vii
TABLE OF CONTENTS
CHAPTER TITLE
DECLARATION
DEDICATION
ACKNOWLEDGEMENT
ABSTRACT
ABSTRAK
TABLE OF CONTENTS
LIST OF TABLES
LIST OF FIGURES
LIST OF ABBREVIATIONS
LIST OF SYMBOLS
LIST OF APPENDICES
1 INTRODUCTION
1.1 Research Background
1.2 Problem Statement
1.3 Objectives of the Study
1.4 Scope of the Study
1.5 Organization of the Thesis
2 LITERATURE REVIEW
2.1 Osmotic Process
2.2 Forward Osmosis
2.3 Forward Osmosis Advantages
2.4 Forward Osmosis Applications
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7
8
9
1
5
1
10
10
11
12
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2.5 Selection of the membrane configuration
2.6 Forward osmosis challenges
2.6.1 Concentration polarization
2.6.2 Reverse diffusion of solute
2.6.3 Membrane development
2.6.4 Membrane fouling
2.7 Recent development in TFC FO membranes
3 RESEARCH METHODOLOGY
3.1 Research Design
3.2 Experimental Procedure
3.3 Material Selection
3.3.1 Polymer
3.3.2 Pore Forming Additives
3.4 Synthesis of TFC FO Membrane with
Nanocomposite Substrate
3.4.1 Preparation of Nanocomposite Membrane
Substrate
3.4.2 Preparation of PA Active Layer
3.4.3 Membrane Post-treatment
3.5 Synthesis of Thin Film Polyamide Nanocomposite
FO Membrane
3.5.1 Synthesis of TiO2/HNTs composites
3.5.2 Preparation of Membrane Substrate
3.5.3 Synthesis of Polyamide-Nanocomposite
Selective Layer
3.6 Forward Osmosis Design and Set up
3.7 Evaluation of Forward Osmosis Membrane
Performances
3.8 Characterization
3.8.1 Electron Microscopy
3.8.2 Atomic Force Microscopy
3.8.3 Water Contact Angle
3.8.4 Membrane Porosity
3.8.5 Fourier Transform Infra-Red Spectroscopy
3.8.6 X-ray Diffractometer
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21
23
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41

3.8.7 Transmission Electron Microscopy
3.8.8 X-ray Photoelectron Spectroscopy
3.8.9 Zeta Potential Analayzer
4 SYNTHESIS AND CHARACTERIZATION OF
THIN FILM COMPOSITE FO MEMBRANES
USING PSF/HNT AS MEMBRANE SUBSTRATES
4.1 Introduction
4.2 Results and Discussion
4.2.1 Effect of HNTs Loading on the Properties of PSF Substrate
4.2.2 TFN membranes prepared from PSF and
PSF-HNTs substrate
4.2.3 Effect of HNTs loading on the performance of TFN membrane during RO experiments
4.2.4 Effect of HNTs loading on the performance of TFN membrane during FO experiments
4.3 Conclusions
5 SYNTHESIS AND CHARACTERIZATION OF
NOVEL THIN FILM NANOCOMPOSITE FO
MEMBRANES EMBEDDED WITH HNT FOR
WATER DESALINATION
5.1 Introduction
5.2 Results and Discussion
5.2.1 Characterization of HNTs
5.2.2 Effect of HNTs loadings on the Properties of Composite Membrane
5.2.3 Effect of HNTs loading on the performance of TFN(H) membrane during RO experiments
5.2.4 Effect of HNTs loading on the performance of TFN(H) membrane during FO experiments
5.2.5 Effects of TFN(H) membrane on organic fouling behavior
5.2.6 Effect of Intermolecular Adhesion Force
5.2.7 Effect of Membrane Rinsing on Pure Water
Flux Recovery
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102 x
6
5.3 Conclusions
SUPERHYDROPHILIC TIO2/HNTS
NANOCOMPOSITES AS A NEW APPROACH
FOR FABRICATION OF HIGH PERFORMANCE
THIN FILM NANOCOMPOSITE MEMBRANES
FOR FO APPLICATION
6.1 Introduction
6.2 Results and Discussion
6.2.1 Characterization of synthesized TiO2/HNTs
6.2.2 Characterization of composite membranes
6.2.3 Effect of TiO2/HNTs loading on the performance of TFN(T/H) membrane during RO experiments
6.2.4 Effect of TiO2/HNTs loading on the performance of TFN(T/H) membrane during F O/PRO experiments
6.2.5 Effects of TiO2/HNTs on organic fouling behavior of TFN(T/H) membrane
6.3 Conclusions
7 GENERAL CONCLUSION AND
RECOMMENDATION
7.1 General conclusion
7.2 Recommendation
REFERENCES
Appendices A-E
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147-151
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xi
LIST OF TABLES
TABLE NO. TITLE
4.4
4.5
5.1
5.2
5.3
3.1
3.2
3.3
4.1
4.2
4.3
6.1
The physical and chemical material characteristics
The composition of dope, aqueous and organic solutions used for the FO membranes fabrication.
Compositions of TFC FO membranes embedded with different loadings of HNTs.
Effect of HNTs concentration on the properties of PSF substrate with respect to pure water flux, contact angle, overall porosity, pore size and S value.
EDX results on the top surface of substrate membranes
Comparison between the separation properties of TFN membranes prepared in this work and commercial CTA membranes
Water flux (LMH = L/m2.h) and solute flux (gMH = g/m2. h) of TFN FO membranes prepared from different types of PSF substrates in FO orientation.
Water flux (LMH = L/m2.h) and solute flux (gMH = g/m2. h) of TFN FO membranes prepared from different types of PSF substrates in PRO orientation.
XPS results for TFC and TFN(H) membrane with respect to element concentration (in atomic percentage).
Root average arithmetic roughness (Ra) and root mean surface roughness (Rms) and root peak-to-valley (Rpv) values of the TFC and TFN(H) membranes.
Comparison between the separation properties of TFN(H) membranes prepared in this work and commercial CTA membranes.
XPS results for TFC and TFN(T/H) membrane with respect to element concentration (in atomic percentage).
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6.2 Comparison between the separation properties of
TFN(T/H) membranes prepared in this work and commercial CTA membranes. xii
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xiii
LIST OF FIGURES
FIGURE NO.
2.5
2.6
2.7
2.8
2.9
2.10
2.11
2.12
2.1
2.2
2.3
2.4
TITLE PAGE
The potential advantages of FO utilized in water treatment. applications of FO in the fields of water, power and life science
Comparison between the water flux in PRO and FO orientations under membrane fouling in different feed concentrations.
Schematic illustration of external and internal concentration polarization in a FO membrane with asymmetric structure.
A schematic presentation of the impact of reverse draw solute diffusion on CEOP in FO for two different draw solutions: (a) NaCl and (b) dextrose.
Morphology of asymmetric PBI nanofiltration hollow fiber membrane.
Morphology of the as-cast CA double-skinned FO membrane.
A schematic diagram and FESEM images of the nascent
CA membrane cast on glass plate and phase transited in water.
The cross-sectional view of commercial FO membranes from HTI: (a) FO-1 and (b) FO-2.
SEM micrographs of substrate (a) top surface and cross­ section and (b) polyamide skin layer of TFC-FO membranes.
SEM images of (a) nanofiber PES, (b-d) PES-based TFC polyamide membranes.
Schematic illustration of layer-by-layer assembly of PAH and PSS.
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32
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16
13
14

4.3
4.4
4.5
4.6
4.7
4.8
5.1
2.13
2.14
2.15
3.1
3.2
3.3
3.4
3.5
3.6
3.7
4.1
4.2
Comparison of organic fouling behavior in FO and RO membranes.
Schematic diagrams of (a) the crystalline structure of halloysite, and (b) the structure of a HNT.
Schematic Structures of TiO2/HNTs and the Photocatalytic
Process over TiO2 /HNTs.
Schematic representation of the experimental procedure
Structure of polysulfone polymer
Schematic of doping preparing equipment with mechanical stirring.
Interfacial polymerization process, (a) MPD solution and
(b) TMC solution.
The design of closed-loop lab-scale FO permeation cell.
Cross flow RO system
Schematic diagram of forward osmosis setup.
3D AFM images of the top surface of PSF substrates prepared from different nanotubes loadings, (a) Substrate
(control), (b) Substrate 0.25, (c) Substrate0.50 and (d)
Substrate 1.0.
FESEM images of the top surface and cross section of PSF substrates prepared from different HNTs loadings, (a)
Substrate (control), (b) Substrate 0.25, (c) Substrate 0.5
and (d) Substrate 1.0.
XRD patterns for (a) HNTs, (b) Substrate (control) and (c)
Substrate0.5.
ATR-FTIR spectra from 1800 to 800 cm-1 for Substrate
(control), Substrate 0.5 and TFC membrane.
FESEM morphologies of TFC and TFN membranes, (a) top surface view of TFC membrane, (b) top surface view of TFN 0.25 membrane, (c) top surface view of TFN 0.5 membrane, (d) top surface view of TFN 1.0 membrane.
FESEM morphologies of TFC and TFN membranes. (a) cross- section view of TFC membrane (b) cross-section view of TFN 0.5 membrane.
AFM images of PA selective layer morphology of (a)
TFC, (b) TFN0.25, (c) TFN 0.50 and (d) TFN 1.0
membranes.
Water flux and NaCl rejection of TFC and TFN membranes (Test conditions: 2.5 bar, 25oC and 20mM
NaCl aqueous solution).
Schematic illustration of TFN(H) FO membrane formation.
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74 xiv

6.1
6.2
6.3
6.4
5.6
5.7
5.8
5.9
5.2
5.3
5.4
5.5
5.10
5.11
5.12
5.13
5.14
FESEM images of HNTs at different magnification, (a)
20,000x and (b) 50,000x
ATR-FTIR spectra from 1900 to 800 cm-1 for (a) PSF, (b)
TFC membrane and (c) TFN0.1(H).
XRD patterns for (a) TFC, (b) HNTs and (c) TFN0.1(H).
FESEM images of the top surface and cross section of
TFN(H) prepared from different HNT loadings, (a) TFC,
(b) TFN0.01(H), (c) TFN0.05(H) and (d) TFN0.1(H).
3D AFM images of the top surface of (a) TFC, (b)
TFN0.01(H), (c) TFN0.05(H) and (d) TFN0.1(H).
Water contact angle of TFN(H) membranes prepared from different HNTs loading.
Z potential of TFC and TFN0.05(H) membranes.
Water flux and NaCl rejection of TFC and TFN(H) membranes (Test conditions: 2.5 bar, 25oC and 20 mM
NaCl aqueous solution).
W ater flux of TFN(H) F O membrane prepared from different HNTs loading.
Solute flux of TFN(H) F O membrane prepared from different HNTs loading.
The effect of HNTs on the organic fouling of the composite membrane in FO mode (Test conditions: Feed solution: 10 mM NaCl with 200mg/L BSA, draw solution:
2.0 M NaCl, cross-flow velocity: 32.72 cm/s on both sides of the FO membrane and temperature: 25oC).
The effect of HNTs on the organic fouling of the composite membrane in FO mode (Test conditions: Feed solution: 10 mM NaCl with 200mg/L BSA and 1 mM
CaCl2, draw solution: 2.0 M NaCl, cross-flow velocity:
32.72 cm/s on both sides of the FO membrane and temperature: 25oC).
Normalized water fluxes of the BSA-fouled raw TFC PA and TFN0.05(H) membranes before and after washing with de-ionized water (Feed solution, 10 mM NaCl; draw solution, 2.0 M NaCl; cross-flow velocity, 32.72 cm/s on both sides of the FO membrane and temperature: 25°C).
Schematic illustration of TiO2/HNTs preparation and incorporation in to PA selective layer of TFN(T/H) FO membrane.
Schematic mechanism of in-situ growing of TiO2 nanocrystals on to the halloysie nanotubes.
XRD patterns for HNTs and TiO2/HNTs composite.
ATR-FTIR spectra for HNTs andTiO2/HNTs.
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6.6
6.7
6.5
6.8
6.9
6.10
6.11
6.12
6.13
6.14
6.15
FESEM images of TiO2/HNTs at different magnification,
(a) 150,000x and (b) 200,000x, TEM (C) and corresponding high magnification TEM image (D) of
TiO2/HNTs.
ATR-FTIR of PSF substrate, TFC membrane and TFN0.1 membrane, (a) full spectra (800-4000 cm-1) and (b) detailed spectra (800-1800 cm-1).
FESEM images of the top surface and cross section of membrane prepared from different TiO2/HNTs loadings,
(a) TFC, (b) TFN0.01(T/H), (c) TFN0.05(T/H) and (d)
TFN0.1(T/H).
3D AFM images of the top surface of (a) TFC, (b)
TFN0.01(T/H), (c) TFN0.05(T/H) and (d) TFN0.1(T/H) together with Ra roughness value.
Water contact angle of composite membranes prepared from different TiO2/HNTs loading.
Zeta potential of TFC and TFN0.05(T/H) membrane.
Water flux and NaCl rejection of TFC and TFN(T/H) membranes (Test conditions: 2.5 bar, 25oC and 20mM
NaCl aqueous solution).
Water flux of TFN(T/H) FO membrane prepared from different TiO2/HNTs loading.
Solute flux of TFN(T/H) FO membrane prepared from different TiO2/HNTs loading.
The effect of TiO2/HNTs on the organic fouling of the composite membrane in FO mode (Test conditions: Feed solution: 10 mM NaCl with 200mg/L BSA, draw solution:
2.0 M NaCl, cross-flow velocity: 32.72 cm/s on both sides of the FO membrane and temperature: 25oC).
Normalized water flux of the BSA-fouled raw TFC PA and TFN0.05(T/H) membranes before and after washing with DI water in FO orientation (Feed solution, 10 mM
NaCl; draw solution, 2.0 M NaCl; cross-flow velocity,
32.72 cm/s on both sides of the FO membrane and temperature: 25°C).
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120 xvi

LIST OF ABBREVIATIONS
FO
FTIR
HTI
HNT
ICP
XRD
Sc
Sh
CP
CTA
ECP
MW
NF
PA
PAI
PAN
AFM
DMAc -
MPD -
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Schmidt number
Sherwood number
Concentration polarization
Cellulose triacetate
External concentration polarization
Forward Osmosis
Fourier Transform Infrared Spectroscopy
Hydration Technologies Inc
Halloysite nanotube
Internal concentration polarization
X-ray diffractometer
Molecular weight
Nanofiltration
Polyamide
Polyamide-imide
Polyacrylonitrile
Atomic force microscopy
Dimethylacetamide
1,3 -Phenyl endiamine xvii

PS -
FESEM -
PVP -
Re
RO
SEM sPEEK - sPSf -
-
-
-
TFC
TEA
UF
-
-
-
PEG
TMC
PES
PI
PIP
TEM
PRO
PSF
-
-
-
-
-
-
-
-
Polyethylene Glycol
1,3,5-enzenetricarbonyl Trichloride
Polyether sulfone
Polyimide
Piparazine transmission electron microscopy
Pressure retarded osmosis
Polysulfone
Polystyrene
Field Emission Scanning Electronic Microscope
Polyvinylpyrolidone
Reynolds number
Reverse osmosis
Scanning Electron Microscope
Sulfonated poly(ether ether ketone)
Sulfonated polyethersulfone
Thin-film composite
Triethylamide
Ultrafiltration xviii

LIST OF SYMBOLS
A
B
C -
CF,b, CD,b -
CF,i, CD,i -
-
-
CF,m, CD,m -
D
IP
Js
Jw
K
L/t p
R
M -
MWCO -
P -
-
-
-
-
-
-
-
-
Water permeability coefficient (m3/m2.s.Pa)
Solute permeability coefficient (m/s)
Concentrationof salt (mol/l)
Salt concentration of the bulk feed and draw solution
Concentration of feed and draw solution near membrane surface inside porous supports
Concentration of feed and draw solution near membrane surface
Solute diffusion coefficient (m2 s-1)
Interfacial polymerization
Reverse salt flux (g m-2 h-1)
Water flux (m3m-2 s-1)
Water transport coefficient (m.s-1)
Thickness( ^ m)
Molality (M)
Molecular weight cut-off (kDa)
Pressure (bar)
Material density (g.cm-3)
Solute rejection (%) xix

S
T
W
Wd
Ww
AP
A^, A^,
O'
Membrane structural parameter (m)
Membrane thickness (m)
Power (W/m2)
Dry membrane weight(g)
Wet membrane weight (g)
Osmotic pressure (Pa)
Osmotic pressure of the bulk feed and draw solution (Pa)
Osmotic pressure of feed and draw solution near membrane surface (Pa)
Osmotic pressure of feed and draw solution near membrane surface inside porous supports (Pa) hydraulicpressuredifference (bar)
Osmotic pressure difference and effective osmotic pressure xx difference (Pa)
Membrane porosity
Reflection coefficient
Pore tortuosity

xxi
LIST OF APPENDICES
APPENDIX
A
B
C
D
E
TITLE
Osmotic pressure of NaCl at different concentration
Diffusivity of NaCl at various concentration
Concentration calibration curve
Chemical structures of membrane materials
List of publications
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