Aquatic Redox Chemistry

605 Pages·2011·27.12 MB·English

by  Paul G. Tratnyek

g Aquatic Redox Chemistry
s.or001
cw
1 | http://pubs.ak-2011-1071.f
1b
mber 24, 20oi: 10.1021/
ed
ept1 |
S1
N on 2, 20
Aer
Gb
HIem
Cpt
MISe
OF b):
V We
NIe (
Uat
y D
d bon
Downloade Publicati
In Aquatic Redox Chemistry; Tratnyek, P., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2011.
g
s.or001
cw
1 | http://pubs.ak-2011-1071.f
1b
mber 24, 20oi: 10.1021/
ed
ept1 |
S1
N on 2, 20
Aer
Gb
HIem
Cpt
MISe
OF b):
V We
NIe (
Uat
y D
d bon
Downloade Publicati
In Aquatic Redox Chemistry; Tratnyek, P., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2011.
1071
ACS SYMPOSIUM SERIES
Aquatic Redox Chemistry
Paul G. Tratnyek, Editor
Oregon Health & Science University
g
s.or001 Timothy J. Grundl, Editor
cw
1 | http://pubs.ak-2011-1071.f ESUbtneerivhfeaarrnsdi-tByKao.rfHlWsaUisdcnoievnresrliseni–itänMt,iTlEwübadiuinktgoeeern
1b
mber 24, 20oi: 10.1021/
ed
ept1 |
S1
N on 2, 20
Aer
Gb
HIem
Cpt
MISe
OF b):
V We
NIe (
y UDat Sponsored by the
d bon ACSDivisionofEnvironmentalChemistry
Downloade Publicati ACS Division of Geochemistry
AmericanChemicalSociety,Washington,DC
DistributedinprintbyOxfordUniversityPress,Inc.
In Aquatic Redox Chemistry; Tratnyek, P., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2011.
LibraryofCongressCataloging-in-PublicationData
Aquaticredoxchemistry/PaulG.Tratnyek,TimothyJ.Grundl,StefanB.
g Haderlein,editor[s];sponsoredbytheACSDivisionofEnvironmentalChemistryandACS
s.or001 DivisionofGeochemistry.
cw
1 | http://pubs.ak-2011-1071.f G1IIr.SnocBGuplunNr.ddoc9ewums7na.8dbt-e-wi-0br-a-l-(8itCAoe4rgaC1rrr2aeSb-pco2shhn6yai5cmcrag2ople-no4r-te-seCfinueotrm-ne-Cngscroeeernssigseaersnes;.sds12ei0.ns7d.O1eI)xx.i.Tdaratitonny-erke,dPuacutiloGn.reIIa.cGtiorunn--dCl,oTnigmreostsheys.J3.,.
mber 24, 201oi: 10.1021/b 1C9G5h55eB31m1-.41iIs99ItI-r7.-y.dH.7cV7a2..dA3Ae6rml7eei2nr0i,c1Sa1tnefCanheBm.iIcVa.lASmoceireitcya.nDCivhiesimonicaolfSGoecoiecthye.mDiisvtirsyi.onofEnvironmental
ed 2011031438
ept1 |
S1
N on 2, 20
Aer
Gb
HIem ThepaperusedinthispublicationmeetstheminimumrequirementsofAmericanNational
Cpt Standard for Information Sciences—Permanence of Paper for Printed Library Materials,
MISe ANSIZ39.48n1984.
OF b):
V We Copyright©2011AmericanChemicalSociety
NIe (
y UDat DistributedinprintbyOxfordUniversityPress,Inc.
d bon
Downloade Publicati Ao$Df4lrl0tihv.R2eei5,UgDhp.Stlasun.sRCv$eeo0rspse.y,7rr5vMiegpAdhe.tr0RAp1eac9pgt2rie3osi,gasrUllapoSpawhiAdie.cdtRocfoeothppreuyinbiCntleigocrpanbytaeirloyigunohsnoetdrCotrnhleelapyatr,rpoapednrroucmevctiiCidtoteeendndtftebohryra,tsISanaelcpce.te,ioro2-fn2cps2haa1Rgp0eot7essreoifnwre1oeth0ooi8dsf
bookispermittedonlyunderlicensefromACS.Directtheseandotherpermissionrequests
toACSCopyrightOffice,PublicationsDivision,115516thStreet,N.W.,Washington,DC
20036.
Thecitationoftradenamesand/ornamesofmanufacturersinthispublicationisnottobe
construedasanendorsementorasapprovalbyACSofthecommercialproductsorservices
referenced herein; nor should the mere reference herein to any drawing, specification,
chemicalprocess, orotherdataberegardedasalicenseorasaconveyanceofanyright
or permission to the holder, reader, or any other person or corporation, to manufacture,
reproduce,use,orsellanypatentedinventionorcopyrightedworkthatmayinanywaybe
relatedthereto. Registerednames,trademarks,etc.,usedinthispublication,evenwithout
specificindicationthereof,arenottobeconsideredunprotectedbylaw.
PRINTEDINTHEUNITEDSTATESOFAMERICA
In Aquatic Redox Chemistry; Tratnyek, P., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2011.
Foreword
The ACS Symposium Series was first published in 1974 to provide a
mechanism for publishing symposia quickly in book form. The purpose of
the series is to publish timely, comprehensive books developed from the ACS
g sponsoredsymposiabasedoncurrentscientificresearch. Occasionally,booksare
s.or001 developed from symposia sponsored by other organizations when the topic is of
cw
1 | http://pubs.ak-2011-1071.f fpkoaerpeanepBrispnermftoeoparreeyrsiaatbtgeteoreeatexnhicdnelcgucodhtmeoedmpptruioesbhtblreiyesnthstaeiauvrdebfiooecocnoukcvse,e.trthahegeepbaroonopdkof;sooerdtihnteatrebsrlemesotatfyocbtoheneateadnudtdesideisntocreepv.riSoeovwmieddee
1b
mber 24, 20oi: 10.1021/ caaodnmddempdr.aenDhuersnacsfrtisivpeotnsfecashrsea.pptrWeerpshaearnreedappienpercro-aprmervieairteaew-,reeodavdpeyrrvifoioerrwmtoaofitr.nainltarcocdeupcttaonrcyecohrarpetjeercstioarne,
ed
ept1 | As a rule, only original research papers and original review papers are
S1
N on 2, 20 included in the volumes. Verbatim reproductions of previous published papers
Aer arenotaccepted.
Gb
HIem
Cpt
MISe
OF b): ACSBooksDepartment
V We
NIe (
Uat
y D
d bon
Downloade Publicati
In Aquatic Redox Chemistry; Tratnyek, P., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2011.
Preface
Lifeandcyclingofinorganicandorganicmatteronearthisdriventoalarge
extent by electron transfer (i.e. redox) reactions. This makes understanding
aquatic redox processes essential to all aspects of biogeochemistry, from
g remediation of legacy contamination problems, to sustaining environmental
011 | http://pubs.acs.or1/bk-2011-1071.pr001 himrmneedfleoatobulatxiDehllsni,e,tpcysaterpoonoicdtfbmeeybtsraosatnedhtnhasresgifnvcioanbionrtgrnmugetraraeadomtclitloohaesnnttyhadaosebntfaoedcnlomihtrchegcrsmaeopennpriritcovocraciagclaeleeinstsnssydpi.ecesinco,cAiofoamrqmtgiauooapqabnnouti,iiualccintbzicdrciaoeostdnia.orotveanxadmiolapiaxnnrboadinlccihettssysee.,smqeTutsioehsxtsuertixsyrc,aeittariyitqon,unthaatetnhoiidcerf
4, 2102 environmentalsciences,therehavebeenfewattemptstoprovideacomprehensive
mber 2oi: 10. tpheerscpoemctmivuenointythoifsatqoupaicti.cAreudnoixquceheomppisotrstuanriotsyetofrobmrinagstoygmepthoesriuamwaidtethrean2g3e9othf
n Septe2011 | d AcoCnStriNbuattiioonnsaloMfeDeotinnagld(2L1.-2M5aMcaalracdhy2.0T10hrionuSgahnouFtrahnicsisccaore,eCr,AP)rionf.hoMnoarcoaflatdhye
AN oer 2, made influential contributions to many aspects of aquatic redox chemistry,
Gb including inorganic, organic, and biogeochemical electron transfer processes in
CHIptem naturalwatersandsediments.
MISe The symposium—which was co-sponsored by the ACS Divisions of
OF eb): Environmental Chemistry and Geochemistry—attracted a large number of
V W
NIe ( high-qualitycontributionsfromadiversegroupofleadingscientists(representing
Uat environmental and aquatic chemistry, surface chemistry, electrochemistry,
y D
d bon photochemistry, theoretical chemistry, soil chemistry, geochemistry, geology,
deati microbiology, hydrology, limnology, and oceanography) and engineers
ac
wnloPubli (environmental, civil, and chemical). At the symposium, the synergy between
o theseresearcherswaspalpable,whichledtotheideathatavolumebasedonthe
D
symposiumwouldbetimelyandconstructive.
Thescopeofthisvolumewasplannedtoprovideacomprehensiveoverview
ofthestateoftheartinaquaticredoxchemistry. Majorareasofinterestinclude
interactions between iron, natural organic matter (NOM), and contaminants
including metals, metalloids, and organic pollutants. The contributed chapters
were selected and edited to highlight recent developments in the field, but also
to introduce fundamental aspects and approaches of aquatic redox chemistry in
a systematic and didactic way. To this end, this volume should be effective as
teachingmaterialforupperlevelstudentsinenvironmentalscienceorengineering,
aswellasbeingavaluableresourceforscientistsandpractitioners.
In the future, the frontiers in aquatic redox chemistry will be transformed
by increasingly interdisciplinary research efforts and emerging analytical
xi
In Aquatic Redox Chemistry; Tratnyek, P., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2011.
methods. Thesedevelopmentsshouldgreatlyimproveourabilitytocharacterize
the interrelated spatial and temporal dynamics that complicate the speciation
of reactants and mechanisms of electron transfer in natural and engineered
aqueous systems. Current knowledge gaps are particularly large with regard to
the mechanistic understanding of heterogeneous electron transfer processes at
interfaces,especiallythosebetweenwaterandmineralsorbacteria. Thus,forthe
foreseeable future, aquatic redox chemistry will continue to be a dynamic and
challengingfieldofresearch.
Theeditorsgratefullyacknowledgeallthosewhocontributedtotheplanning
and implementation of this volume and the symposium on which it was based.
We are particularly indebted to the authors and reviewers of each chapter, all of
whomfulfilledtheirroleswithveryhighstandards. Wealsothanktheattendeesof
g
acs.orpr001 twhheiscyhmhpeolpseiudmtofosrhathpeeirthneumfinearoluosutccoommme.enFtisnaanlldy,thwoeugthhatnpkrotvhoeksitnagffsoufggtheestAioCnsS,
2011 | http://pubs.21/bk-2011-1071. DDStieevpfiaasrnitomnBe.onHftwaEdhneovrilcreooinnntmriebnuttaeldCthheemsyimstrpyo,siDumiviasniodnbooofkG. eochemistry, and Books
4, 10
mber 2oi: 10. CenterforAppliedGeosciences
n Septe2011 | d EDb-7er2h0a7r6d,-KTaürblisnUgenniversitätTübingen
AN oer 2, ++449977007711259075391(4fa8x()telephone)
Gb
HIem [email protected](e-mail)
Cpt
MISe
OF eb):
V W TimothyJ.Grundl
NIe (
Uat
y D GeosciencesDepartment
ded bation UniversityofWisconsin−Milwaukee
wnloaPublic (M41il4w)a2u2k9e-e4,7W65I(5t3e2le0p1hone)
o
D
[phone](fax)
[email protected](e-mail)
PaulG.Tratnyek
DivisionofEnvironmentalandBiomolecularSystems
OregonHealth&ScienceUniversity
20000NWWalkerRoad
Beaverton, OR97006
[phone](telephone)
[phone](fax)
[email protected](e-mail)
xii
In Aquatic Redox Chemistry; Tratnyek, P., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2011.
Chapter 1
Introduction to Aquatic Redox Chemistry
Timothy J. Grundl,1,* Stefan Haderlein,2 James T. Nurmi,3
and Paul G. Tratnyek3
g
s.or001 1GeosciencesDepartmentandSchoolofFreshwaterSciences,Universityof
mber 24, 2011 | http://pubs.acoi: 10.1021/bk-2011-1071.ch 32DCievnistieornfoorfEAnWpvpSiilsricceoiodennnmGscieeennoU-tsMancliDi*ievlagwn-enr7craud2esun0isBtkd,7yielE6,o@e,Bbm,TueeMorüwalhvibemlacewinrur.eadtglodau-enKrukn,eSaOery,lsRsWteU9mI7n5s0i,v30eO26r0rs1eitgäotnTHübeainltghen&,
ed
Sept11 |
n 20 Oxidation-reduction (redox) reactions are among the most
AN oer 2, important and interesting chemical reactions that occur in
Gb aquatic environmental systems, including soils, sediments,
CHIptem aquifers, rivers, lakes, and water treatment systems. Redox
MISe reactionsarecentraltomajorelementcycling,tomanysorption
OF eb): processes, to trace element mobility and toxicity, to most
V W
NIe ( remediationschemes,andtolifeitself. Overthepast20years,a
Uat greatdealofresearchhasbeendoneinpursuitofprocess-level
y D
d bon understanding aquatic redox chemistry, but the field is only
deati beginning to converge around a unified body of knowledge.
ac
wnloPubli Thischapterprovidesaverybroadoverviewofthestateofthis
Do convergence, including clarification of key terminology, some
relatively novel examples of core thermodynamic concepts
(involving redox ladders and Eh-pH diagrams), and some
historical perspective on the persistent challenges of how to
characterize redox intensity and capacity of real, complex,
environmental materials. Finally, the chapter attempts to
encourage further convergence among the many facets of
aquatic redox chemistry by briefly reviewing major themes in
thisvolumeandseveralpastvolumesthatoverlappartiallywith
this scope.
©2011AmericanChemicalSociety
In Aquatic Redox Chemistry; Tratnyek, P., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2011.
Definitions and Scope
Historically, the terms oxidation and reduction arose from experimental
observations: oxidationreactionsconsumedO byincorporatingOintoproducts
2
and reduction reactions reduced the mass or volume of products by expelling O
(1). Chlorinesubstitutionisequivalenttooxygeninthiscontext,sochlorination
is oxidation and dechlorination is reduction. A similarly empirical definition of
reduction is that it usually involves incorporation of hydrogen, and, therefore,
oxidation can be regarded as dehydrogenation (e.g., dehydrogenase enzymes
catalyzeoxidation).
More rigorously, oxidation-reduction (redox) reactions are commonly
understood to occur by the exchange of electrons between reacting chemical
g species. Electronsarelost(ordonated)inoxidation,andgained(oraccepted)in
s.or001 reduction. Oxidation of a species is caused by an oxidizing agent (or oxidant),
mber 24, 2011 | http://pubs.acoi: 10.1021/bk-2011-1071.ch ifwbgeesrllaeoheesnomccieexcttTrrrhicaoordheolnniaeazndcscdetcecertdeeafiien)opdnpn.sntestisisffittwieynoheriinaolttsehvsifpocec(eatnerhcspo.riegefirnamo.dsc,rtueiotcd(hcnaaaeien-nldfisLdgsenppqeieaiteuwcsigcoaieiifittnsenhecssmteftr((doooe(oer2bdrmfi)yem,rnloea)iorrd,tneseiurodtdecgnupdtrescaeuonenfrx(eedpttr)r)hcoa,e.eoslnwendcBSshcee,ieirsfimcöpbnhcntuisiilstttdateicroenodaldnonyntat,shmtbatereheelorslade.deetiuxenlJacelt)u)ertc.iesntoaTrtdbnnohaeadnesdrsseemlafs(adrcuatooitnoldmretdnes-r
ed
Sept11 | allowsforredoxreactionsthatoccurbyatom-transferaswellaselectrontransfer
n 20 mechanisms. While often ignored, the role of atom-transfer mechanisms can be
AN oer 2, important,particularlyinredoxreactionsinvolvingorganiccompounds.
HIGemb Redoxreactions,definedinclusiv,arecentraltomanypriorityandemerging
Cpt areas of research in the aquatic sciences. This scope includes all aspects
OF MIeb): Se aoqfutahteica(qi.uea.,ticaqsuceioeunsc)esa:spneocttsjuosftetnhvoisreonimnvenotlavlinpgrotcheessheysdirnostphheeraet,mbouspthaelrseo,
V W
NIe ( lithosphere, biosphere, etc. (3). As a field of study, aquatic redox chemistry
y UDat also has multidisciplinary roots (spanning mineralogy to microbiology) and
d bon interdisciplinary applications (e.g., in removal of contaminants from water,
adecati sediment,orsoil). Despiteitscross-cuttingappeal,however,verylittlepriorwork
wnloPubli hasusedaquaticredoxchemistryasaniche-definingtheme. Themainexception
Do tothisappearstobeseveralpublicationsbyDonaldMacalady(e.g,(4)),whichis
convenient and appropriate—and not entirely coincidental—given the origins of
thisvolume(seePreface).
Core Concepts
Any redox reaction can be formulated as the sum of half-reactions for
oxidation of the reductant and reduction of the oxidant. The overall free energy
ofaredoxreactionisdeterminedbythecontributinghalf-reactions,andthefree
energy of each half-reaction depends on the reactants, products, and solution
conditions. At a common set of standard conditions, the free energies—or
correspondingredoxpotentials—canbeusedtocomparetherelativestrengthof
oxidantsandreductantsandtherebydeterminethethermodynamicfavorabilityof
2
In Aquatic Redox Chemistry; Tratnyek, P., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2011.
the overall reaction between any particular combination of half-reactions. This
type of analysis is well suited for a variety of graphical representations, the two
most common of which are redox ladders and Eh-pH (or Pourbaix) diagrams.
Thefundamentalsofconstructingthesediagramsarepresentedinnumeroustexts
on aquatic chemistry (3, 5, 6), geochemistry (7, 8), and other fields (9). Some
newdatathatcouldbeusedinconstructingsuchdiagramsaregiveninChapters
2, 3and4ofthisvolume.
Figure1isaredoxladderthatsummarizesadiverserangeofredoxcouples
thataresignificantinaquaticredoxchemistry. Thetopofthefigureisboundedby
severalstrongoxidants(e.g.,hypochlorite,monochloramine,andozone)thatare
capable of oxidizing essentially any compound found in aquatic environments.
Similarly, the bottom of the figure is bounded by strong reductants (zerovalent
g
mber 24, 2011 | http://pubs.acs.oroi: 10.1021/bk-2011-1071.ch001 mewomesTunnxhaeacvgiettjdhieiaornaoTrlroa,snevhsn)ettseeesmroirtrerhaamfioedtlarhnlrnetiwsetrntsdaaeyaa.rndictlseaedoocerTrxlcuezluthaesricmnpnceesooetsaacnnredttbomdalponiroieneteefxianrooCidFsctdfniichissassgreyatcne.eoppsutdnftsttsueiet1smnmcarengsinoidanssd2s.tpgiutdrnHarraoeeneayqCscvddlspueohuessoa1tacpnste1cptieetdhacitcsoanelisfotlrte(yolsrtTys1ihs,tEftt8ieaehabs.AnmlaeuvlynPtorodasteclruh)uodoetemtoomsyhuifxedelpot,mreoicfamsuotinttecnuhardnrodtpeoenzlfblefsegoyoistrraacuodmlbthnvehilmdatlaoteihltrteeriyeimntnfnaobtefibiarnam-oqembsellueiaddisaststamtbehooildycesff.
ed theseTEAPs. TheTEAPthatprovidesthemostenergyrecovery(thoseatthetop
Sept11 | oftheredoxladder)favorsthetypesofmicroorganismsthatutilizethatprocess.
AN on er 2, 20 Alasddtherebmeocostmfeasvomraobsltefaevleocrtarbolne.aTccheipstporroicsedssepclaenterde,stuhletinnesxetqTuEenAtiPalopnrothgerersesdioonx
Gb
HIem (in space or time) from TEAPs higher on the redox ladder to those below. This
MICSept basicunderstandingofTEAPsandtheireffectonaquaticredoxchemistryiswell
OF eb): established, but a detailed understanding of the fundamental controls on these
V W processesisstillemerging,asdiscussedinChapter4ofthisvolume.
NIe ( Once environmental conditions are established, however, many important
Uat
y D redoxreactionsproceedwithoutfurthermediationbyorganisms. Thesereactions
ded bation are considered to be abiotic when it is no longer practical (or possible) to
wnloaPublic hlianlkf-rtehaecmtiotnos arnepyrepsaerntitceudlairnbtihoelo2gnidc-a6lthacctoilvuimtyns(4,in1F0)ig.. T1hucsa,nmbaenymoorfethoer
Do
less a/biotic—depending on conditions—and the overall favorability of these
processesisnotnecessarilyaffectedbymicrobiologicalmediation(i.e.,theredox
ladder applies either way). However, systems where biotic and abiotic controls
on contaminant fate are closely coupled currently are frontier areas of research
(e.g., Chapters19-24).
The 2nd-6th columns in Fig. 1 arranged so they represent families of major
redoxactivespeciesinorderfromrelativelyoxidized(andoxidizing)torelatively
reduced (and reducing). Thus, the second column includes the reactive oxygen
species that arise mostly by photochemical processes in natural waters. The
chemistry of some of these processes is described in Chapters 8 and 9. Other
oxidants that arise mainly in water treatment processes are not shown because
they plot above the scale used in the figure, but two are discussed in later:
3
In Aquatic Redox Chemistry; Tratnyek, P., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2011.