Fabrication Of Anisotropic Poly (4-Methyl-1-Pentene) Membrane For CO2 And N2 Gas Separation
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Date
2021-06-01
Authors
Zainuddin, Muhd Izzudin Fikry
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Carbon dioxide (CO2) separation from flue gas with the use of membrane
technology has become the focus of researchers over the past decades due to its lower
energy consumption and cheaper alternative. In this thesis, anisotropic poly(4-methyl-1-pentene) (PMP) was studied to determine the feasibility of using PMP to separate
CO2 from nitrogen (N2) gas. A full dense PMP membrane with various PMP wt% was
fabricated at both 20 and 70 ℃ to determine the effect of temperature on dense layer
of the membrane. Water contact angle and FTIR-ATR was used to characterize the
fabricated PMP membrane. The water contact angle of PMP membrane surface
without modification such as plasma treatment or coating that have been obtained
ranged between 105⁰ and 116⁰ which makes the membrane to be classified as
hydrophobic membrane. The SEM image on the cross section of the full dense PMP
membrane also showed no significant difference of the dense layer between the
membrane that undergo dry phase inversion at 20 ℃ and 70 ℃. CO2 and N2 gas
permeance as well as the selectivity does not differ greatly with fabrication
temperature. 5 wt% PMP fabricated at 20 ℃ seems to be the best condition to fabricate
anisotropic PMP membrane based on the gas permeance test. The CO2 and N2
permeance is 5.91 ± 0.29 GPU and 0.51 ± 0.03 GPU respectively, and with CO2/N2
selectivity as 11.57 ± 0.10. The parameter was then used to fabricate anisotropic PMP
membrane with varying dry phase inversion time from 10 to 60 seconds. The CO2
permeance increased by 10 times while the N2 permeance increased by 5 times on
average which makes the CO2/N2 selectivity dropped by half from the full dense PMP
membrane. SEM imaging is used to observe the effect of dry phase inversion time on
the thickness of the dense layer of the fabricated anisotropic PMP membrane. With 40
second dry phase inversion time, it appears to be the best duration to fabricate the
anisotropic PMP membrane. The CO2 and N2 permeance is recorded to be 51.49 ±
1.56 GPU and 9.90 ± 0.58 GPU respectively with selectivity of CO2/N2 gas as 5.21 ±
0.15 with the least deviation. Water-ethanol mixture is not suitable as coagulation bath
due to the immiscibility between cyclohexane and water. Using higher alcohol chain
will reduce the solubility parameter between cyclohexane and the alcohol which will
cause the reduction in porosity of the PMP membrane in the porous section. In our
case, we conclude that introducing water component as a mixture to the coagulation
bath is not suitable for the production of PMP membrane with cyclohexane as its
solvent as water and cyclohexane is immiscible and will form two-phase system.