查找使用阿拉丁产品的科研文献

Generation of nitrogen-containing compounds by cellulose nitrogen-rich pyrolysis under CO2/N2 atmosphere: Influence mechanism of different catalysts

Shanjian Liu,Wenjing Zhao,Weming Yi,Zhisen He,Jiawen Zhang,Haining Wang

This study investigates nitrogen-rich catalytic pyrolysis of cellulose in an N 2 /CO 2 atmosphere, focusing on the synergistic effects of catalysts and CO 2 on bio-oil composition. The results show that catalyst acidity governs product selectivity, markedly enhancing high-value nitrogen-containing compounds while suppressing carbonyl species. Among the catalysts tested, Al-MCM-41 exhibited the strongest promotion of nitrogen-containing compounds, increasing their relative content from 22.24% (without catalyst) to 88.83%. HZSM-5, Mo 2 C, and γ-Al 2 O 3 favored the formation of furans, esters, and sugars, whereas CO 2 facilitated biomass decomposition and altered product distribution. In addition, catalysts significantly regulated nitrogen heterocycles, increasing pyridine, pyrrole, and nitrile contents. Biochars obtained with HZSM-5 and Al-MCM-41 showed abundant oxygen-containing functional groups, indicating improved pore structure development. These findings demonstrate an effective catalytic strategy for the selective conversion of biomass into high-value nitrogen compounds.

A crystal seeds-assisted synthesis of microporous and mesoporous silicalite-1 and their CO2/N2/CH4/C2H6 adsorption properties

Chang Wang,Jiaqi Liu,Jiangfeng Yang,Jinping Li

Synthesis of ultra-high silica (SiO 2 /Al 2 O 3  > 1800) MFI type zeolite such as silicalite-1 is still considered to be luxury because of the long synthesis time (5–12 days). Here, this material with a highly uniform mesoporous (20 nm) structure was crystallized in a shorter time (20 h) using a crystal-seeds method when an appropriate amount of potassium fluoride was added. Characterization techniques including XRD , SEM, TEM and liquid nitrogen adsorption provided detailed information on the two kinds of porous structure silicalite-1. Due to the “smooth” adsorption surface of silicalite-1 containing few equilibrium ions, it is ideal for the separation of gas mixtures containing non-polar molecules with similar physical properties. Moreover, the CH 4 , N 2 , CO 2 and C 2 H 6 adsorption properties were also investigated. Microporous silicalite-1 has a high adsorption capacity for CH 4 , N 2 , CO 2 and C 2 H 6 and adsorption selectivity for CH 4 /N 2 , CO 2 /N 2 , CO 2 /CH 4 and C 2 H 6 /CH 4 . Although a lower adsorption capacity was observed for mesoporous silicalite-1, the pore size did not affect the outstanding adsorption selectivity, on the contrary, the selectivity of mesoporous silicalite-1 was improved.

Enhancement of CO2/N2 Switchability and stability in cellulose nanofibers pickering emulsions by CO2-responsive rosin-grafted hydroxyethyl cellulose

Xujuan Huang,Tong Liu,Yujian Zhang,Xuexuan Zhou,Qunqun Bian,Yongyang Cheng,Zhaosheng Cai

The MPAN-g-HEC product exhibits CO 2 responsiveness. • CO 2 gas protonates MPAN-g-HEC to MPAN + -g-HEC. • MPAN + -g-HEC can enhance the stability of CNF-based Pickering emulsion. • Alternating CO 2 and N 2 in the system switches the emulsification and separation. Cellulose has been widely used in conventional Pickering emulsions, yet its application in stimulus-responsive Pickering emulsions remains relatively limited. In this paper, cellulose-based CO 2 /N 2 stimuli-responsive polymer compounds (MPAN-g-HEC) were prepared through the hydrophobic modification of hydroxyethyl cellulose using the maleopimaric acid 2-dimethylaminopropylamine imide with a tertiary amine group (MPAN). The grafting rate of MPAN-g-HEC was controlled by adjusting the HEC-to-MPAN mass ratio. Specifically, five grafted products (MPAN-g-HEC I∼V) were prepared, and the grafting rate increased from 9.24% to 48.43%. The addition of CO 2 resulted in the protonation of MPAN-g-HEC, converting it to the MPAN + -g-HEC. The critical micelle concentration (CMC) values of MPAN + -g-HEC ranged from 0.28 to 0.88 g/L, with corresponding surface tensions of 40.8–43.3 mN/m. The product with the best performance (MPAN-g-HEC IV, abbreviated as MPAN-g-HEC) is used to enhance the stability of Pickering emulsions of cellulose nanofibers. These stimuli-responsive Pickering emulsions exhibit stability due to the electrostatic interactions between MPAN + -g-HEC and CNF, as well as the formation of interfacial films at the oil-water interface. In addition, the alternating passage of CO 2 and N 2 can achieve the interconversion between emulsification and demulsification, and the process is reversible. Rheological tests show that the G′ and G″ tend first to decrease and then increase, indicating that the Pickering emulsion first undergoes damage and then reforms a network structure. Download: Download high-res image (192KB) Download: Download full-size image

Microwave-DES activation of poplar-derived ultramicroporous carbon for efficient CO2/N2 separation with extremely high pore utilization rate

Sheng Hongliang,He Tao,Li Ye,Cao Chengyang,He Song

Poplar wood was employed as the precursor to develop a coupled “microwave self-gasification & aqueous post-modification” protocol that enables instantaneous activation within a microwave field, yielding activated carbon dominated by ultra-micropores (< 0.7 nm). Despite a modest BET surface area of ~ 900 m²/g, the material exhibits an exceptional CO₂ uptake of 180.4 mg/g at 0 °C and 1 bar—1.6-fold higher than at 25 °C—while N₂ uptake remains below 30 mg/g under the same conditions. On a pore-volume basis, the carbon stores 443.79 mg CO₂ per cm³ at 0 °C and 278.62 mg/cm³ at 25 °C. CO₂ adsorption proceeds via a multilayer mechanism with the isosteric heat (Qst) decreasing from 45 to 23 kJ mol⁻¹, whereas N₂ follows a monolayer pathway with Qst held between 20 and 24 kJ mol⁻¹. IAST calculations reveal that CO₂/N₂ selectivity rises from 70 to 90 with increasing pressure at 0 °C and levels off around 50 at 25 °C. Dynamic breakthrough experiments deliver a separation factor of 8.28 for a 15% CO₂/85% N₂ mixture. GCMC simulations further indicate that O–C = O-functionalized surfaces confer the highest CO₂ capacity, while C–S–C motifs are the least favorable in competitive adsorption.

ZIF-8 hollow nanotubes based mixed matrix membranes with high-speed gas transmission channel to promote CO2/N2 separation

Qiuchen Wang,Yan Dai,Xuehua Ruan,Wenji Zheng,Xiaoming Yan,Xiangcun Li,Gaohong He

Carbon nanotubes (CNTs) with 1D gas transport channel has great prospect in MMMs based CO 2 separation. However, the insufficient compatibility with polymer and inner diameter of CNTs limit further improvement of their CO 2 separation performances. In this work, the unique ZIF-8 hollow nanotubes (HNTs) were proposed to construct high-speed gas transmission channel in MMMs by a three-step method (electrospinning-calcination-hydrothermal), aiming at concurrently improving the gas permeability and selectivity. The hollow inner cavity provides long-range and low-resistance gas transmission channels to ensure high gas permeability. At the same time, the ZIF-8 crystals composing the tube wall can not only screen for gas molecules pair, but also strengthen the affinity between the filler and polymer matrix by its organic ligands, thus the gas selectivity can be raised. Compared with ZIF-8 nanoparticles and ZnO HNTs, ZIF-8 HNTs based MMMs present competitive CO 2 separation. When the loading of ZIF-8 HNTs is 5 wt%, the gas separation performance shows the best, in which the CO 2 permeability is 147 Barrer and the CO 2 /N 2 selectivity is 68, approaching to the 2008 Robeson upper limit and surpassing most reported CNTs/Pebax based membranes. Therefore, the proposed ZIF-8 HNTs are promising for MMMs based CO 2 separation.

Solvent influence on the textural properties and CO2/N2 separation performance of novel Pebax-1657/attapulgite mixed matrix membranes

Siraj Ahmad,Shaohan Lian,Yaxin Tan,Run Li,Quan Zhao,Chunfeng Song,Qingling Liu,Shijian Lu

Mixed matrix membranes (MMMs) have gained significant attention in CO 2 separation. However, the symmetrical dispersion of inorganic filler nanoparticles during MMMs fabrication is still a crucial challenge. The present work investigates the outcome of N-Methyl-2-pyrrolidone (NMP) and N-N-Dimethyl-formamide (DMF) solvents on MMMs texture, perm-selectivity and nanoparticles dispersion. Scanning electron microscopy (SEM), Fourier-transform-infrared (FTIR) and X-Ray Diffraction (XRD) analyses were also performed for membrane characterization. The MMMs fabricated with NMP solvent showed competitive CO 2 permeability (120.20 barrer) and CO 2 /N 2 selectivity (69.31) compared to the membranes prepared with DMF solvent. It has been indicated that the molar volume, boiling point and solubility parameters were significant factors in the solvent selection. Moreover, the effect of operating temperature on gas transport properties showed substantial impact in perm-selectivity, at 3 bar feed-pressure, with the temperature dropping from 40 °C to 0 °C, the CO 2 /N 2 gases selectivity increased from 69.31 to 105.50, equating to a 64.8% decrease in CO 2 permeability.

Ultrafast room temperature synthesis of GrO@HKUST-1 composites with high CO2 adsorption capacity and CO2/N2 adsorption selectivity

Feng Xu,Ying Yu,Jian Yan,Qibin Xia,Haihui Wang,Jing Li,Zhong Li

An ultrafast synthesis method is developed for the preparation of composites of graphite oxide and HKUST-1, GrO@HKUST-1. Fast synthesis of GrO@HKUST-1 composites can be quickly achieved at room temperature within 1   min. The synthesized composites were characterized by XRD, SEM, N 2 adsorption, FTIR and TGA. The isotherms of CO 2 and N 2 on the as-synthesized materials were measured and the isosteric heats of CO 2 adsorption were estimated. The CO 2 /N 2 adsorption selectivities were predicted by means of ideal adsorbed solution theory (IAST). Results show that the GrO@HKUST-1 composites have higher BET surface area and pore volume than the parent HKUST-1. The CO 2 adsorption capacity of 2GrO@HKUST-1 (2% of GrO) is up to 9.02   mmol/g at 1   bar and 273   K, giving an increase of 32% in comparison of the parent HKUST-1. The isosteric heat of CO 2 adsorption on 2GrO@HKUST-1 is slightly higher than that of HKUST-1, suggesting the stronger interaction between CO 2 molecules and 2GrO@HKUST-1. The CO 2 /N 2 adsorption selectivity of 2GrO@HKUST-1 is significantly enhanced over pristine HKUST-1. At 1   bar, the CO 2 /N 2 adsorption selectivity of 2GrO@HKUST-1 is up to 186, while that of parent HKUST-1 is only 103. This rapid room temperature synthesis route is promising for new MOF-based composites.

Mixed matrix membranes with intrinsic microporous/UiO-66 post-synthesis modifications with no defects for efficient CO2/N2 separation

Fei Wang,Zhe Wang,Junjian Yu,Shuai Han,Xiangwei Li,Yan Wang

Mixed matrix membranes (MMMs) based on metal–organic frameworks (MOFs) are expected to realize efficient separation of CO 2 . However, interfacial compatibility issues between MOFs and polymer matrices limit their performance. In this work, a post-synthesis modification (PSM) strategy was adopted to convert UiO-66 into porous liquids (PLs). MMMs were prepared by incorporating PLs into PIM-1 matrix. The PLs have a liquid-like behavior and can be evenly scattered in PIM-1 matrix to form an interface without defect. The SEM morphology analysis further certified that MMMs had no interface defect and PLs had brilliant compatibility with the polymer film . In addition, the CO 2 -philic ether bonds of the EO fragments enable the MMMs to have superior CO 2 selective separation. Compared with pure PIM-1, the highest CO 2 permeability was improved by 158.0 % and 62.5 % was the increase in CO 2 /N 2 selectivity, arriving at 7211.7 Barrer and 26.0, respectively. Meanwhile, the overall separation performance of MMMs for CO 2 /N 2 exceeds the 2008 Robson upper limit, showing outstanding gas separation performance.

Preparation of light weight paraffin microspheres based on CO2/N2 switchable emulsion for enhancing plugging performance of drilling fluid

Meng Cai,Chenyang Xu,Yu Tan,Weichao Du,Zhiyu Huang,Cunchuan Zheng

Ultrahigh CO2/CH4 and CO2/N2 adsorption selectivities on a cost-effectively L-aspartic acid based metal-organic framework

Daofei Lv,JiaYu Chen,Kexin Yang,Houxiao Wu,Yongwei Chen,Chongxiong Duan,Ying Wu,Jing Xiao,Hongxia Xi,Zhong Li,Qibin Xia

Using porous materials to selectively adsorb CO 2 from flue gas or natural gas is a promising method for mitigating CO 2 emission and purifying methane. Here, we synthesized an L-aspartic acid based microporous metal-organic framework (MIP-202) and studied its adsorptive separation performance for CO 2 /CH 4 and CO 2 /N 2 mixtures. Results show that MIP-202 had ultrahigh CO 2 /CH 4 (72.9 and 241.5 for CO 2 /CH 4  = 50/50 and 10/90, respectively) and CO 2 /N 2 (1,950,000 and 2129.1 for CO 2 /N 2  = 50/50 and 15/85, respectively) IAST selectivities at 298 K and 100 kPa. The high selectivity was verified by the calculations of Henery’s law selectivity and breakthrough experiments. Metropolis Monte Carlo simulation calculations show that CO 2 with greater polarizability and quadruple moment tends to occupy the pore walls of large cages with higher polarity, while the less polar CH 4 or N 2 majorly being adsorbed in the pore walls of small cages with lower polarity, resulting in the ultrahigh CO 2 /CH 4 and CO 2 /N 2 separation selectivities. MIP-202 exhibits low CO 2 adsorption enthalpy (17.2–30.7 kJ/mol), superior persistent reusability after five cyclic adsorption experiments, easy desorption performance at 298 K, moderate water and moisture stability, good stability under dry and humid SO 2 atmosphere, and low ligand cost ($36/kg). MIP-202 extrudates were prepared by an extrusion molding method using hydroxypropyl cellulose (HPC) as the binder and they retained 97.35% CO 2 uptake of MIP-202 powder at room temperature and pressure. This work shows that MIP-202 is an industrially promising material for the separation of CO 2 /CH 4 and CO 2 /N 2 mixtures.

Amino-ionic liquids assisted highly compatible mixed matrix membrane of ZIF-8 and PIM-1 for efficient CO2/N2 separation

Zhaojie Wang,Xinle Sun,Qinglong Liu,Caifeng Xia,Qikang Yin,Siyuan Liu,Xiaoqing Lu,Hongyu Chen

Mixed matrix membranes (MMMs), which incorporate metal-organic frameworks (MOFs) nanofillers within a polymer matrix, offer a highly promising solution for CO2 capture and separation. However, poor interfacial compatibility and filler aggregation in MMMs pose significant challenges to enhancing CO2/N2 separation performance. Here, we present a novel approach using amino ionic liquid modification to optimize MMMs, where the modified AFIL promotes the formation of ZIF-8 with well-defined facets and sharp edges, and enhances the compatibility between ZIF-8 particles and PIM-1 polymer matrix for favorable CO2 affinity and selective CO2 transport. The resulting 10 wt.% AFIL@ZIF-8/PIM-1 exhibits exceptional gas separation performance with a CO2 permeability of 7864262.2 Barrer and a CO2/N2 selectivity of 29.661.96. More importantly, the incorporation of AFIL into the ZIF-8 pores significantly enhances the thermal stability and aging resistance of AFIL@ZIF-8/PIM-1 MMMs via structural support and hydrogen bonding interactions. This work provides a practical approach to developing hybrid membranes for CO2/N2 separation, showcasing improved overall performance and strong interfacial compatibility.

Engineering multifunctional MDPCs@MOFs via selective thermal etching integrates low-resistance transport with strong adsorption for enhanced CO2/N2 separation

Runlin Han,Faxiang Feng,Zanming Zhu,Guilin Dong,Xiaobing Liu,Minggang Guo,Xiaohang Yang,Jiahao Qin,Huahao Wang,Yan Dai,Gaohong He

Metal-organic frameworks (MOFs) based Mixed-matrix membranes (MMMs) still present challenges in overcoming the traditional trade-off between permeability and selectivity in gas separation. Functionality of MOFs demonstrates great potentials in overcoming this issue. In this study, hierarchically structured multifunctional C@Fe 2 O 3 @ZIF-8 was proposed to construct strong adsorbed and low-resistance transport pathways enabling high CO 2 sieving through a “selective thermal etching” strategy. Leveraging the thermal stability difference between MIL-88 A(Fe) and ZIF-8, the core undergoes selective pyrolysis while preserving the crystalline ZIF-8 shell. The ZIF-8 shell enhances CO 2 /N 2 separation while optimizing interfacial compatibility, whereas the porous carbon core provides mesoporous structures for enhanced gas transport and ultramicroporous regions for improved CO 2 adsorption. Meanwhile, paramagnetic Fe 2 O 3 in the core layer enables optimized distribution of C@Fe 2 O 3 @ZIF-8 within the Pebax matrix. The C@Fe 2 O 3 @ZIF-8/Pebax MMM exhibits 216.46 % and 65.12 % improvements in CO 2 permeability and CO 2 /N 2 selectivity, respectively, over the Pebax matrix, exceeding the 2019 McKeown upper bound. This study pioneers a novel approach for constructing advanced multicomponent materials with customizable hierarchical structures by synergistically integrating high-throughput carbon channeling with MOFs molecular sieving technology.