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Forward Osmosis: Progress and Challenges Department of Chemical and Environmental Engineering Yale University New Haven, Connecticut Menachem Elimelech 2014 Clarke Prize Conference, November 7, 2014, Huntington Beach, California

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  • Forward Osmosis: Progress and Challenges

    Department of Chemical and Environmental Engineering Yale University

    New Haven, Connecticut

    Menachem Elimelech

    2014 Clarke Prize Conference, November 7, 2014, Huntington Beach, California

  • Water Flux Eqn:

    Feed

    Permeate

    mw PAJ

    Hydraulic Pressure

    water

    MEMBRANE

    water

    Wa

    ter

    flu

    x, J

    w

    P

    0

    RO (P > )

    Reverse Osmosis (RO)

  • MEMBRANE

    water

    water

    Draw Solution

    Feed

    Permeate

    Water Flux Eqn:

    mw AJ

    Wa

    ter

    flu

    x, J

    w

    P

    0

    FO (P = 0)

    Forward Osmosis (FO)

  • Wa

    ter

    flu

    x, J

    w

    P

    0

    Flux reversal point (P = )

    PRO (P < )

    MEMBRANE

    water

    water

    Pressurized Draw

    Solution Feed

    Permeate

    Water Flux: PAJ mw

    Pressure Retarded Osmosis (PRO)

  • Wa

    ter

    flux,

    Jw

    P

    0

    Flux reversal point (P = )

    PRO (P < )

    Engineered Osmosis

    RO (P > )

    FO (P = 0)

  • Overview of Presentation

    Energy Aspects of Forward Osmosis Fouling Propensity and Reversibility in Forward Osmosis Desired Membrane Properties and Reverse Solute Flux Applications of Forward Osmosis

  • Membrane

    Draw Solution Recovery Process

    Product water

    Feed Water

    Concentrate

    Diluted Draw Solution

    Concentrated Draw Solution

    Energy Input

    The Forward Osmosis Process

  • Energy Input in FO: No Free Lunch.

    Cant beat thermodynamics Separation energy of draw solution is proportional to the osmotic pressure of draw solution Input energy > energy equivalent to draw solution osmotic pressure Potential innovations through use of low-cost forms of energy (e.g., low-grade heat), rather than prime (electric) energy

  • SE = P (R) Permeate

    Brine

    SE: Specific energy P: Applied pressure (R): Brine osmotic pressure at recovery R

    RO Energy Consumption

    Shaffer et al. (2014), in press, 10.1016/j.desal.2014.10.031.

  • SEmin=

    SEmin= D

    D is always >

    Permeate Brine Draw

    Comparing Energy of RO and FO-RO

  • SEmin (FO-RO) = D > = SEmin (RO)

    Condition for net driving force in FO

    FO-RO Always Requires More Energy than RO Alone

  • Overview of Presentation

    Energy Aspects of Forward Osmosis Fouling Propensity and Reversibility in Forward Osmosis Desired Membrane Properties and Reverse Solute Flux Applications of Forward Osmosis

  • Organic Fouling Reversibility in Forward Osmosis

    0 500 1000 1500 20000

    2

    4

    6

    8

    10

    0

    7

    14

    22

    29

    36Flux of clean membrane

    Flux after

    cleaning

    Flu

    x (

    l/m

    2/h

    )

    Flu

    x (m

    /s)

    Time (min)

    Fouling Cle

    an

    ing

    FO membrane: CA (Hydration Tech)

    Organic foulant (200 mg/L alginate); 50 mM NaCl; 0.5 mM Ca2+

    Cleaning: 50 mM NaCl, increased crossflow, 15 min

    Mi and Elimelech, Journal of Membrane Science, 348 (2010) 337345.

  • FO Exhibits Fouling Reversibility with a Wide Range of Foulants

    Alginate BSA Gypsum Silica0.0

    0.2

    0.4

    0.6

    0.8

    1.0

    Flux recovery by rinsing

    Flux after fouling

    No

    rma

    lize

    d F

    lux

    Foulant TypeShaffer et al. (2014), in press, 10.1016/j.desal.2014.10.031.

  • In Situ Surface Modification for Fouling Resistance

    C O Cl

    C O Cl

    C O Cl NH2-PEG

    Interfacial Polymerization

    Polysulfone Support Layer Nascent Polyamide Layer

    PEGylation

    In Situ Modified Membrane

    C O NH

    PEG

    C O NH

    PEG

    MPD+TMC

    Control In Situ Modified0

    20

    40

    60

    80

    100

    120

    Control In Situ Modified

    Con

    tact

    Ang

    le (

    )

    Lu et al. Environ. Sci. Technol. 2013, 47, 1221912228.

  • Modified Membrane Exhibits Organic Fouling Resistance

    Control In Situ Modifed

    80

    85

    90

    95

    100

    Nor

    mal

    ized

    Wat

    er F

    lux,

    Jw/J

    w,0(%

    )

    Fouling Cleaning

    0 100 200 300 400 500

    80

    85

    90

    95

    100

    Polyamide In Situ Modified

    Nor

    mal

    ized

    wat

    er fl

    ux, J

    w/J

    w,0(%

    )

    Cumulative Permeate Volume (ml)

    Control

    Lu et al. Environ. Sci. Technol. 2013, 47, 1221912228

  • Overview of Presentation

    Energy Aspects of Forward Osmosis Fouling Propensity and Reversibility in Forward Osmosis Desired Membrane Properties and Reverse Solute Flux Applications of Forward Osmosis

  • D

    tK

    s

    Tortuosity,

    Porosity,

    Thickness, ts thin film (active layer)

    support layer

    K Solute resistance to diffusion ts Support layer thickness Tortuosity

    Porosity D Draw solute diffusivity

    Membrane structural parameter,

    S

    Current Focus: Reducing Structural Parameter of Membranes

  • S = 9583 m

    TFC-RO

    S = 390 m

    TFC-FO

    Significant Progress in the Past 10 Years

    Yip et al. Environ. Sci. Technol. 2010, 44, 38123818

  • Low Structural Parameter is Critical for Obtaining High Water Flux

    Shaffer et al. (2014), in press, 10.1016/j.desal.2014.10.031.

  • Challenge: Minimize Reverse Draw Solute Flux

    Membrane

    Draw Solution Recovery Process

    Product water

    Feed Water

    Concentrate

    Diluted Draw Solution

    Concentrated Draw Solution

    Js

  • The Driving Force for Reverse Draw Solute Permeation

    A highly concentrated draw solution generates the osmotic gradient that drives the flux of water

    The high concentration of draw solute also drives the reverse permeation of draw solute.

    w mJ A

    ns mJ f c

    Js

    Jw

    Feed Draw

  • Analytical Expression for Reverse Solute Flux

    , ,exp exp

    1 exp exp

    w wD b F b

    s

    w w

    w

    J S Jc c

    D kJ A

    J J SB

    J k D

    , ,exp exp

    1 exp exp

    w wD b F b

    w

    w w

    w

    J S J

    D kJ A

    J J SB

    J k D

  • Model Predicts Reverse Solute Flux for Salt and Neutral Solutes

    0.01 0.1 1 10 100

    0.01

    0.1

    1

    10

    100

    Urea

    Ethylene Glycol

    Glucose

    NaCl

    Experimental Solute Flux (mol m-2 h

    -1)

    Pre

    dic

    ted

    So

    lute

    Flu

    x (

    mo

    l m

    -2 h

    -1)

    180.2 g/mol

    60.1 g/mol

    62.1 g/mol

    0.72 nm

    Yong et al., Journal of Membrane Science 392393 (2012) 917

  • Defined as ratio of forward water flux to reverse salt flux

    Representative of the volume of water produced per moles (or mass) of solute lost

    Depends solely on the membrane active layer permeability and selectivity

    Reverse Flux Selectivity (RFS): An Important Design Parameter

    TnRB

    A

    J

    Jg

    s

    w

  • Membranes Are Constrained by the Permeability-Selectivity Tradeoff

    Yip et al. Environ. Sci. Technol. 2011, 45, 1027310282

    Geise et al., Journal of Membrane Science 2011, 369 (1-2), 130-138.

    TnRB

    A

    J

    Jg

    s

    w

    Goal: Maximize B

    A

  • Overview of Presentation Energy Aspects of Forward Osmosis Fouling Propensity and Reversibility in Forward Osmosis Desired Membrane Properties and Reverse Solute Flux Applications of Forward Osmosis

  • The Goal of FO is NOT to Replace RO!

    RO is the Gold Standard for Desalination

    FO can be used in Applications where RO cannot

  • Potential Applications of FO

    High salinity feed waters that cannot be treated by RO (RO limited to feed water up to about 40,000 ppm)

    Very difficult to treat feed waters (i.e., feed waters with very high fouling potential)

    Zero liquid discharge (ZLD)

    Pre-treatment to improve the performance of conventional desalination processes

  • Applications in Oil and Gas

    Gregory et al., Elements, Vol. 7, 2011, 181186

  • Applications in Oil and Gas: Very Hard to Treat Shale Gas Waters

    Gregory et al., Elements, Vol. 7, 2011, 181186 Upper Limit Conc. (mg/L)

    TDS: 260,000

    Hardness: 55,000

    Alkalinity: 1,100

    Calcium: 31,000

    Cannot be treated by pressure-driven membrane processes (RO/NF)

  • The Green Machine: Treatment of Water from Hydraulic Fracturing

    Source: Hydration Technologies Innovation (HTI)

  • Low-Grade Heat

    Nature, 452, (2008) 260

    McCutcheon et al., Desalination, 174 (2005) 1-11.

    FO Desalination with Thermolytic Draw Solutions

  • Desalination 312 (2013) 6774

    Brine Concentrator for Treatment of High Salinity Shale Gas Wastewater

    Oasys Water Inc.

    TDS = 75,000 mg/L

    TDS = 300 mg/L

  • FO in ZLD Schemes as Brine Concentrator

    Shaffer et al. (2014), in press, 10.1016/j.desal.2014.10.031.

  • Pre-treatment for Conventional Desalination Technologies

    Shaffer et al. (2014), in press, 10.1016/j.desal.2014.10.031.

  • Concluding Remarks The Promise Low fouling propensity Can treat high salinity brines Can treat challenging wastewaters Can be integrated with established technologies (e.g. RO)

    and zero liquid discharge (ZLD) schemes

    The Challenges Development of low-cost high performance membranes Minimizing reverse draw solute flux More pilot demonstrations Development of full-scale systems

  • Acknowledgments Current and former research group at Yale Collaborations: Korea University (Prof. S. Hong), Wollongong University (Prof. Long Nghiem Funding: National Science Foundation, Office of Naval Research, Department of Energy, US EPA, Cornell-KAUST

    http://www.yale.edu/images/captions/2.html