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