CA2289280A1

CA2289280A1 - Use of aerogels as adsorption agents

Info

Publication number: CA2289280A1
Application number: CA002289280A
Authority: CA
Inventors: Werner Sievers; Andreas Zimmermann
Original assignee: Individual
Current assignee: Cabot Corp
Priority date: 1997-04-18
Filing date: 1998-04-17
Publication date: 1998-10-29
Also published as: EP0975405B1; JP2010264451A; CN1256645A; JP5762702B2; DE59813467D1; KR20010006531A; CN1244400C; EP0975405A2; WO1998047594A2; EP1690593A1; WO1998047594A3; JP2001521441A

Abstract

According to a first liquid purification method, the liquids to be purified are brought into contact with the aerogels from a liquid phase acting as adsorption agents during a time period which is long enough to enable adsorption of impurities contained in the liquids. In a second liquid or gas purification method, the gases or liquids to be purified are brought into contact with hydrophobized aerogels acting as adsorption agents during a time period which is long enough to enable adsorption of impurities contained in the gases or liquids.

Description

14.OKT.1999 11 14 LUDERSCHMIDT~ SCHUELER & PARTNER ~dR.056 S.4i48 Description Use of aerogds as adsorption agems The invention rdetrs to the use of xrogel= ai adsorption agetttss a method of pu:ifying liquids and gases ad well as a method of isoladag orgaoie co>»pounds from liquids.
for pur'if~ring gases wad ~quic~ as well as for subsrance sepantaaa, a plurality of azdsorptioa a~ arc uaad which adsorb fadividual compounds ar groups of oompounda frora a liquid er gas nnixtute so permitting separation. AS a rule;
haterogeutrou9 adsosptioa aQeu~, psrtieul4rly solid adsorgtiort agarts. are used for parify~iag Tiqulds and gase.. Exatrrples of known adsorption agepts are aativazed carbon 4nd polymeric adsorption egcnt~, A muub~c of ar~,saic and morgsr>;c compounds can be adaorbod with acCivatad carboy In this respect, the bqr~dnop~whidty of the activated cesboh can scarcely be varitd ~ order for instance io perniit selective sdsorptioa from s mixture of ootnpounda of differing h~drephobiciey. For exar4ple, activated carbons whioh are u~ted in ws9te air ttachnology, r bav~e a ctromr grater absorption property which reduces the adsorpdoa capacity av~Zable for other compouttda which are to be adsorbed. This water absorption capacity can be a i drawback not only as the case of wsute gases which xre suurated with or which coatstin w~auf vapour but iaatead, they also play a~ imporZani pan is water vapour regenerated activated eubon plant. Whetc the rs~eratioa of activated carbon plant with waxer vapour is concetn~, a time'-imensive drying ate has w be utcorporated f~allowing steanmtg during a~bieb the rtwist atanrated carbon a dual, rnostty with ambient air. Thus, rtgenaation of the activated carbon is both time sad labour-cr~nsumit~. Where the use of activztad carbon err aetivatod efllce is used as an adsorption agent in the adsorption of 8nm waste gees, particularly in plant for cleansing waste air, the adswbers have mo Ix regeoelsted iu ut, inert auttosphere. 3n the rose of the ad:ntptiori and deaorption of rotbbust~le 9olvenis; it c8n otAe~nuisc result in the fortruitiaa of ''hot spots"s i.e.

l4.Ok'T. 1999 11 ~ 14 LUDERSCHMIDT. SCHUELER & PARTfJER fJR.056 5.5: 48 a stt~oulderir~g poclccxs which can cause the emire adsorption plate to bs burned off.
Therefoae, in a~a~a to water vapour, mostly oiuo~cn is used as a desorption $gent. In ' addipon, additjonsl ~foty meets are often r~uired suueit ac appuuas for the con~olled tloodirtg of tbs plant with orti~ishiag water in the evaat of fire. Such safety precautions are very cost iate~mive. For certain ad.sarptioa tasks, it is not possible to use ac~tiYated carbon. For instaaca, acciv,ted carbon cannot lee used in the fiae.clcansirg of pharmaceutical active principles and produce, because activated carbons ooznain not iacoagiderable orb conxitueat: which can only be partially reducal by coc~intens'rve rnahods such as acidulation Ia the process of pharauacological active substances, tlurefure; wharf adsorption processra are us0d a product-friendly raethods, the proeesse: work trrith polymeric adsorption agents. 'Pnlymetic sdsorpaan agemtt arc as a rule ~highiy cross-linked polymers, fair example aver based on ayreaeldivinyl beasene. These polymeric adsorption agents ire widely used in the purification ofbiologically and chemically prod~ued medicastumts.
Polynuao adsorption agents swell an varyiria degrees as a function of the solvent used so that when dimensian~,~ the correspor:ding e~uipmeat, due aTiowauce must be made for the possb~r inece~ed deal loadi~. The bydnophobicity of polymeric $dsotptian agems is oNy a~ctable within relatively natroov liuat:.
The punblam on which the precut in~pon is based is that of providing ld~rption agents winch can! be used puticuLerly for the ueatment of wane gases, ss well as fnr the cleansiaa or putificuioa of pharmaceutical scinre ptittciples arid avoiding the abo~e-mcationed dntw~aks of aotivaTed carbon attd polyrneiic adsorption agents.
~ldaxding to the ittvP.ntion, the ptobleta is rtsotved by the uoe of aaogcii as adsarptiou a~~ts tbr adsorption from liquid phase. Futtherroore, hydrophobic and hydrophilic i aorogiev amid preferably terogele which have been rendered wslet repellent are generally used ag sdaosptiori agars. F~uthatao~r~q, in accordance with the invenrion, for adsorption from the gaseous pba~ adsorpaoa its one used which voatain aaogels wbich xrt not present as z mixture vrith saavated arboa ar activated alurama.

l4.Ok:.T.199'~ 11:15 LUDERSEHMIDT. S~HUELER ~. PART~aER PJR.~Sf 5.548 ,!' ~ ~ A~ads which as a tide ate highly Porous ~ttetiala consisting of silicon or metal modes ,,.
with a density is the range from 70 to 400 k~cu.m aid an loner ~wfac8 area of up to t Oo0 sg.a~l,~ one predomiru~tly u~d as hear i~l$tin~ s Once they have very I
ow heat loss factors.
,, Hithuto, se<ogels have only beg described as adsorption stgents in a gas adsorption dement is w~hioh, they are bond.cd with activated taboo andlor activated shimins jointly in a matrix oea~a~ ~papeca allow da~r which mainly consist of inorganic $bres and which are kyenad erlartAtaued on curt ianother. M~1 siliata arro~ls arc used which ue not fed add which are disclosed for exatnplz in DE A 39 37 563. The gas s~d5osption is tnaanly used for binding atmospheric humidity.
According to.the iuveru~on, it has boett found that aaogels can be used ouutandit~gly as adsorption ae~ezrce in gas and liquid pbase~.
i Stu'~able aero~eia are described far ea~pie ip D~Ar43 16 540, Dl~-A-43 b3 54>Q, ~~~A~i4 22912, D~-Mq4 39 217, W4 96I229~2, DF~A-195 250 21 and WO 98145591 as well as in the as yet unpublished Ge~m4n Paten Application 196 48 798.6.
~~i~~ , The sefogds pa'odt>CCd in accordanoc with the aforemetrtioned citations ate bydtophobic 8y pyrolysis, preferably at 300 to 600°C is an Oz atmosphe~ey it is possible to produce therefrom hydmplu~ic aero~els such a9 are disclosed for iristaoce in WO
96r2b89o.
The aero~s wed socasding to tlae im~rtion have very high iruter suzfaae areas of 100 to l00o and prM~b~r 3Do to 700 sq.talg, daermined by 81:'f rneaaurrements using tutcagcn ald9orption. Aa a rule, the pore volume amauats to t.5 to 3.5 and preferably 2 to 3 ~ cm/g. Amajor part ofthe pore radu falls in the range $am 1 m lSo end preferably in the range frocq 1 to 30 and pardc~lar~r pre&rably is the range from 5 to 20 ttaitornetera ~i I 'lie aerog~els is this Case usually bout comiwtous ports, i.e. all pours are acoesstble from tie ~dge of the ~pu~icle. Where activated cnrbAn or a~ivat~ed coka are cotreerrnd, this property can only be achievsd by an additional process stage, thermal activttian.
,r I
t 14.04~'T. 1999 li ~ 15 LUDERS~=HMIDT. St:HUELER & PARTNER fJR.055 S.7ia8 The aecogets eats be produced in any form suitable for use xs an adsorpsica agent. For exempla, according w producciaa, sa the aeragt! rosy be ~rrnsent in powder fnsm, as a moulded put of azzy shape, pr,,ly in tba farm of rode or stnah crisis: having diatnetere from 1 tn a mm and ps frarn 3 to 1 A true, or as granules. The aesogcls can also be used in the forth of pellets or tablets. For adsoTp~ian irt the liquid phase, pral~ably powd~tad ulsorbiag egemg aro uood which by reason of the grnerally leaaa mass vanefer and diffusion coafficienu, the aim is for short chffusion pethe. When used in the gas phts~ posable for adaoipove gas ion or waxta air ~rificatiors, preferably granules, tablets, peuets or shaped forn>s of aerog~ are used since pres9ure losses can be mirdrrased by reason of a hiigh ptoportian ofi~icu so that duet problems far et~apl a due to discharge from art adsntption colus~ lordly occur. 'The desired fona of ae~gda can be achieved directly in the produaioa process so that it is pos~'bIc to wove nay oubse-. Consequently, production is less expensive than for exaatple the moulding of activated cuboa which has ~rsr to be Bound and than moulded so shape.
Ths adsorption propezzies of the auogels can be adjusted under control by appropriate snrPtee modicCc~tiom which give' the saagela a hydrophdie ar hydrophobic ehuacter.
Pcrfua6ly, they atn be r~der~ad water repellent by si~rlaroa of rbe aecogels, for ~ple by mew of trimethyl chlaras~ne. When they are rendered yvater repellc~t, the water adearption capaeiry of the aerogels can be gnarly reduced so that the warer is scarcely ab~e is wet the au~ees, Thw, for dcart~ple in the adsorption of waste gases which 'oo~in water vsponr, the adwrption capacity is eat reduced by the adsocptian of water Ia'additios~ s~o timpiptensiva drying stage is required is water vapour regeneration ofthe eeiogclo.
,~ , ,f,,,. , ~: n In the race of solvent ad:orptxoo, paracuJarly in plant for waste air purification, it is pPsc~'bie to di>pknfe with additior~l safety prerautios~s such as ~tt~e required ~or instance when activated ~eatban adsorption agaus are used, since the aerogets have a very high uuipersture stability and are non-combustible. Thus, the aerogol9 can be veey ~u~ ~ ~ ~ ~ Pte, t~ ~snds of the Clean Air ~ puticula~ with tegarad to opetuiottsl safety and tyr beir~ maintained.

14. OE:T. 1999 11 ~ 15 LUDERSCHMIDT. SCHUELER & P~IRTr~IER r~IR. 055 S. J% 48 t ~1i17~C$QOa p~~M S11ff8fS VlllLally aO dOliV~ tlfi~ d111C t4 tfallltS-h In addition to s>olveat wdsorpttio~n is waste sir purification plsm, the aeragels according to the imrentiaa can be used four ugr lmowr~ adsa~p~tion appticatioru is which adscuption from the gaseous phase is required F.~camples ue the separation of gas mixture8 and the adsorption of impurities from gases. Where impurities are coaeetned, these can far Ie ha g~ous impucitia such as niarogea axides, sulphur mddes, carbon monoxide, ammorda or org~tuc gases, That' may also be vaporised liquids or droplets of liquid i strained in a gas Sow 'iiydrophilicaliy mochfied atrogelt can also be usoci fvt' drying ' ~rsea, i.e. for eliminating water.
° ''~
Zf the ad~pdoa capacity of the aetogeas used according to the iaventian is exhausted, ';: xbea the aerogels can be regeaeratad by.)mown methods. For example, the adsorbed substttncea can be ~ by hens. Elimination by nteaus of other gay arch as steam is possible and the appropriate methods are known to a man skilled in the art.
°
~, i n 1 The terra "gaaeotte phase" 8anecauyr deaetee a nvxwro of oubstaru~ hasrrl as a gas er gas mixture. The gas or gas rrri~we can therefore also contain rolid and in particular Liquid constltuans.
The zerogels according to tha invention can f rttb~ar be used ss adsorption agesus far adsotptio~ from a plurality of >iguid ph~es, 'The esprescion "liquid phasel~
can thereby inetude hortsogenous solutions, emulaons, dispersions, liquids which captain gees in sblutiaa, arid mixtwes. A liquid thereby secvcs as s carries plisse from which i1~9t8tICt.1 it's ~90Tbed by tile 8Cf0~elS
~S
~e ~,. 1 n ;
Consequertdy, gases, liquids or dis:anred subau~ or even aol'~da can be eWninated from liquids. 'I!»e rruy be or~nic or inorgat~ic~ substances. In particular, organic subatancxa such a: hydrocarbotu, particularly aramauc or chlorinated hydrocarbons, can be i eliminated- As liquid9 is this reipeKt, any suitable solvent such as water yr organic soh~ ea~a ba usod. ~dsorpaan preferably takes place ftotn water or aqueous sohreats.

14. Ok.T. 1999 i i ~ i5 LUDERSCHf~1IDT. SCHUELER & PARTfJER NR. ~55 The adsorbed co~aunds can, after srparatioa ofthe adsotptian ahem from the liquid,., be released fra,a the liquid by suitable processes, for example by hestitq~
washing out or eTutzo:L Duriap rlu adsorption of organic water-c,onuiniag oubot~uces, the aerogels acco~g ro the invenpan e~bit highly selective adsarprion properties.
Therefore, they can be r~dily used for purif~ittg ir~d,~strial eat or waste water fl om Isboratoriea_ ,'Ibe aeragats aecattling to the invetnioa can, is addition to the purifcuion of liquids, also be used foc isolatizta organic compounds from liquids or snixartn of liquids.
Here, the 'aim is the isolation aitd reeovery of vr~anic compounds which are to a certain exxenc pce,~t in inteaae>y muted fore and, aleng with ~ ocher canstitucrr~s, may be present in liquids or mid o~f liquids. 1n this re~pact, the highly selective adaacgcion of aerogeLC
can be advaatageausly used is order to isolate spoaal organic compounds from a plurality of possibly similar organic corttpaunds in a liquid.
Prefaabfy, the osgaadc oa~v~md: are isolucd from aqtuous liguids. In particular, these are agricultural chemicals or phernaacanical substances which are isolated from the mother liquors which occur du>i~ their production. Examples of such agriculnua!
chemicals ~e active substances having habiadsl, tungicidat or insecticidal properties.
Where the mauufscwrr of native phurriaccutical substaneat a concerned, the coats of prpce~it~ ofd coastiriue a substamial portion of the overall costs. A
aricrobiologically produced product cuusa for cxaanplc be processed in several stages iu as product-friendly al marv~er as possible. .Processusg Thereb~t implies the separszion and purification of the erti~c plea) substance from the lion solution. Whore the cure of the trutjotity of all ~utic~tt substances is concerned, one or a plurality of adsorptive puti6cation stagci 4rc required ~xamptes of active pharmaceuticslo are aat~iotics which are obtained from the fatmenmtiort solutions which oowr dining their producuon_ Ia particular, the semgels are used for cteaasir~ arid separatlnQ the antibiotic known as cephalosporin C
(CPC).
,~ a~~ , ;;.
r 14, uKT. 1999 11- 15 LUDER5CHfIIDT. SCHUELER & PARTfJER fJR.0S6 S. 10149 r k I
' icy r~son of the high selectivity of the aerogds according to the invention where active ~ phatts atr coned, paraw>atiy C~~ the proces:iag and pu~r~c~uian methods cure merlcediy ~mPl~od and rccelerate~d. THe mvartion also relasae to the purif catian grad isolating processes which atr iavolwed in the aforementioned applications.
,v;
r ' '~ ~, 'a A rottlaod to the in~remioa for the purification of gages is cbarsctetised in that the $~ses to be put~i~ed ate, for a petiod of time adequate for the adcotpdon of impunitiea ca~ia~d in the gases, brought irno contact as adsarptiaa a~tau wish acrogels which ate Mrt prosant as a mixNtt with activated cubon or activated alumitra. Tye cornsponding contact times are known to a man skilled in the art but are prefa~ably in a page from x.001 t0 ~. ~ 1 3eCOMl.S.
A method of pacifying liquids according to the im~eotian it Cbaracteiised iu that far a ~aiod of tiaae euffieicnt for adsorption of itapuritiae caataihcd in the liquid are brought jrno contact with aerogels whirl: serve as adsorption agems.
~ n , ~~~~~ iM ~~
p fia~ar iacthod of g gases or liquids a characterised is that tl>e gee: or liattids to be pt~od ate bt~ougitt into contact with water repellent s~geu ac ad'otptiwi agents fac a period of tits adequate for adsvrppon ofimpuraies c~totted in the Bases or liquids, A method accorditag to the invention 6or isolati~ organic cotnpoundc frarm liquid is charaeterisod in that the liquids containie~ the a~pnic eampatutd are brought into contact with aerogels as adsorption agents for a period of time sWcient for adsorption of the ~aaic anmpaunds, the serogds then being separated $~ the liquids aatd aubse~rlY
the orgusic couapourida ate 9epanted fratn the aemgels. Separadnn can thereby take I , ~~e iu acaondanca with the methods. Where the purtficgcion ef liquids and c~
;w i~qlatioa of organic carapounds from liquids is concerned, rriatmera v~rith the aerogels t~ke~c place its periods of time which are Jwwn to a man 9kdled in the act at~d preefieerably for a period of 1 io 50 seconds. ,,~~~'a Separation of the seragels from the oTga~c compounds obtained sect be canted out sa deBC~'bed above by elution urith a solYau,~7pos~laly as argadic aolvenc or a salt salntioa ~ ~m '. i 14.OKT.1999 11:1? LUDER~CHMIDT. S~HUELER & PARTfIER ~JR.055 S.11l4(3 i The aerogels used in aceaz~danec with the4 invemaan are preferably used w'rcbout any fiut~r airtier subst:ttxs or other adsorption agerns. I3owevcr, they c~ al:o be used in ~inat~ with other adaoipcian egeritt la the ease of ad:orpaon, gaseous p1z$sg they ~ are also not used as a mixture with actNated carbon or activated alumna, where noa-ttiodi~ed arrogels are concerned. For example, however, an adsorption stage wig aerogels caa folloar ors iota as adsorption stage with activated carbon or accivztcd The funkiest adsorption oases can thereby be used for fimhe'r purification of the gases, liquids or organic compounds. Adsotptiots a"geMs which calf be combined 'with the sem8cls accordip,g to the inv~e:stion are known to a man skilled iti the art.
The invattion is explained in ges~er detail hereinafter with reference to ExampJcs u~d iu corrjunrrian ~ab with tire atu~ched drawings, in which:
Fi$. l is a diagism shawitag the loadissg of aerogel wrtb di~'~a organic compounds as a function of their conveattxtion ire water.
~ r ~~ ~ n Adsorption of wares-concxining iub~tances Iti order to display the sete~ve adsotptioa of organic compounds front waste water benze~ pheAOl, toluene, 1,2,diohloroathwe utd p-chloropb~cnol was selected as ' eicar~ples o~'the groups oFaratnatic usdlor chlorinated hydrocarbon's. These compounds west brought into coenact with aerogel in various coneesstiations in water at 25qC, the a~toii~ble lcadiag of the aerogds bebtg~ measured In thin sea pest, the recta were oQnducted iu a qhafting vessel. To this end, 6 g hydrophobic aerogel produced similarly ~ to the exam sat put m DE-A..a3 42 548 'P~ (particle size 0.1 taro, specific itu~er surface area spprax. 540 sq.mlg) was b~cot:ght iti contact with rbe aqueous to bs punted, 1I1 ~~ r1d YeS9~~.
~B Regarding measut~eateac ofthe bquid concetraaeoa before and aflcr the aalsaiption t'isae which amounted to A muiuswa of 2 hours atuil a~si4brium was estabtis~Kd, it was pas5ib~le m ea,lculate the qusruity of adsorbed subssaace from a ma9s~
balance, The results art shown iu Fig. 1.
~ Tt~e r~lts sbowrl is Fig. 1 show that ae:ogels c~ ba very sads~ctatfy used for ,puri~yis~
ti i f i ~. ~ l c ' i4.OKT.i999 ii:i? LUDERSCHrIIDT. SCHUELER & PARTr~ER r~R.056 S.lE~aB
c The rmrh5 sbo~rn in l~g.1 sbw thu vero6elo can be very ~isfsetor~y used for pnri~g waste worst containing otgaofc imputitiea.
. ~, 9 Example 2 and Cotnparuive 8xamples wdsorption of as arnibiatic As an example of the processing of as acanre pbatm8ceutical from tht farzaeatation solution arising duringproductiop, the xl3otption ofthe ttttt'btotic ceplutosporin C (CPC) wu inves~Od. poring production, CPC pccuca in a coacenaapon o~a fewgnms per ' litre of~nn solution and hu to be ~ from thin solution in as careful a way ' a~ possible. In thin respect, it must 6e borers in taind trot in addition to a considerable l ra~ber of other awino ands, salts, atLd other con~ts, the agueoua fermemaaAo solution contains as by-products oFbio:yitttiesis desaresyl-CPC (D-CpC) or deaaceTO~cy ,. , CPC (p0-CpC), For purification by adsr ~oJption, ii i: of g~eat ir~ortutce that only the CPC but trot the D-C'PC and AO-CPC i9 abs~od The aero~els accotdi~ m the invention could be used is this case with a high level of Selectivity, i.e_ ii is substantially ' only CPC wbicb is adsorbed. For the iw ~estigatioa, the hydrophobic aocogal oval used as Example 1.
For the investi~etions, a fetinetrtsiioa solutipn with a CPC coateat of 10 gJl, D-CPG of 2 ~/1 and DO-CPC of 0.1 gll eras used. A total of I litre of this station solution was pumped through a 5~red bed packing with 100 g anrc~el, Afterwards, the adsorbed sub~aces were washed out with 1 litrz of isopmpanal_ At'~lypis of the amoums of ' ~ rdsbrbAd CPC, p-CPC sod DO-CPC was conducted by HPLC mea.~remont_ l:or -~ pirpoaes of eor~paii9nn, a adsorption agents, the reins XIIp 16 of Mrs:rS.
Rohm and A~s as well as SP X35 of Mecs:ss. Mitsubishi Chc~icals were used.
I l ~~' d~~P~
~ r, ,' , ,., p The resulu of the equil~rium losdings of the aerogds iu g per hg secogel and the aetectivities are listed in the foudadr~g Tabli' 1:
v .

14. OKT. 1939 1l ~ 18 LIJDERSCHMIDT, SGHIJELER & PARTNER PJR. ~55 S. 1:3!43 r~
Table 1 Equil'b~usa loa~g and seJeccivity r'.
Ad~rbiag agrat CPC D-CPC i».CPC Selccrivity .,w...
XA.D 16 50 g/kg 6 g/1~ 0.3 P/Jcg 7_9 6 SJkB 0.4 glkg 8.3 Aerogel 23 g/jcg Z glkg 0.13 gJkg 10.7 ~~~wr.~i~-~~wm.. ~.y~.-. www~--.~~.
i r.
k ~.y Y
fibs odectivity of the arrogel is u>are than 2D~. better than with the comparuive ~clwrprio~ agerru~, so that a oansiderably better purification of CPC vs made posaibla purthermore, the ~riuia 'n egu lo~adt g of the aer~el was measured at di~reat CpC
'ttationa. At a CPC conctatratioa ~of 2.S g/J, the loadipg xmouoted to 8 g/Jcg, at 5 g/1 it was 16.5 g/fcg and at 7.5 gl1 it was 2o g/!c8 and st 10 gll is wag Z3 g/kg.
~R., ~ , ., , . .. _ . _ __..-. ._. _ _.. _._ _._.. .
.---._-._ _. __~_ _ _

Claims

claims

1. Use of aerogels as adsorption agents for adsorption from a liquid phase.

2. Use of hydrophobic and hydrophilic aerogels as adsorption agents.

3. Use of adsorption agents containing aerogels which are not present as a mixture with activated carbon or activated alumina for absorption from a gaseous phase.

4. A process for Purifying liquids, characterised in that the liquids to be purified are brought into contact with aerogels as adsorption agents for a sufficient period for adsorption of impurities contained in the liquids.

5.A process for the purification of gases or liquids, characterised in that the gases or liquids to be purified are brought into contact with water repellant aerogels as adsorption agents for a period of time sufficient for absorption of impurities contained in the gases or liquids.

6. A process for the purification of gases, characterised in that the gases to be purified are brought into contact with aerogels which are not present as a mixture with activated carbon or activated alumina, as absorption agents, for a period of time adequats for adsorption of impurities contained in the gases.

7. A process for the isolation of organic compounds from liquids, characterised in that the liquids containing the organic compounds are brought into contact with aerogels as adsorption agents for a period of time sufficient for absorption of the organic compounds, after which the aerogels are separated from the liquids and then the organic compounds are separated from the aerogels.

8. A process according to claim 7, characterised in that the organic compounds are isolated from aqueous liquids.

9. A process according to claim 8, characterised in that the organic compounds are agricultural chemicals and active pharmaceuticals which are isolated from mother liquors occurring during their production.

10. A process according to claim 9, characterised in that the active pharmaceuticals are anobiotics which are isolated from fermentation solutions.