SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Yang Jiao,Qi Wu,Wei Xu,Wei Lai,Luqi Xiao,Xue Mei,Hongjun Zhang,Shuangjiang Luo
Tailoring the microporous architecture of the precursors facilitates the gas separation performance in carbon molecular sieve (CMS) membranes. Herein, we report a facile strategy to tune the gas separation performance of CMS membranes through coordination between rare earth and imidazoles in the hierarchical triptycene-based polybenzimidazole (TPBI) precursor. By optimizing the pyrolysis condition and rare earth doping level, the resulting CMS membranes exhibited unprecedented H 2 and He permeabilities and high gas selectivities, and the TPBI-Yb 0.67 @700 CMS membrane exhibited a 3-fold increase in H 2 permeability and a 2-fold increase in H 2 /CO 2 selectivity compared to the TPBI-CMS@700 CMS membrane. It was demonstrated by the solution/diffusion coefficients and microporosity analysis that the enhancement of gas separation performance originated from the more pronounced hierarchically slit-like micropore structure, as well as the boosted diffusion and sorption selectivities. The TPBI-Yb 0.67 @700 membrane displayed a H 2 permeability of 8648 Barrer and a mixed-gas H 2 /CO 2 selectivity of 14.5 at 150 °C, far exceeding the experimental CMS upper bound.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Bingyu Zhao,Haojie Li,Zian Chen,Jiawei Lin,Yaodong Liu
The potential of carbon molecular sieve membranes (CMSM) for gas separation is widely recognized, and the key precursor for these membranes is polyimide (PI). This study focuses on enhancing the gas separation properties of CMSMs by introducing a unique structural element, Tröger’s bases, into polyimides, resulting in the creation of five distinct polyimides containing Tröger’s bases (PI-TBs). The incorporation of Tröger’s bases has a profound impact on the arrangement of polymer chains within the PIs, leading to a substantial improvement in gas permeability without compromising selectivity. Following carbonization at 600 °C, the resultant CMSMs exhibit significantly enhanced gas permeability while preserving, and in some cases, improving gas selectivity. Among the various types of diamines considered, the 6FDA variant of PI-TB stands out, boasting outstanding gas permeability with a H 2 permeability of 4991.0 Barrer and a H 2 /CH 4 selectivity of 30.7; this level of performance surpasses the 2015 Robeson’s upper bound. Furthermore, thermal analysis coupled with mass spectrometry (TG-MS) reveals that the pyrolysis of Tröger’s bases commences prior to that of polyimide . This sequential degradation process facilitates the formation of pyridine N and promotes the π-stacking of PI chains; both of which are instrumental in maintaining excellent gas selectivity. These findings provide valuable insights into the roles of Tröger’s bases in enhancing the gas separation performance of PIs and CMSMs, offering a promising avenue for further advancements.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Membranes
·
2021
·Vol. 11
·期 8
·618
·
IF 4.106
Haojie Li,Shan Xu,Bingyu Zhao,Yuxiu Yu,Yaodong Liu
Blending and heat-treatment play significant roles in adjusting gas separation performances of membranes, especially for incorporating thermally labile polymers into carbon molecular sieve membranes (CMSMs). In this work, cellulose acetate (CA) is introduced into polyimide (PI) as a sacrificial phase to adjust the structure and gas separation performance from polymer to carbon. A novel result is observed that the gas permeability is reduced, even when the immiscible CA phase decomposes and forms pores after heat treatment at 350 °C. After carbonization at 600 °C, the miscible CA has changed without contribution, while the role of the immiscible CA phase has changed from original hindrance to facilitation, the composite-based CMSM at a CA content of 10 wt.% shows highest performances, a H2permeability of ~5300 Barrer (56% enhancement) with a similar H2/N2permselectivity of 42. The structural analyses reveal that the chain interactions and phase separation behaviors between CA and PI play critical roles on membrane structures and gas diffusion, and the corresponding phase structural evolutions during heat treatment and carbonization determine gas separation properties.Keywords:cellulose acetate;polyimide;chase separation behavior;carbon molecular sieve membranes
研究领域:
材料科学
·
膜分离技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2023
·
IF 9.5
Junhao Xin,Xiaowei Zhou,Guolong Huo,Zhiguang Zhang,Yuchen Zhang,Shuanyan Kang,Zhongde Dai,Nanwen Li
In the current study, three 6FDA 1 /BPDA 1 -based polyimides (PIs) containing different diamine moieties (DMB, TCDB, TFDB) were selected to prepare CMS membranes (CMSMs), providing a systematic study of PIs with different side group functionalization. The resultant CMSMs were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, and CO 2 absorption measurements. Pure gas (N 2 , O 2 , CH 4 , CO 2 ) and mixed gas (CO 2 /CH 4 ) permeability tests were also conducted. The resultant CMSMs exhibited attractive gas separation performance. Compared to DMB-based PI, TFDB-based with trifluoromethyl (-CF 3 ) side groups exhibited ultra-high permeability (P CO2 = 14938 Barrer, P O2 = 3146 Barrer) and moderate selectivity (α CO2/CH4 = 20.3, α O2/N2 = 4.5), while CMSMs prepared from PI with chlorine functionalization showed higher gas permeability (P CO2 = 6031 Barrer, P O2 = 1311 Barrer) and selectivity (α CO2/CH4 = 46.2, α O2/N2 = 6.5). The results indicated that side group functionalization on PIs exerts a considerable influence on the gas permeation properties of CMSMs.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Haojie Li,Zi-An Chen,Bingyu Zhao,Junhao Xin,Longlong Wang,Ke Xiao,Huazhang Zhao,Yaodong Liu
Carbon molecular sieve (CMS) membranes present significant advantages and considerable potential for the precise separation of hydrogen gas, promoting the utilization of clean hydrogen energy. Recently, molecular or atomic-level doping exhibits a strong capacity to adjust the structure and performance of CMS membranes. However, there is limited understanding of how fine-tuning through molecular doping can adjust the physical properties of the microscopic carbon structures within CMS membranes. In this study, small molecule siloxanes are incorporated into precursor to facilitate the in-situ formation of silicon-doped CMS membranes at the molecular level. Interestingly, by modulating the side groups of the siloxanes, we can selectively adjust the morphology and size of the micro-carbon sheets within CMS membranes, thereby enabling precise tuning of the pore structure, separation performance and anti-aging ability. The resulting CMS membranes exhibit exceptional H 2 /CH 4 separation capabilities, significantly surpassing 2015 upper bounds. Besides, silicon-based functional groups and enlarged carbon structure effectively inhibit the physical aging of CMS membranes. This insight offers a more nuanced and controlled approach to precisely tailor microstructure of CMS membranes for efficient H 2 separation.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ChemSusChem
·
2018
·Vol. 11
·期 5
·916-923
·
IF 7.411
Zhenggong Wang,Huiting Ren,Shenxiang Zhang,Feng Zhang,Jian Jin
Graphical Just touching base : New carbon molecular sieve (CMS) membranes are fabricated with the use of a Tröger's base (TB)-based microporous polyimide as the polymer precursor, and their gas-separation performance is investigated. The comprehensive gas-separation performance of the TB–CMS membranes is improved relative to that of most state-of-the-art CMS membranes derived from common polyimides reported so far. Carbon molecular sieve (CMS)-based membranes have attracted great attention because of their outstanding gas-separation performance. The polymer precursor is a key point for the preparation of high-performance CMS membranes. In this work, a microporous polyimide precursor containing a Tröger's base unit was used for the first time to prepare CMS membranes. By optimizing the pyrolysis procedure and the soaking temperature, three TB–CMS membranes were obtained. Gas-permeation tests revealed that the comprehensive gas-separation performance of the TB–CMS membranes was greatly enhanced relative to that of most state-of-the-art CMS membranes derived from polyimides reported so far.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2025
·
IF 3.9
Zhi Li,Xingyu Chen,Guanran Zhao,Yaohao Guo,Wei Zhao,Linfeng Lei,Zhi Xu
Membrane-based CO2 separation technology is highly desired for natural gas sweetening, and the development of advanced membrane materials with low cost and high CO2/CH4 separation factors under high pressures is the key to the membrane market. Herein, cellulose-derived carbon molecular sieve (CMS) hollow fiber membranes within macropores were constructed by incorporating a thermal labile polymer of poly(vinyl butyral) (PVB). During a controlled carbonization protocol, the spun cellulose membranes formed the CMS membrane matrix, while the PVB formed homogenized macropores. As a result, the generated macropores in the CMS hollow fiber membranes (CHFMs) effectively reduced the gas transport resistance, confirmed by an increased CO2 permeance by ∼2.9-fold from 8.48 to 24.72 GPU (CHFM-1) compared to CHFM-0. Moreover, the membranes were evaluated using a simulated high-pressure natural gas stream (3.44 mol % CO2–87.0 mol % CH4–9.56 mol % N2) and showed good separation performance with a CO2 permeance of 11.66 GPU and a CO2/CH4 separation factor of 38.3 at 30 bar feeding. A long-term durability test over 100 h at 20 bar with a slight decrease in permeance further verified its potential for CO2 removal from high-pressure natural gas.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2022
·
IF 10.53
Li Yin,Dongfeng Li,Hongxia Guo,Shuai Wang,Tiexin Zhang,Yunling Liu,Fangyuan Gai,Xiaogang Zhao
Incorporating functional materials into polymer precursors is an effective way to prepare carbon molecular sieve (CMS) membranes for solving the trade-off problem between permeability and selectivity of gas separation. In this work, we induced ZIF-8 nanoparticles (from 5 to 20 wt%) as a doping agent to construct a series of phenolphthalein-based cardo poly (arylene ether ketone) (PEK-C) -based hybrid carbon molecular sieve (ZCMS) membranes for CO 2 /N 2 separation via an oxidation and a carbonization process with pyrolysis temperature in the range of 500–700 °C. The carbonized ligand and metal centre of ZIF-8 offered additional pores of carbon matrix, which tailored the ultramicropores of ZCMS membranes for both excellent CO 2 permeability and selectivity. By treating with the temperature of 600 °C, ZCMS-600-15 (ZCMS membrane based on 15 wt% of ZIF-8-doped PEK-C) exhibited the highest CO 2 permeability of 8902 Barrer, which was 1.8 times higher than that of CMS-600 (CMS membrane based on naked PEK-C). ZCMS-600-15 showed an ideal CO 2 /N 2 selectivity value of 42.2, which is also higher than that of other samples, indicating that the appropriate doping amount of ZIF-8 is 15 wt% and the proper carbonization temperature is 600 °C. Moreover, among all the samples, ZCMS-600-15 also showed a superior CO 2 permeability of 8285 Barrer and the highest CO 2 /N 2 selectivity of 24.08 for an equimolar mixture of CO 2 and N 2 , far exceeding the 2008 Robeson upper bound. Therefore, our results suggest that incorporating MOFs into polymer precursors to prepare hybrid carbon molecular sieve membranes by carbonization process could solving the trade-off problem between permeability and selectivity, introducing new possibilities for industrial application.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2024
·
IF 8.4
Lingyu Liu,Qixuan Li,Luxin Sun,Aqib Riaz,Jianxin Li,Yingge Wang,Ingo Pinnau,Xiaohua Ma
One major challenge of helium recovery from natural gas by membranes is the development of materials offers both high He permeability and He/CH 4 selectivity. Here, ultrahigh performance He separation membranes were achieved by directly fluorination of a carbon molecular sieve (CMS) membrane that derived from pyrolyzing a polyimide at 550 °C. The FCMS550-60, fluorinated for 60 s, showed an unprecedented combination of high He permeability of 3432 Barrer and ultrahigh He/CH 4 selectivity of 5329 that is located far beyond any He/CH 4 trade-off lines. Additionally, it also exhibited outstanding mixed-gas separation properties with a He permeability of 1765 Barrer and He/CH 4 selectivity of 4114 at 20 bar. The largely enhanced He/CH 4 selectivity resulted exclusively from a boost in diffusion selectivity, which is originated from the formation of C–F bonds inside the micropores of the CMS membrane that remarkably enhanced the sieving ability of the FCMS membrane. This work provides a broad prospect for the application of FCMS membranes for He recovery from natural gas and other resources.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CARBON
·
2022
·
IF 11.307
Haojie Li,Qiang Zhang,Zhixuan Xie,Bingyu Zhao,Yuxiu Yu,Yaodong Liu
Simultaneously enhancing the gas permeability , selectivity and aging stability of carbon molecular sieve membrane (CMSM) is extremely difficult. Facing such poser, a novel silicon doped CMSM at molecular level was prepared by copolymerizing siloxane with single Si– O –Si unit into the backbone of polyimide (PI). This can effectively avoid prior separated structure or multiple Si– O –Si structures and strongly alter the chains packing and thermostability of PI, finally determine the pore structure and thermodynamic behavior . The simple design adjustment simultaneously exhibits the triple enhanced effects on the gas permeability, selectivity and aging stability. The best molecule doped CMSM exhibits the ultra-high H 2 permeability (12482 Barrer, 87% higher), 26% higher H 2 /CH 4 selectivity, and 32% higher H 2 /N 2 selectivity than pure PI based CMSM. Additionally, such CMSM also has a much better aging stability than pure CMSM and most reported CMSMs . After stabilization, it still maintains a high H 2 permeability (8000 Barrer). And the hyper-aging CMSM also exhibits a good aging resistance showing a H 2 permeability of 5300 Barrer, as well as high selectivity of H 2 /CH 4 (125) and H 2 /N 2 (106) after 35 days. This work opens a new way on designing CMSM with excellent performance through heteroatom doping to need future application.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Guozhen Liu,Renhao Li,Xi Chen,Long Cheng,Yu Liu,Gongping Liu,Wanqin Jin
Carbon molecular sieve (CMS) membranes with exceptional separation performance and scalable processing are promising for precise gas separation. However, their broad applicability is hampered owing to stability issues, mainly resulting from physical aging. Herein, we manipulate the pyrolysis temperature (550 °C, 650 °C and 750 °C) to regulate the gas transport properties and control the physical aging of CMS membranes derived from 6FDA-DAM polyimide. The morphology, chemical composition and pore size of the membranes were characterized using SEM, IR, XPS and XRD. Results demonstrated that the pore structure of CMS membranes shows densification with increasing the pyrolysis temperature, affording enhanced separation efficiency for gas pairs: H 2 /N 2 , H 2 /CH 4 , and CO 2 /CH 4 pairs based on the size-sieving effect. Moreover, the effect of aging is more considerable for membranes pyrolyzed at a higher temperature. In addition, the membrane subjected to pre-aging treatment via vacuum storage exhibit better, stable gas separation performance beyond the upper-bond for polymeric membranes. The separation mechanism of the CMS membranes reveals that gas permeation behavior is dominated by diffusion. Tailoring gas permeation and physical aging can provide an alternative approach to tune the gas transport properties of CMS membranes.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2024
·
IF 8.4
Lu Bai,Yongchao Sun,Tianyou Li,Jianyu Guan,Yijun Liu,Gaohong He,Canghai Ma
Carbon molecular sieve (CMS) membranes have garnered substantial attention for their ability to separate similarly sized gas mixtures. Despite their high gas permeability, CMS membranes exhibit moderate selectivity for the C 2 H 4 /C 2 H 6 gas pair. To address these issues, this study explores two types of polyimide precursors made from 2-(4-aminophenyl)benzo[d]oxazol-5-amine (APBO) and p-diaminobiphenyl (DABP) with 6FDA monomer to prepare CMS membranes. The integration of the flat, rigid polybenzoxazole (PBO) structure with the bulky, twisted 6FDA structure facilitates the formation of ultramicropores and micropores in the CMS membrane. The 6FDA-APBO-based CMS membrane, pyrolyzed at 700 °C, exhibits superior C2H4 permeability and C 2 H 4 /C 2 H 6 selectivity compared to the 6FDA-DABP-derived CMS membrane. Moreover, 6FDA-APBO-based CMS achieves an exceptional C 2 H 4 permeability of 160.8 Barrer with a C 2 H 4 /C 2 H 6 selectivity as high as 13.7, significantly surpassing the C 2 H 4 /C 2 H 6 upper bounds for both the polymeric and CMS membranes. The design principle provides an effective approach to enhance the C 2 H 4 /C 2 H 6 separation performance of membranes, paving the way for the development of energy-efficient C 2 H 4 /C 2 H 6 separation processes.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）