Cleaning Our Water with Nanotechnology

Transcription

1 CleaningOurWaterwithNanotechnology Organization:MuseumofScience,Boston Contactperson:KarineThate GeneralDescription StagePresentationwithDemos CleaningOurWaterwithNanotechnology isapublicpresentationaboutourdrinkingwater andhowwecanmakecontaminatedwatersafetodrinkusingavarietyoftechnologies including3newnanotechnologiesforwaterpurification.duringthepresentation,audiences considerthefollowingquestions:whichcontaminantsdowehaveinourwaterthatmakesit unsafetodrink?howdowetypicallypurifyourwater andwhatarethe shortcomings/limitationsofthosetechnologies?howcannewnanotechnologiespurifyour drinkingwaterinnewwaystohelpusinsituationswherelarge scalewatertreatmentisn t appropriate?thepresentationincludesavarietyofdemonstrationstoillustratehowthese technologiesworkandsomemodelstohelpvisitorsvisualizewhat shappeningwiththese technologiesatthenanoscale. ProgramObjectives Bigidea: Topurifyourdrinkingwater,weneedtoremovecontaminantsincludingthosethataremuch toosmalltosee(tinymicrobesandchemicals).whilelarge scalewatertreatmentplantswork well,therearetimes/places/situationswherewedon thaveaccesstothesefacilitiesandneed topurifyourwateratthepointofuse.nanotechnologyisprovidingsomenewwaystopurify ourwateratthepointofuse(betterfilterstoremovetinymicroorganismsandpreventfilterfouling). Learninggoals: Asaresultofparticipatinginthisprogram,visitorswillbeableto: 1. Recognizethatwatersourcescanbecontaminatedbymicrobesandchemicals contaminantsthataretoosmalltosee. 2. Understandthatthesecontaminantsneedtoberemovedtomakethewatersafeto drink. 3. Learnthatnanotechnologyhasmadepossiblesomenewwaterpurificationtechnologies thatcleanwaterverysimply,effectively,andwithverylittlepower. 1

2 NISENetworkcontentmapmainideas: [X] 1.Nanometer sizedthingsareverysmall,andoftenbehavedifferentlythanlarger thingsdo. [X] 2.Scientistsandengineershaveformedtheinterdisciplinaryfieldofnanotechnologyby investigatingpropertiesandmanipulatingmatteratthenanoscale. [X] 3.Nanoscience,nanotechnology,andnanoengineeringleadtonewknowledgeand innovationsthatweren tpossiblebefore. [X] 4.Nanotechnologieshavecosts,risks,andbenefitsthataffectourlivesinwayswecannot alwayspredict. NationalScienceEducationStandards: [] 1.ScienceasInquiry [] K 4:Abilitiesnecessarytodoscientificinquiry [] K 4:Understandingaboutscientificinquiry [] 5 8:Abilitiesnecessarytodoscientificinquiry [] 5 8:Understandingaboutscientificinquiry [] 9 12:Abilitiesnecessarytodoscientificinquiry [] 9 12:Understandingaboutscientificinquiry [X] 2.PhysicalScience [] K 4:Propertiesofobjectsandmaterials [] K 4:Positionandmotionofobjects [] K 4:Light,heat,electricity,andmagnetism [] 5 8:Propertiesandchangesofpropertiesinmatter [] 5 8:Motionsandforces [] 5 8:Transferofenergy [] 9 12:Structureofatoms [X] [X] 9 12:Structureandpropertiesofmatter [X] 9 12:Chemicalreactions [] 9 12:Motionsandforce [] 9 12:Conservationofenergyandincreaseindisorder [] 9 12:Interactionsofenergyandmatter 3.LifeScience [X] K 4:Characteristicsoforganisms [] K 4:Lifecyclesoforganisms [X] K 4:Organismsandenvironments [X] 5 8:Structureandfunctioninlivingsystems [] 5 8:Reproductionandheredity [] 5 8:Regulationandbehavior [X] 5 8:Populationsandecosystems [] 5 8:Diversityandadaptationsoforganisms 2

3 [] 9 12:Thecell [] 9 12:Molecularbasisofheredity [] 9 12:Biologicalevolution [] 9 12:Interdependenceoforganisms [] 9 12:Matter,energy,andorganizationinlivingsystems [] 9 12:Behavioroforganisms [] 4.EarthandSpaceScience [] K 4:Propertiesofearthmaterials [] K 4:Objectsinthesky [] K 4:Changesinearthandsky [] 5 8:Structureoftheearthsystem [] 5 8:Earth'shistory [] 5 8:Earthinthesolarsystem [] 9 12:Energyintheearthsystem [] 9 12:Geochemicalcycles [] 9 12:Originandevolutionoftheearthsystem [] 9 12:Originandevolutionoftheuniverse [X] 5.ScienceandTechnology [X] K 4:Abilitiestodistinguishbetweennaturalobjectsandobjectsmadebyhumans [X] K 4:Abilitiesoftechnologicaldesign [X] K 4:Understandingaboutscienceandtechnology [X] 5 8:Abilitiesoftechnologicaldesign [X] 5 8:Understandingaboutscienceandtechnology [X] 9 12:Abilitiesoftechnologicaldesign [X] 9 12:Understandingaboutscienceandtechnology [X] 6.PersonalandSocialPerspectives [X] K 4:Personalhealth [] K 4:Characteristicsandchangesinpopulations [X] K 4:Typesofresources [X] K 4:Changesinenvironments [X] K 4:Scienceandtechnologyinlocalchallenges [X] 5 8:Personalhealth [X] 5 8:Populations,resources,andenvironments [] 5 8:Naturalhazards [X] 5 8:Risksandbenefits [X] 5 8:Scienceandtechnologyinsociety [X] 9 12:Personalandcommunityhealth [] 9 12:Populationgrowth [X] 9 12:Naturalresources [X] 9 12:Environmentalquality [X] 9 12:Naturalandhuman inducedhazards [X] 9 12:Scienceandtechnologyinlocal,national,andglobalchallenges [X] 7.HistoryandNatureofScience 3

4 [X] K 4:Scienceasahumanendeavor [X] 5 8:Scienceasahumanendeavor [X] 5 8:Natureofscience [] 5 8:Historyofscience [X] 9 12:Scienceasahumanendeavor [X] 9 12:Natureofscientificknowledge [] 9 12:Historicalperspective 4

5 TableofContents GeneralDescription...1 ProgramObjectives...1 TableofContents...5 TimeRequired...6 BackgroundInformation...6 Definitionofterms...6 Program specificbackground...6 Materials...9 SetUp...11 ProgramDelivery...11 Safety...11 SuggestedScript:...11 Tipsandtroubleshooting...18 Commonvisitorquestions...19 GoingFurther...20 CleanUp...21 UniversalDesign...22 Credits

6 TimeRequired Set up Program CleanUp 15minutes 20minutes 10minutes BackgroundInformation Definitionofterms Nanoisthescientifictermmeaningone billionth(1/1,000,000,000).itcomesfromagreek wordmeaning dwarf. Ananometerisoneone billionthofameter.oneinchequals25.4millionnanometers.asheet ofpaperisabout100,000nanometersthick.ahumanhairmeasuresroughly50,000to100,000 nanometersacross.yourfingernailsgrowonenanometereverysecond. (Otherunitscanalsobedividedbyonebillion.Asingleblinkofaneyeisaboutone billionthof ayear.aneyeblinkistoayearwhatananometeristoayardstick.) Nanoscalereferstomeasurementsof1 100nanometers.Avirusisabout70nmlong.Acell membraneisabout9nmthick.tenhydrogenatomsareabout1nm.atthenanoscale,many commonmaterialsexhibitunusualproperties,suchasremarkablylowerresistanceto electricity,orfasterchemicalreactions. Nanotechnologyisthemanipulationofmaterialatthenanoscaletotakeadvantageofthese properties.thisoftenmeansworkingwithindividualmolecules. Nanoscience,nanoengineeringandothersuchtermsrefertothoseactivitiesappliedtothe nanoscale. Nano, byitself,isoftenusedasshorthandtorefertoanyoralloftheseactivities. Program specificbackground Cleanwater forhumansandanimals,foragriculture,forindustry isafundamental necessity.nearlyabillionpeopleworldwide,however,donothaveaccesstocleandrinking water,andmillionsdieeachyear(mostlychildren)fromwaterbornediseasescontractedfrom unsafewatersources.it snotpossibletotellwhetherwaterissafetodrinkjustbyvisual inspection,asthecontaminantscanbeonthemicro andnano scale.topurifywaterfor 6

7 humanconsumption(drinkingwater),weneedtoremove(orreducetheconcentrationof): particulatematter,parasites,bacteria,algae,viruses,fungiandarangeofdissolvedchemicals. Large scalewatertreatmentplantscleanwatereffectivelyusingavarietyofpossible techniques: Chemicaltreatments Forexample,chlorine,chloramines,iodine,ozonation(ozone bubbles),etc.thesetypicallyactasdisinfectantsandkill/inactivatethemicrobesinthe water. UVtreatment UVlightdamagesthegeneticmaterialofmicrobes,inactivatingthem. Variousfiltrationtechnologies(includingmembranefiltersandreverseosmosis) Cleansthewaterbyexcludingcontaminantsbasedonsize.Eithertheholesinthe membranearesmallenoughtopreventcertainparticlesfrompassingthrough,orthe contaminantsinthewateradheretothesurfaceofthematerialinthefilter. Flocculation Clarifiesthewaterbycausingaprecipitatetoform.Addingachemical coagulantthatcreatesclumpsofimpuritiesthatcanberemovedbyphysicalmethods. Formorebackground,theWikipediaarticleonWaterPurificationisagoodplacetostart ( tofindouthowthewateristreatedinyourarea. However,thelarge scalewatertreatmentplantsandthecentralizedwaterdistributionand purificationinfrastructureswerelyoninindustrializedcountriesareenormouslyexpensive,and areenergeticallyandchemicallyintensiveandrequireskilledengineersandlaborers.thereare certainsituationsandplaceswherecentralizedwatertreatmentisn tanoptionand point ofuse watertreatmentisrequired inareastoopoororremotetohavecentralizedwater treatment;inplaceswerepopulationisgrowingveryquicklyanddemandoutstripssupply; afternaturaldisasterswhencentralizedutilitiesshutdown;orafterawatermainbreak(our owncrumblinginfrastructurewillmakethisabiggerissueintheusainthecomingdecades) whenthewatersupplyiscontaminatedduringdistribution.inthesecases,wewanttopurify thewateratthepointofuse whereitwillbeconsumed.pointofusewatertreatmentshould beportable,simple,effective,easy to use,inexpensiveandrequireverylittleornopower. Someofthepopular point of use watertreatmentscurrentlyavailableorcommonlyused include: Britafilters activatedcarbonfilters.somecontaminantsadsorbtotheactivated carbon butonit sownit snotsufficientforpurifyingwatertomakeitpotable.it s appropriateforuseinhomestoimprovethelook,tasteandsmellofwaterthatis alreadytreated. Micro filters commonlyusedbyhikers/campers.theseremovesomemicrobes(down tothemicronsize butnotnano sizedviruses).thesedon ttreatanykindofchemical contamination. Chemicaltreatments chlorinetabletsordrops,oriodine.thesetreatbiological contamination,butmanypeopledon tlikethetasteanddon twantto clean their 7

8 waterbyaddingchemicalstoit they dratherjustremovethecontaminantswithout addinganythingtothewater. Nanotechnologyprovidesmanypromisingsolutionsforimproving decentralized or point ofuse watertreatment basically,becomingmoreefficientandeffectiveaboutremovingallthe contaminantsinwatertomakeitsafetodrink.thetechnologiesdiscussedinthisparticular presentationdealwithmembranesornano filters thateitherhavenano sizedpores,orthat utilizenanomaterials(carbonnanotubes)tofilteroutcontaminants.thereareother nanotechnologiesrelatedtowaterpurification everythingfromnanosensorstodetect contaminantsinthewater,nanomaterialstohelpwithwaterpollutionremediation,tonew desalinationtechnologiesandeverythinginbetween.thenanofiltersforwaterpurificationare themostdevelopedofthesetechnologieswhichiswhyi vefocusedonthemforthis presentation. Afewgreatoverviewarticlesonthistopicinclude: NanotechnologyandtheChallengeofCleanWater ( NanotechnologyandWaterTreatment( Water,Nanotechnology spromises,andeconomicreality ( TwomuchmoredetailedreportsbytheMeridianInstituteinclude: Nanotechnology,Water,andDevelopment ( ous&site=website) OverviewandComparisonofConventionalandNano BasedWaterTreatment Technologies ( Anonymous&site=website) AsImentioned,therearemanypossiblenanotech enhancedwatertreatments fartoomany tocoverinashortpresentation,sothreespecific(andrelativelysimple)nanotech enabled waterfiltrationtechnologiesarementionedinthisprogram: 1)TheLifesaverbottle anultrafiltrationmembrane.theholesinthismembraneareonly15 nanometersinsize,smallenoughtokeepoutthesmallestviruses.thewebsitehasmore informationabouthowitworks,andthefaqsareworthwhiletoo. CEOtalkingabouthowthetechnologyworks veryeasytounderstandandgreatbackground. technologyisalreadycommerciallyavailable. 2)SeldonTechnologiesWaterStickandWaterBox a Nanomesh filterwhichincorporates carbonnanotubes.thenanomeshallowswatertoflowthroughquicklyatahigherratethanan ultrafiltrationmembrane,butthecarbonnanotubesattractcontaminants.microbesand 8

9 chemicalsadsorb(sticktothesurfaceof)tothecntsleavingthewaterchemicalfree.lotsof infoontheirwebsite: insciencenewsspotfornewenglandcablenews.youcanseethevideohere: isavailableforexport,buttechnicallystillbeing tested intheus. 3)ElectrochemicalCarbonNanotubeFilter inventedbychadvecitis,aprofessoratharvard University.It sstillintheresearchphase,butispromisinginearlytests.acarbonnanotube filterthattakesadvantageoftheelectricalconductivityofcarbonnanotubes.byhookingup smallpowersourcetothefilter,itiselectrifiedanddoeselectrochemistryasthewaterpasses through.theelectricalcurrentkillsordegradesthemicrobesorchemicalcontaminants, slowingtheprocessoffilter fouling,keepingthefiltercleanforlongerandreducingtheneed forfrequentcleaningorreplacementofthefilter.moreinformationonchad sresearchhere: technology.seas.harvard.edu/.twojournalarticlesonthistopicinclude: C.D.Vecitis,M.H.Schnoor,Md.S.Rahaman,J.Schifmann,M.Elimelech,"Electrochemical MultiwalledCarbonNanotubeFilterforViralandBacterialRemovalandInactivation", EnvironmentalScience&Technology,2011,45, C.D.Vecitis,G.Gao,H.Liu,"ElectrochemicalCarbonNanotubeFilterforAdsorption, Desorption,andOxidationofAqueousDyesandAnions",JournalofPhysicalChemistryC,2011, 115,3621. Thatsaid,thereareofcourseconcernsandunansweredquestionsonhowtodistributethese technologieseconomically,equitably,etc.theseconcernsarenotexplicitlydealtwithinthis presentation(asitwouldexpandanalreadylongpresentation),butquestionsonthistopic oftencomeupafterthepresentation,soit sagoodideatohavereadsomebackground. Materials CleaningOurWaterwithNanotechnology PowerPointpresentationincludingthefollowing videos: Man_drinks_water_from_Charles.mov(forslide3) Filter_Fouling.mov(forslide22) Electrochemical_Filter.mov(forslide24) Aclearaquariumtankorclearjugfilledwith dirty waterfrom anylocaloutdoorsource(riverorlake).besuretoincludefloating debris,garbage,plantmatter,etc. Note:Thiswillneedtobecoveredandreplacedeveryweekortwoasitgetstoo smellyanddirtyifleftuntended. Asmallkitchensievewithhandle(toscoopphysicaldebrisfrom water) Clearplasticcup 9

10 Afewwaterfiltrationtechnologies,forexample: BritaFilter(availablefromAmazonoranydepartmentstore) IodinetabletsandChloridedioxidedropsortablets(availablefromAmazon,REIorsimilar outdoorstore) Amicrofilterforcampers/hikers Empty5gallonbottlefromofficewatercooler. Regularsize½literor20ozbottleofwater. Ananotech enhancedwaterfilterfordemonstration eitherthelifesaverbottleorseldon s WaterStick.LifesaverbottlecanbepurchasedfromAmazonforapprox.$150. TheSeldonWaterstickisnotyetavailablecommercially,butyoumaycontactSeldon Technologiestoseeiftheywillgiveyouasampleproductfor testing. Aclearjugfilledwith dirty watertouseoneithernanotechenhancedtechnology,anda cleanemptyglasstocollectthecleanwater.watercaneitherfromanaturalwatersource,you can dirty thewateryourselfwithfoodcoloring. Note:Practiceusingthefiltersfirsttobecomecomfortablewiththem.Forexample,withtheLifeSaverbottle,the cleanwatercomesoutwithgreatforceifyoupumptoomuch.also,theseldonwaterstickneedstobe primed beforetheshow,soyoucangetcleanwaterwithjustafewpumps. 2kitchencolanders/sieveswithdifferentsize holes onewithfinemesh(typicalsieve); anotherwithlargerholes(morelikeagrilling basket). 2differentsizedandcoloredbeads large beadstorepresentbacteria;smallerbeadsto representviruses.note:thesmallerbeadsshould besmallenoughtofallthroughthesievewiththe largeholes soonlythelargerbeadsarecaught. Thefinemeshsieveshouldcatchboththesmalland largebeads. 2clearplasticcups(eachholdingamixedcombinationofsmallandlargebeads representing contaminatedwater) Aplasticcontainertocatchthebeadsthatfallthroughthesieve.Includepapertowelsorfoam atthebottomofthecontainertopreventbeadsfrombouncing. Amodelofabacteriaandvirus 10 15cminsizeapprox.Thesecaneitherbemadefrom smallrubberorstyrofoamballs,oryoucouldusestuffedmodelslikethese: couldalsowork(searchonlinefor pufferworm toys). Smallballrepresentingavirus shouldbesmallerthan2cm. 10

11 CarbonNanotubemodel.Forexample: nanotubemodel W.html Smallfoampiecesofdifferentcolorsandsizetorepresent differentcontaminants Velcrostrips/pieceswithsticky backstoattach/detachfoam piecestocarbonnanotubemodel. SetUp Time:15minutes Collectwaterfromalocal,nearbywatersource(hopefully,thisisdoneaheadoftime).Atank ofwatercanbeusedforseveralshows,butshouldn tbekeptformorethanaweekorso. Setuppropsontable/cartasgroupedinthematerialslistabove,sotheyarereadilyaccessible whencalledforinthescript. TestoutorprimetheLifeSaverwaterbottleorSeldonWatersticktomakesureit sreadytogo forthepresentation. ProgramDelivery Time:20minutes Safety Donotletvisitorsdrinkcontaminatedorcleanedwaterfromthetanksorwaterpurification devices.ifusingeithernanotechenhancedwaterpurificationtechnology,besurethatthe clean hoseorenddoesnotgetcontaminatedbydirtywater.museumeducatorswantingto showthedevicesinactionmaydrinkthecleanedwateriftheyarecomfortable(andifthey re surethey veusedthedevicesproperly),butabetteroptionistouse simulated dirtywaterin thenanotechdevices(withfoodcoloringandsoliddebris),insteadofwaterfromanatural dirty watersource. SuggestedScript: (Feelfreetoadapt/revisetotailorcontenttoyourvisitors). 11

12 [Slide1 TitleSlide] Goodafternooneveryone,andwelcometo.Mynameis andtoday,i mgoingtotalkabouthowwecleanourwater. [Slide2 DirtyRiverWater] IhaveatankI vefilledupfromtheriver/lakerightnearoutsidethemuseum from (namelocalwatersource)(fillaglassfromthetank).howmanyof youwouldbewillingtodrinkthiswaterrightoutofanurban,pollutedwatersource?(raises hand,lookingencouraging?)anyone?(hamitupanddramatizeasnecessary...ifkids volunteer,askthem REALLY?!?Youthinkyourparentswouldletyoudrinkthis?!?! ) Notmanyofyou Whynot?(Solicitsanswersfromtheaudiences ) WhatifItoldyouthat [Slide3 MandrinkingwaterfromCharlesRivervideo] THISmanthat drankwaterrightoutofapollutedriver.hisnameisalancummingsandhe s theceoofavermontstartupcompanycalledseldontechnologiesthatusesnanotechnology topurifydrinkingwater.so,toputhistechnologytothetestheusedittodrinkwaterrightout ofthecharlesriver apollutedriverthatrunsrightthroughthecenterofboston anddidit ontvinfrontofnewenglandviewers. [Slide4 DirtyRiverWater] So,whatdoyouthinkYOU dhavetodofirsttocleanthewatertoapointwhereyouwouldbe comfortabledrinkingit? (holdsupprops/examplesofthesefiltrationtechnologies) Whatifyouskimmedupallthejunkfloatingonthetop(usingasieve)? WouldyoutrustyourBRITAfilter? Wouldyouthinkboilingitwouldbeenough? Whataboutiodineorchlorinetreatments? Well,mostpeoplethinkthosewouldn tbesufficient afterall,it sanurban,pollutedriver throughaveryhighlypopulatedarea.allsortsofbadstuff dangerouschemicals,pollutants, waste,overflowfromthesewers endsupintheriver.butwhataboutariverlike... [Slide5 Mountainstream] THIS?Haveyoueverbeenoutinthecountryhikingorcampingandcomeacrossthese beautifulcrisp,cleanmountainstreams Everbeentemptedtojustscoopupahandfulsand takeafewsips Now,isTHATagoodidea? 12

13 Mostofyouknowthatit snotagoodidea.whilechemicalpollutantsmaynotbeabig problemouthere,thereareotherthingstobeconcernedabout.nomatterhowcleanit LOOKS therearecontaminantsthataretoosmalltosee.youdon tknowwhat shappening justupstream. [Slide6 Moose/Beaver orreplacewithimagesofyourlocalwildlife] Yousee,animalsliketheseguysaren tverycarefulaboutwheretheyputtheirwaste... [Slide7 hiker] andsometimesneitheraretheseanimals. Therearesomenastylittlecrittersinanimalwastethatcanmakeyouprettysick. So,whataretheselittlecrittersthatI mtalkingabout? [Slide8 WantedPoster] Thebacteria,virusesandprotozoathatcausewaterbornedisease! [Slide9 Imagesofmicrobes] Giardiaforone.Thiscritterisaprotozoanparasite it stiny,butcanmakeyouverysick causingdiarrhea,nausea,cramps. Otherdangersarebacterialikethisone E.coli.Orothertypesofbacteriathatcausedisease likecholeraandtyphoid Butthat snotall wealsohavetobeworriedabout viruses likehepatitis,orrotavirus...all ofwhichmakeyouveryill. Bacteria,protozoaandvirusesmakeALOTofpeopleverysick.World wide,water borne diseasesareresponsibleforkillingabout2millionpeopleeachyear mostofthemchildren. Thetrickythingisthattheyaremuchtoosmalltoseeinourwater soyoucan ttellbylooking atitwhetheryourwaterissafetodrink...millionsofbacterialcellscanfitinasingledropof water. Whichbringsustoournextquestion... Betweenthechemicalpollutantswehaveinoururbanwater,tothesemicrobesthatcanbe foundinanywatersource,howdoweactuallygetthesetinythingsoutofwaterandmake sureit scleanenoughtodrink? Welltheanswertothatdependsonwhoweare,andwherewelive. [Slide10 kitchenfaucet] 13

14 Mostofusdon thavetoworryaboutthat it salreadydoneforusbythetimeitgetstoour homes chemicalpollutantsanddangerousmicrobesareremovedfromourwater.thewater thatcomesoutofourkitchensinksissafe wecandrinkitwithoutworryingbecauseourlargescalewatertreatmentplantsworkprettywell.forexample,thewaterhereatthemuseumis treatedatalarge scalewatertreatmentplant,andthisishowthewateristreated [Slide11 watertreatmentfacility] (Feelfreetocustomizethisslidewithimagesanddetailsofyourlocalwatertreatment check outtheirwebsitetoseehowit streated ifnot,justusethisexampleasa typical large scale watertreatmentplant) (Forexample,themuseum swateroriginallycomesfrom reservoirorgroundwaterin location.travelsthroughpipesuntilitarrivesat watertreatmentplant) Theplanttreatsthewaterinafewsteps firsttheyaddachemicalthatcreatesfloatingclumps ofimpuritiesthatareskimmedoff.duringthenextstep,theyaddozonebubbleswhich disinfectthewaterandkillsallthebacteria,viruses,andprotozoa.thentheyputitthrough anotherfiltertoremoveorganiccompounds,andfinallytheyadd2morechemicals Chlorine andchloramine whichkillanyleftovermicrobes butmoreimportantly,theystayinthe waterandkeepitfreefrommicrobesasittravelsthroughthemilesofundergroundpipeson it swaytothemuseumortoyourhomes. That sjustoneexampleofhowwateristreated andit sprettytypical butsomeother treatmentplantsmightuseothertreatments(uv,reverseosmosis).theyusuallyworkpretty wellandprovidemillionsofuswithsafecleanwater. Butthere sstillaproblem Theyallrequirelotsof: [Slide12 energy,money,infrastructure,engineers] energy,money,infrastructure,chemicals,andskilledengineersandlaborers. Andthereareplacesorsituationswhenwedon thaveaccesstoallthisforcentralizedwater treatment Anyideaswhatsomeofthosemightbe?(Solicitanswersfromaudience...Perhaps promptthemwith haveyouevertraveledanywherewhereitwasn tsafetodrinktapwater? ) [Slide13 remote,poorandoverpopulatedareas] Indevelopingcountries manyareastoopoorortooremotetohavecentralizedwater treatment.somecountrieslikeindiaandchinaarehavingtroublekeepingupwithdemand theycan tbuildwatertreatmentplants,orlaydownpipefastenoughtomeetthegrowing population. [Slide14 disasterdamage] AfterdisasterslikeHurricaneKatrinaorthetsunamisinAsia,orthequakesinHaitiandJapan. Utilitiesshutdownaftermajorcrises,andresidentsfindthereisnocleanwaterorpower available. 14

15 [Slide15 crumblingpipes] Evenhereathome whenwehaveawatermainbreakorotherproblemwithourpipes.our owninfrastructureisold manyofourpipeswereputinplaceacenturyagoormoreand they rehavinganincreasingnumberofproblems.haveyoueverhadaboilwaterorderaftera watermainbreakinyourcommunity?thosesituationscouldenduphappeningmoreandmore often. So,whatdowedo? [Slide16 bottledwater] Wecancartinbottledwater It ssafe,portable,andyoucanhavesafedrinkingwater ANYWHERE...butit sreallyheavysonotsoeasytomovearound justthinkhowmuchwater youuseeveryday fromdrinkingtocookingtobathingtolaundrytowateringyourlawn it reallyaddsup.thenationalaverageforwateruseisabout98gallonsofwaterperpersonper day!(show5gallonwatercoolerbottleasprop)that salmost20ofthese5gallonbottles.that wouldweighmorethan800pounds 800poundsofwaterforeachperson!Imaginehauling thataround.nottomentionthattheproduction,transportationanddisposalofplasticwater bottlesisanenvironmentalnightmareinitself.(percapitausevarieswidelybylocation from alowof50gallonsperpersonperdayinthenortheasternstatestoahighofnearly200gallons perpersonperdayinsomesouthwesternstates.findouttheuseinyourareatocustomizethis toyourlocation.a5gallonwaterbottleweighsabout40pounds). [Slide17 3researchers] That swhyresearchersarelookingfornewsolutions technologiesthatcanhelpussimply, cheaplyandeasilycleanwateronthespotwithoutalotofequipmentorpowerorhavingto addchemicals Purifywaterwhereyouwanttouseit takingeverythingoutofthewaterthat wewanttoremove,withouthavingtoaddchemicalsintothewater. So,I mgoingtosharewithafewstoriesabout3peoplewhosawthisproblemandwantedto dosomethingaboutit findnewwaysandnewtechnologiestopurifyourwater.thecommon thread?all3ofthesepeopleusenanotechnologytodothat.thefirst2technologiesare alreadydevelopedandcommerciallyavailable,thelasttechnologyisstillintheresearchphase andundergoingdevelopment. [Slide18 LifeSaverbottleimages] ThefirstandsimplesttechnologyisfromMichaelPritchardintheUK.Afterwatchingthe aftermathofthetsunamisinsoutheastasiaandthefloodinginneworleansafterhurricane Katrina thatherealizedwhataproblemitwastogetfreshlifesavingcleanwatertopeoplein disasters andhewasinspiredtodosomethingaboutit.hecreatedthe Lifesaver bottle. Justpopopenoneend,fillitwithanywateryoucanfind(evenfromapuddle)pumpthehandle afewtimesandoutcomescleanwater.(showpropifyouhaveit) Reallysimple,nopowerisneeded,andyoucangetthousandsoflitersofwaterwithasingle filter. 15

16 Thewayitworksissimilartoanyfilter youpushthewaterthroughamembranethathastiny holes. Basically,it sasieve likewhatyoumightuseinthekitchen(showprop) butwithmuch smallerholesbecauseitneedstogetouttinybacteriaandviruses.nowalotofpeoplethink thatbacteriaandvirusesareaboutthesamesize(showbacteriaandvirusmodel similarin size).butthat snotthecase.bacteriaaremuch,muchbiggerthanviruses.ifiwasthesizeofa bacteria aviruswouldbesmallerthanthissmallmodel(showsmallermodel approxsizeof pingpongball).letssaythiscuprepresentssomedirtywater theorangeballsrepresent bacteria,andthegreenballsrepresentmuchsmallerviruses...nowalotoffiltershaveholes thataresmallenoughtokeepoutbacteria(demo pour2sizeballsthroughaseive larger ones(bacteria)aretrapped,butsmalleronespassthrough),buttheholesaretoobigtokeep outthetinyviruses(thegreenparticles).soyouneedafilterwithmuchsmallerholes. TheLifeSaverbottle(showbottle)filterhasmuchsmallerholes about15nminsize small enoughtokeepouteventhesmallestviruses.soitworksmorelikethismodel(showsievewith smallerholesandpoorbacteria/virusesballsthroughit everythingiscaught).youcansee bothbacteriaandvirusesaretrappedbythisfilter becauseithassuchsmallholes.it ssimple andeffective anddoesn tjustcomeinthisbottleformat they vealsomadeajerrycan versionthatcansupplyvillagesandschoolswithcleanwater itwasrecentlyputtothetestin Haiti. Butwecandobetter thissolvestheproblemoftakingthesmallestbiologicalcontaminants out,butwithholestoosmall,itlimitshowmuchwatercanflowthroughquickly.also,small poresizeonafilterdoesn tremovedissolvedchemicalcontaminantsonit sown weneed somethingmore... [Slide19 AlanCummingsandtheWaterBox] SothatbringsusbacktoAlanCummings theguyishowedatthestartofthepresentation whodrankwateroutofboston scharlesusingthisdevice(showwaterstickifyouhavephysical prop,otherwiseshowimageofwaterbox).hiscompanyseldontechnologies basedoutof Vermont,developedabetterwaterfilter.Nowtheirinspirationforthistechnologycamefroma littlefartherafield SPACE! [Slide20 Spacestationandastronaut] TheyfirstdevelopedthisfilterforNASA becauseoneofthebiggestlimitsinhavingmanned spaceflightisprovidingenoughcleanwaterfortheastronauts andsincewaterissoheavy, theydon twanttocarrymuchofit sonasawaslookingfortechnologiesthatwouldallow themtopurifysmallamountsofwaterrightonspacecraft toletthemrecycleandreuse water,sospacecrafthavetobringlessofitwiththem.theyalsowantedthewaterfiltertobe smallanduseverylittlepower.stephaniewilsonisoneoftheastronautsthatusedaprototype ofthedevice. [Slide21 NanomeshfilterandWaterBox] 16

17 Seldon stechnologyiscalledananomeshfilter itactuallyhaslargerporesize(holes)thanthe lifesaverbottletoletthewaterflowthroughatafasterrate,butalsousesamaterialcalled carbonnanotubestogetridofcontaminantsinthewater.nowcarbonnanotubes(show model)aretinytubesmadeofcarbon thismodelshowsyoutheirshapeandstructure but therealonesareabout100milliontimessmaller onlyafewnanometersacross thousandsof timesthinnerthanthewidthofasinglehumanhair. Whywouldwewanttoaddthistoourfilter?Well,alotofpollutants(showfoampieces representingpollutants)willadsorb basicallysticktoorattachto carbon.it sthesameidea withactivatedcarbonfilters likebritafiltersforexample.buttheydothisonthesurfaceof carbon.(stickstuffpollutantstooutsideofcntmodel(velcro)).becausethesetubesareso tinyhavelotsofsurfaceareaandthey rearrangedinsuchawaytoletwaterflowthrough muchmoreeasilythanactivatedcarbonfilters,sotheyaremuchmoreeffectiveandtrapping andremovingmicrobesandchemicals. Theyhaveafewdifferentversions awaterstickthatsomeonecouldusetodrinkwaterright fromapollutedsource,afilteryoucouldhookuptoindoorplumbing,orawaterboxthatis portabletopumplargervolumesofwater.(demonstratewaterstickonstage).hereyoucan seethefilterinaction it stakingpollutedwaterfromthejugontheleftandputtingclean drinkingwaterintheglassontheright.(takeasip!) [Slide22 filterfoulinganimation] Thosetechnologiesworkwell butafterawhilethefilterwillclogandwaterwon tflow throughaseasilyorbecleanedaswell.andsincewe retrappingmicroorganismslikebacteria thesemicrobescanstartgrowingonthefilter.that scalledfilter foulinganditmeansthatwe needtocleanorreplacethefilterregularly.actually,thisistrueofanyfilteringtechnology. Wouldn titbegreattohaveaself cleaningfilter?onenanoresearcherhasanideaofhowto dothat. [Slide23 ChadVecitisandCNTfilter] MeetChadVecitis,ayoungresearcheratHarvard,whohasagreatideaforimprovingwater filtersevenmore thetechnologyheisdevelopingtakesthesecarbonnanotubefiltersastep farther. Hestartswithacarbonnanotubefilter thisphotohere itlooksprettysimilartotheother onewesawfromseldon.butdr.vecitisistakingadvantageofanotherpropertyofcarbon Nanotubes thattheyareextremelygoodatconductingelectricity. [Slide24 ElectrochemicalCNTfilteranimation] 17

18 Thatmeanswecanhookupapowersourcetoourfilter(itdoesn tevenneedtobeapowerful one evenafewaabatterieswouldproduceenough) andelectrifyit.we redoing electrochemistrynowasthewaterrunsthroughthefilter thatsoundsfancy butallthat meansisthatwereusingelectricitytokill/inactivate/degradethebacteriaandvirusesand othercontaminantsthatbuildupthefiltertohelpkeepitcleanandslowfilterfouling,soyou don tneedtocleanorreplacethefilterasoften. So,thistechnologyisstillintheresearchphaseandisn tavailableyet,butit spromising it takeseverythingoutthatwewanttoremovefromthewater ANDit sessentiallyaselfcleaningfilter simpleandusesonlyasmallamountofpower.andthistypeoftechnology couldalsomakeabigdifferenceforourlarge scalewatertreatmentaswell. [Slide25 Drippingfaucet] So,thesearejustafewstoriesofrealpeoplewhoareusingscienceandengineeringskillsto findrealsolutionstoverybigproblems.these3nanotech basedwaterfiltersareproviding someinnovativewayswecouldprovidecleandrinkingwater simply,cheaply,withlittlepower tomorepeople,inmoresituationsandplaces.theyaresimplesolutions,butthescience behindthesetechnologieshasonlyjustbecomeavailableinthelast10yearswith nanotechnology.now,nanotechisnotasilverbulletsolutiontothisproblem butitisgoingto bepartofawholesuiteofsolutionsthataddressourwaterchallengesinthecomingdecades. Theevenbiggerissueisthattheworldisrunningoutofcleanwatersourcesforourgrowing population.we resoluckytohavecleanwaterdeliveredrighttowhereweliveandwork that wedon tneedtocollectitmilesawayandcarryitbacktoourhomes...butthatdoesn tmean wecanbewastefulwithit.whatwecandorightnowisconservewater thinkabouthow muchyou reusingeveryday 3gallonsofwaterperminuteintheshower,40gallonsperload oflaundry,15gallonspercycleofyourdishwasher,runningyourgardenhoseis9gallonsper minute.thinkaboutyourwateruseandhowyoumightreduceit ashortershower,waiting untilyouhaveafullloadtodothelaundry,wateringyourlawnatnightorintheearlymorning. Therearelotsofsimplestepswecanalltakeeachdaytoconservewater ourmostvaluable resource. [Slide26 Questions?] Thankyouverymuchforjoiningmetoday.I mhappytoansweranyquestionsyouhave. Otherwise,Ihopeyouenjoytherestofyourdayhereatthemuseum. [Slide27 30 Credits] Tipsandtroubleshooting Thispresentationcanbeenhancedandmademorerelevanttoyourvisitors,byresearchinga littlebitaboutyourlocalwatertreatmentandlocalwateruse.afewslides/imagescanbe customizedtoreflectwhathappensinyourarea. 18

19 Besuretotestthenanotech enhancedfiltersaheadoftimeasittakesafewtriestoget comfortablewithhowtheyworkandthebestwaytodemonstratethisonstage. Commonvisitorquestions Asidefromthequestionsbelow,thispresentationseemstodrawawidevarietyofquestionson waterpurificationorwasterwatertreatmentingeneral(orspecificquestionsaboutyourlocal watertreatmentplant),aswellasquestionsonwell waterqualityconcerns,andafewother topicsoutsidethescopeofthepresentation.readingsomegeneralbackgroundarticlesonhow wateristreatedcouldbehelpful,orreferthemtoyourlocalwaterdepartmentwhoshouldbe abletoanswer. Arethesetechnologiesalreadybeingused(alreadyavailableonthemarket)? Theansweris yes forthefirst2technologiesand notyet forthe3 rd technology.the LifeSaverbottlehasbeeninuseandcommerciallyavailableforthelastfewyears.TheBritish militaryinparticularusethistechnologyinthefield.forthelastcoupleofyears,theseldon WaterStickhasbeenavailableforexport,butstillis undertesting intheunitedstates.it snot commerciallyavailableyet,butisbeingdistributedinlimitedquantitiesaspartof testing.the USmilitaryisalreadyabigcustomerforSeldonandhaspurchasedandcurrentlyuselarge numbersofwatersticksandwaterboxes.bothcompanieshavedonatedmaterials/suppliesfor reliefeffortsinthedevelopingworldandtheirtechnologiesarealreadybeingusedforselect projectsinhaiti,japan,rwanda,andelsewhere. ChadVecitis stechnologyisnotyetavailable it sonlyintheresearchphaseandhispublished papersareproofofconcept.chadwouldneedaninvestor/companytocommercializehis technology. Howexpensivearethesetechnologies?Cheapenoughtouseindevelopingcountries?Arewe abletodistributethesewheretheyareneeded? Asistypicalofanynewtechnology,theyarestillrelativelyexpensive($150fortheLifeSaver Bottleand$100fortheWaterStick).Whilethey vebeendistributedinsmallquantitiesfreeof chargeforreliefefforts,largescaledistributionofthesetechnologiesisn tyetpossible.this presentationmainlytacklesthescienceoftheproblem,astheeconomic,political,andlogistical barrierstoequitablydistributingthesetechnologiesisanothermatterentirely andquitea complexoneatthat.aninterestingonlinearticle Water,Nanotechnology spromises,and EconomicReality( addressesthistopicandisa wortharead. What sthedifferencebetweenanactivatedcarbonfilterandacarbonnanotubefilter? Activatedcarbonfilters likebritafilters arequitecommon.theyaresimplymadeofa carbonrichmaterialthathasbeenprocessedinsuchawaytogiveitlotsofsurfacearea.brita filtersforexamplearemadeofcharredcoconuthusks.contaminantsadsorbto(sticktoor reactwith)thesurfaceofthecarbonhelpingcleanthewater.whiletheactivatedcarbonhas lotsofsurfacearea,itcanbedifficulttostructurethefilterinsuchawaytoallowthewaterto 19

20 flowfreelyandquicklyandforthecontaminantstohavelotsofaccesstothesurfaceofthe areaofthecarbonforadsorption. Carbonnanotube(CNT)filtersworkinthesamegeneralwayasactivatedcarbon exceptthe nanostructureofacarbonnanotubeallowsyoutobettertakeadvantageoftheincrediblylarge surfaceareaofcnts.thecntfiltercanbestructuredsothatwatercanflowquicklyandeasily throughthelargepores,whilethecontaminantsarebroughtincloseproximitytothesurface ofthecarbonnanotubesotheyareattractdandtrappedbythefilter.cntscanalsobe speciallymarked/taggedtoattractcertaincontaminants. Doanyofthenanotubesendupinthefilteredwater?Aren ttheydangerous? Seldon stestshaveshownthereisnomeasurabletraceofcntsintheeffluent(cleanwater). WhileaerosolizedCNTshavebeenaconcernduringmanufacturing,theredoesnotseemtobe anyhealth/safetyconcernforuseofthecntfilterssincetheyarenotpassingintothewater thatisfiltered. Whathappenstothesefiltersaftertheyarefinishedtheirusefullife?Aretheredisposal concerns? Likealmostanywaterfilterthathasfinisheditsusefullife,itwillbedisposedofinalandfill. Therearen tyetfacilitiestotreat/recycle/reusethesefilters.disposalconcernsdonotseemto beanygreaterthanforotherwaterfilters.however,thisbringsupagoodpointthatasthereis muchresearchintonewmaterials,thereisalsoalotresearchintotheimpactofthe lifecycle ofnanomaterialsfrom cradletograve fromharvestingrawmaterialsandmanufacture,to use,todisposal tomakesurethatwearen tcreatingnewenvironmentalorsocietalproblems whiletryingtosolveone. GoingFurther Thebestsourcesforadditionalinformationwouldbethewebsitesofthetechnologies highlightedinthispresentation,orthewebsiteofyourlocalwaterdepartment. Afewgreatoverviewarticlesonthistopicinclude: NanotechnologyandtheChallengeofCleanWater ( NanotechnologyandWaterTreatment( Water,Nanotechnology spromises,andeconomicreality ( TwomuchmoredetailedreportsbytheMeridianInstituteinclude: Nanotechnology,Water,andDevelopment ( ous&site=website) OverviewandComparisonofConventionalandNano BasedWaterTreatment Technologies ( Anonymous&site=website) 20