with th xprimntal brakthrough curvs. Kywords: Air pollution, chlorinatd volatil organic compounds, activatd carbon, adsorption, fixd bd 1. Introduction Chlorinatd volatil organic compounds (CVOCs) ar sub-group of volatil organic compounds (VOCs) which producd from sourcs such as organic solvnts, dgrasrs, clanrs, lubricants, and liquid fuls. CVOCs ar mittd into rciving nvironmntal from thir sourcs and may lad to srious nvironmntal problms (watr/groundwatr, soil and air contamination) as wll as halthy problms (poising, cancr and irritation). Du to ths harmful ffcts, CVOCs missions should b ssntially limitd and controlld [1-5]. Thr ar two common tchniqus for controlling of CVOCs: Th rmoval/rcovry tchniqus (adsorption, absorption, condnsation and mmbran sparation) and th dstruction tchniqus (oxidation and bio-filtration). Th lattr, spcially oxidation, has som disadvantags such as th formation of undsirabl by-products and snsitiv opration conditions. In contrast, among th rmoval/rcovry tchniqus, th adsorption procsss is th most slctd on bcaus of its advantags of lowr opration cost, tmpratur, and its us also in vry low CVOC concntrations [6-1]. Th adsorption procsss ar widly carrid out by using porous solid matrials (adsorbnts) which hav highly surfac ara in a fixd bd adsorbr. Du to its hydrophobic and organophilic surfac proprtis and its larg surfac ara and por volum as a rsult of its vast of pors and micro-pors, activatd carbon is commonly usd as adsorbnt matrial for VOCs rcovry [8, 9, 11-13]. Romanian Biotchnological Lttrs, Vol., No.,

2 MEHMET KALENDER, CEVDET AKOSMAN To dsign of fixd-bd adsorbrs, thr ar two important proprtis that ar ndd to undrstand: knowldg of adsorption quilibrium and dynamic brakthrough bhaviour btwn th adsorbnt and adsorbat. Numrous modls hav bn dvlopd to dfin th knowldg of adsorption quilibrium and to prdict brakthrough curvs of fixd bd adsorption of activatd carbon [14-16]. Som important adsorption isothrms usd to account for knowldg of adsorption quilibrium ar Frundlich, Langmuir, Braunr-Emmt-Tllr (BET) and Dubinin-Radushkvitch-Kaganr (DRK) modls. Thr ar also diffrnt modl quations such as Yoon and Nlson dvlopd as mpirical, Whlr quation and dactivation modl for brakthrough analysis of fixd bd adsorption systms. Th dactivation modl has bn mainly applid to brakthrough curv analysis of gas (spcially acidic gass such as SO, H S and CO )-solid (silica gl, calcind limston, soda ash and zolit) systms in a fixd bd ractors [1, 15-]. Park t al. [16], Suyadal t al. [1], and Suyadal [] hav showd that th dactivation modl has bn succssfully applid to VOCs adsorption/dsorption on an activatd carbon bd. This study aims to xplor CVOCs (chloroform and carbon ttrachlorid) adsorption capacity on plltd activatd carbon and to prdict brakthrough curvs by using th xprimntal data fittd to Yoon Nlson and dactivation modls in a fixd bd adsorbr.. Thory Thr hav bn many mathmatical modls dvlopd as adsorption isothrm quation to account for th knowldg of adsorption quilibrium in th litratur. Som of ths quations commonly usd ar Frundlich, Langmuir, Braunr-Emmt-Tllr (BET) and Dubinin-Radushkvitch-Kaganr (DRK) quations. Ths isothrms wr usd in ordr to apply th xprimntal adsorption data in this study. Th Frundlich quation is on of th arlist mpirical quations for modling adsorption quilibrium data and xprssd as [15, 3, 4]. q F 1 n K C (1) whr qis th quilibrium adsorption capacity, C is th quilibrium concntration, n ar th Frundlich isothrm paramtrs. Th Langmuir quation is a monolayr adsorption isothrm and writtn as K F and q q m bc () 1 bc whr q m and b ar th Langmuir isothrm paramtrs. Th BET quation is drivd by using th sam assumptions as thos usd in th Langmuir isothrm for multilayr adsorption isothrm. Th mathmatical xprssion of BET quation is dfind as follows C 1 c 1 C q C qc qc 1 (3) whr q and c ar th BET isothrm paramtrs. 146 Romanian Biotchnological Lttrs, Vol., No., 15

3 Rmoval of chlorinatd volatil organic compounds by fixd bd adsorption tchniqu: adsorption quilibrium and brakthrough analyss It has bn showd that th adsorption of inorganic gass and organic vapours on porous and microporous adsorbnt matrials such as activatd carbon and molcular siv can b dscribd by th DRK quation [18, 19, 1, 5]: q a b C (4) xp[ ln ( )] whr a andb ar th DRK isothrm constants. Th fflunt concntration of pollutant in th fixd bds varis from % to 1% with changing tim. Whn th concntration rachs dgr of saturation, th pollutant in th gas stram snt out to th adsorption column cannot b adsorbd any longr. This momnt is calld as brakpoint. Th plot (tim-th fflunt concntration or dimnsionlss concntration, C *, that is th ratio of th fflunt concntration to th inlt concntration) obtaind from th concntration history (for th lapsd tim from initial to th brakpoint) of th pollutant in th gas stram is calld as brakthrough curv [6]. Th adsorption capacity, q, of th fixd bd adsorption can b calculatd from th brakthrough curv xprssd as t Q C C dt q m (5) whr C and C ar th inlt and fflunt concntrations of CVOCs rspctivly, Q is th volumtric flow rat, m is th mass of adsorbnt matrial, and t is th tim. Th valu of adsorption capacity in th stat of quilibrium is dfind as th quilibrium adsorption capacity ( q ) and can b writtn t r Q C C dt q m (6) whr t r is th tim whn th adsorption brakthrough is rachd [18, 7]. In ordr to obtain th brakthrough curv by using th xprimntal data, on of th mpirical xprssions commonly usd is th Yoon and Nlson quation [1, 15, 17, 4]: C 1 k t* t C 1 (7) whr k is th adsorption rat constant, t is th brakthrough tim, t * is th tim rquird for 5% adsorbat brakthrough calld as th stoichiomtric brakthrough tim. Anothr thortical xprssion usd to obtain th brakthrough curv is dactivation modl quation writtn as [16, 18-] C xp ks xpkdt C (8) whr is th surfac-tim S Q ; k s is th obsrvd adsorption rat constant, S is initial surfac ara of th adsorbnt, Q is volumtric flow rat of th tracr-rich carrir gas stram introducd to th fixd bd adsorbr, and k d is first-ordr dactivation rat constant. Romanian Biotchnological Lttrs, Vol., No.,

4 MEHMET KALENDER, CEVDET AKOSMAN 3. Mthodology 3.1. Matrials A commrcial coal basd plltd activatd carbon, namly Envirocarb AP4-5, was obtaind from Chmviron Carbon Corporation. Th surfac ara and micropor volum of activatd carbon sampl wr masurd by th BET and t-plot mthods (Quantachrom AUTOSORB-1). Th tru dnsity of activatd carbon sampl was dtrmind by hlium pycnomtr (Quantachrom MVP-1). Th particl siz rang of th plltd activatd carbon sampl was 6-8 msh. Som proprtis of th activatd carbon usd in th xprimntal studis ar listd in Tabl 1. Bfor bing usd in th fixd bd xprimnts, th activatd carbon was drid at 378 K in an ovn for rmoving th moistur for at last 4 hours and it was stord in imprmabl glass cap. Chloroform (CHCl 3, 99.9% GC purity) and carbon ttrachlorid (CCl 4, 99.9% GC purity) wr slctd as CVOCs for using in th xprimnts. Som proprtis of CVOCs usd in th xprimntal studis ar givn in Tabl. 3.. Mthods Th adsorption xprimnts wr prformd in a fixd bd xprimntal st up illustratd in Figur 1. Th systm consists of a fixd bd adsorption column mad of glass with.3 m lngth and.5 m ID, an vaporator unit, a constant tmpratur controlling units, rotamtrs, and a gas chromatography (GC) dvic with a thrmal conductivity dtctor (SRI- 861). About 5 g of th plltd activatd carbon sampl was usd in th xprimntal studis. Nitrogn was usd as th carrir gas in th xprimnts. Th carrir gas stram at th out of nitrogn cylindr was dividd into two lins. On lin was passd through th CVOCs vaporator to mak a stram saturatd with CVOCs. Thn, th CVOCs-saturatd stram and th othr lin wr mixd at th out of th vaporator systm with a T pip to obtain gas strams with diffrnt CVOCs concntrations. Th vaporator was hatd by a watr bath and th dsird amount of CVOCs in gas strams wr adjustd by varying both th tmpratur of th watr bath and th rats of stram lins. Th pip lin mad of glass with.1 m ID through from th vaporator to th fixd bd column was hatd by a hating band consisting of lctrically rsistant controlld by a digital thrmostat to prvnt from condnsation of CVOCs. Th carrir gas containing dsird concntration of CVOCs was passd through th column. Th gas sampls of 1 ml wr takn from at fflunt stram and wr analysd by GC to dtrmin th concntration of CVOCs at diffrnt tim intrvals. Th fixd bd xprimnts wr ndd that th fflunt concntration of CVOCs qualld th inlt concntration. Th fixd bd adsorption column was hatd by a hating jackt mad of glass. Hot watr was supplid to th jackt by using a Grant sris of watr bath and r-circulator providing accurat tmpratur control in rang of 53 to 373 K. In ordr to obtain vapour standard sampls for GC analysis, diffrnt volums of th liquid sampls for CVOCs wr vaporatd in 5 ml imprmabl glass vials by using an ovn at th tmpratur of th boiling point of CVOCs for svral hours. Thn, th vapour sampls of 1 ml wr takn from th vials by using had-spac tchniqu and analysd by GC. In this way, standard curv (th pak ara vs. known concntration) obtaind was usd in dtrmining unknown concntrations of th gas strams containing CVOCs. Th GC analyss wr prformd by using a stainlss stl packd column (Carbowax, 6-ft x 1/8-in). Th tmpraturs of column and dtctor wr 8 C and 1 C, rspctivly. Th injction tmpratur was sam as th column tmpratur. Th xprimntal studis wr carrid out at atmosphric prssur, th tmpratur of 313 K, th gas flow rat of 3 L/min and varying initial gas phas concntration of CVOCs (5-15 ppmv). 148 Romanian Biotchnological Lttrs, Vol., No., 15

5 Rmoval of chlorinatd volatil organic compounds by fixd bd adsorption tchniqu: adsorption quilibrium and brakthrough analyss 4. Rsults and Discussion 4.1. Adsorption Equilibrium Th xprimntal data for brakthrough curvs and adsorption isothrms hav bn obtaind from th fixd bd xprimntal studis. Th data wr compard with th thortical adsorption isothrms and th brakthrough modl quations discussd in chaptr 1. Figur illustrats typical xprimntal brakthrough curvs showing chang in dimnsionlss concntration (C*) with tim for chloroform (a) and carbon ttrachlorid (b) in diffrnt inlt concntrations. As sn from Figur, th brakpoint tims of both CVOCs studid hav bn dcrasd with incrasing inlt concntration. Howvr, th brakthrough tim valus of chloroform ar largr than thos obtaind with carbon ttrachlorid. This rsult rflcts that th adsorption of chloroform is gratr than carbon ttrachlorid. Th xprimntal adsorption capacity (q) valus of both CVOCs studid wr calculatd from Eq. 5 by using th xprimntal brakthrough curvs data shown in Figur. Figur 3 shows changs in th xprimntal adsorption capacitis of both CVOCs with tim for diffrnt inlt concntrations. As sn Figur 3, th adsorption capacity valus of chloroform ar gratr than thos of carbon ttrachlorid for all inlt concntrations. It is also obsrvd that th adsorption capacity valus of th CVOCs usd incras with incrasing tim. Aftr a whil (t r ), th stat of quilibrium whn no chang in ths valus occurs with tim is stablishd. Th xprimntal quilibrium adsorption capacity (q ) valus wr thn calculatd by using Eq. 6. Figur 4 shows comparison of th xprimntal adsorption isothrms of chloroform (a) and carbon ttrachlorid (b) with th adsorption isothrm modls usd on th activatd carbon sampl. As shown in Figur 4, th quilibrium adsorption capacity of both CVOCs incrass with incrasing quilibrium concntration. Th modl paramtrs of Langmuir, Frundlich, DRK isothrms of th CVOCs studid wr dtrmind by th non-linar stimation mthods (quasi-nwton and Hook-Jvs) by using th xprimntal adsorption capacity valus. Bcaus stimation procss for th original form of BET isothrm did not convrg, linarizd form of this isothrm was usd in stimation of th BET paramtrs. Th modl constants and corrlation cofficints ( R ) of th isothrms usd for chloroform and carbon ttrachlorid ar givn in Tabls 3 and 4, rspctivly. From Tabls 3 and 4, it was obsrvd that th xprimntal adsorption quilibrium data of both chloroform and carbon ttrachlorid on th activatd carbon sampl usd wr in agrmnt with th Frundlich and Langmuir isothrm quations. Corrlation cofficints (R ) valus btwn ths isothrm quations and th xprimntal data of both CVOCs studid wr ovr.98 as givn in Tabls 3 and 4. q m and K F valus obtaind for chloroform wr thr tims as much as ths valus obtaind for carbon ttrachlorid. This rsult could b xplaind by dipol momnt and acntric factor valus of chloroform as shown in Tabl, which is gratr than thos of carbon ttrachlorid. On of th most important physical proprtis ffcting on th CVOCs adsorption is th molcul polarity. Th dipol momnt is th masur of nt molcular polarity. Th largr th dipol momnt, th highr th polarity and th adsorptivity. Bcaus it is also th masur of molcul gomtry, th acntric factor is mor important paramtr usd in dtrmining of th adsorptivity [8, 9]. Th thory of DRK isothrm is basd on a por filling mchanism for adsorption on porous adsorbnts such as activatd carbon, zolit and silica gl [18, 19]. Th b constant of th DRK isothrm givn in Eq. 4 dpnds on th charactristic nrgy of th systm. Th charactristic nrgy rlats to th avrag width of th micropors [3]. Thus th b paramtr cannot b ngativ [18, 19, 3]. As sn Tabls 3 and 4, th DRK modl was also in agrmnt with th xprimntal data with R valus gratr than.97 for CVOCs studid Romanian Biotchnological Lttrs, Vol., No.,

6 MEHMET KALENDER, CEVDET AKOSMAN on th activatd carbon, but th valu of b paramtr for this modl was dtrmind as ngativ which was an unxpctd rsult. Similar rsult was also obtaind for th BET modl; on th othr hands, among th modls usd th BET quation was th modl with th lowst corrlation cofficint valus. 4.. Modlling of Adsorption Brakthrough To dtrmin th dynamic bhaviour of th fixd bd usd in this study, th xprimntal brakthrough curvs obtaind for both CVOCs studid adsorption on th activatd carbon sampl wr fittd to th Yoon Nlson and th dactivation modl quations. Figur 5 illustrats th brakthrough curvs obtaind from th xprimntal and th Yoon Nlson (a) and dactivation (b) modls for diffrnt inlt chloroform concntrations. Comparisons of th xprimntal data and rsults of Yoon Nlson and dactivation modls for diffrnt inlt carbon ttrachlorid concntrations ar shown in Figur 6. Th paramtrs of Yoon Nlson and dactivation modls for both CVOCs studid wr calculatd by non-linar stimation by using th xprimntal brakthrough data obtaind. Tabls 5 and 6 tabulat th rsults for th Yoon Nlson and dactivation modl paramtrs and th corrlation cofficints (R ) calculatd of chloroform and carbon ttrachlorid at various inlt concntrations, rspctivly. As sn Tabls 5 and 6, th prdictions of both Yoon Nlson and dactivation modls ar wll fit to th xprimntal data bcaus of th high valu of th corrlation cofficint (R ). As xpctd, it was obsrvd that th stoichiomtric brakthrough tim (t*) valus of both CVOCs givn in Tabls 5 and 6 wr dcrasd with incrasing th inlt concntration [4]. It was also found that, in gnral, th rat constant valus of Yoon Nlson (k ) and dactivation (k d ) modls for chloroform givn in Tabl 5 wr indpndnt of th inlt concntration. It was obsrvd that, on th othr hand, th valus of k and k d for carbon ttrachlorid givn in Tabl 6 was incrasd with incrasing th inlt concntration. Ths rsults wr in agrmnt with prvious studis in th litratur [1,, 31]. 5. Conclusions Th adsorption charactristics and brakthrough analysis of th CVOCs, namly chloroform and carbon ttrachlorid, on th plltd activatd carbon wr invstigatd in a fixd bd adsorbr at th tmpratur of 313 K. Th xprimntal adsorption isothrms of CVOCs wr compard with four adsorption isothrms (Frundlich, Langmuir, DRK and BET). Th xprimntal adsorption capacity data of both CVOCs wr in agrmnt with th rsults obtaind from solutions of Frundlich and Langmuir isothrms. Th DRK and BET modl rsults did not fit to th xprimntal adsorption capacity data, bcaus som paramtrs such as b and q of ths modls wr ngativ. K F and q m valus (6.98 and 137.9) of chloroform on th activatd carbon usd wr gratr than thos valus (.6, 43.41) of carbon ttrachlorid. Th xprimntal brakthrough curvs obtaind for CVOCs studid wr in good agrmnt with th Yoon Nlson and dactivation modl quations. Th valus of th t*, k and k d for chloroform rangd from 83.44,.76 and.486 to 3.3,.799 and.557 at th tmpratur of 313 K, whras for carbon ttrachlorid, th valus rangd from 19.,.1437 and.949 to 6.99,.66 and.189 at th tmpratur of 313 K, rspctivly. 6. Acknowldgmnts This work was supportd by th Rsarch Foundation of Fırat Univrsity, Turky (Projct No FÜBAP-1315). 15 Romanian Biotchnological Lttrs, Vol., No., 15

7 Nomnclatur Rmoval of chlorinatd volatil organic compounds by fixd bd adsorption tchniqu: adsorption quilibrium and brakthrough analyss a : constant in th DRK isothrm b : constants in Langmuir and DRK isothrms c : constant in th BET isothrm C : fflunt gas phas concntration (ppmv) C : quilibrium gas phas concntration (ppmv) C : inlt gas phas concntration (ppmv) C* : dimnsionlss fflunt gas phas concntration (-) k d : first-ordr dactivation rat constant for th dactivation modl (min -1 ) k s : obsrvd adsorption rat constant (m min -1 ) K F : constant in th Frundlich isothrm k ' : adsorption rat constant in th Yoon Nlson quation (min -1 ) m : mass of adsorbnt (g) n : Frundlich xponnt q: adsorption capacity (mg g -1 ) q : quilibrium adsorption capacity (mg g -1 ) q m : constant in th BET isothrm (maximum adsorption capacity) (mg g -1 ) q : constant in th BET isothrm Q : volumtric flow rat (L min -1 ) Q : volumtric flow rat of th tracr-rich carrir gas stram introducd to th fixd bd adsorbr dfind in th dactivation modl (L min -1 ) S : initial surfac ara of th adsorbnt dfind in th dactivation modl (m g -1 ) S g: BET surfac ara of th adsorbnt (m g -1 ) t: tim or brakthrough tim, min t r : tim whn th adsorption brakthrough is rachd (min) t*: stoichiomtric brakthrough tim (min) Grk lttrs ρ bad : bd dnsity (g cm -3 ) ρ s : tru dnsity (g cm -3 ) τ: surfac-tim S Q dfind in th dactivation modl (min m -1 g -1 ) Rfrncs (1) KS HWANG, CHOI DK, GONG SY, CHO SY. Adsorption and thrmal rgnration of mthyln chlorid vapor on an activatd carbon bd. Chmical nginring scinc, 5, (1997). () A GIAYA, THOMPSON RW. Singl-componnt gas phas adsorption and dsorption studis using a taprd lmnt oscillating microbalanc. Microporous and msoporous matrials, 55, (). (3) Y-C CHIANG, CHIANG P-C, HUANG C-P. Effcts of por structur and tmpratur on VOC adsorption on activatd carbon. Carbon, 39, (1). (4) T KOBAYASHI, SHIMIZU Y, URANO K. Analysis of adsorption quilibrium of volatil chlorinatd organic compounds to dry soil. Journal of hazardous matrials, 18, (4). (5) J-H TSAI, CHIANG H-M, HUANG G-Y, CHIANG H-L. Adsorption charactristics of acton, chloroform and actonitril on sludg-drivd adsorbnt, commrcial granular activatd carbon and activatd carbon fibrs. Journal of hazardous matrials, 154, (8). (6) EN RUDDY, CARROLL LA. Slct th bst VOC control stratgy. Chmical Enginring Progrss;(Unitd Stats), 89 (1993). (7) MJ RUHL. Rcovr VOCs via adsorption on activatd carbon. Chmical Enginring Progrss;(Unitd Stats), 89 (1993). (8) FI KHAN, KR GHOSHAL A. Rmoval of volatil organic compounds from pollutd air. Journal of loss prvntion in th procss industris, 13, (). (9) A GHOSHAL, MANJARE S. Slction of appropriat adsorption tchniqu for rcovry of VOCs: an analysis. Journal of loss prvntion in th procss industris,15, (). Romanian Biotchnological Lttrs, Vol., No.,

8 MEHMET KALENDER, CEVDET AKOSMAN (1) W-T TSAI. A rviw of nvironmntal hazards and adsorption rcovry of claning solvnt hydrochlorofluorocarbons (HCFCs). Journal of loss prvntion in th procss industris, 15, (). (11) MH STENZEL. Rmov organics by activatd carbon adsorption. Chmical Enginring Progrss;(Unitd Stats), 89 (1993). (1) C CHUANG, CHIANG P, CHANG E. Modling VOCs adsorption onto activatd carbon. Chmosphr, 53, 17-7 (3). (13) J ZHU, LIANG H, FANG J, ZHU J, SHI B. Charactrization of Chlorinatd Tir Drivd Msoporous Activatd Carbon for Adsorptiv Rmoval of Tolun. CLEAN Soil, Air, Watr, 39, (11) (14) DM RUTHVEN. Principls of adsorption and adsorption procsss. (1984). (15) W-T TSAI, CHANG C-Y, HO C-Y, CHEN L-Y. Adsorption proprtis and brakthrough modl of 1, 1- dichloro-1-fluorothan on granular activatd carbon and activatd carbon fibr. Sparation Scinc and Tchnology, 35, (). (16) SW PARK, CHOI BS, LEE JW. Brakthrough Data Analysis of Adsorption of Tolun Vapor in a Fixd Bd of Granular Activatd Carbon. Sparation Scinc and Tchnology, 4, 1-33 (7). (17) S YAŞYERLI, AR I, DOĞU G, DOĞU T. Rmoval of hydrogn sulfid by clinoptilolit in a fixd bd adsorbr. Chmical Enginring and Procssing: Procss Intnsification, 41, (). (18) T KOPAÇ, KOCABAŞ S. Sulfur dioxid adsorption isothrms and brakthrough analysis on molcular siv 5A zolit. Chmical Enginring Communications, 19, (3). (19) T KOPAÇ, KOCABAŞ S. Adsorption quilibrium and brakthrough analysis for sulfur dioxid adsorption on silica gl. Chmical Enginring and Procssing: Procss Intnsification, 41, 3-3 (). () B FICICILAR, DOGU T. Brakthrough analysis for CO rmoval by activatd hydrotalcit and soda ash. Catalysis today, 115, (6). (1) Y SUYADAL, EROL M, OGUZ H. Dactivation modl for th adsorption of trichlorothyln vapor on an activatd carbon bd. Industrial & nginring chmistry rsarch, 39, (). () Y SUYADAL. Dactivation modl for dsorption of tricholorothyln vapor from granular activatd carbon. Industrial & nginring chmistry rsarch, 4, (3). (3) D DO DUONG. Absorption Analysis: Equilibria and Kintics: Imprial Collg Pr; (4) S-W LEE, PARK H-J, LEE S-H, LEE M-G. Comparison of adsorption charactristics according to polarity diffrnc of acton vapor and tolun vapor on silica alumina fixd-bd ractor. Journal of Industrial and Enginring Chmistry, 14, 1-17 (8). (5) P MOURAO, CARROTT P, RIBEIRO CARROTT M. Application of diffrnt quations to adsorption isothrms of phnolic compounds on activatd carbons prpard from cork. Carbon, 44, 4-49 (6). (6) N MOHAN, KANNAN G, UPENDRA S, SUBHA R, KUMAR N. Brakthrough of tolun vapours in granular activatd carbon filld packd bd ractor. Journal of hazardous matrials, 168, (9). (7) F GIRONI, CAPPARUCCI C, MARRELLI L. Adsorption of MTBE vapors onto activatd carbon. Journal of Chmical & Enginring Data, 48, (3). (8) Y-S BAE, LEE C-H. Sorption kintics of ight gass on a carbon molcular siv at lvatd prssur. Carbon, 43, (5). (9) F RODRIGUEZ-REINOSO, MOLINA-SABIO M, MUNECAS M. Effct of microporosity and oxygn surfac groups of activatd carbon in th adsorption of molculs of diffrnt polarity. Th Journal of Physical Chmistry, 96, (199). (3) F STOECKLI, LÓPEZ-RAMÓN MV, MORENO-CASTILLA C. Adsorption of phnolic compounds from aquous solutions, by activatd carbons, dscribd by th Dubinin-Astakhov quation. Langmuir, 17, (1). (31) T KOPAÇ, KOCABAŞ S. Dactivation modls for sulfur dioxid adsorption on silica gl. Advancs in Environmntal Rsarch, 8, (4). (3) RC REID, PRAUSNITZ JM, POLING BE. Th proprtis of gass and liquids. (1987). (33) L SCHEFLAN, JACOBS MB. Th handbook of solvnts. Toronto, Nw York, London, 78 (1953). 15 Romanian Biotchnological Lttrs, Vol., No., 15

9 Rmoval of chlorinatd volatil organic compounds by fixd bd adsorption tchniqu: adsorption quilibrium and brakthrough analyss Tabl 1. Som proprtis of th activatd carbon usd in this study Paramtrs Raw matrial Coal basd BET surfac ara, S g (m /g) t-mthod micropor volum (ml/g).34 Bd dnsity, bd (g/ml).48 Tru dnsity, s (g/ml) 1.1 Moistur contnt (%W/W) 5. Particl siz, msh (95%) 6-8 Activatd carbon AP4-5 Tabl. Som physical proprtis of CVOCs usd in this study [3, 33] Compound Molcul formula Molcul wight (g/mol) Mlting point ( C) Boiling point ( C) Liquid dnsity (g/ml) Vapour dnsity (g/l) Dipol momnt (Dbys) Pitzr s acntric factor Chloroform CHCl Carbon ttrachlorid CCl Tabl 3. Adsorption paramtrs of slctd adsorption isothrms for chloroform adsorption on th activatd carbon Isothrm Paramtrs Frundlich KF 6.98 n.6 R.988 Langmuir qm b.7 R.996 DRK a 4. b.9741 R.974 BET q c R.756 Romanian Biotchnological Lttrs, Vol., No.,

10 MEHMET KALENDER, CEVDET AKOSMAN Tabl 4. Adsorption paramtrs of slctd adsorption isothrms for carbon ttrachlorid adsorption on th activatd carbon Isothrm Paramtrs Frundlich KF.6 n.56 R.996 Langmuir qm b.4 R.99 DRK a 7.4 b.9989 R.981 BET q c R.916 Tabl 5. Paramtrs of Yoon Nlson and dactivation modls for adsorption of chloroform on th activatd carbon at various inlt concntrations Inlt concntrations (ppmv) of CHCl 3 Yoon Nlson paramtrs t * (min) k (min -1 ) R Dactivation modl paramtrs k (min -1 ) Inlt concntrations (ppmv) of CCl 4 Tabl 6. Paramtrs of Yoon Nlson and dactivation modls for adsorption of carbon ttrachlorid on th activatd carbon at various inlt concntrations Yoon Nlson paramtrs t * (min) k (min -1 ) R k s d R Dactivation modl paramtrs k (min -1 ) k s d R Captions Figur 1. Exprimntal st up: (1) nitrogn gas cylindr, () rotamtrs, (3) constant tmpratur watr bath, (4) vaporator, (5) hating jackt, (6) fixd bd adsorption column, (7) gas chromatography, (8) computr. Figur. Variation of dimnsionlss concntration in th fflunt gas phas with tim for chloroform (a) and carbon ttrachlorid (b) at diffrnt inlt concntrations. Figur 3. Variation of th xprimntal adsorption capacity of chloroform (a) and carbon ttrachlorid (b) on th activatd carbon with tim at diffrnt inlt concntrations. Figur 4. Adsorption quilibrium data for chloroform (a) and carbon ttrachlorid (b) on th activatd carbon. Figur 5. Comparison of th xprimntal brakthrough curvs with th Yoon Nlson (a) and dactivation (b) modls for chloroform adsorption on th activatd carbon at various inlt concntrations. Figur 6. Comparison of th xprimntal brakthrough curvs with th Yoon Nlson (a) and dactivation (b) modls for carbon ttrachlorid adsorption on th activatd carbon at various inlt concntrations. 154 Romanian Biotchnological Lttrs, Vol., No., 15

11 Rmoval of chlorinatd volatil organic compounds by fixd bd adsorption tchniqu: adsorption quilibrium and brakthrough analyss Figur C* C* Figur (a) 5 ppmv 5 ppmv 75 ppmv 15 ppmv (b) 3 ppmv 5 ppmv 75 ppmv 15 ppmv q (mg g -1 ) 6 q (mg g -1 ) 15 Figur (a) 5 ppmv 5 ppmv 75 ppmv 15 ppmv 1 3 ppmv 5 ppmv 5 75 ppmv 15 ppmv (b) q (mg g -1 ) 8 6 q (mg g -1 ) 15 Figur C (ppmv) (a) Exprimntal Frundlich Langmuir BET DRK C (ppmv) (b) Exprimntal Frundlich Langmuir BET DRK Romanian Biotchnological Lttrs, Vol., No.,

12 MEHMET KALENDER, CEVDET AKOSMAN C* C* Figur ppmv 5 ppmv. 75 ppmv 15 ppmv prdictd (a) ppmv 5 ppmv. 75 ppmv 15 ppmv prdictd (b) C* C* Figur ppmv 5 ppmv. 75 ppmv 15 ppmv prdictd (a).4 3 ppmv 5 ppmv. 75 ppmv 15 ppmv prdictd (b) 156 Romanian Biotchnological Lttrs, Vol., No., 15