TABLE OF CONTENTS
CHAPTER
1
TITLE
PAGE
DECLARATION
ii
DEDICATION
iii
ACKNOWLEDGEMENTS
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENTS
vii
LIST OF TABLES
xii
LIST OF FIGURES
xiv
LIST OF ABBREVIATIONS
xvii
LIST OF SYMBOLS
xviii
LIST OF APPENDICES
xx
INTRODUCTION
1
1.1
Research Background
1
1.2
Problem Statements
4
1.3
Objectives of the study
5
1.4
Research scopes
6
1.5
Significance of research
7
1.6
Organization of the thesis
7
viii
2
ASSEMBLED OF POLYACRYLONITRILE PREPARED
BY ELECTROSPINNING PROCESS AND A REVIEW
OF ANTIBACTERIA ACTIVITY
9
2.1
Introduction
9
2.2
Precursor selection
11
2.3
Polymeric fibre preparation
15
2.4 Silica nanoparticle for increasing mechanical strength
17
2.4
Module construction
17
2.5.1 Design and procedure
18
2.6
2.5.1.1 Sprayer
19
2.5.1.2 Collecting Device
21
Antibacterial membrane for bacteria
22
2.7. Silver and gold loaded membranes for bacteria removal
23
2.8
Disinfection in water and wastewater treatment
26
2.9
Membrane technology in bacteria removal
29
2.10 Advantages of antibacterial membrane over the other
bacteria removal method
3
32
METHODOLOGY
34
3.1
Electrospinning system
36
3.1.1
Power supply
37
3.1.2
Sprayer
38
3.1.3
Collecting Device
39
Membrane Materials and Formulation
40
3.2.1
Membrane Polymer
40
3.2.2
Solvent
41
3.2
3.3
3.4
Preparation of Fiber Membranes
42
3.3.1
41
Polymer Dope Preparation
Optimization of the process condition on spun nanofiber
membrane using Response Surface Methodology (RSM)
3.5 Membrane Synthesisn
43
45
3.5.1
Scanning Electron Microscope (SEM)
45
3.5.2
Fourier Transform Infra-Red Spectroscopy (FTIR) 46
ix
3.6
4
5
3.5.3
Mechanical Strength
46
3.5.4
Pore Size Analysis
47
3.5.5
Contact angle measurement
48
3.5.6
Chemical Oxygen Demand (COD) Measurement
49
3.5.7
Total Suspended Solids (TSS) Measurement
49
3.5.8
Amonia Nitrogen (NH3-N) Measurement
50
Performance testing
50
3.6.1
50
Pure water permeation (PWP)
3.6.2 Antibacterial tests
51
3.6.3 Filtration of environmental sample
52
ELECTROSPINNING PROCESS
55
4.1
Introduction
54
4.2
Direction of Electrospinning
56
4.3
Mechanical properties of pan/silica composite fibers
prepared via dry-jet wet spinning process
60
4.3.1
4.3.2
4.3.3
4.3.4
61
62
62
66
Experimental
Characterization methods
Results and discussion
Conclusions
EFFECTS OF ELECTROSPINNING PARAMETERS:
PROCESS OPTIMIZATION BY APPLICATION OF
RESPONSE SURFACE METHODOLOGY
68
5.1
Introduction
68
5.2
Response surface methodology
70
5.3
Experimental
72
5.3.1 Materials and dope preparation
72
5.3.2 Electrospinning
72
Characterizations nanofibers membrane
73
5.4.1 Pore size
73
5.4.2 Clean water permeability
74
Results
75
5.4
5.5
x
5.5.1 Model fitting and statistic analysis
75
5.5.2 Response surface methodology approach
for optimization of factors
5.6
6
79
5.5.3 Effect of interactive factors
80
5.5.4 The optimum processing
85
5.5.5 Verification of the results
86
Conclusions
87
EFFECT OF DOPE CONCENTRATIONS ON THE
STRUCTURAL AND PORE SIZE OF NANOFIBERS
7
MEMBRANE
88
6.1
Introduction
88
6.2
Materials and dope preparation
90
6.3
Electrospinning
90
6.4
Fibers characterizations
91
6.5
Results and discussions
93
6.6
Conclusions
96
PERFORMANCE OF ELECTROSPUN NANOFIBERS FOR
WATER FILTER APPLICATION
97
7.1
Introduction
97
7.2
Methods
99
7.2.1
Materials and dope preparation
99
7.2.2
Membrane production process
100
7.2.3
Removal of pathogens
101
7.2.3.1 Culture mechanism of bacterial spot
101
7.2.3.2 Antibacterial activity
102
Evaluation of the physical characteristics
101
7.2.4.1
101
7.2.4
Clean water permeability
7.2.4.2 COD, TSS, NH3-N removal guide method
7.3. Results and discussion
102
103
xi
7.3.1
Removal of pathogens
103
7.3.1.1 Culture mechanism of bacteria spot
7.3.2
8
7.3.1.2 Antibacterial activity
103
Physical characteristics of the nanofiber membrane
105
7.3.2.1. Clean water permeability (CWP)
105
7.4
Nanofiber membrane used in stand-alone applications
105
7.5
Conclusions
106
CONCLUSIONS
108
8.1
General conclusions
108
8.2
Optimum conditions for produced wastewater treatment
109
8.3
Recommendations for Future Works Future Works
111
REFERENCES
Appendices A – J
113
`
128-144
xii
LIST OF TABLES
TABLE NO.
TITLE
1.1
Composition of wastewater
2.1
The advantages and disadvantages of various precursors to
the carbon fiber production
2.2
5
13
Mechanical properties of some commercially available
PAN based carbon fibers
2.3
PAGE
14
Comparison of commonly used disinfectants in
water reclamation
27
2.4
The difference between bacteria, viruses and protozoa
28
5.1
RSM procedure to optimize the process
parameters for the electrospinning process
5.2
Anova for response surface quadratic model for response
pore size
5.3
86
Predicted and experimental value for the responses at
optimum condition
6.1
78
Optimum value of the factors (process
parameters) for maximum response result
5.7
78
Anova for response quadratic model for response
clean water permeability
5.6
77
Anova for response surface quadratic model for response
young modulus
5.5
77
Anova for response quadratic model for response
contact angle
5.4
75
87
Concentration of dope, contact angle on the fiber diameter
and pore size
94
xiii
6.2
Other technique to validate the pore size
95
7.1
Composition of wastewater
100
7.2
Removal of COD, TSS and NH3-N
105
8.1
Optimum process conditions for refinery produced
wastewater treatment
109
xiv
LIST OF FIGURES
FIGURE NO.
1.1
TITLE
PAGE
Electrospinning principle and resulting of nanofiber mat
(SEM picture)
3
2.1
The structure of PAN
15
2.2
Diagram of a typical solution electrospinning apparatus
consisting of a syringe containing solution mounted on a syringe
pump, a high voltage source and a stationary, grounded target
18
2.3
Schematic of nanofibers spraying device
20
2.4
Collecting device for Collecting device for electrospinning
nanofibers membrane
2.5
22
Images of PES-0.5AgNO3 (a) and (c), PES-2.0AgNO3 (b)
and (d) showing inhibition zone against E.coli (a), (b) and
S.aureus (c), (d). The red arrows are pointing at the inhibition
ring possessed around membrane circular discs
2.6
Pressure driven membrane processes classified principally
by average pore diameter
2.7
25
31
Simplified concept schematic of membrane separation.
A desired component (water) is allowed to pass through while
non-desired component (bacteria) is retained.
31
3.1
Schematic of experimental design
35
3.2
Electrospinning Apparatus
37
3.3
Power supply
38
3.4
Sprayer
39
3.5
Schematic of nanofibers spraying device
42
3.6
Characterization of membrane performances
45
xv
3.7
Schematic diagram of the cross-flow permeation testing system 52
3.8
Environmental waste samples were kept in low temperature
before Analysis
3.9
Experimental set-up used in the antibacterial test –
E.coli filtration.
4.1
53
54
Effect of increasing capillary-screen distance on 15 wt.% Estane
electrospinning at 10 kV and 3 ml/h. Average diameter range
1 µm – 148 nm and bead size 10 µm – 2, 5 nm. The average
diameter of fibers and bead-size decreases with increasing
capillary-screen distance
4.2
57
Effect of increasing capillary-screen distance on 20-wt.% Estane
electrospinning at 10 kV and 3 ml/h. Average diameter range
5 μm – 333 nm. The average diameter of fibers decreases with
increasing capillary-screen distance
4.3
58
Effect of increasing capillary-screen distance on 25 wt.% Estane
electrospinning at 10 kV and 3 ml/h. Average diameter range
5 μm – 905 nm. A broad distribution of fiber diameters was
abstained
4.4
59
Effect of electric potential on 20 wt.% Estane electrospinning at
3 ml/h and 15 cm capillary-screen distance. Diameters of fiber
decrease with increasing voltage
4.5
Effect of process parameters on fiber diameter, produced by
electrospinning
4.6
59
60
SEM comparison of dry-wet spinning PAN/silica composite fiber
with different silica contents. (A) 0.5 wt.%, (B) 1 wt.%,
(C) 2 wt.%.
4.7
63
The cross-sectional structures PAN/silica composite fiber
with different silica contents. (A) 0 wt.% (pure PAN),
(B) 0.5 wt.%, (C) 1 wt.%, (D) 2 wt.%.
4.8
64
FTIR spectra of PAN/Silica fibers with different silica contents.
(A) 0 wt.% (pure PAN), (B) 0.5 wt.%, (C) 1 wt.% and
(D) 2 wt.%.
4.9
The tensile strength (A) and Young’s modulus (B) of
PAN/silica composite fibers with the change of silica
65
xvi
composition (wt.%) respectively.
5.1
3D-contour plots of pore size as functions of polymer
concentration and screen distance
5.2
83
3D-contour plots of clean water permeation (CWP) as
functions of polymer concentration and voltage
6.1
82
3D-contour plots of young modulus as functions of polymer
concentration and screen distance.
5.4
81
3D-contour plots of contact angle as functions of polymer
concentration and screen distance
5.3
66
84
SEM fractographs of nanofiber membranes (magnification
20000x) fabricated fromdopes of different PAN concentrations
(a) 14 wt.% (b) 16 wt.% and (c) 18 wt.%.
7.1
Electrospinning principle and resulting of nanofiber mat
(SEM picture)
7.2
98
Illustration of nanofiber membrane filtration set up for
stand-alone application
7.3
94
101
Content of E.coli; (a) control E. coli (b) water from hospital
(c) water from river (d) water from pond
103
7.4
Antibacterial activity
104
7.5
Filtration system
106
xvii
LIST OF ABBREVIATIONS
ANOVA
-
Analysis of Variance
COD
-
Chemical Oxygen Demand
DMF
-
Dimethylformamide
FTIR
-
Fourier Transform Infra-Red Spectroscopy
H2O
-
Water
MF
-
Microfiltration
NH3-N
-
Ammonia Nitrogen
NF
-
Nanofiltration
PAN
-
Polyacrylonitrile
RSM
-
Response Surface Methodology
S.D.
-
Standard Deviation
Ti2O
-
Titanium Dioxide
TMP
-
Transmembrane Pressure
TSS
-
Total Suspended Solid
UF
-
Ultrafiltration
xviii
LIST OF SYMBOLS
a
–
Stokes–Einstein radius (m)
Ak/Δx
–
Ratio of membrane porosity to membrane thickness (m-1)
A
–
Membrane surface area (m2)
Cm
–
Concentration of solute in the fluid at the feed (mol.m-3)
Cp
–
Concentration of solute in the permeate solution (mol.m-3)
dp
–
Pore diameter (nm)
D
–
Diameter of a tube (m)
Js
–
Averaged solute flux over membrane surface (mol.m-2.s-1)
Jpwp
–
Pure water permeability (m3.m-2.h-1 or m.s-1)
Jv
–
Permeate flux (m3.m-2.h-1 or m.s-1)
k
–
Boltzmann’s constant (1.38 kg.m2.s-2.K-1)
M
–
Molecular weight (g.mol-1)
Ms
–
Molecular weight of the solvent (g.mol-1)
n
–
Stokes–Einstein coefficient (dimensionless)
ρ
–
Density of liquid (kg.m-3)
P’
–
Local solute permeability (m2. S-1)
P
–
Solute permeability (m.s-1)
Pf
–
Feed pressure (bar)
Pr
–
Retentate pressure (bar)
Pp
–
Permeate pressure (bar)
rp
–
Pore radius (nm)
rs
–
Stokes radius (nm)
Re
–
Reynolds number (dimensionless)
Qp
–
Permeate flow (kg.m-2)
T
–
Temperature (0C)
xix
Greek letters
ε
–
Porosity of the membrane (%)
η
–
Solution viscosity (N.s.m–2)
ℓ
–
Membrane thickness (m)
μs
–
Geometric mean diameter of solute molecule at R = 50% (nm)
μ
–
Solvent viscosity
(water viscosity at 25oC, 0.894×10–3 kg.m–1.s–1)
xx
LIST OF APPENDICES
APPENDIX
TITLE
PAGE
A
List of publications
123
B
Electrospinning system
125
C
The instruments used in membrane characterization
127
D
Experimental set-up for flux and bacteria removal measurement
130
E
Preparation of agar plates for antibacterial test
131
F
Experimental set-up for bacteria removal using vacuum
filtration cell
132
G
Example of calculation
133
H
Parameter Limits of Effluent of Standard A and B Environmental
I
Quality (Industrial Effluents) Regulation 2009
134
2D of Response Surface Methodology
143