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NANOSPONGESSOAK UP CONTAMINANTSAND CUT CLEANUP COSTS

POLYMER COULD BECOME A NATURAL EXTENSION

OF EVERY DRINKING FAUCET IN THE WORLD

L os Alamos National Laboratory researchers have developed reusable

nanosponges, a polymer-based materialthat forms nanometer-sized pores thatcan absorb and trap organic contaminantsin water, which are proving highlyeffective in cleaning up organiccontaminants in an industrial setting.

A nanometer is one-billionth of a meter.

The nanosponge polymer could become anatural extension of every drinking faucet inthe world, according to Los Alamos polymerchemist DeQuan Li.

The polymer also could be used to clean uporganic explosives, remediate undergroundwater and clean up oil or organic chemical

ÓChemistDeQuan L i ( left )and graduatestudent Min Mahave developeda new polymerthat can absorband traporganiccontaminantsin water .

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EDITORKathy DeLucas

MANAGING EDITORMeredith Coonley

STAFF WRITERTheresa Salazar

Send comments/questions todateline@lanl.gov

CONTRIBUTING WRITERSteve Sandoval

CONTRIBUTING PHOTOGRAPHERJohn Bass

PRINTING COORDINATORG.D. Archuleta

LOS ALAMOS NATIONAL LABORATORY

PUBLIC AFFAIRS OFFICE, MS P355

LOS ALAMOS, NM 87545

spills, especially in water — all while decreasing cleanup costsassociated with current technologies.

Conventional processes using either activated carbon or zeolites areinefficient in reducing low-concentration contaminants in water and aretotally ineffective in removing organic compounds from water down tothe parts-per-trillion level, Li said.

The molecular binding between organic contaminants and the polymeris 100,000 times greater than with activated charcoal and the process is100 percent reversible.

Activated carbon is made from material burnt in a super-heated,oxygen-rich atmosphere creating small holes throughout the grain ofcharcoal that effectively increases the carbon’s surface area, making itmore reactive.

Zeolites are a group of crystalline aluminosilicates with three-dimen-sional frameworks that form uniform surface pores enclosing internalcavities and channels and are used commercially as molecular sieves,mostly for gas separations.

The shape and size of the surface pores and internal cavities physicallyor chemically trap large chemical molecules within their lattice,breaking them into smaller ones.

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But both activated char-coal and zeolites havedrawbacks in waterpurification: They areeasily deactivated bymoisture in the air andcannot function effec-tively once they arecompletely saturatedwith water.

Zeolites, for example,are good for absorbingwater from organics butnot vice versa.

Discovered by Li andgraduate student MinMa, the newly developedmaterial is made of poly-meric building blockscalled cyclodextrins thatform cylindrical cages totrap organics.

The nanosponge has a love-hate relationship with water. The polymer’scages have hydrophilic sites that have an affinity for water andhydrophobic sites that are repelled by water. This characteristic makesthem useful in water yet able to attract organics.

The hydrophobic sites prefer the organic contaminant over the water.The water actually drives the organic compound into the polymer’s cage-like structure. Researchers rinse the saturated polymer with ethanol torelease the trapped contaminants and the nanosponge can be reused.

So far the research team has developed polymers to bind withtrichloroethylene, toluene, phenol derivatives and a number of dyecompounds. Li can fabricate the nanosponge material into granularsolids, powders and optical-quality thin films.

Such flexibility enables users to customize the polymer for multipleapplications and formats accommodating different water-treatmentconfigurations and needs, Li said. For example, a polymer designed as amembrane could be placed on a household water faucet. This

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ÓGraduatestudent Min Mabegins anexper iment bypour ingcontaminatedf lu id into aburette — aglass tube witha tap on theend of i t .

membrane could purify watermuch like conventional filtersdo to soften it.

The only difference is that watersofteners introduce sodium ionsin exchange for the calcium ionsthat make the water hard; thepolymers add nothing to thetreated water.

Another advantage the polymershave is that the polymers arerelatively cheap to manufacture;they are one step away from acommercially available product:cyclodextrins in starch.

The conversion is 100 percenteffective; all the starch cyclodex-trins are converted completely topolymer products. Mass produc-tion may bring down the costbelow the current price of acti-vated carbon or zeolites, Li said.

Unlike carbon and zeolites, the porous polymers remain effective in airand do not absorb moisture from the air. Activated carbon and zeolitesmust be “activated” before use or they lose their effectiveness to removecontaminants. But the polymers require no activation and can be placedimmediately into the contaminated medium for

in situ treatment.

The tiny sponge-like polymer can be readily incorporated into industrialand municipal online water purification systems, Li said.

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ÈDecontaminatedwater dr ips into

a beakerafter pass ingthrough thenanosponge

polymer. Thenanosponge

can be removedfrom thef i l t rat ion

device, r insedwith ethanol to

re lease thecontaminants ,

and reused.

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FINDING BETTER WAYSTO TRAVEL

SIMULATION SYSTEM EXAMINES NEW APPROACHES

FOR GETTING PEOPLE WHERE THEY WANT TO GO

A new transportation forecasting tool soon will help metropolitan

planners design future roads andtransit systems.In a recent study conducted in the Dallas-Fort Worth area, Los Alamos researchers usedthe Transportation Analysis and SimulationSystem, or TRANSIMS, to create a virtualmetropolitan region with a complete represen-tation of the region’s residents, their activitiesand the transportation infrastructure.

TRANSIMS is a set of integrated analyticaland simulation models and supporting databases that examines alternatives which helpcommuters and other travelers reach theirdestinations with less hassle and grief.

The computational system representsthousands of roadway and transit seg-ments, intersection signalsand signs, traveler originsand destinations andpossibly millions of peopleand vehicles.

Metropolitan planners mustplan the growth of theircities according to the strin-gent transportation systemplanning requirements ofthe Intermodal SurfaceTransportation Efficiency Actof 1991 and the Clean AirAct Amendments of 1990.

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PRESIDENT

BRIEFED ON TRANSIMS

Pres ident C l inton (second fromleft ) and Secretary of EnergyFeder ico Peña ( left ) rece ive af i rst-hand demonstrat ion byLaboratory Director John Browneon TRANSIMS, a new transport-at ion forecast ing tool developedto ass ist metropol i tan p lanners inthe des ign of future roads andtrans it systems. The demon-strat ion was part of a br ief ing thepres ident received on Los A lamossupercomput ing in i t iat ives , whicha lso inc luded global oceanmodel ing. The Feb. 3 v is i t was thepres ident’s second to theLaboratory in f ive years . Dur inghis three-hour v is i t to Los A lamos,the pres ident addressed agather ing of Laboratoryemployees and their fami l ies , andmade a quick stop at the loca lh igh school , where the bandserenaded him with “Louie, Louie.”

These lawsrequire eachstate and itsmetropolitanareas to worktogether todevelop 3-yearand 20-yeartransportationimprovementplans that esti-mate futuretransportationneeds and eval-

uate ways to manage and reduce congestion. The plans also mustexamine the effectiveness of building new roads and transit systems andlimit the environmental impact of the various strategies.

Accurate planning requires an analytical capability that properlyaccounts for travel demand, human behavior, traffic and transit opera-tions, major investments and environmental effects.

Existing planning tools that are based on methods developed in the 1950suse lumped information and representative behavior to predict averageresponse and average usage of transportation facilities. They don’t accountfor individual traveler response to the transportation environment.

TRANSIMS, however, emphasizes the complex nature of individualsinteracting with the transportation system. It generates a syntheticpopulation and places households and individuals within themetropolitan area. The demographic makeup and spatial distribution ofthe artificial population comes from census data and matches that of theregion’s real population.

Based on survey data, TRANSIMS then builds a model of householdand individual activities that might occur at home, work, school orshopping centers. Trip plans that include departure times, travel modesand specific routes are created for each individual to reach his or herdaily activities.

TRANSIMS simulates the movement of individuals by executing theirtrip plans throughout the transportation network. The simulation alsoincludes individuals’ use of vehicles such as cars or buses, on a second-by-second basis.

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ÈThe

micros imulat ionof the Da l las-

Fort Worth areacovers a 25square-mi leregion that

inc ludesfreeways,

arter ia ls andloca l streets

near two majorshopping mal ls

— the Ga l ler iaand Va l ley V iew.

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This virtual world of travelers mimics the traveling and drivingbehavior of real people. The interactions of individual vehicles producerealistic traffic dynamics from which analysts use TRANSIMS to esti-mate vehicle emissions and judge the overall performance of thetransportation system.

In this context, a complete transportation system includes travelers,freight, vehicles, roadways, sidewalks, paths, intersections, transit sched-ules and even policies.

Los Alamos researchers are developing and implementing computermodels that imitate situations, for example, where travelers choosevarious routes as opposed to others due to traffic congestion or whentravelers change from car to bus or vice versa which in turn affect atransportation system’s performance.

The executed route and mode travel times of individuals obviouslydiffers from the information that was used to plan each trip in the firstplace. So, these travel times are gathered from the travel simulation,used to replan the individuals’ activities and trips, and the travel simula-tion is run again.

This iteration between the planning model and travel simulation isrepeated until the trip plans and simulated travel do not change signifi-cantly between runs. Thus, a complete study may involve numerouscases and may require hundreds of executions of the activity-demandmodel, trip-planning model and the travel simulation.

To address the computa-tional demands, Los Alamosresearchers apply methodsthat simplify the modeling ofthe individual traveler’sinteractions with the trans-portation system but produceappropriate dynamic behaviorof the transportation systemas a whole.

For instance, quick-running,simple models were createdin which vehicles hop-ping along the roadwaygenerate realistic traffic flowand congestion.

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TRANSIMS’v i rtua l wor ldmimicsthe trave l ingand dr iv ingbehavior ofrea l people.

Ô

The researchers studyprocedures that rapidlyselect the nearest loca-tion for a traveler’sactivity and that findthe travel modes androutes that are theshortest or quickestbetween locations.

The Dallas-Fort Worthstudy emphasized aninitial TRANSIMScapability for evalu-ating traffic flowdependence on road-way alternatives. Them i c r o s i m u l a t i o ncovered a 25-square-mile region thatincluded freeways,arterials and localstreets. The region’scenter is at the inter-section of two majorroadways — Interstate635 and the DallasNorth Tollway —located near two majorshopping malls —Galleria and Valley View.

Two alternative roadway improvements were evaluated for improvedaccess through the region, to the Galleria and to other locations in theregion. A freeway change added another lane to I-635 in both directions.An arterial change included additional lanes on four major arterials,additional frontage roads to improve traffic flow and Galleria access andseveral redesigned major intersections.

Los Alamos researchers found that TRANSIMS provides new ways ofmeasuring the effectiveness of transportation system changes. Todemonstrate, individual travel times can be grouped in five-minute

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ÓThe topcomputer-generatedimage s imulatesthe present-daytraff ic f lownear theGal ler ia and theI-635 and Dal lasNorth Tol lwayinterchange.The TRANSIMSs imulat ionindicates s low,congestedtraff ic on thetol lway and amajor arter ia lstreet . Thelower imageshows reducedcongest ion andimprovedtraff ic f low fora TRANSIMSs imulat ion withimprovementsto severa larter ia l streets .

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intervals according to the trip starting time. Statistical properties of eachgroup can be calculated.

So, in addition to comparing the traditional average travel time duringthe peak period of traffic congestion, the time dependence and the rangeof travel times can be compared between cases. The Dallas-Fort Worthstudy successfully demonstrated the TRANSIMS interim operationalcapability and indicated various ways in which it can be used to eval-uate transportation alternatives.

The next phase in TRANSIMS development focuses primarily on theinteraction between the planning models and the travel simulation, butalso will incorporate activity demand and the capability for emissionspredictions. This case study will be conducted in Portland, Ore.

Researchers anticipate that once TRANSIMS is developed, it will be usedin every city where congestion and pollution are major concerns.

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ÓAn aer ia l v iewof the roadsnear theGal ler ia andVal ley V iewmal ls .

RESEARCHERS AWARDED$5 MILLION

INNOVATIVE PROJECTS WILL SPEED UP

ENVIRONMENTAL CLEANUP

Eight Los Alamos projects have received grants from the Department of Energy for innovative projects aimed

speeding up environmental cleanup. This research programfocuses on the fundamental science needed to developtechnologies that reduce costs and risks to the environment,workers and communities. The program takes advantageof laboratory and university expertise to carry outlong-term research.

The projects, which were awarded nearly$5.5 million, range from studying funda-mental chemistry to how radioactivecontaminants move through the environ-ment to aging effects in waste-storage tanks.

DOE awarded $46 million in grants for 66projects nationwide at national laboratories,universities and private institutions for the1998 fiscal year, which began Oct. 1, 1997.The grants from DOE’s EnvironmentalManagement Science Program fund basicresearch projects that make DOE’s environ-mental cleanup efforts more cost-effectiveand efficient.

The Los Alamos projects, which will befunded over three years, are:

• An investigation of the fundamentalchemistry of technetium, a radioactivebyproduct of uranium decay. The $900,000grant was awarded in partnership withLawrence Berkeley National Laboratory.The principal investigator is Carol Burns ofChemical and Environmental Researchand Development.

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ÓBefore andafter photos of s i teremediat ion atMater ia lDisposal Area M.

• A study of electrochemistry mechanisms to help develop morerobust and less expensive methods for stabilizing plutonium- anduranium-bearing residue materials at DOE sites. The grant is for$750,000 and the principal investigator is David Morris of Bioscienceand Biotechnology.

• Basic research in chemistry intended to aid development of new waysto simulate the complex ingredients in high-level radioactive wastetanks on DOE sites, which in turn can help lead to better treatmenttechniques. The grant is for $550,000 and the principal investigator isRebecca Chamberlin of Nuclear and Radiochemistry.

• Materials science research aimed at improving the durability of thewaste forms proposed for long-term disposal of DOE radioactive wastes,focusing on the thermodynamics of actinide-bearing mineral wasteforms. The grant is for $1,150,000 and the principal investigator is MarkWilliamson of Advanced Technology.

• Research aimed at a better understanding of the chemical behavior oftechnetium, including how technetium complexes behave in wastes atDOE’s facility at Hanford, Wash. The grant is for $730,000 and the prin-cipal investigator is Norman Schroeder of Nuclear and Radiochemistry.

• An environmental science study into how local conditions can affectthe movement of contaminants, such as plutonium, in soils on DOEsites. The grant is for $900,000 and the principal investigator is DavidBreshears of Environmental Science.

• A study of the chemical behavior of plutonium in contaminated soilson DOE sites to understand risks to the public and the environment andto develop appropriate cleanup methods. The grant is for $750,000 andthe principal investigator is Mary Neu of Nuclear and Radiochemistry.

• Basic research into instrumentation that can determine the chemistryof complex mixtures such as the large volumes of mixed radioactive andhazardous waste on DOE sites. The grant is for $655,000 and the prin-cipal investigator is Phillip Hemberger of Environmental Science andWaste Technology.

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BRIEFLY …

THE LABORATORY AND NEW MEXICO STATE UNIVERSITY HAVE ESTABLISHED APARTNERSHIP that will help attract new researchers to the Los Alamos Neutron Science Center andcreate a high-quality physics-research program at the university. “The agreement between the Laboratoryand NMSU will broaden and strengthen cooperation between the two institutions,” said newly appointedLANSCE Director Roger Pynn. Professor Heinrich Nakotte has been chosen to hold a joint positionbetween NMSU and LANSCE devoting half-time to each position. The agreement spans six years or untilNakotte achieves a tenured position in NMSU’s Physics Department. Congressman Joe Skeen (R-N.M.)and incoming Laboratory Director John Browne formalized the agreement at Skeen’s Washington office.

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IN THIS ISSUE:

NANOSPONGES SOAK UP

CONTAMINANTSP A G E 1

FINDING BETTER WAYS

TO TRAVELP A G E 5

RESEARCHERS AWARDED

$5 MILLION FOR

ENVIRONMENTAL

CLEANUPP A G E 1 0

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