Concentration by pervaporation of brown crab volatile compounds from dilute model solutions: Evaluation of PDMS membrane

Concen a ion by pe apo a ion o b own c ab ola ile compounds om dilu e model solu ions: e alua ion o PDMS memb ane Rod igo Ma ínez, Ma ía Te esa Sanz ∗ , Sag a io Bel án Depa men o Chemical Enginee ing, Uni e si y o Bu gos, 09001 Bu gos. Spain Abs ac Pe apo a ion expe imen s wi h PERVAPTM 4060 memb ane ha e been pe o med o s udy i s abili y o concen a e some a oma compounds iden i ied in he b own c ab boiling juice om a model dilu e aqueous solu ion. The e ec o eed concen a ion, pe apo a ion empe a u e and pe mea e p essu e on he pe apo a ion pe o mance o he memb ane has been analyzed. The esul s ob ained wi h PERVAPTM 4060 memb ane we e compa ed wi h expe imen s pe o med in a p e ious wo k wi h a POMS/PEI memb ane. Memb ane ma e ial seems o be a key ac o in he pe mea e a oma p o ile. The p esence o non- ola ile compounds, such as sodium chlo ide, in b own c ab boiling juice sligh ly imp o es pe apo a ion pe o mance in he concen a ion ange s udied in his wo k. Ba ch pe apo a ion expe imen s p o e ha he la o loss pe cen age du ing long ope a ion ime is high, especially o he mos ∗ Co esponding au ho . Tel.: +34 947 258810. Fax: +34 947 258831. E-mail add ess e [email protected] ola ile compounds. Addi ionally, i has been shown ha pe apo a ion can be signi ican ly imp o ed by modi ying he pe mean ci cui by means o wo s age condensa ion s ep. Keywo ds: ola ile compounds, pe apo a ion, sal e ec , PDMS memb ane 1. In oduc ion Shell ish la ou is a high alue ood p oduc . The liquid e luen o he sea ood indus y, p oduced du ing boiling p ocess, con ains impo an amoun s o la ou componen s [1]. B own c abs a e ound in he Eas e n A lan ic and a e hea ily exploi ed comme cially, being a ailable h oughou he yea . This wo k is pa o a wide s udy o conside he con e sion o he b own c ab e luen p oduced du ing boiling in o a aluable ola ile concen a e. Memb ane sepa a ion echniques ep esen a po en ial pa hway o he p oduc ion o a na u al a oma concen a e and a disposable e luen [2, 3]. In a p e ious s udy [4], o ganophilic pe apo a ion h ough a polyoc ylme hylsiloxane memb ane was shown o be able o concen a e some compounds o he b own c ab boiling juice om a model dilu e aqueous solu ion. In his wo k, pe apo a ion h ough a polydime hylsiloxane memb ane has been pe o med o compa e he abili y o he wo polyme s, POMS and PDMS, o eco e some a oma compounds ound in he b own c ab boiling juice om model dilu e aqueous solu ions. The e ec o some impo an a iables ha de e mine he inal a oma p o ile, such as eed concen a ion, pe apo a ion empe a u e and pe mea e p essu e has been s udied. B own c ab boiling juice con ains o ganic compounds and non- ola ile compounds. The in luence o he p esence o non- ola ile componen s, such as sal s (e.g.: sodium chlo ide) was also analysed by a ying he sal con en in he eed solu ion. Fo indus ial applica ions, ba ch ope a ion is p e e ed o a con inuous ope a ion i he a oma eco e y is a sho - e m ope a ion wi h ela i ely small amoun o ex ac s [5]. In his wo k, ba ch p ocess has been pe o med o eco e a oma compounds om model solu ions. Finally, ac iona ion expe imen s ha e been also pe o med o imp o e he pe apo a ion pe o mance by using a wo condensa ion s ep a he pe mea e side. 2. Theo y Solu ion/di usion model is used o desc ibe he anspo o pe mea ing componen s h ough he memb ane being p opo ional o he di e ence in pa ial apo p essu e a bo h sides o he memb ane acco ding o equa ion 1 [6]: ( ) pi s iii i ,OVipypxQJ −γ= (1) whe e Ji is he pa ial pe mea ion lux o componen i, QOVi i s p essu e-no malized pe mea ion lux (pe meance), xi i s mole ac io in he eed, γ i i s ac i i y coe icien , s i p i s sa u a ion apo p essu e a he eed empe a u e, yi, i s mole ac ion in he pe mea e and pp he pe mea e p essu e. In case o pe apo a ion o dilu e aqueous solu ions, ac i i y coe icien s a in ini e dilu ion ( ∞ γi ) a e used as eed-side ac i i y coe icien s. In his wo k, he ac i i y coe icien s a in ini e dilu ion in wa e we e ob ained om p e ious wo k in which ac i i y coe icien s a in ini e dilu ion we e ob ained by using he headspace gas ch oma og aphy echnique [7]. The sepa a ion pe o mance o a pe apo a ion memb ane, in case o dilu e aqueous solu ions, can be desc ibed in e ms o he en ichmen ac o . The en ichmen ac o o a gi en componen is he ela ionship be ween i s concen a ion in he pe mea e and he eed: ,ip,ii ww=β (2) In dilu e sys ems, as a oma eco e y sys ems, he sol en en ichmen ac o is close o one; he e o e a oma en ichmen ac o s o o ganic compounds can be conside ed equal o he co esponding sepa a ion ac o s. The e is usually an opposi e end be ween pe mea ion lux and sepa a ion ac o , i.e.: when one ac o inc eases he o he dec eases. This way, a pe apo a ion sepa a ion index (P.S.I.) has been de ined as a measu e o he sepa a ion abili y o a memb ane [8]: P.S.I. = J o · Sepa a ion ac o (3) To desc ibe he ba ch ope a ion sys ems, he ollowing exp ession in e ed by She and Hwang [5] was used: V C K a x x ln o o L o,i i                       + −=         (4) She and Hwang [5] in oduced he e m KL o conside he la o loss a e and ep esen s how quickly he o ganic compound is los due o se e al easons such as sys em leakage, pa ial condensa ion o incomple e collec ion in he pe apo a ion sys em. In Eq. 4 xi is he mole ac ion o componen i in he eed ank, xi,o is he ini ial mole ac ion o componen i a he beginning o he p ocess, Vo is he ini ial olume o he eed solu ion, and is he ope a ion ime. The pa ame e a is de ined as: V o i s ii,OV K C ApQ a− γ = ∞ (5) whe e C o is he o al mole concen a ion o he eed solu ion ( o dilu e sys ems C o becomes app oxima ely he pu e wa e mola densi y), A is he memb ane a ea and KV is he o al pe mea ion olume low a e (dV = -KVd ). Acco ding o She and Hwang [5] he esidue pe cen age and eco e y pe cen age a e calcula ed by equa ions (6) and (7) espec i ely: () () 100 · V K 1% esidue V o i , L K/CKa1 O V ++        −= (6) ( ) ( ) ( ) 100· V K 11 KCKa1 Ka1 %e yco e V o i,L K/CKa1 O V V o i,L V                −− ++ + = ++ (7) 3. Expe imen al sec ion 3.1. Ma e ials An o ganophilic dense memb ane was used in his s udy: PERVAPTM 4060 (Sulze Chem ech, Swi ze land), a memb ane whose ac i e laye is based on polydime hylsiloxane (PDMS). A mul icomponen dilu e aqueous solu ion was p epa ed wi h se en selec ed ola ile compounds [4] belonging o di e en chemical classes: 1-oc en-3-ol (Sigma Ald ich, 98 %), 1-pen en-3-ol (Sigma Ald ich, 99 %), 3-me hylbu anal (Sigma Ald ich, 97 %), hexanal (Sigma Ald ich, 98 %), benzaldehyde (Sigma Ald ich, >=99 %), 2,3-pen adione (Sigma Ald ich, 98 %) and e hyl ace a e (Sigma Ald ich, HPLC g ade). Some he modynamic p ope ies o he selec ed compounds a e lis ed in Table 1. 3.2. Pe apo a ion expe imen s Pe apo a ion expe imen s we e pe o med wi h a pla e and ame labo a o y s ainless s eel pe mea ion cell (Sulze Chem ech) wi h an e ec i e memb ane a ea in con ac wi h he eed mix u e o 170 cm2 [9]. The empe a u e o he eed liquid mix u e was kep cons an (± 0.5 ºC) by using a he mos a o hea he s i ed ank eed eac o . The pe mea e was condensed on wo pa allel glass cold aps cooled by liquid ni ogen o ensu e ha pe mea e was ully collec ed. Pe mea e p essu e was egula ed wi h an ai - inle loca ed be ween he condense s and he acuum pump. Fo s eady s a e ope a ion he eed eac o has a 5 L capaci y. This way, due o he small amoun o pe mea e p oduc , he concen a ion o he ola ile compounds in he eed ank was kep app oxima ely cons an along ope a ion. The eed low a e was se o 70 kg·h-1. This low was enough o a oid concen a ion pola iza ion in he concen a ion ange s udied in his wo k. Fo uns eady s a e ope a ion he a io memb ane a ea o ini ial eed olume (A/Vo) was highe han o s eady s a e ope a ion; hus eed concen a ion o ola ile compounds con inuously dec eases as pe apo a ion akes place. In case o ac iona ion a he pe mea e side, wo condense s we e placed in se ies in one o he wo pa allel pe mea e ci cui s. The i s condense was cooled by a e ige an ba h using a Julabo FP50 c yos a . The second condense was cooled wi h liquid ni ogen, ac ing as a o al condense . The chemical s abili y o he memb ane was checked by measu ing pu e wa e lux a e e ence ope a ing condi ions. 3.3. Sample analysis Pe mea e and eed concen a ion was measu ed o -line using a Hewle Packa d (6890) gas ch oma og aph (GC) equipped wi h se ies connec ed he mal conduc i i y (TCD) and lame ioniza ion (FID) de ec o s. Helium, 99.999 % pu e, was used as ca ie gas. The GC column was a 007 FFAP 25 m × 0.25 mm bonded phase used silica capilla y column. The injec o and de ec o s we e kep a 200 ºC and 250ºC espec i ely. The o en was ope a ed a p og ammed empe a u e, om 40ºC o 220ºC. 1-hexanol was used as in e nal s anda d o analysis o he sample. 4. Resul s and discussion. Fi s , he e ec o di e en ope a ing a iables, such as eed concen a ion, pe apo a ion empe a u e and pe mea e p essu e, on he pe apo a ion pe o mance o PERVAPTM 4060 memb ane is p esen ed. Fu he , hese esul s a e compa ed wi h a p e ious wo k [4], whe e pe apo a ion was ca ied ou wi h a POMS/PEI memb ane. A e wa ds, he esul s ob ained in ba ch ope a ion a e p esen ed. Then, he e ec o sodium chlo ide is analysed by a ying he sal concen a ion in he eed. Finally some p elimina y ac iona ion esul s by using wo condensa ion s eps a e discussed. 4.1. E alua ion o PERVAPTM 4060 memb ane pe o mance. E ec o eed concen a ion The e ec o eed concen a ion was in es iga ed in he ange o 0.1 o 50 ppm a a ixed pe apo a ion empe a u e (26ºC) and pe mea e p essu e (300 Pa). Since expe imen s we e ca ied ou a e y dilu e concen a ion, o al pe mea ion lux was close o wa e pe mea ion lux and emained almos cons an (0.0054 mol/m2s) wha e e he ola ile compounds eed concen a ion. Figu e 1 shows he o ganic compounds pe mea ion luxes as a unc ion o i s eed concen a ion. I can be obse ed a linea ela ionship o all he compounds s udied in his wo k ( 2 > 0.99 excep o 2,3-pen anedione ha shows a 2 = 0.97). Since ac i i y coe icien s a in ini e dilu ion a e cons an , and he polyme ic memb ane swelling can be conside ed negligible, he p essu e-no malized pe mea ion lux (pe meance) o he o ganic compounds and wa e , and consequen ly he sepa a ion ac o , will emain cons an . Table 2 epo s he en ichmen ac o s and pe meances ob ained h ough he PDMS memb ane. Benzaldehyde was ound o ha e he highes en ichmen ac o and pe meance. This way, Baudo and Ma in [10] assessed ha pe apo a ion memb anes a e e y pe mselec i e o aldehydes con aininig a benzene ing, which enhances hei hyd ophobici y and, consequen ly, hei solubili y in he pe apo a ion memb ane. E hyl ace a e and 1-oc en-3-ol also exhibi high sepa a ion ac o s. On he o he hand, he selec i i y o 2,3-pen anedione was ound o be he lowes , wi h a sepa a ion ac o alue o 10. E ec o pe apo a ion empe a u e The ope a ing empe a u e was a ied in he ange 26 ºC o 40 ºC. The expe imen s we e ca ied ou a h ee di e en eed concen a ions (1, 5 and 10 ppm) and a ixed pe mea e p essu e (300 Pa). Wa e pe mea ion lux inc eased exponen ially om 0.0054 mol/m2s o 0.012 mol/m2s in he empe a u e ange s udied in his wo k. Figu e 2 shows he e ec o empe a u e on ola ile compounds pe mea ion lux a an o ganic eed concen a ion o 10 ppm. The e ec o eed empe a u e can be desc ibed by an A henius ype equa ion:        −= RT E exp·JJ i,a o,ii (8) whe e Ea,i is he appa en ac i a ion ene gy o pe mea ion, Ji,o he p eexponen ial ac o and T he absolu e empe a u e. Table 3 epo s he appa en ac i a ion ene gies o pe mea ion o a oma compounds and wa e o he PDMS memb ane. This pa ame e cha ac e izes he o e all e ec o empe a u e on he pe meabili y and he d i ing o ce o pe mea ion [11]. A highe alue o he appa en ac i a ion ene gy indica es a mo e sensi i e beha iou owa ds empe a u e changes. Table 3 shows ha Ea,i o mos o he o ganic compounds is highe han ha o wa e , excep o benzaldehyde and e hyl ace a e. Howe e , hese di e ences a e no high. The e o e, i canno be gene alized o PDMS memb ane ha en ichmen ac o s o ola ile compounds inc ease wi h empe a u e, al hough o some o he ola ile compounds, such as 1-oc en-3ol, he inc ease o he en ichmen ac o wi h empe a u e is ema kable. This beha iou can be obse ed in Figu e 3 ha shows he en ichmen ac o a he ou empe a u es s udied in his wo k a a ixed eed concen a ion o 10 ppm o all he ola ile compounds. The e ec o empe a u e on selec i i y depends on changes o so p ion o o ganic compounds on he memb ane and i s di usion h ough he memb ane. Acco ding o Feng and Huang [11] he ac i a ion ene gy o pe mea ion, Ep, which cha ac e izes he empe a u e dependence o he memb ane, can be es ima ed by sub ac ing he hea o apo iza ion om he calcula ed appa en ac i a ion ene gy (Ep = Ea - ΔH ). The calcula ed ac i a ion ene gy ollows he o de : Ep,1-pen en-3-ol (-8.8 kJ/mol) < Ep,e hylace a e (- 8.6 kJ/mol) < Ep,benzaldehyde (-5.3 kJ/mol) < Ep,hexanal (-1.8 kJ/mol) < Ep, wa e ( -0.5 kJ/mol) < Ep,1-oc en-3-ol (10.5 kJ/mol) < Ep,3-me hylbu anal (17.0 kJ/mol) < Ep,2,3pen adione (28.1 kJ/mol). Nega i e alues o Ep indica e ha he memb ane’s pe meabili y dec eases wi h inc easing empe a u e. Ep can be exp essed as he ac i a ion ene gy o pe mea ing compounds o di use h ough he memb ane, ED, plus he en halpy o dissolu ion, ∆Hs (Ep = ED + ∆Hs) [11]. En halpy o dissolu ion is usually nega i e due o exo he mic Kujawski and K ajewski [17] p oposed he applicabili y o he empi ical Se scheno equa ion: si o,i i ckln =         γ γ ∞ ∞ (9) o desc ibe he inc ease o o ganic pe mea ion lux wi h sal concen a ion. In Eq. 9 ∞ γi is he ac i i y coe icien a in ini e dilu ion in sal y solu ions, ∞ γo,i he ac i i y coe icien a in ini e dilu ion in pu e wa e , cs he sal concen a ion and he p opo ionali y ac o , ki, is he sal ing-ou coe icien . This way he ln (Ji, sal y solu ions/Ji,non-sal ysolu ion) can be plo ed as a unc ion o NaCl concen a ion and compa ed wi h da a o he ac i i y coe icien s ob ained in p e ious wo k [7]. Table 5 lis s he slopes o hese plo s oge he wi h he alues p e iously epo ed in he s udy o he ac i i y coe icien s a in ini e dilu ion. I can be obse ed ha he alues o he slopes ob ained o he ln (Ji, sal y solu ions/Ji,non-sal ysolu ion) we e lowe han he alues p e iously epo ed [7]. The e o e, blocking e ec canno be conside ed negligible. As an example Figu e 10 ep esen s he applicabili y o he Se scheno equa ion o e hyl ace a e. In his Figu e, he alues o he ac i i y coe icien s a in ini e dilu ion ob ained in a p e ious wo k ha e been also plo ed. 4.5. Mul is age condensa ion o he a oma compounds. In sec ion 4.1 en ichmen ac o s we e epo ed in he ange o 10 o 2,3-pen anedione o 39 o e hyl ace a e. Ma in e al. [18] p oposed o modi y he downs eam sec ion wi h a mul i-s age condensa ion s ep o imp o e he pe apo a ion pe o mance. In his wo k, some expe imen s ha e been pe o med by using wo condense s placed in se ies. The componen s o he pe mea e apou ha e di e en condensa ion po en ials, hus yielding an addi ional sepa a ion ac o [19]. The dis ibu ion o wa e and o ganic compound in each condense depends on he empe a u e o he i s condense , he ola ili y o he componen s, he low o he condensable and ine gases in he pe mea e side and he s ipping e ec be ween condense s [20, 21]. Pe apo a ion expe imen s ha e been ca ied ou a a ixed empe a u e o 26ºC and pe mea e p essu e o 300 Pa. Feed concen a ion was abou 1 ppm o all he o ganic compounds. Two di e en empe a u es we e ied in he i s condense -4 ºC and - 10ºC. Table 6 shows he pe mea ion lux pe cen age collec ed in bo h condense s as a unc ion o empe a u e in he i s condense . As i can be obse ed, he pe cen age collec ed in he i s condense inc eases as he condensa ion empe a u e in he i s condense dec eases. Due o he e iciency in wa e emo al in he i s condense , en ichmen ac o s o he o ganic compounds collec ed in he second condense imp o e conside ably (Table 7) compa ed o one condense . Table 7 also epo s he sepa a ion ac o ha would be ob ained on he basis o apou -liquid equilib ium (VLE) a 40ºC. This ela i e ola ili y a in ini e dilu ion, ∞ α w,i , is de ined as: 𝛼𝛼𝑖𝑖,𝑤𝑤 ∞=𝑝𝑝𝑖𝑖 𝑠𝑠 𝑝𝑝𝑤𝑤 𝑠𝑠𝛾𝛾𝑖𝑖 ∞ (10) whe e pis and piw a e he sa u a ion apou p essu e o o ganic compounds and wa e espec i ely and 𝛾𝛾𝑖𝑖 ∞ is he ac i i y coe icien a in ini e dilu ion. The sepa a ion ac o s ob ained wi h one condense we e lowe han he sepa a ion ha would be achie ed on he basis o VLE. Howe e , wi h a wo condensa ion s ep he new sepa a ion ac o s ob ained a e, o some o he compounds, e en highe han he alues o he ela i e ola ili y. Concen a ion o he mos ola ile compounds in he pe mea e collec ed in he i s condense was e y low. Tha indica es ha mos o he pe mean molecules o hese o ganic compounds we e mainly collec ed in he second condense p obably due o a s ipping e ec . Howe e , he concen a ion o he a oma ic compounds in he second condense is less han expec ed based on mass global balance wi h he esul s ob ained wi h one condense . This ac can be due o he e y high loss a es ound o hese compounds in he s udies pe o med in non-s eady s a e (sec ion 4.3). The non-s eady s a e expe imen s e ealed ha he concen a ion o he high ola ile compounds is la gely condi ioned by he ime employed in each un due o he high alue o he la o loss a e. The ope a ion ime used in he ac iona ion expe imen s was longe han in he expe imen s ca ied ou wi h one o al condense , due o he ac ha insu icien quan i ies o he analysis we e collec ed in he second condense , especially in he expe imen s ca ied ou a he lowes empe a u e in he i s condense . 5. Conclusion PERVAPTM 4060 memb ane has been ound o be e ec i e o eco e some key a oma compounds ound in he b own c ab boiling juice om a model dilu e aqueous solu ion. The e ec o eed concen a ion, pe apo a ion empe a u e and pe mea e p essu e on pe apo a ion pe o mance has been analyzed. An inc ease o he a oma eed concen a ion inc eases o ganic pe mea ion lux due o an inc ease in he pe mea ion d i ing o ce. Pa ial and o al pe mea ion lux inc eased wi h empe a u e and pe mea ion lux dec eased as pe mea e p essu e inc eased. The esul s ob ained unde s eady s a e ope a ion wi h PERVAPTM 4060 we e compa ed wi h hose one ob ained wi h a POMS/PEI memb ane. To al pe mea ion lux was highe o PERVAPTM 4060 memb ane han o POMS/PEI. Based on he di e en e ec o empe a u e o bo h ypes o memb anes i was concluded ha so p ion con ibu ion was mo e impo an o PERVAPTM 4060 memb ane han o POMS/PEI memb ane. F om ba ch pe apo a ion expe imen s, i was ound ha he loss o ola ile compounds inc eases wi h ope a ion ime. Loss pe cen age was high o ola ile compounds wi h low pe mea ion a e and high la ou loss a e. Highe memb ane a ea would help o educe he loss pe cen age. The p esence o NaCl sligh ly imp o ed he e iciency o a oma eco e y om dilu e aqueous solu ions. This ac can be a ibu ed o he “sal ing ou ”. Howe e he inc ease in pa ial pe mea ion lux is lowe han he co esponding “sal ing ou ” e ec concluding ha blocking e ec canno be neglec ed. Modi ying he pe mea e ci cui wi h a wo condensa ion s ep can be an e icien way o imp o ing he pe apo a ion pe o mance, since i has been obse ed a conside able inc ease o he en ichmen ac o s ega ding one condensa ion s ep. Howe e , he design mus be op imized since impo an losses o some o he ola ile compounds, especially he mos ola iles, ha e been obse ed. Fu he s udies will be ca ied ou wi h he indus ial b own c ab boiling juice o s udy he abili y o pe apo a ion echnique. Nomencla u e a = pe mea ion a e cons an , m3·s-1 (Eq. 4) A = memb ane a ea, m2 C o = o al mola concen a ion in liquid phase, mol·m-3 (Eq. 4) Ea = appa en ac i a ion ene gy o pe mea ion, kJ·mol-1 H = Hen y’s law cons an , Pa J = pe mea ion lux, mol·s-1·m-2 k = sal ing ou coe icien KL = la o loss a e, mol·s-1 (Eq. 4) KV = o al pe mea ion olume low a e, m3·s-1 (Eq. 5) QOV = p essu e-no malized pe mea ion lux, mol·s-1·m-2·Pa-1 p = p essu e, Pa P.S.I. = pe apo a ion sepa a ion index R = gas cons an , kJ·mol-1K-1 T = absolu e empe a u e, K V = olume o eed solu ion, m3 x, y = mol ac ion = ime, s γ = ac i i y coe icien β = en ichmen ac o subsc ip s i = componen p = pe mea e = eed uppe sc ip s s = sa u a ion ∞ = in ini e dilu ion Acknowledgmen s Financial suppo om he MICINN h ough CTQ2008-04999-PPQ is g a e ully acknowledged. R. Ma inez acknowledges he JCyL Educa ion Minis y. Re e ences [1] Y.J. Cha, K.R. Cadwallade , H.H. Baek, Vola ile la o componen s in snow c ab cooke e luen and e luen concen a e, J. Food Sci. 58 (1993) 525-530. [2] S. C os, B. Ligno , P. Bou seau, P. Jaouen, Re e se osmosis o he p oduc ion o a oma ic concen a es om mussel cooking juices: a echnical assessmen , Desalina ion 180 (2005) 263-269. [3] S. C os, B. Ligno , P. Bou seau, P. Jaouen, Technical and economical e alua ion o an in eg a ed memb ane p ocess capable bo h o p oduce an a oma concen a e and o ejec clean wa e om sh imp cooking juices, J. Food. Eng. 77 (2006) 697-707. [4] R. Ma ínez, M. T. Sanz, S. Bel án, Concen a ion by pe apo a ion o ep esen a i e b own c ab ola ile compounds om dilu e model solu ions, J. Food. Eng. 105 (2011) 98-104. [5] M. She, S. T. Hwang, Reco e y o key componen s om eal la o concen a es by pe apo a ion, J. Memb . Sci. 279 (2006) 86-93. [6] I. Blume, J.G. Wijmans, R.W. Bake , The sepa a ion o dissol ed o ganics om wa e by pe apo a ion, J. Memb . Sci. 49 (1990) 253-286. [7] R. Ma ínez, M.T. Sanz, S. Bel án, E. Co cue a, Ac i i y coe icien s a in ini e dilu ion o a oma compounds in wa e : e ec o empe a u e and sal concen a ion, J. Chem. Eng. Da a 57 (2012) 1480-1485. [8] R.Y.M. Huang, J.W. Rhim, Sepa a ion cha ac e is ics o pe apo a ion memb ane sepa a ion p ocesses, in Else ie (Ed.), Pe apo a ion Memb ane Sepa a ion P ocesses, Ams e dam, 1991, pp. 111-180 [9] P. Delgado, M.T. Sanz, S. Bel án, Pe apo a ion o he qua e na y mix u e p esen du ing he es e i ica ion o lac ic acid wi h e hanol, J. Memb . Sci. 332 (2009) 113-120. [10] A. Baudo , M. Ma in, Pe apo a ion o a oma compounds: compa ison o memb ane pe o mances wi h apou -liquid equilib ia and enginee ing aspec s o p ocess imp o emen , Food Biop od. P ocess. 75 (1997) 11-142. [11] X. Feng, R.Y.M. Huang, Es ima ion o ac i a ion ene gy o pe mea ion in pe apo a ion p ocesses, J. Memb . Sci. 118 (1996) 127-131. [12] V. Ga cía, E. Pong acz, E. Muu inen, R.L. Keiski, Pe apo a ion o dichlo ome hane om mul icomponen aqueous sys ems, J. Memb . Sci. 326 (2009) 92- 102. [13] M. She, S.-T. Hwang, E ec s o concen a ion, empe a u e, and coupling on pe apo a ion o dilu e la o o ganics, J. Memb . Sci. 271 (2006) 16-28. [14] J. Olsson, G. T aga dh, In luence o empe a u e on memb ane pe meabilibi y du ing pe apo a i e a oma eco e y, Sep. Sci. Technol. 34 (1999) 1643-1659. [15] R. Clémen , Z. Bendjama, Q. T. Nguyen, J. Neel, Ex ac ion o o ganics om aqueous solu ions by pe apo a ion. A no el me hod o memb ane cha ac e iza ion and p ocess design in e hyl ace a e sepa a ion, J. Memb . Sci. 66 (1992) 193-203. [16] F. Lipnizki, S. Hausmanns, R.W. Field, In luence o impe meable componen s on he pe mea ion o aqueous 1-p opanol mix u es in hyd ophobic pe apo a ion, J. Memb . Sci. 228 (2004) 129-138. [17] W. Kujawski, S. R. K ajewski, In luence o ino ganic sal on he e ec i eness o liquid mix u es sepa a ion by pe apo a ion, Sep. Pu i . Technol, 57 (2007) 495–501. [18] M. Ma in, C. Hammami, D. Beaumelle, Sepa a ion o ola ile o ganic compounds o m aqueous mix u e by pe apo a ion wi h mul i-s age condensa ion, J. Food Eng. 28 (1996) 225-238. [19] L.M. Vane, F.R. Al a ez, A.P. Mai al, R.W. Bake , Sepa a ion o apo -phase alcohol/wa e mix u es ia ac ional condensa ion using a pilo -scale dephlegma o : enhancemen o he pe apo a ion p ocess sepa a ion ac o , Ind. Eng. Chem. Res. 43 (2004) 173-183. [20] F. Gascons Viladoma , I. Souchon, V. A hés, M. Ma in, Memb ane ai s ipping o a oma compounds, J. Memb . Sci. 277 (2006) 129-136. [21] A. Baudo , M. Ma in, Imp o ed eco e y o an es e la o compound by pe apo a ion coupled wi h a lash condensa ion, Ind. Chem. Eng. Res. 38 (1999) 4458- 4469. Table 1. Physicochemical p ope ies o he ola ile compounds. (MW = molecula weigh , BP = boiling poin , ps = sa u a ion p essu e, γ∞ = ac i i y coe icien a in ini e dilu ion, H = Hen y’s cons an ). Compound MW, g/mol BP, ºC p26ºC 𝑠𝑠, Pa γ26º𝐶𝐶 ∞ H 26ºC ·10-4, Pa 1-Oc en-3-ol 128.2 174-5 65 1779 11.6 1-Pen en-3-ol 86.1 114.4 1348 38 5.1 3-Me hylbu anal 86.1 92.5 7035 127 89.3 Benzaldehyde 106.1 178.8 181 504 9.1 2,3-Pen anedione 100.1 108 2918 133 38.8 Hexanal 100.2 128.3 1540 599 92.3 E hyl Ace a e 88.1 77.1 13045 62 80.9 Table 2. Pe apo a ion pa ame e s o PERVAPTM 4060. Compa ison o PERVAPTM 4060 and POMS/PEI memb anes (TPV = 26ºC, pp = 300 Pa). PERVAP TM 4060 POMS/PEI Compound β QOV,i·107 (mol/m2sPa) PSI (mol/m2s) β QOV,i ·107 (mol/m2sPa) PSI (mol/m2s) 1-Oc en-3-ol 36 18.5 2.0∙10 -1 120 8.6 8.8∙10 -2 1-Pen en-3-ol 25 29.6 1.4∙10 -1 25 3.1 1.9∙10 -2 3-Me hylbu anal 18 1.1 1.0∙10 -1 5 0.03 3.9∙10 -3 Benzaldehyde 51 35.8 2.8∙10-1 93 7.5 7.5∙10-2 2,3-Pen anedione 10 1.4 6.8∙10 -2 7 0.1 5.2∙10 -3 Hexanal 23 1.4 1.3∙10 -1 22 0.2 1.7∙10 -2 E hyl Ace a e 39 2.7 2.2∙10-1 7 0.04 5.6∙10-3 Wa e 17.5 2.0 Figu e 1. E ec o ola ile eed concen a ion on ola ile compound pe mea ion lux (TPV = 26 ºC, pp = 300 Pa) o PERVAPTM4060. 0.E+00 1.E-06 2.E-06 3.E-06 0.E+00 3.E-06 6.E-06 9.E-06 Ji (mol/m2s) xi (mol/mol) 1-oc en-3-ol 1-pen en-3-ol 3-me hylbu anal benzaldehyde 2,3-pen anedione hexanal e hyl ace a e Figu e 2. E ec o pe apo a ion empe a u e on ola ile compound pe mea ion lux (Ci. eed ≈ 10 ppm, pp = 300 Pa) o PERVAPTM4060. -18 -17 -16 -15 -14 -13 -12 -11 3.15 3.2 3.25 3.3 3.35 3.4 ln Ji (mol/m2s) 1000/T (K) 1-oc en-3-ol 1-pen en-3-ol 3-me hylbu anal benzaldehyde 2,3-pen anedione hexanal e hyl ace a e Figu e 3. E ec o pe apo a ion empe a u e on he sepa a ion ac o o he ola ile compounds (Ci. eed ≈ 10 ppm, pp = 300 Pa) o PERVAPTM4060. 0 10 20 30 40 50 60 70 En ichmen ac o T=26ºC T = 30ºC T = 36ºC T = 40ºC Figu e 4. E ec o pe apo a ion empe a u e on he lux and d i ing o ce a io o PERVAPTM4060 (C eed ≈ 10ppm, pp = 300 Pa). DF =d i ing o ce o he p ocess. 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 J40ºC/J26ºC and DF40ºC/DF26ºC J40ºC/J26ºC DF40ºC/DF26ºC Figu e 5. E ec o pe mea e p essu e on pa ial pe mea ion lux o PERVAPTM4060 (Ci. eed ≈ 1 ppm. T eed = 26ºC). The con inuous lines a e o guide he eye. 0.E+00 2.E-08 4.E-08 6.E-08 8.E-08 1.E-07 0500 1000 1500 2000 Ji (mol/m2s) pp (Pa) 1-oc en-3-ol 1-pen en-3-ol 3-me hylbu anal benzaldehyde 2,3-pen anedione hexanal e hyl ace a e Figu e 6. E ec o pe mea e p essu e on he en ichmen ac o s o he ola ile compounds o PERVAPTM4060 (Ci. eed ≈ 1 ppm. T=26°C). 0 10 20 30 40 50 60 70 En ichmen ac o 300 Pa 400 Pa 600 Pa 900 Pa 1200 Pa 1800 Pa Figu e 7. E ec o memb ane ma e ial on he pe mea e a oma p o ile (T = 26ºC, Ci = 10 ppm pp = 300 Pa. 1-oc en-3-ol 1-pen en-3-ol 3-me hylbu anal benzaldehyde2,3-pen anedione hexanal e hyl ace a e Feed solu ion PDMS, 26ºC, 300 Pa POMS, 26ºC, 300 Pa Figu e 8. E olu ion o eed concen a ion o e ime in he pe apo a i e eco e y o a oma compounds (TPV = 26ºC, pp = 300 Pa, = 11 h). The con inuous lines ep esen he model p oposed by She and Hwang [5]. -7 -6 -5 -4 -3 -2 -1 0 0 5 10 ln x i /x i,0 (h) 1-oc en-3-ol 1-pen en-3-ol 3-me hylbu anal benzaldehyde 2,3-pen anedione hexanal e hyl ace a e Figu e 9. In luence o sal concen a ion on he en ichmen ac o o he o ganic compounds o PERVAPTM4060 (C eed = 1ppm, T eed = 40ºC. Pp = 300 Pa). 0 10 20 30 40 50 60 70 80 En ichmen ac o 0 mol/kg 0.34 mol/Kg 0.43 mol/kg 0.51 mol/kg 0.85 mol/kg Figu e 10. Compa ison be ween he e ec o sal concen a ion on e hyl ace a e pa ial pe mea ion lux (○) and ac i i y coe icien s a in ini e dilu ion (▲). 0.0 0.2 0.4 0.6 0.8 1.0 1.2 00.5 11.5 2 ln (Ji,sal y/Ji,non-sal y), ln(γi∞/γi,o∞) CNaCl (mol/kg)