Transcript 명지대 환경소재

고분자 환경 소재
고분자 분리막 및 자성이온교환수지
정범석
고분자하이브리드연구센터
한국과학기술연구원
Polymer and Colloids Lab, Korea Institute of Science and Technology
고분자 분리막
고분자 분리막 (membrane)기술 이란?
기공 및 물리, 화학, 생물학적 특성을 이용해 혼합물로부터 특정 성분을 분리, 농축,
재이용하는 고분자 물질을 재료로 한 filter로써, 환경/공업 분야 등 광범위한 영역에서
적용되고 있는 기술.
수처리막
기능
내오염성 및 내화학성이 우수한 정밀여과막 및 한외여과막
혼합 액체의 입자 분리, 정제 및 재이용에 탁월한 효과
용수 처리 - 초순수, 무균수 제조, 해수 담수화, 음료수
폐수 처리 - 전착 도료 회수, 오일폐수 분리, 중수도재이용
식품 공업 – 탈지유 농축, 음료의 청정화
바이오 산업 – 단백질 분리 농축, 효소 정제
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이용 분야
수처리막의 기능과 이용분야
Colloids
Algea
100 m
Dissolved salts
Ca, Mg, Na
Organic macromolecules
Bacteria
Pollens
Organic compounds
Viruses
Yeasts
10 m
1 m
0.1 m
0.01 m
0.001 m
0.0001 m
Reverse Osmosis
Nanofiltration
Ultrafiltration
Microfiltration
Sand filter
분리막의 친수화 와 fouling
분리막 친수화 처리기술
분리막 표면처리 기법
Chemical modification
Surface polymerization
Polymer coating
(예) 소수성 PE막에 친수성 화학종 도입과정
Hydrophobic PE
R
C
*
n
*
n
O
O
O
O
grafting
O
O
대표적 수처리용 분리막 소재
polyolefin 계열 : PE, PP
polyether 계열: PSf, PES
polyacryl 계열: PAN
n
*
HO
O
HO
hydrolysis
O
n
*
Hydrophilic PE
친수성 고분자를 이용한 분리막 개발
분리막 소재용 고분자
Polymers
 water
Structure
RO
O
Cellulose Acetate (CA)
RO
O
59±3
O R
x
RO
OR
O
OR
CH3or H
R=
Polyacrylonitrile (PAN)
57±3
x
N
CH3
Polycarbonate (PC)
O
O
CH3
O
Polyimide (PI)
x
O
N
O
N
O
O
N
O
Polyproplene (PP)
79±2
N
O
x
O
83±2
x
CH3
CH3
Polysulfone (PSf)
78±1
O
O
S
O
O
CH3
Polyethersulfone (PES)
O
S
O x
O
F
x
82±2
92±2
F
Polytetrafluoroethylene (PTFE)
x
F
O
F
117±2
Classification of Polymeric Membranes
Symmetric
dense
porous
Asymmetric
porous
porous with
skin
macrovoid
macrovoid with
skin
Method for Polymeric Membrane Preparation
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TIPS (Thermally Induced Phase Separation);
Change in casting solution temperature.
Air-Casting and Evaporation;
Evaporation of the volatile solvent in casting solution.
NIPS (Nonsolvent Induced Phase Separation);
Change in composition by the addition of nonsolvent.
Exposure to vapor or immersion in nonsolvent bath.
Asymmetric membrane formation
Phase separation by immersion precipitation
Polymer + solvent(s)
Nonsolvent (bath)
• Typical morphology of asymmetric membranes
skin
sublayer
finger-like
sponge-like
Phase separation and membrane formation
Phase inversion method (immersion precipitation method)
• immersion of polymer solution into a coagulation medium
• exchange of solvent with nonsolvent
• phase separation occurs
NS
Polymer
binodal line
NS
NS
P+S
composition path
Solvent
S
Nonsolvent
Hollow Fiber Fabrication Process :
bore liquid
polymer solution
bore
liquid
polymer
solution
spinning
nozzle
Flat Sheet Fabrication Process :
polymer
solution
knife
porous support fabric
Membrane morphology
Thermodynamic parameters
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Choice of solvent/nonsolvent pairs
Polymer concentration
Composition and temperature of gelation medium
Composition and temperature of polymer solution
Kinetic parameters
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Exchange rate of solvent/non-solvent pairs
Diffusion of polymer
Coalescence of phase-separated domains
Membrane Morphology ; Solvent effect
(a) PI/DMSO 15wt%
(b) PI/NMP 15wt%
Solution Viscosity
30000
Viscosity (cP)
25000
PI in DMSO
PI in NMP
20000
15000
10000
A
5000
0
10
15
Concentration (wt%)
20
Phase Diagram
PI
PI
80
binodal
spinodal
tie-line
cloud point
critical point
gelation point
80
20
90
90
10
100
100
Water
DMSO
0
10
20
0
NMP
0
Water
10
20
Membrane Morphology; temperature effect
(a)
(b)
(c)
(a) PI/NMP 19 wt% (b) PI/DMSO 15 wt% at 45OC
solution (c) PI/DMSO 15 wt% at 30OC bath
Membrane Morphology ; cosolvent effect
GBL/NMP: 100/0
40/60
80/20
20/80
- Sponge-like  finger-like as NMP content increases
- Heat of mixing effect is clear
60/40
CH3
N
0/100
C O
1-methyl-2-pyrrolidinone (NMP)
O
C O
g-butyrolactone (GBL)
Membrane Morphology ; coagulation bath
10/1
10/2
10/3
10/4
Ratio of water/NMP is given by Vol/Vol.
Membrane Morphology: polymeric additives
10k
40 k
PVP concentration: 5 wt%.
360 k
Membrane Morphology ; additive effect
PI: 15 wt%, PVP 40k, solvent: NMP (high affinity with water)
macrovoid suppression
PI: 15 wt%, PVP 40k, solvent: GBL (low affinity with water)
PVP:
0%
1%
3%
macrovoid promotion
5%
8%
Membrane Morphology ; Inorganic addives
1 wt% LiCl
5 wt% LiCl
3 wt% LiCl
5 wt% CaCl2
5 wt% LiCl
Nonsolvent: water/MeOH (2/1).
5 wt% MgCl2
Observation of phase separation
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Optical microscope
Recording to animation file
Plotting depth vs. time
water drop
optical
microscope
polymer solution
※ An optical microscope snapshot of the progress of phase-separation
3 sec
7 sec
11 sec
18 sec
Phase separation rate
600
NMP
GBL/NMP: 20/80
GBL/NMP: 40/60
GBL/NMP: 60/40
GBL/NMP: 80/20
GBL
Length (mm)
500
400
- Diffusion process
- Decrease as GBL content increase
(effect of heat of mixing)
300
200
100
0
0
1
2
3
4
5
Square root time (s1/2)
6
7
Solvent diffuse-out rate
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Observation of solvent diffuse-out
- NMR spectroscopy
polymer solution
- Advantage in mixed-solvent system
- Measurement in different immersion time
- Plotting calculated value vs. time
D2 O