Molybdenum Disulfide as a Novel 2D Nano-porous
Membrane for Water Desalina:on
PI: Narayana R. Aluru
Presenter: Mohammad Heiranian
DepartmentofMechanicalScienceandEngineering,
BeckmanIns:tuteforAdvancedScienceandTechnology,
UniversityofIllinoisatUrbana−Champaign
DesalinationusingMolybdenum
disulfide(MoS2)
DNAbasedetectionusinghybrid Hexagonalboronnitridewaterinteractionusing
graphene-DNAorigamipores
quantumMonteCarlo
Highwaterflowrateswhile
OrigaminanoporeretardsDNA
rejectingionseffectively
translocationspeedimproving
(NatureCommutations2015,N.R. thesingleresolution
Aluru)
(ACSNano,underreview,N.R.
Aluru)
Forcefielddevelopmentfor
theinteractionbetween
waterandhBN
(JournalofChemicalPhysics
2015,N.R.Aluru)
*  BWnodeshavesufficientlyhighmemory
of64GBpernode(AStampedenodehas
32GB)
*  BWnodeshaveahighpeakmemoryof
GB/s
*  Efficientforcalculationsrequiringreading
andwritinglargeamountofdata
Node
PeakMemoryGB/s
BlueWaterCrayXE
102
NICSKrakenCrayXT
25.6
NERSCHopperXE
ANLIBMBG/Q
85.3
42.6
ScalingofQWalkandNAMDonBlueWaters
35
DNA origami
30
Relative scaling
25
20
15
10
5
0
0
200
400
600
800
1000
Number of cores
Waterdesalination,DNAorigamisequencingandMonteCarlocalculationscost
~150,000,~300,000and~275,000nodehoursonBlueWaters
1200
*  Permeationrateisoneofchallengesinreverse
osmosis
*  Thinmembranesareadvantageousasflux
scalesinverselywiththickness
*  Graphenehasseveralordersofmagnitude
higherpermeationratethanthatof
existingmembranes
*  Addinghydroxylgroupstographene
pores(hydrophilic)enhanceswater
permeation
*  MoS2:twotypesofatomswiththicknessof
about1nm
*  ItismechanicallyrobustwithYoung’s
modulus(270+/-100GPa)
*  MoS2wasshowntoprovidebetterresultsin
DNAsequencingcomparedtographene
Geise,G.M.etal.J.Polym.Sci.BPolym.Phys.48,1685–1718(2010).
Suk,M.E.&Aluru,N.R.J.Phys.Chem.LeU.1,1590–1594(2010).
Cohen-Tanugi,D.&Grossman,J.C.NanoLett.12,3602–3608(2012).
Feng,J.etal.NanoLett.15,3431–3438(2015).
Farimani,A.B.,Min,K.&Aluru,N.R.ACSNano8,7914–7922(2014).
* 
* 
* 
* 
3typesofporeswithsizesrangingfrom20to60Å
1molarofsalt(seawater,0.599M)
Moleculardynamicssimulations
Force-fielddevelopedbyLiangetal.usedforMoS2 2
Liang,T.,Phillpot,S.R.&Sinnott,S.B.Phys.Rev.B79,245110(2009)
*  Ionrejectionofsmallporesis100%foralltypesofpores
*  Forlargerpores,ionsescapethroughtheporereducingrejectionefficiency
Å
*  Waterrateincreasessharplyasporeareaincreasesfrom~20to~50(single-file
2
waterinsmallpores)
Percentage of ion rejection
100
90
Mixed A=36.16 Å
Mixed A=55.45 Å
Mo-only A=18.02 Å
Mo-only A=51.03 Å
Mo-only A=56.42 Å
S-only A=19.01 Å
S-only A=57.38 Å
Graphene A= 59.67 Å
Filtered water molecules (#)
Mo-only at 250 MPa
2
2
2
2
80
2
2
2
70
2
1600
1400
A=18.02 Å
A=25.72 Å
A=51.03 Å
A=56.42 Å
1200
1000
2
2
2
2
800
600
400
200
0
50
100
150
200
250
300
External pressure (MPa)
350
0
2
4
6
Time (ns)
8
10
*  Waterfluxasafunctionof
appliedpressure
*  Similarporeareas:Mixed55.45,
Mo-only56.42,S-only57.38and
graphene59.67Å
*  Mo-onlyhashighestrateof
permeationfollowedbyMixed,
S-onlyandgraphenepores
2
Water flux (#/ns)
200
Mixed
Mo-only
S-only
Graphene
150
100
50
0
50
100
150
200
250
300
External pressure (MPa)
350
* 
* 
* 
* 
HighratesinMo-onlyporeisexplainedbyhigherwaterdensityandvelocity
HigherdensityinMo-onlyporecanbeattributedtohydrophilicnatureofMo
AveragedensityofwaterfollowsorderofMo-only>Mixed>S-only(1.47,1.37and
1.31g/cm3)
Averagevelocityofwateris8.26,7.53and7.51m/s
Water density (g/cm3)
3.5
12
Mixed
Mo-only
S-only
3.0
2.5
2.0
1.5
1.0
8
6
4
0.5
2
0.0
0
0
2
4
6
Distance from the center of the pore (Å)
Mixed
Mo-only
S-only
10
Velocity (m/s)
0
2
4
6
Distance from center of pore (Å)
*  VelocityprofilesatsitesofSandMo
*  InMo-onlypore,velocityishigheratMo.VelocitiesarehigherinSsiteinS-onlypore
*  ArrangementofMoandSsitesandgeometryofporematterinvelocities
*  AllatomsMowithsamegeometry:shapesofvelocityprofilesareidentical
0.34 nm
Gravelle,S.,Joly,L.,Ybert,C.&Bocquet,L.J.Chem.Phys.141,18C526(2014).
Farimani,A.B.,Aluru,N.R.&Tajkhorshid,E.Appl.Phys.Le/.105,83702–83702(2014).
Mo-Only: MoS2
0.5 nm
*  Conicalnanoporeshavehigherfluxesand
permeationrates(aquaporin,solid-state
nanopores)
*  Mo-onlyhasaconicalnanoporegivingriseto
higherfluxes
Graphene
Hydrophobic edges
S-Only: MoS2
* 
Permeationrateis
theoreticallyenhancedby5
ordersofmagnitude
comparedtoMFI-type
zeolite
*  Thereisa70%improvement
inpermeationratecompared
tographene
Percentage of ion rejection
*  Ionrejectionandwaterfluxaretwoimportantfactorsdefiningeffectiveness
andperformance
100
90
MFI Zeolite
Seawater RO
Brackish RO
Nanofiltration
High-flux RO
Graphene
Mo-only MoS2
80
70
1E-5
Pendergast,M.M.&Hoek,E.M.V.EnergyEnviron.Sci.4,1946–1971(2011).
1E-4
1E-3
0.01
0.1
1
10
Water permeation rate (L/cm2/day/MPa)
*  MoS2membranesarepromisingforwaterpurificationandsalt
rejection
*  ConicalarchitectureofMo-onlyporewithspecialarrangementof
hydrophobicedgesandhydrophiliccenterenhanceswater
permeation
*  WaterpermeationratesassociatedwiththeseMoS2membranesare
foundtobe2to5ordersofmagnitudegreaterthanthatofcurrently
usedmembranematerialsand70%betterthangraphenenanopore
SpecialthankstoBlueWatersfor
makingthispossible!