High Performance Polyamide - PowerPoint Presentation

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High Performance Polyamide Thin Film Composite (PA-TFC) Desalination Membranes Modified by Zwitterionic Silanes

Selda Erkoc Ilter*, Jalal Sharabati**, Farzin Saffarimiandoab**, Serkan Guclu**, Derya Yuksel Imer**, Ismail Koyuncu**, Serkan Unal*, Yusuf Z. Menceloglu*

*Sabanci University, Istanbul, Turkey**Istanbul Technical University, Istanbul, Turkey

254th ACS

National Meeting & Exposition August 20-24, 2017 Washington, DC

erkocs

@

sabanciuniv

.edu

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Introduction Desalination Technology Reverse Osmosis PA-TFC Membranes

The project: Modification of PA-TFC Membranes by Zwitterionic Silanes Surface coating -Characterization and performance Interfacial polymerization (IP) -Characterization and performance Conclusion AcknowledgementsOutline

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Ultimate way to obtain fresh water is desalination, the process

of removing salt and other minerals from seawater, brackish water, or wastewaterDesalinationMinimum Salinity(ppm or mg/kg)Maximum Salinity(ppm or mg/kg)Seawater15,00050,000Brackish water1,50015,000Rivers5001,500Fresh water0500Gabriel Eckstein & Yoram Eckstein, 19 Amer. Int'l L.R. 201 (2003), p. 204

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International Desalination Association, 2015Desalination by the Numbers 18,426The total number of desalination plants worldwide  More than 86.8 million cubic meters per dayThe global capacity of commissioned desalination plants   150The number of countries where desalination is practiced

  More than 300 millionThe number of people around the world who rely on desalinated water for some or all their daily needsThe biggest desalination plant, Ras Al-Khair, Saoudi Arabia Reverse-osmosis desalination plant in Barcelona, SpainDesalination capacity103 m3/day

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Frost&Sullivan, September 2015Reverse osmosis (RO) is the

most dominant technology in the global desalination marketDesalination Plants (Technology Segmentation)

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Reverse Osmosis (RO) Operating Principlefeed

permeateretantateRO membraneSaline waterFresh water

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The key terms used in the reverse osmosis: Salt rejection: Percentage of salt in feed that does not pass across membrane (%)

Water Flux: Permeate produced per unit time per unit membrane area (L.m-2.h-1) Cost (energy, cleaning, operating etc.) Water Flux (Energy-efficient membranes) Salt Rejection Chemical Stability: Chlorine resistance Fouling Resistance Mechanical StabilityMajor Concerns in RO Desalination Membranes

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Polyamide Thin Film Composite (PA-TFC) RO MembranesCommercially

most advantageous reverse osmosis (RO) desalination membranes are polyamide thin film composite (PA-TFC) membranesNon-woven fabrics (~100 μm) Polysulfone (PSf) support layer (~ 40 μm) Polyamide active layer (~0.2 μm)Feed sidePermeate sideJ. of Memb. Sci. 370 (2011) 1-22

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Interfacial Polymerization (IP)Elimelech, M., Phillip, W. A. The Future of Seawater Desalination: Energy, Technology, and the Environment, Science 2011, 333

, 712MPDTMCPS supportMPD aq.soln.TMC hexane soln.Interfacial Polymerization (IP) PA-TFC membraneAdsorbed water phaseJ.E.Cadotte, US Patent 4,277,344, 1981

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Main Challenges of PA-TFC Membranes Energy

Cost / FluxSolutions: increasing hydrophilicity (more hydrophilic monomers or additives etc.) nanotechnology (nanoparticles, nanotubes, nanofillers etc.)There is a need for high flux, energy-efficient membranes Fouling Chlorine ResistanceFactors affecting fouling surface hydrophilicity surface charge surface roughness

Solutions: modifing PA chemical structure (different monomers or surface chemical reactions) surface

coatings

Chlorine resistance: aliphatic diamines>cycloaliphatic diamines>aromatic

diamines

Guo

-

dong

Kang

, et al.,

Water

Research

46 (2012) 584

V.T.Do et al.,

Environ

.

Sci

.

Technol

. 46 (2012) 852

Guo

-

Rong

Xu

et al.,

Desalination

328 (2013) 83

Jeong

B.H et al., J.

Membr

.

Sci

. 294 (2007) 1

Ratto

T.V., US2009/049087 (2010)

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The Project: Modification of PA-TFC Membranes by Zwitterionic Silanes

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The Use of Zwitterionic Structures in Membranes Increase in hydrophilicity

Electrostatic hydration layer Resistance to fouling (anti-fouling) Facility in water uptake Zwitterionic co-monomers, coatings, nanoparticles, surface chemical reactions etc.Membrane substrate

Thin water layer

lipids

bacteria

proteins

carbohydrates

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Modification of TFC Membranes by Zwitterionic Silanes2) via Interfacial Polymerization

(IP)Condensation polymerization (sol-gel method)R=Trimethoxy Zwitterionic Silane; (CH3O)3Si-(CH2)n-X+-(CH2)m-Y-CompoundsStructureSulphobetaine Silanes X= R4N+ Y=RSO3-Carboxybetaine SilanesX= R4N+ Y=RCO2-Phosphobetaine SilanesX= R4N+ Y=R2PO4-

1) via Surface CoatingZwitterionic Polysiloxane-Polyamide (PA) Hybrid NetworkPA-g-

Zwitterionic polysiloxane

AimsAnti-fouling

High

flux

Chlorine

resistance

Commercial

membrane

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141. Modification via Surface CoatingPA-g-Zwitterionic

polysiloxaneSWC 5

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1. Modification by Surface CoatingPA-g-Zwitterionic polysiloxane

surface coatingSynthesis :tert-Amine Silane + Sultone Sulphobetaine Silane SWC5

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Characterization of Zwitterionic Silanes1H-NMR spectrum (CDCl

3)13C-NMR spectrum (CDCl3)

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Coating Process(surface coating)

SWC5 zwitt. silane in water(1.0%, 1.5%, 2.0 %)Commercial virgin Hydranautics SWC5 membraneWashing: 0.5% H2SO4 and 1% NaOHEtching: 0.01M (potassium persulfate-potassium metabisulfite)Contact with 1%, 1.5% or 2% aqueous silane solutionModified Membrane

Wetting: 5% (w/v) propylene glycolDrying (120 o

C, 15

min)Curing (120

o

C

, 30

min

)

D.H.

Shin

et al./J. of

Membr

.

Sci

. 376 (2011) 302

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Water Contact Angles

Surface hydrophilicities increased by the effect of coatingsContact angle (o)CM EPBS MPBS MPPS1.0%1.5%2.0%CM

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Zeta Potential MeasurementsModified membranes had negative charged

surfacespHZeta potential (mV)CMEPBS-2%MPBS-2%MPPS-2%

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XPS spectra of (a) unmodifed membrane and (b) coated membrane by 1.5% MPBS aq.

soln. XPS ResultsHigh resolution XPS spectra for N1s of (a) unmodifed membrane and (b) coated membrane by 1% EPBS aq. soln.b) Coated membranea) Control membrane

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Flux and Salt Rejection PerformanceBrackish water desalination conditions:

2000 ppm NaCl, 20 bar, 25 oC Flux (L.m-2.h-1)Salt rejection (%)Flux (L.m-2.h-1)Salt rejection (%)

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Organic Fouling TestsDTAB and Xanthan gum

were used as models for organic fouling

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DTAB FoulingDTAB1000 ppm DTAB, 20 bar, 25 oCAdsorbed

DTAB fouling layer are relatively loose and easily removable in coated membranesSpan of fouling

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Xanthan Fouling1000 ppm Xanthan, 20 bar, 25 oCXanthan

Modified membranes displayed enhanced anti-fouling behavior against xanthan Time (min)Span of fouling

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2. Modification via Interfacial PolymerizationZwitterionic Polysiloxane-Polyamide

(PA) Hybrid Network

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PS support layerMPD (2%) + MPPS70oC

, 10 min curingZwitterionic polysiloxane-polyamidehybrid TFC membraneAdsorbed water phase= MPD= R-Si(OH)3 TMC (0.1%)IP2. Modification by interfacial polymerizationMPPS conc. in aq. phase (%)

Percentage of MPPS to MPD (%) 0.1

5

0.2

10

0.5

25

1

50

2

100

Aqueous

solution

Hexane

solution

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SEM Surface

Morphologies0%5%25%100%MPPS conc. in aq. phase (%)Percentage of MPPS to MPD (%) 0.150.2100.525

1502

100

MPPS

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MPPS conc. in aq. phase (%)Percentage of MPPS

to MPD (%) Salt rejection (%)Flux (L.m-2.h-1)0098.8 ± 0.425.3 ± 10.1598.4 ± 0.328.4 ± 2

0.210

98.9

± 0.233.2 ± 2

0.5

25

9

8.9

± 0.6

2

6.7

± 1

1

50

98.

8

± 0.3

24

.0

± 2

2

100

98.3

± 0.1

27.2

± 2

3

1

% increase in flux

at high salt rejection

Flux and Salt Rejection Performance

Seawater

desalin

ation

conditions:

32000

ppm

NaCl

, 55 bar, 25

o

C

MPPS

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Chlorine Resistance(32000 ppm NaCl, 55 bar, 500 ppm chlorine solution)The effect of chlorine exposure (8h) on salt rejection

Significant enhancement for chlorine resistance was achieved with the membranes MPPS-1.0% and MPPS-2.0% MPPS0 1000 2000 3000 4000100 90 80 70 60 50Salt rejection (%)Chlorine exposure (ppm.h)ControlMPPS-0.1% MPPS-0.2% MPPS-0.5%MPPS-1.0%MPPS-2.0%MPPS conc. in aq. phase (%)

Percentage of MPPS to MPD (%) 0.15

0.2

10

0.5

25

1

50

2

100

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Conclusions Trimethoxy zwitterionic silanes have been used for

the modification of PA-TFC membranes. Membranes have been modified by silanes via surface coating and interfacial polymerization (IP). Surface coating: Although the permeability of resulting membranes decreased by the effect of coating layer, a tendency to enhance salt rejection was observed. Coated membranes displayed improved fouling resistance to DTAB and xanthan. IP:

31% increase in flux at high salt rejection (98.9%) was achieved in seawater desalination conditions. In addition, the modified membranes, MPPS-1% and MPPS-2%, showed significantly

enhanced chlorine

resistance.

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The project is supported by The Scientific and Technological Research Council

of Turkey (TÜBİTAK) Project No:113Y376.Sabancı University-Istanbul Technical University-MEMTEKAcknowledgementThank you!XPS AnalysisBaris Yagci (Koc University)

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32Membranesc a (%)Rrms b (mm)

Ra c (mm)CM-0.4350.353EPBS1.00.5570.4121.50.4050.3082.00.6580.512MPBS1.00.4670.3811.50.541

0.4212.00.7940.658MPPS1.0

0.647

0.5371.50.589

0.480

2.0

0.528

0.439

Surface roughness values of modified RO membranes by optic

profilometer

.

a

Weight

percent

of

sulfobetain

silane

coupling

agents

in

aqueous

coating

solution

b

Root

mean

square

roughness

c

Arithmetic

average

roughness

Surface

Roughness

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BSA Fouling1000 ppm BSA, 20 bar, 25 oCBSAAt the

pH of deionised water, BSA carries a net negative chargeS. Azari, L. Zou, J. of Membr. Sci. 2012, 401-402, 68-75 Time (min)

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Water Contact AngleMPPS conc. in

aqueous phase (%)MPPS conc. in aq. phase (%)Percentage of MPPS to MPD (%) 0.150.2100.525150

2100MPPS

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35