Study of the Effect of Inorganic Particles on the Gas Transport Properties of Glassy Polyimides for Selective CO<sub>2</sub> and H<sub>2</sub>O Separation
Abstract:Three polyimides and six inorganic fillers in a form of nanometer-sized particles were studied as thick film solution cast mixed matrix membranes (MMMs) for transport of CO2, CH4 and H2O. Gas transport properties and electron microscopy images indicate good polymer-filler compatibility for all membranes. The only filler type which demonstrated good distribution throughout the membrane thickness at 10 wt. % loading was BaCe0.2Zr0.7Y0.1O3 (BCZY). The influence of this filler on MMM gas transport properties was s… Show more
“…The first was the evaporation of excess water at 100 °C causing around 5 wt% mass loss in each membrane, while the second was the starting decomposition of P84 co-polyimide that was different in each sample. The pristine membrane started to decompose at a temperature of 531.33 °C, which is consistent with the previously reported data [ 34 , 35 , 43 ]. This indicated the high thermal stability of P84 co-polyimide.…”
This research introduces zeolite carbon composite (ZCC) as a new filler on polymeric membranes based on the BTDA-TDI/MDI (P84) co-polyimide for the air separation process. The separation performance was further improved by a polydimethylsiloxane (PDMS) coating to cover up the surface defect. The incorporation of 1 wt% ZCC into P84 co-polyimide matrix enhanced the O2 permeability from 7.12 to 18.90 Barrer (2.65 times) and the O2/N2 selectivity from 4.11 to 4.92 Barrer (19.71% improvement). The PDMS coating on the membrane further improved the O2/N2 selectivity by up to 60%. The results showed that the incorporation of ZCC and PDMS coating onto the P84 co-polyimide membrane was able to increase the overall air separation performance.
“…The first was the evaporation of excess water at 100 °C causing around 5 wt% mass loss in each membrane, while the second was the starting decomposition of P84 co-polyimide that was different in each sample. The pristine membrane started to decompose at a temperature of 531.33 °C, which is consistent with the previously reported data [ 34 , 35 , 43 ]. This indicated the high thermal stability of P84 co-polyimide.…”
This research introduces zeolite carbon composite (ZCC) as a new filler on polymeric membranes based on the BTDA-TDI/MDI (P84) co-polyimide for the air separation process. The separation performance was further improved by a polydimethylsiloxane (PDMS) coating to cover up the surface defect. The incorporation of 1 wt% ZCC into P84 co-polyimide matrix enhanced the O2 permeability from 7.12 to 18.90 Barrer (2.65 times) and the O2/N2 selectivity from 4.11 to 4.92 Barrer (19.71% improvement). The PDMS coating on the membrane further improved the O2/N2 selectivity by up to 60%. The results showed that the incorporation of ZCC and PDMS coating onto the P84 co-polyimide membrane was able to increase the overall air separation performance.
“…As the P84 is hydrophobic, having a hydrophobic filler is preferred since it has better adhesion owing to character similarity. This leads to the thermal stability improvement [ 58 ]. Figure 9 ( a ) TGA/DTA and ( b ) DSC curve of all prepared membranes.…”
Section: Resultsmentioning
confidence: 99%
“…The glass transition temperature ( T g ) of all the prepared membrane was determined by differential scanning calorimetry (DSC). Generally, filler particle would give a plasticization effect to the polymer membrane that would reduce the T g value [ 58 ]. The improved T g value ( table 2 ) after filler introduction means there is macromolecular chain rigidification that occurs in the polymer.…”
This research involved carrying out a unique micro-mesoporous carbon particle incorporation into P84 co-polyimide membrane for improved gas separation performance. The carbon filler was prepared using a hard template method from zeolite and known as zeolite-templated carbon (ZTC). This research aims to study the loading amount of ZTC into P84 co-polyimide toward the gas separation performance. The ZTC was prepared using simple impregnation method of sucrose into hard template of zeolite Y. The SEM result showing a dispersed ZTC particle on the membrane surface and cross-section. The pore size distribution (PSD) of ZTC revealed that the particle consists of two characteristics of micro and mesoporous region. It was noted that with only 0.5 wt% of ZTC addition, the permeability was boosted up from 4.68 to 7.06 and from 8.95 to 13.15 barrer, for CO
2
and H
2
respectively when compared with the neat membrane. On the other hand, the optimum loading was at 1 wt%, where the membrane received thermal stability boost of 10% along with the 62.4 and 35% of selectivity boost of CO
2
/CH
4
and H
2
/CH
4
, respectively. It was noted that the position of the filler on the membrane surface was significantly affecting the gas transport mechanism of the membrane. Overall, the results demonstrated that the addition of ZTC with proper filler position is a potential candidate to be applicable in the gas separation involving CO
2
and H
2
.
“…Although, a specific trend is not observed, the addition of amino-modified COK-12 silica imparts a positive effect on the CO characteristics that can influence the gas transport behavior. 56,57 In general terms, the addition of fillers has a positive effect both in gas permeability and selectivity in glassy polymers when a good compatibility and interfacial adhesion are achieved. But, this can change depending on other interfacial morphologies that may occur, such as polymer rigidification, agglomeration, or some kind of interfacial voids around particles, whose effect would depend on voids distribution and their possible interconnectivity.…”
Section: Characterization Of the Prepared Pbibased Mmmsmentioning
This work reports the preparation and characterization of mixed matrix membranes (MMMs) based on mesoporous ordered COK‐12 silica modified with 3‐aminopropyltrimethoxysilane as filler, and a series of polybenzimidazoles with different main‐chain structure as polymer matrix. Polybenzimidazoles (PBIs) were prepared from 3,3′‐diaminobenzidine and several dicarboxylic acids with different chemical structure. The physicochemical studies, as well as thermal, structural, and morphological properties of MMMs were determined by Fourier transform infrared spectroscopy, thermogravimetric analysis, X‐ray diffraction (XRD), and scanning electron microscopy. In addition, gas permeability properties of MMMs were tested by using a gas mixture of CO2/CH4 at different upstream pressures. Results indicated that thermal stability of PBI above 400°C is kept even after the addition of the modified COK‐12 silica. The d‐spacing of the PBI membranes determined by XRD was slightly increased with the addition of the modified COK‐12 silica particles. The permeability tests carried out at operating pressures of 50 and 150 psi showed that the addition of amino‐modified COK‐12 silica particles improved significantly the CO2 permeability of MMMs with respect to the pristine PBI. At the same time, the selectivity values were also enhanced, which in some cases were found to be more than double compared to the respective pristine membrane. The contribution of the modified COK‐12 silica on the gas transport properties was more promising in MMMs comprising PBIs with less rigid backbone chemical structure.
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