Wijiyanti, Rika (2019) Mixed Matrix Hollow Fiber Membrane Polysulfone-zeolite Templated Carbon : Fabrication, Characterization And Gas Separation Study. Doctoral thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
This study introduces a structurally engineered carbon, named as zeolite templated carbon (ZTC), as a new filler membrane for superior gas separation performance. It is produced by carbon filling inside zeolite-Y template to combine the advantage of each materials and eliminate both weakness. The open and no rigid pore structure of ZTC would facilitate its compatibility with polymer matrix. In addition, the ZTC could reach a higher specific surface area with almost micropore content compared to zeolite and carbon alone. It was noticed that large surface area could improve the gas permeance, while the ordered pore structure increased the membrane selectivity. As a result, this filler could improve the overall separation performance of the mixed matrix membrane (MMM). This thesis aims to investigate the feasibility of separating gas using ZTC filler in order to find high performance material.
Zeolite-Y as a ZTC template, was prepared by hydrothermal method. In this study, two different ZTCs with distinct pore properties were used. The ZTC was synthesized by impregnation method with sucrose as carbon precursor, named as ZTC-1. Meanwhile, the ZTC prepared by combination of impregnation and chemical vapor deposition (CVD) is referred as ZTC-2. Polysulfone polymer was used as a matrix membrane. The MMM was fabricated into hollow fiber module via dry-wet spinning method. The obtained fiber was sealed with PDMS by dip-coating method. For other treatment, the fiber was subjected to the heating treatment above PSF’s Tg. The membrane performance was tested using single gas (CO2, O2, H2, N2 and CH4) and mixed-gas (CO2/CH4 and H2/CH4).
The result demonstrated that structural ordering of ZTC from two step routes is higher than the ZTC from the single carbon deposition. Also, in this case, the surface area of ZTC-2 is larger with higher micropore content. Having a very high surface area with almost no mesopores is more favourable in gas separation membrane, because mesopores results in a lower selectivity. Furthermore, the selectivity enhancement of MMM with acceptable permeance was obtained at lower ZTC-1 loading, while the increased in ZTC-1 loading lead to the poorer selectivity with much higher permeance due to the presence of severe unselective barrier between the ZTC-1 and matrix. Compared to PSF membrane, PSF/ZTC-1 0.4 wt% recorded the highest selectivity improvement for CO2/CH4 (290%), CO2/N2 (219%), O2/N2 (117%) and H2/CH4 (272%), but marginal decrement was observed on the permeances (PCO2, PO2 and PH2). When binary gas (CO2/CH4 and H2/CH4) was separated by the membranes, significant differences were observed in the separation performance due to competitive sorption and the effect of non-ideal gas behavior in the mixed-gas system. By performing PDMS coating, the MMM selectivity of CO2/CH4, O2/N2, CO2/N2 and H2/CH4 was improved up to 46.42 (780%), 6.06 (215%), 35.14 (481%) and 92.57 (491%), respectively, compared to that of uncoated MMM, while the decrease in permeance was minimal when 0.25 wt% ZTC-1 was loaded. When the fibers were heated, the selectivity of CO2/CH4, O2/N2 and CO2/N2 at 0.25 wt% loading was found to be enhanced up to 652%, 246% and 458%, respectively, with very low permeances which lead to undesirable resistance to gas transport. Furthermore, a remarkable enhancement in permeance (about 112%) and selectivity were observed for coated MMM filled with ZTC-2. Compared to ZTC-1 filled MMM, PSF/ZTC-2 recorded higher CO2/CH4, O2/N2, CO2/N2 and H2/CH4 selectivity of 59.75, 7.32, 38.25 and 159.42, respectively, with CO2, O2 and H2 permeances of 81.86, 15.66 and 218.40 GPU, respectively. When the zeolite carbon composite (ZCC) or ZTC material prior template removal was loaded within PSF, the separation performance was lower compared to neat PSF. It can be concluded that permeance and selectivity enhancement could be achieved even at low loading (0.25 wt%) and the ZTC filler could be a promising candidate for a new mixed matrix membrane for CO2, O2 and H2 separation.
| Item Type: | Thesis (Doctoral) |
|---|---|
| Uncontrolled Keywords: | Mixed-matrix membranes Zeolite-templated carbon Polysulfone Hollow fiber Gas separation |
| Subjects: | Q Science > QD Chemistry > QD117 Absorption |
| Divisions: | Faculty of Natural Science > Chemistry > 47001-(S3) PhD Thesis |
| Depositing User: | Rika Wijiyanti |
| Date Deposited: | 30 Jul 2024 02:37 |
| Last Modified: | 30 Jul 2024 02:37 |
| URI: | http://repository.its.ac.id/id/eprint/70685 |
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