CO2/CH4 and H2/CH4 Gas Separation Performance of CTA-TNT@CNT Hybrid Mixed Matrix Membranes

Abstract

This study explored the underlying synergy between titanium dioxide nanotube (TNT) and carbon nanotube (CNT) hybrid fillers in cellulose triacetate (CTA)-based mixed matrix membranes (MMMs) for natural gas purification. The CNT@TNT hybrid nanofillers were blended with CTA polymer and cast as a thin film by a facile casting technique, after which they were used for single gas separation. The hybrid filler-based membrane depicted a higher CO2 uptake affinity than the single filler (CNT/TNT)-based membrane. The gas separation results indicate that the hybrid fillers (TNT@CNT) are strongly selective for CO2 over CH4 and H2 over CH4. The increment in the CO2/CH4 and H2/CH4 selectivities compared to the pristine CTA membrane was 42.98 from 25.08 and 48.43 from 36.58, respectively. Similarly, the CO2 and H2 permeability of the CTA-TNT@CNT membrane increased by six- and five-fold, respectively, compared to the pristine CTA membrane. Such significant improvements in CO2/CH4 and H2/CH4 separation performance and thermal and mechanical properties suggest a feasible and practical approach for potential biogas upgrading and natural gas purification.

Inner‐coated highly selective thin film nanocomposite hollow fiber membranes for the mixture gas separation

“…Figure 9 points out that CO 2 gas shows higher permeance compared to the CH 4 gas, because of the TFN hollow fiber membrane's high uptake affinity towards CO 2 than CH 4 . With the addition of nanofillers, because of their high surface area, tunable pore structure, as well as the presence of amine groups in the TFN membrane the solubility of CO 2 gas, becomes higher on the hollow fiber membrane surface shows high permeance 61 . At 1 bar pressure, the APTMSH@TFN‐3 membrane shows 22.3 GPU CO 2 permeance which is higher because the mobility of the polymer chain in a cross‐linked polymer structure increased at lower pressure resulting in the increased gas permeance at low pressure.…”

“…With the addition of nanofillers, because of their high surface area, tunable pore structure, as well as the presence of amine groups in the TFN membrane the solubility of CO 2 gas, becomes higher on the hollow fiber membrane surface shows high permeance. 61 At 1 bar pressure, the APTMSH@TFN-3 membrane shows 22.3 GPU CO 2 permeance which is higher because the mobility of the polymer chain in a cross-linked polymer structure increased at lower pressure resulting in the increased gas permeance at low pressure. It is found that in mixture gas separation the gas permeance is always lower compared to pure gas because of the competitive sorption between the gases.…”

Influence of alternating magnetic field's frequency and exposure time on distribution of α‐Fe2O3/TiO2 fillers for gas separation membranes: Quantitative approach

“…Consequently, the permeability of gases decreases in general. Conversely, the nature of TiO 2 fillers in our study has a high affinity toward CO 2 gas as they exhibit great adsorption capacity toward it 42 . The reduction in cluster size would also mean an increase in the effective surface area of particles, thereby suggesting the increase in permeability of CO 2 gases relative to CH 4 , as demonstrated in MF2.…”

“…Conversely, the nature of TiO 2 fillers in our study has a high affinity toward CO 2 gas as they exhibit great adsorption capacity toward it. 42 The reduction in cluster size would also mean an increase in the effective surface area of particles, thereby suggesting the increase in permeability of CO 2 gases relative to CH 4 , as demonstrated in MF2. On the other hand, the decrease in cluster amount and increase in average cluster size led to lower permeability values as observed in MT2 and MF3, possibly due to lesser effective filler surface area to interact with CO 2 gases.…”

Performance of amine‐functionalized MIL‐53 incorporated thin‐film nanocomposite Pebax membranes for CO2/CH4 mixed gas separation

“…11,12 Metal-organic frameworks (MOFs), known as porous particles with the potential to surpass the upper bound of Robeson, have been broadly utilized in mixed matrix membranes (MMMs) for gas separation [13][14][15] by developing new organic compounds such as molecular sieve materials, 16,17 silica, 18,19 covalent organic frameworks, [20][21][22] zeolites, [23][24][25] and carbon nanotubes. 26,27 Pebax 2533 consists of polyethylene oxide (PEO) soft and polyamide (PA) hard segments. It is also a type of water-swellable polymers (WSPs).…”