membranes for water treatment: properties and characterization · advanced membrane technologies...

Advanced Membrane TechnologiesStanford University, May 07, 2008Advanced Membrane TechnologiesStanford University, May 07, 2008

Ingo Pinnau, Ph.D.

Membranes for Water Treatment:Properties and Characterization

Membrane Separation Processes and CharacteristicsMembrane Separation Processes and Characteristics

Molecular(Nonporous)

< 10Solution/Diffusion

ReverseOsmosis (RO)

Mesopores20 - 500Size ExclusionUltrafiltration(UF)

Macropores500 - 50,000Size ExclusionMicrofiltration(MF)

Macropores> 50,000Size ExclusionParticleFiltration

TransportRegime

Pore Size (Å)

SeparationMechanism

Process


0.001 0.01 0.1 1.0 10 100 1,000

Beach sand

Granular activated carbon

Human hair

Yeast cells

Bacteria

Paint pigment

Oil emulsion

Albumin protein

Endotoxin/ Pyrogen

Colloidal silica

Asbestos

Pesticides/ Herbicides

Aqueous salts

Viruses

Metal ions

0.0001(µm)

Sugars

Reverse Osmosis

Nanofiltration

Ultrafiltration

Microfiltration

Particle Filtration

Membrane Characteristics:Porous MembranesMembrane Characteristics:Porous Membranes

MonovalentMonovalentionsions

MultivalentMultivalentionsions

SuspendedSuspendedsolidssolidsWaterWater VirusesViruses BacteriaBacteria

MicrofiltrationMicrofiltration




UltrafiltrationUltrafiltration

Membrane Characteristics:Non-Porous MembranesMembrane Characteristics:Non-Porous Membranes




NanofiltrationNanofiltration




Reverse Reverse OsmosisOsmosis

Ideal Membranes for UF, NF and RO ApplicationsIdeal Membranes for UF, NF and RO Applications

High water flux (low capital cost)High solute rejection (high water purity)Long-term stability of water flux and rejection(Membrane fouling)Mechanical, chemical and thermal stabilityMinimum pre-treatment (backflushing and chemical treatment)Can be processed into large-scale membranes and modulesInexpensive!

Problems of Current Membranes Used in UF and RO ApplicationsProblems of Current Membranes Used in UF and RO Applications

Poor long-term stability of water flux(Membrane Fouling)

Backflushing and chemical treatment

High membrane replacement cost

Poor resistance to chlorine

Membrane system size

Major Foulant Types in Natural and Industrial WastewaterMajor Foulant Types in Natural and Industrial Wastewater

ScalingScaling

ColloidalColloidalFoulingFouling

BiofoulingBiofouling

OrganicOrganicFoulingFouling

Surface Structure of a Typical UF MembraneSurface Structure of a Typical Surface Structure of a Typical UF MembraneUF Membrane


Porous SurfacePorous Surface

UnfouledUnfouled MembraneMembrane Fouled Membrane

Surface Fouling

Internal Fouling

Schematic Structures of Porous and Non-Porous UF MembranesSchematic Structures of Porous Schematic Structures of Porous and Nonand Non--Porous UF MembranesPorous UF Membranes

Microporous Ultrafiltration MembraneSelective skin layerSelective skin layer

Porous substratePorous substrate

Non-Porous Ultrafiltration Membrane

NonNon--porous hydrophilicporous hydrophilicSurface coating (0.1Surface coating (0.1--0.5 0.5 µµm)m)

Porous substratePorous substrate

Cross-Section of a Non-PorousUF MembraneCross-Section of a Non-PorousUF Membrane

Nonporous PolymerNonporous PolymerCoating LayerCoating Layer(~ 0.3 (~ 0.3 µµm)m)

MicroporousMicroporousSupport MembraneSupport Membrane

Long-Term Water Flux of Porous and Non-Porous Ultrafiltration MembranesLong-Term Water Flux of Porous and Non-Porous Ultrafiltration Membranes

10

100

1,000

0 5 10 15 20 25 30 35

Water flux(L/m2•h)

Permeation Time (Days)

Microporous PVDF module

Non-porousPebax 1074/PVDF

module

water flushwater flush

pure water Feed: 1% motor oil in waterFeed pressure: 150 psigFeed temperature: 23°C

Fouling Index of Porous and Non-Porous Ultrafiltration Membranes for Separation of Oil/Water Emulsions

Fouling Index of Porous and Non-Porous Ultrafiltration Membranes for Separation of Oil/Water Emulsions

0.01

0.1

1

0 5 10 15 20 25 30 35

Fouling Index H2O(t)/JH2O(0)


MicroporousPVDF module

Pebax 1074 module

pure water

water flushwater flush

Long-Term Permeation Properties of Porous Ceramic and Ceramic/Polymer Composite Membranes

Long-Term Permeation Properties of Porous Ceramic and Ceramic/Polymer Composite Membranes

0

0.5

1

1.5

2

2.5

0 20 40 60 80 100 120

Permeation Resistance

(psi/gfd)

Time (hours)

Backflush

Ceramic Module

Ceramic/Pebax 1074Module

Feed: Bilge water ; permeate flux: 40 gfd

Membrane Types Used in Ultrafiltration, Nanofiltration and Reverse Osmosis

Membrane Types Used in Ultrafiltration, Nanofiltration and Reverse Osmosis

Integral asymmetric membrane (Cellulose acetate)Integral asymmetric membrane (Cellulose acetate)

Selective layer (Material A)

Microporous substrate(Material A)

ThinThin--film composite membrane (Polyamide)film composite membrane (Polyamide)

Selective layer (Material A)

Microporous substrate(Material B)

2003 RO/NF Membrane Sales2003 RO/NF Membrane Sales

444

58

11

3034

Share (%)

15Others12TriSep15Toyobo

18Koch/Fluid Systems

27GE Osmonics36Toray

99Nitto Denko/ Hydranautics

115Dow/FilmtechSales ($ MM)Company

R. Truby, Water Executive, September/October 2004, p.11 (Supplement of Ultrapure Water 21, 2004)

4Plate-and-frame

5Cellulose acetate hollow fiber

module

91Polyamide spiral-wound(8’x40’)

Market Share (%)Module Type

•• Expected RO/NF membrane lifetime ~ 3Expected RO/NF membrane lifetime ~ 3--5 years.5 years.•• Actual RO/NF membrane lifetime ~ 7Actual RO/NF membrane lifetime ~ 7--12 years.12 years.•• Membrane replacement makes up for ~ 60% of annual sales.Membrane replacement makes up for ~ 60% of annual sales.

R. Truby, Water Executive, September/October 2004, p.9 (Supplement of Ultrapure Water 21, 2004)

2003 RO/NF Module Sales Distribution

Incremental Changes in Spiral-Wound RO Module PerformanceIncremental Changes in Spiral-Wound RO Module Performance

Dave Furukawa (1999)

99.37.041.940.141999

30.83.521.660.191995

7.92.011.320.341990

2.61.561.100.651985

1.01.001.001.001980

Figure ofMerit

Reciprocal Salt Passage(Normalized to 1980)

Productivity(Normalized to 1980)

Cost (Normalized to 1980 U.S.$)

Year

Figure of Merit = (Productivity) x (1/Salt Passage)Cost

Interfacial Polymerization for Preparation of Thin-Film Composite RO MembranesInterfacial Polymerization for Preparation of Thin-Film Composite RO Membranes

Hydrocarbon/acid chloridesolution

Polyamide layer~ 0.1-0.2 µm

Aqueousaminesolution

Poroussupport

Heat cure

Formation of FT 30 Thin-Film Composite MembraneFormation of FT 30 Thin-Film Composite Membrane

NH2

NH2

ClOC

COCl

COCl

NH NHCO CO

CO

HN NHCO CO

COOH

n 1- n

Formation of PEC 1000 Thin-Film Composite MembraneFormation of PEC 1000 Thin-Film Composite Membrane

N N

NO

O

O

HOH2CH2C

CH2CH2OH

CH2CH2OH O CH2OHH2SO4

O CH2CH2N N

NO

O

O

CH2CH2

CH2CH2OCH2CH2CH2

N

N NCH2

O

HO3S

CH2 CH2CH2O

O

O

O

Rejection and Water Flux of RO Seawater Desalination MembranesRejection and Water Flux of RO Seawater Desalination Membranes

Organic Solute Rejection of Commercial RO MembranesOrganic Solute Rejection of Commercial RO Membranes

Surface Structures of InterfacialAromatic Polyamide Composite Membranes

Surface Structures of InterfacialAromatic Polyamide Composite Membranes

28 gfd 28 gfd

37 gfd 45 gfd

S.-Y. Kwak, D.W. Ihm, J. Membrane Sci. 158 (1999) 143-153

Cross-Section of Interfacial Polyamide Composite Membranes (BW 30)Cross-Section of Interfacial Polyamide Composite Membranes (BW 30)

Ridge and valleyRidge and valleystructurestructure~ 0.2 ~ 0.2 -- 0.5 0.5 µµmm

Selective layerSelective layer~ 500 ~ 500 -- 1,000 1,000 ÅÅ

Surface Structure of Uncoated and Coated RO MembranesSurface Structure of Uncoated and Coated RO Membranes

Uncoated Coated

Surface Structure of Uncoated and Coated RO Membranes (AFM)Surface Structure of Uncoated and Coated RO Membranes (AFM)

ESPA-3

ESPA-3 - coated

AFM pictures courtesy of Jennifer Louie, Stanford University

Performance of Commercial and Modified RO Membranes for Wastewater Treatment

Performance of Commercial and Modified RO Membranes for Wastewater Treatment

0

10

20

30

40

50

0 5 10 15 20 25 30

Water Flux

(L/m2•h)


SWC-2

SWC-2/Pebax 4011

Feed: 900 ppm mineral oil; 100 surfactant DC 193Pressure: 500 psigTemperature: 25°C

AcknowledgementsAcknoAcknowledgements

Financial support was provided by Office of Naval Research and SERDP

Special thanks to my colleagues Isabelle Ciobanu, Sylvie Thomas and Alvin Ng.

membranes for water treatment: properties and characterization · advanced membrane technologies...

Documents