Track membranes: principles and...
Transcript of Track membranes: principles and...
Development of novel type of track etch membranes for gas separation process
by
Olushola Rotimi ADENIYI
Supervisors: Prof. L. Petrik
(University of the Western Cape) Prof. A. Nechaev Prof. P. Yu. Apel
(Flerov Laboratory of Nuclear Reactions)
Outline
• Acknowledgement
• Introduction
• Objective
• Experimental approach
Results (preliminary)
Introduction
• Heavy ion irradiation on polymeric membranes
• Advanced technology in the fabrication of well-defined pore geometry on polymer films
• Some of the uses of track-etched membrane includes; microfiltration, ultrafiltration of water, biological fluids, gas media filtration etc
Objective
• To investigate effects of latent tracks on polymers and their gas selectivity and permeability properties
• Adopt a robust approach in the development
of flat sheet track etched polymer membrane for gas selectivity and permeability studies
Experimental approach
Metal deposition
Substrate functionalization
Penetrant gas
Permeate
Retentate
GC
Membrane
Membrane cell Thermostat
Gas permeability measurement
a. Xe +126 (1.5 MeV)
b. chemical etching (time, concentration etc)
Choice deposition technique ( i.e. electroless plating)
Investigate deposition parameters and their
direct effect on adhesion, film thickness,
uniformity etc
Fig. 1 Schematics of gas permeability reactor
Experimental Approach in development of flat gas separation polymeric membranes
Native PET film (23mcm) Xe irradiated PET film
Xe irradiated with Al foil11mcm/PET film
1M NaOH etching under various time 3, 6, 9 and 12 minutes
Gas permeability and selectivity studies
Xe 126 ion
Xe 126 ion
Using polyethylene terephathalate (PET) films as a model
/
/
i
c VQ
Sp c c
V - gas is carrier flow rate, m3/s; S - membrane area, m2; p is atmospheric pressure, Pa; ci - penetrant concentration in upstream, vol. %, с/ - penetrant concentration in downstream, vol. %.; D- dense layer thickness
P = Q d ,
,j
i
j
iij
P
P
Q
Q
Gas Permeability
Permeability coefficient
Ideal selectivity
Gas permeability parameters
Gas permeability studies
Sample P, cm cm3/cm2 s cm Hg
Не СО2 СН4
PETF 1,0E-10 1,2E-11 1,3E-12
PETF 1 (Хе+126,E-1,5 MeV/W) 1,1E-10 1,4E-11 1,4E-12
PETF 2 (Хе+126,E-1,5 MeV/W, Al-foil) 1,1E-10 1,6E-11 1,5E-12
Sample α
Не/СО2 Не/СН4 CO2/CH4
PETF 8,7 80 9,2
PETF 1 (Хе+126,E-1,5 MeV/W) 8,1 79 10
PETF 2 (Хе+26,E-1,5 MeV/W, Al-foil, 6,7 73 10
Table 1 Gas permeability of PETF films irradiated by Xe+126
Table 2 Gas selectivity of PETF films irradiated by Xe+126
Fig. 2 The dependence of gas permeability on time of etching for irradiated PETF films
Fig. 3. The dependence of ideal gas selectivity on time of etching for irradiated PETF films
1,0E-10
1,0E-09
1,0E-08
1,0E-07
1,0E-06
1,0E-05
0 5 10 15
Pe
rme
abili
ty, c
m3
/ cm
2 s
cm
Hg
Etching time, min
He
CO2
CH4
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10 12
Sele
ctiv
ity
Etching time, min
He/CH4
CO2/CH4
Study of influence of time of etching on PETF gas permeability properties
Surface morphological studies (SEM)
a b
c
d e
1M NaOH track-etched PET films at different etching time: (a) 0, (b) 3, (c) 6, (d) 9 and (e) 12 minutes
Fig. 1. SEM cross-section 9 minutes track-etched PET
Estimation of influence of time of etching on thickness of dense layer
Fig. 2. SEM cross-section 12 minutes track-etched PET
Time of
etching, min
d, m
He CO2 CH4
0 20 20 20
3 10 11 10
6 9 10 6
9 4 4 0,8
12 0,3 0,1 0,1
Calculated thickness of dense layer
IR results
500 650 800 950 1100 1250 1400 1550 1700 1850 2000
% T
1102
972
Wavenumber (cm-1)
1625
1587
1458
1397
1378
1181
689
634
a
b
c
d e
851
1959
PET structure
KEY:
Etching time
(a) 0, (b) 3, (c) 6, (d) 9 and (e) 12 minutes
Future work
• Irradiate polymethylpentene (PMP) and PI polymers under similar condition as PET
• Conduct gas permeability and selectivity measurement PMP and PI
• Compare results with PET gas permeability and selectivity data
• Adapt membrane for hydrogen gas permeability and selectivity
Acknowledgement
DST (South Africa) NRF (South Africa) UC JINR (Russia) FLEROV LABORATORY (Russia) 7th SA-JINR Coordinators Colleagues
спасибо