Development of high performance and defect-free asymmetric polyethersulfone membranes for O2/N2 separation

Development of high performance and defect-free asymmetric polyethersulfone membranes for O2/N2 separation

The objective of this study is to develop high performance and defect-free asymmetric polyethersulfone (PES) membranes for O2/N2 separation by manipulation of phase inversion process and rheological factors, including different type of nonsolvent additives, polymer concentration, shear rate and evap...

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Main Author: Ridzuan, Norida
Format: Thesis
Language:English
Published: 2004
Subjects:
TP Chemical technology
Online Access:http://eprints.utm.my/id/eprint/6124/1/NoridaRidzuanMFKT2004.pdf
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spelling my-utm-ep.61242018-09-19T05:03:20Z Development of high performance and defect-free asymmetric polyethersulfone membranes for O2/N2 separation 2004-08 Ridzuan, Norida TP Chemical technology The objective of this study is to develop high performance and defect-free asymmetric polyethersulfone (PES) membranes for O2/N2 separation by manipulation of phase inversion process and rheological factors, including different type of nonsolvent additives, polymer concentration, shear rate and evaporation time. Asymmetric flat sheet membranes were fabricated using a pneumatically-controlled casting machine through a simple dry/wet phase inversion process. 1-methyl–2- pyrolidone (NMP) was employed as a solvent while distilled water (H2O) and ethanol (EtOH) were used as nonsolvent additives (NSA). For the first stage of this study, three types of casting solution using H2O as NSA and three types of casting solution using EtOH as NSA had been formulated through titration method. On the next stage, the membranes were fabricated at constant shear rate and evaporation time which is 233.37 s-1 and 12s respectively. Consequently, from the pure gas permeation test results, it was found that the optimum weight percent of PES in casting solution were 32.62 wt% and 26.71 wt % when H2O and EtOH were used as NSA, respectively. Both of the casting solutions were chosen for optimizing the effect of shear rate and evaporation time. Finally, the membranes were fabricated at five different shear rates ranging from 111.67s-1 to 744.44s -1 and at six evaporation times ranging from 8s to 20s. The results showed that as the shear rate increased, the selectivity and pr essure-normalized flux increased until critical shear rate was reached. The best shear rate was found at 233.33s -1 and 148.89s-1 when H2O and EtOH were used as NSA, respectively. The rheologicaly induced molecular orientation in asymmetric membranes was observed by analyzing the wave length showed by Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (FTIR-ATR). On the other hand, as evaporation time was increased, the selectivity would increase but the pressure-normalized flux would decrease. The best evaporation time was found at 12s for both casting solution. Thus, the different NSA showed different influence on gas separation characteristics and structures of the produced membranes. The newly developed PES membranes with new casting solution formulation that used H2O as the NSA, exhibited O2/N2 selectivity and pressure -normalized flux at about 7.95 and 9.71 GPU for O2 respectively. The average skin layer thickness of these membranes was approximately 538.32Å. As for the membranes using EtOH as NSA, the O2/N2 selectivity and pressurenormalized flux were 5.01 and 14.07 GPU for O2, respectively. The calculated average skin layer thickness was about 369.77Å. Therefore, the PES membranes prepared from NMP/H2O solvent systems proved to provide the best separation characteristics compared to those membranes produced from NMP/ EtOH solvent system. As a conclusion, the combination of phase inversion process and rheological factors had successfully developed high performance, defect-free and hyperthinskinned layer PES asymmetric membranes for O2/N2 separation. 2004-08 Thesis http://eprints.utm.my/id/eprint/6124/ http://eprints.utm.my/id/eprint/6124/1/NoridaRidzuanMFKT2004.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:62073 masters Universiti Teknologi Malaysia, Faculty of Chemical and Natural Resources Engineering Faculty of Chemical and Natural Resources Engineering
institution Universiti Teknologi Malaysia
collection UTM Institutional Repository
language English
topic TP Chemical technology
spellingShingle TP Chemical technology
Ridzuan, Norida
Development of high performance and defect-free asymmetric polyethersulfone membranes for O2/N2 separation
description The objective of this study is to develop high performance and defect-free asymmetric polyethersulfone (PES) membranes for O2/N2 separation by manipulation of phase inversion process and rheological factors, including different type of nonsolvent additives, polymer concentration, shear rate and evaporation time. Asymmetric flat sheet membranes were fabricated using a pneumatically-controlled casting machine through a simple dry/wet phase inversion process. 1-methyl–2- pyrolidone (NMP) was employed as a solvent while distilled water (H2O) and ethanol (EtOH) were used as nonsolvent additives (NSA). For the first stage of this study, three types of casting solution using H2O as NSA and three types of casting solution using EtOH as NSA had been formulated through titration method. On the next stage, the membranes were fabricated at constant shear rate and evaporation time which is 233.37 s-1 and 12s respectively. Consequently, from the pure gas permeation test results, it was found that the optimum weight percent of PES in casting solution were 32.62 wt% and 26.71 wt % when H2O and EtOH were used as NSA, respectively. Both of the casting solutions were chosen for optimizing the effect of shear rate and evaporation time. Finally, the membranes were fabricated at five different shear rates ranging from 111.67s-1 to 744.44s -1 and at six evaporation times ranging from 8s to 20s. The results showed that as the shear rate increased, the selectivity and pr essure-normalized flux increased until critical shear rate was reached. The best shear rate was found at 233.33s -1 and 148.89s-1 when H2O and EtOH were used as NSA, respectively. The rheologicaly induced molecular orientation in asymmetric membranes was observed by analyzing the wave length showed by Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (FTIR-ATR). On the other hand, as evaporation time was increased, the selectivity would increase but the pressure-normalized flux would decrease. The best evaporation time was found at 12s for both casting solution. Thus, the different NSA showed different influence on gas separation characteristics and structures of the produced membranes. The newly developed PES membranes with new casting solution formulation that used H2O as the NSA, exhibited O2/N2 selectivity and pressure -normalized flux at about 7.95 and 9.71 GPU for O2 respectively. The average skin layer thickness of these membranes was approximately 538.32Å. As for the membranes using EtOH as NSA, the O2/N2 selectivity and pressurenormalized flux were 5.01 and 14.07 GPU for O2, respectively. The calculated average skin layer thickness was about 369.77Å. Therefore, the PES membranes prepared from NMP/H2O solvent systems proved to provide the best separation characteristics compared to those membranes produced from NMP/ EtOH solvent system. As a conclusion, the combination of phase inversion process and rheological factors had successfully developed high performance, defect-free and hyperthinskinned layer PES asymmetric membranes for O2/N2 separation.
format Thesis
qualification_level Master's degree
author Ridzuan, Norida
author_facet Ridzuan, Norida
author_sort Ridzuan, Norida
title Development of high performance and defect-free asymmetric polyethersulfone membranes for O2/N2 separation
title_short Development of high performance and defect-free asymmetric polyethersulfone membranes for O2/N2 separation
title_full Development of high performance and defect-free asymmetric polyethersulfone membranes for O2/N2 separation
title_fullStr Development of high performance and defect-free asymmetric polyethersulfone membranes for O2/N2 separation
title_full_unstemmed Development of high performance and defect-free asymmetric polyethersulfone membranes for O2/N2 separation
title_sort development of high performance and defect-free asymmetric polyethersulfone membranes for o2/n2 separation
granting_institution Universiti Teknologi Malaysia, Faculty of Chemical and Natural Resources Engineering
granting_department Faculty of Chemical and Natural Resources Engineering
publishDate 2004
url http://eprints.utm.my/id/eprint/6124/1/NoridaRidzuanMFKT2004.pdf
_version_ 1747814631627292672

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