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Polymer and Colloids Lab, Korea Institute of Science and Technology
고분자 분리막 및 자성이온교환수지
정범석 고분자하이브리드연구센터
한국과학기술연구원
고분자 환경 소재
고분자 분리막
고분자 분리막 (membrane) 기술 이란 ?기공 및 물리 , 화학 , 생물학적 특성을 이용해 혼합물로부터 특정 성분을 분리 , 농축 , 재이용하는 고분자 물질을 재료로 한 filter 로써 , 환경 /공업 분야 등 광범위한 영역에서 적용되고 있는 기술 .
수처리막 기능
내오염성 및 내화학성이 우수한 정밀여과막 및 한외여과막혼합 액체의 입자 분리 , 정제 및 재이용에 탁월한 효과
이용 분야
용수 처리 - 초순수 , 무균수 제조 , 해수 담수화 , 음료수폐수 처리 - 전착 도료 회수 , 오일폐수 분리 , 중수도재이용식품 공업 – 탈지유 농축 , 음료의 청정화바이오 산업 – 단백질 분리 농축 , 효소 정제
수처리막의 기능과 이용분야
100 m 10 m 1 m 0.1 m 0.01 m 0.001 m 0.0001 m
Reverse Osmosis
Nanofiltration
Microfiltration
Sand filter
Pollens Yeasts
Bacteria Viruses
Algea Organic macromolecules
Colloids Organic compounds
Dissolved saltsCa, Mg, Na
Ultrafiltration
분리막의 친수화 와 fouling
분리막 친수화 처리기술
* n
R
*C
n
OO
O
O O
O
* n
OOH
O
* n
OH
grafting
hydrolysis
Hydrophobic PE
Hydrophilic PE
( 예 ) 소수성 PE 막에 친수성 화학종 도입과정
polyolefin 계열 : PE, PP polyether 계열 : PSf,
PES polyacryl 계열 : PAN
분리막 표면처리 기법
대표적 수처리용 분리막 소재
Chemical modification Surface polymerization Polymer coating
친수성 고분자를 이용한 분리막 개발
분리막 소재용 고분자Polymers water
Cellulose Acetate (CA)
Structure
ROO
RO OR
O O R
RO
OR O
CH3
x
R= or H
N
x
O
CH3
CH3
O
O
x
N N N N
O
O O
O O
O
O
O x
CH3
x
CH3
CH3
O S OO
O
x
O SO
O x
F
x
FF
F
Polyacrylonitrile (PAN)
Polycarbonate (PC)
Polyimide (PI)
Polyproplene (PP)
Polysulfone (PSf)
Polyethersulfone (PES)
Polytetrafluoroethylene (PTFE)
59±3
57±3
78±1
79±2
83±2
82±2
92±2
117±2
Classification of Polymeric Membranes
porous
Symmetric
dense
Asymmetric
porous
macrovoid macrovoid with skin
porous with skin
Method for Polymeric Membrane Preparation
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.
finger-like sponge-like
• Typical morphology of asymmetric membranes
skin
sublayer
Asymmetric membrane formation
Polymer + solvent(s) Nonsolvent (bath)
Phase separation by immersion precipitation
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
P + S
NS
P + S
NS NS
S
binodal line
Polymer
NonsolventSolvent
composition path
Hollow Fiber Fabrication Process :
bore liquid
polymersolution
spinning nozzle
bore liquid polymer solution
Flat Sheet Fabrication Process :
polymersolution
porous support fabric
knife
Membrane morphology
Choice of solvent/nonsolvent pairs Polymer concentration Composition and temperature of gelation medium Composition and temperature of polymer solution
Thermodynamic parameters
Kinetic parameters
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
Concentration (wt%)
10 15 20
Vis
cosi
ty (
cP)
0
5000
10000
15000
20000
25000
30000
PI in DMSO PI in NMP
A
Phase Diagram
Water0 10 20
PI
0
10
20
NMP
80
90
100Water
0 10 20
PI
DMSO
80
90
100
binodal spinodal tie-linecloud pointcritical pointgelation point
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
CN
CH3
O
40/60 20/80 0/100
- Sponge-like finger-like as NMP content increases- Heat of mixing effect is clear
GBL/NMP: 100/0 80/20 60/40
CO
O
1-methyl-2-pyrrolidinone (NMP) -butyrolactone (GBL)
Membrane Morphology ; coagulation bath
Ratio of water/NMP is given by Vol/Vol.
10/1 10/2
10/3 10/4
Membrane Morphology: polymeric additives
PVP concentration: 5 wt%.
10k 360 k
40 k
Membrane Morphology ; additive effect
PVP: 0% 1% 3% 5% 8%
PI: 15 wt%, PVP 40k, solvent: NMP (high affinity with water)
macrovoid suppression
PI: 15 wt%, PVP 40k, solvent: GBL (low affinity with water)
macrovoid promotion
Membrane Morphology ; Inorganic addives
Nonsolvent: water/MeOH (2/1).
5 wt% LiCl3 wt% LiCl
5 wt% LiCl 5 wt% CaCl2 5 wt% MgCl21 wt% LiCl
Observation of phase separation
Optical microscope Recording to animation file Plotting depth vs. time
water drop
polymer solution
opticalmicroscope
3 sec 7 sec 11 sec 18 sec
※ An optical microscope snapshot of the progress of phase-separation
Phase separation ratePhase separation rate
- Diffusion process
- Decrease as GBL content increase
(effect of heat of mixing)
Solvent diffuse-out rateSolvent diffuse-out rate
polymer solution
D2O
polymer solution
D2O
Observation of solvent diffuse-out
- NMR spectroscopy
- Advantage in mixed-solvent system
- Measurement in different immersion time
- Plotting calculated value vs. time