JOURNAL OF MOLECULAR MODELING
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2021
·Vol. 27
·期 6
·1-8
·
IF 1.81
Xu Shuhong,Tan Linfeng,Liu Fan,Cui Yiping,Wang Chunlei,Zhang Rong
Optical properties of N- and F-doping triangular-shaped carbon molecules have been investigated in theory and experiment. The theoretical results showed that carbon molecules with impurity F and Cl have the same characters with pure carbon. Doping N into pure carbon molecule would change the optical rotation at 589 nm. For doping N replacing hydrogen atom structures (N-doping 1 and N-doping 2 molecules), the absorption spectra of them are similar to pure carbon molecule. However, for molecules with impurity N atom in benzene ring (N-doping 3 and N-doping 4 molecules), the peaks of wavelength of absorption spectra shift to long wavelength compared to that of pure carbon molecule. Moreover, the delocalization of molecular orbital (MO) is different from pure carbon molecule, which is caused by the impurity N changing the electrons distribution of benzene ring. We have calculated 3 without H and 4 without H molecules which are removing hydrogen atom in nitrogen atom from N-doping 3 and 4. 3 without H and 4 without H molecules have similar optical properties with pure carbon molecule. The results testified that the impurity N and F would not change the optical properties of carbon molecule if impurity did not change the delocalization of all benzene rings. Graphical abstract
Optical properties of nitrogen- and fluorine-doping carbon molecules investigating in theory and experiment.
研究领域:
材料科学
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化学
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产品关联
DOI
PubMed
高影响因子
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
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化学工程
✓ 已验证
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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
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化学工程
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DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 60
·55272-55281
·
IF 3.289
Chengyun Gao,Minhua Zhang,Fusheng Pan,Lingtao Wang,Jiayou Liao,Teng Nie,Jing Zhao,Keteng Cao,Lei Zhan,Zhongyi Jiang
In this study, hybrid membranes incorporated with sulfonated carbon molecular sieves were fabricated and utilized for pervaporation dehydration of an acetone/water mixture. First, carbon molecular sieves (CMS) were synthesized via a hard template method, and sulfonated by concentrated H2SO4 to prepare sulfonated carbon molecular sieves (SCMS). The pore structure, surface properties and morphological features of CMS and SCMS were examined by XRD, FT-IR, TEM, EDX, nitrogen adsorption–desorption and HRTEM. The results showed that the obtained CMS had an ordered mesoporous structure with cylindrical channels and large surface area. After sulfonation, the surface properties of CMS changed from hydrophobic to hydrophilic. Then, SCMS with different contents were incorporated into a chitosan (CS) matrix to fabricate CS-SCMS hybrid membranes. The incorporation of SCMS can simultaneously create more water transportation pathways due to the ordered mesoporous structure and increase the number of hydrophilic sites due to the sulfonic acid groups within the membranes. When the content of SCMS was 2 wt%, an optimum separation performance with a separation factor of 832 and a permeation flux of 1.81 kg m−2 h−1 was acquired, which was increased by 2 times for the separation factor and 1.67 times for the permeation flux compared with those of the pure CS membrane. Meanwhile, the hybrid membrane showed good long-term stability.
研究领域:
材料科学
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化学工程
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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
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DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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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
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化学工程
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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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
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化学工程
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2025
·
IF 9
Xianjie Wang,Jingdong Gou,Louwei Cui,Jinhui He,Xue Ma,Yaning Zhao,Liuyi Pan,Huiyong Chen,Zhe Jin,Hongyan Wang,Yonghong Zhu,Dong Li
The separation of ethylcyclohexane (ECH) from coal-based C8 naphthenic oil mixtures poses significant industrial challenges due to their similar physicochemical properties. Herein, we investigate the separation performance of carbon molecular sieves with varying pore sizes and oxygen content through dynamic breakthrough experiments and pulse testing with real industrial feedstocks. The results demonstrate that CMS-100 exhibits superior separation efficiency for ECH with an adsorption selectivity of 1.9 (ECH/ trans -1, 2-dimethylcyclohexane) as well as ECH uptake of 49 mg/g, achieving a separation factor of 0.48, attributed to its optimal microporous structure (0.64–0.86 nm). In contrast, CMS-75, characterized by a larger mesopore volume (2–20 nm), facilitates faster desorption rates, aiding in molecular transport. Grand canonical Monte Carlo (GCMC) simulations confirm that variations in substituent arrangement influence the diffusion rates of C8 cycloalkanes within the pore channels, while oxygen-containing functional groups enhance the interaction energies between C8 cycloalkanes and the adsorbent, particularly for ECH, whose larger ethyl group and electronic effects result in stronger adsorption affinity compared to DCH isomers. However, the presence of oxygen functionalities negatively impacts overall adsorption capacity by introducing steric hindrance. These findings underscore the importance of precisely optimizing both pore size distribution and surface chemistry for efficient hydrocarbon separation. This work provides a solid foundation for developing next-generation adsorbents aimed at industrial-scale separation of naphthenic oils.
研究领域:
化学工程
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材料科学
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产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
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2024
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IF 8.3
Yiran Liang,Haoyuan Luo,Daohao Zhou,Xin Zhou,Qibin Xia,Zhong Li
The development of granular carbon materials with outstanding selectivity for the separation of alkenes and alkanes is highly desirable in the petrochemical industry but remains a significant challenge due to closely similar molecular sizes and physical properties of adsorbates. Herein, we report a facile approach of using natural biomass to prepare novel granular carbon molecule sieves with a molecular recognition accuracy of 0.44 Å and propose a new three-region model for the pore size distribution of amorphous porous carbons. Coffee bean-based granule carbon molecular sieves (CFGCs) were prepared with precise micropore regulation with subangstrom accuracy and characterized using molecular probes to reveal the evolution of carbon structure during preparation. The CFGC-0.09–750 demonstrates exceptional selectivity adsorption toward C3H6 while excluding C3H8, with an uptake ratio of 106.75 and a C3H6 uptake of 1.88 mmol/g at 298 K and 100 kPa, showcasing its immense potential in industrial applications for separating C3H6 and C3H8. The novel three-region model established in this work can clearly and reasonably elucidate why the samples CFGCs can screen propylene from propane at the subangstrom level. This study provides important guidance for the development of new carbon molecular sieves with subangstrom accuracy in molecular recognition and separation capacity.
研究领域:
材料科学
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化学工程
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吸附分离技术
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DOI
PubMed
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
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
HIGH PERFORMANCE POLYMERS
·
2022
·
IF 1.73
Rui Yang,Ming Yang Chen,Pei Li
Carbon molecular sieve (CMS) membranes have excellent gas separation property over conventional polymeric membranes and superior anti-swelling property. PMDA-ODA polyimide has high thermal stability and good mechanical property. It has been extensively adopted as the precursor of CMS membrane. However, due to the insoluble nature, PMDA-ODA CMS membranes are limited to configurations like dense symmetric films or composite membranes using porous inorganic or metal substrates. In this work, CMS hollow fiber composite membranes based on an asymmetric PMDA-ODA hollow fiber were successfully prepared for the first time. The neat PMDA-ODA hollow fiber membrane was crosslinked by polyethyleneimine to alleviate pore collapsing during carbonization and then dip-coated by a PMDA-ODA PAA solution to seal the surface defects. The PDMA-ODA CMS composite hollow fiber membranes showed gas permeances of 93.4 GPU, 19.6 GPU, 6.5 GPU, and 4.7 GPU for CO2, O2, N2, and CH4, respectively, with an ideal selectivity of 14.4, 3.0, and 19.8 for CO2/N2, O2/N2, and CO2/CH4 gas pairs, respectively. The attractive gas separation property shows a great potential for industrial application.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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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
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环境工程
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DOI
高影响因子
危险品化学品经营许可证（带存储）