Journal of Natural Gas Science and Engineering
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2018
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IF 2.803
Tengyang Zhu,Xing Yang,Yi Zhang,Yayun Zheng,Xiaoqi He,Jujie Luo
Air pollution gradually aggravated, which accelerates the demand of clean energy (in particular clean natural gas) because of its abundant storage worldwide. However, raw natural gas commonly contains impurity gases, such as CO 2 and N 2 , which reduce the heat of its combustion. Here, we reported new polyamide-poly(propylefne glycol) (PA-PPG) random and block copolymer materials with excellent CO 2 /CH 4 separation performance. These copolymers were characterised by Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy ( 1 H NMR), UV–vis absorption spectrum and X-ray diffraction (XRD). The gas permeation properties of these copolymers were investigated by using five single gases (CO 2 , H 2 , O 2 , CH 4 and N 2 ) at different temperatures (298–328 K) and a feed pressure of 76 cmHg. The effects of chemical structure, PPG content and operating temperature on the gas permeation properties of these copolymers were also further discussed. Results showed that PA-PPG random copolymer membranes exhibited better gas permeation properties than those of PA-PPG block copolymer membranes. PA-PPG random copolymer membrane with 20 wt% PPG exhibited the highest selectivity (CO 2 /CH 4 = 37.31 and H 2 /CH 4 = 33.44) at 298 K and 76 cmHg. The CO 2 and H 2 permeability values were 5.97 Barrer and 5.19 Barrer, respectively.
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高影响因子
ENERGY
·
2019
·
IF 5.537
Jie Yi,Dong-Liang Zhong,Jin Yan,Yi-Yu Lu
In the present work, we report an investigation of using an anionic surfactant sulfonated lignin (SL) to promote gas hydrate formation for CO 2 capture from a CO 2 /CH 4 gas mixture. The experiments were performed at 277.15 K in a stirred tank reactor. The initial overpressure (driving force) for hydrate formation was fixed at Δ P = 2.5 MPa. The impacts of the SL presence on hydrate growth behavior and CO 2 separation efficiency were elucidated. The results indicated that hydrate nucleation was prolonged in the presence of SL but this stage was accelerated when adding 1.0 mol% tetrahydrofuran (THF) into the SL solution. Compared to THF/SL and sodium dodecyl sulfate (SDS) solutions, CO 2 recovery obtained in SL solutions was increased to 63.5 ± 2.9% and the separation factor was 4.0 ± 0.8. Gas consumption obtained in SL solutions was higher than that obtained in other systems like liquid water, SDS solution, THF solution, and tetra- n -butyl phosphonium bromide (TBPB) solution. Therefore, sulfonated lignin can be used as a promising surfactant to improve hydrate formation kinetics as well as the efficiency of CO 2 capture from CO 2 /CH 4 gas mixture, but there still exists a space to increase the CO 2 selectivity in the presence of SL.
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高影响因子
Surfaces and Interfaces
·
2025
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IF 6.3
Chaoqiang Li,Xiangyu Xu,Aizhong Jia
Photocatalytic reduction of CO 2 to chemical fuels is a promising strategy to alleviate the greenhouse effect and energy crisis. This article successfully fabricated Ag/CdS composites with ohmic junction using a two-step method and further verified them by DFT calculations. Meanwhile, photoelectrochemical and electron paramagnetic resonance tests show that Ag/CdS has higher photocurrent density and lower charge transfer resistance, suggesting that the ohmic junction achieves ultrafast electron transfer from CdS to Ag under light irradiation, significantly promoting the separation of photogenerated carriers. Furthermore, the localized plasmon resonance (LSPR) of Ag enhances the light absorption of the catalyst and generates a large number of hot electrons for the photocatalytic reduction reaction. The synergistic effect of ohmic junction and LSPR gives high electron density at the reaction site, which promotes the multiple proton-coupled electron reactions leading to highly selective photoconversion of CO 2 to CH 4 . Under the optimized conditions, the CH 4 yield of the synthesized Ag/CdS is 68.6 μmol·g −1 ·h −1 , which is 25.4 times higher than that of bare CdS, and the CH 4 selectivity increases from 53.8% to 90.1%. This study provides a new idea for the design of CdS-based materials for highly selective reduction of CO 2 to CH 4 .
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2024
·
IF 4.8
Kunpeng Liu,Yixuan Yu,Qi Wang,Lingtong Kong,Tianjun Sun
A comprehensive investigation was conducted to explore the adsorption behaviors of CH 4 over N 2 on ultra-microporous Al/Zr-FDCA frameworks, which were synthesized specifically using the eco-friendly and bio-sourced 2,5-furandicarboxylic acid (FDCA). Characterization results revealed that both Al-FDCA and Zr-FDCA exhibited similar specific surface area and surface groups, leading to comparable methane uptake per-unit mass at atmospheric pressure. However, the presence of Zr nodes generated ultra-micropores around 0.43 nm in size, leading to a pronounced affinity for CH 4 . Zr-FDCA demonstrated a higher CH 4 /N 2 selectivity (8.90) calculated from the isotherms compared to Al-FDCA (3.86). Furthermore, breakthrough experiments indicated that under the same dynamic conditions, Zr-FDCA exhibited 1.5 times higher CH 4 uptake per unit volume and 2.5 times higher CH 4 /N 2 selectivity when compared to Al-FDCA. Initially, a four-step VPSA process was simulated to investigate the separation of CH 4 /N 2 mixture, in which the effects of feed-gas flow rate, adsorption time, adsorption pressure, and desorption pressure in VPSA cycle were extensively evaluated to enhance the purity and recovery of methane. Subsequently, a six-step process was employed for further optimization, achieving a purity of 95.9 % and a recovery of 99.1 %. The obtained results demonstrated the reliability of the established model and highlighted the significant potential of Zr-FDCA for CH 4 /N 2 separation.
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JOURNAL OF POROUS MATERIALS
·
2025
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IF 3.2
Zhang Xu,Peng Xiaoqian,Liu Shaojun,Liu Xiaochan,Liu Guoran,Liu Rongshuang,Niu Jiale,Yuan Zhipeng,Zhang Jing,Yi Xibin,Filatov Serguei
A current challenge for natural gas adsorbed storage technology is to find specialized adsorbent materials that are able to store and deliver large amounts of methane (CH 4 ) near room temperature and at low pressures. In this study, bimetallic MOFs is supported on nitrogen-doped carbon foam derived from melamine (MC@NZn) by vacuum impregnation process as an adsorbent for CH 4 storage. The nitrogen-doped carbon foam with macroporous internetwork combined with high surface area and micro-/mesoporous structure of the NiZn-MOF leads a hierarchical porous structure, which provides efficient and rapid pathways for the penetration of CH 4 molecules and more active sites for CH 4 adsorption. Experimental results show that MC@NZ4 exhibits a CH 4 adsorption capacity of 105.80 cm 3 ·g -1 under 298 K and 60 bar with isosteric heat of adsorption of 10.71 kJ·mol -1 . Furthermore, MC@NZ4 achieves a CH 4 /N 2 adsorption selectivity of 5.63, indicating its potential for CH 4 adsorption. This work provides a simple method to combine MOF powders with three-dimensional skeleton substrate material to fabricate monolithic solid porous materials, which can find potential applications in gas adsorption.
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APPLIED SURFACE SCIENCE
·
2024
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IF 6.3
Meirong Dong,Junchang Xiong,Hongchuan Liu,Zehua Huang,Huaming Hou,Youcai Liang,Jidong Lu
Fe-based oxygen carriers are regarded as a promising class of oxygen carriers in the field of chemical looping combustion. However, the elucidation of the detailed microscopic reaction mechanism of oxygen carriers remains a significant challenge. In this work, we combine in situ spectroscopy, density-functional theory (DFT) calculations, and micro-kinetic modelling to reveal the microscopic reaction mechanism of CH 4 combustion on α-Fe 2 O 3 . The macroscopic reaction characterization of hematite with CH 4 was carried out on a fixed bed, and gas chromatography (GC) was utilized to detect the combustion products (CO 2 , H 2 O and H 2 ). Subsequently, in situ spectroscopy and DFT were combined to reveal the detailed pathways for the CH₄ oxidation process. The results indicated that the reaction intermediates evolve from methoxy (CH 3 O*) to the bridged bidentate formate (b-HCOO*) to the monodentate formate (m-HCOO*), which ultimately leads to the formation of CO 2 through a combination of H transfer and lattice oxygen oxidation. A micro-kinetic model was developed which incorporates surface reaction with the oxygen transport. This revealed that CH 3 O* and CH 3 O* → CH 2 OO* are the key intermediates and radical reactions, respectively, for CO 2 production. The elucidation of the reaction mechanism may prove beneficial for the future development of novel Fe-based oxygen carriers.
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高影响因子
FUEL
·
2024
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IF 6.7
Cheng Wang,Fengsheng Zhan,Shan Wang,Yi Wei,Jianbing Ji
Methane pyrolysis is a promising sustainable technology for CO 2 -free hydrogen production. However, the development of stable methods for methane pyrolysis to produce hydrogen at lower temperatures has presented significant challenges. This study presents a reaction system that combines molten carbonate with Ni/Al 2 O 3 catalyst and investigates methane pyrolysis using this system in a bubble-cap reactor. Remarkably, this system exhibited a low activation energy of 145.8 kJ per mole, enabling the achievement of a methane conversion of 92.5 % at 580 °C by employing a double-layer bubble cap tray configuration. Furthermore, the system showcases sustained activity for a duration of up to 72 h.
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CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Dou Zhang,Ying-jie Sun,Kai-hua Zhang,Guang Yang,Xiao-jing Wang,Yi-lei Li,Hui-yun Han,Xinying Liu,Bao-Hang Han,Fa-tang Li
Synchronizing the directional photogenerated transfer of electrons and regulating the CO 2 photocatalytic reduction process are key to achieving the efficient and highly selective photocatalytic reduction of CO 2 . The design of highly-dispersed active sites and the efficient collaboration of multiple sites are of great importance in attaining the above target. Herein, a reverse etching route was first proposed to confine Bi single atoms and nanoparticles as dual-sites for assisting CO 2 photoreduction on TiO 2 , avoiding the mutual masking of the active sites. The Synergism of the dual-sites achieves the hydrodeoxygenation of * COOH and ushers the directional conversion of CO 2 to CH 4 . Highly dispersed single Bi atoms could induce the transfer of photogenerated electrons, enhance CO 2 absorption, and further provide active sites for reducing CO 2 to *COOH intermediates. Besides, appropriate Bi nanoparticles could promote the separation and transfer of photogenerated and inhibit the formation of hydroxyl groups; more importantly, they could promote the release of protons, which would further accelerate the conversion of *COOH to CH 4 . After being integrated, the optimized dual-Bi/TiO 2 catalyst achieves a CH 4 generation rate of 103.89 μmol·g −1 ·h −1 with an impressive selectivity of 96.87 % as well as remarkable durability for photocatalytic CO 2 reduction. This work provides new insights into developing robust catalysts through the artful design of synergistic catalytic sites for efficient photocatalytic CO 2 conversion.
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Journal of Cleaner Production
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2024
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IF 9.7
Wanru Feng,Jingya Zhang,Jianguo Mi,Junsu Jin,Guolei Xiang,Hong Meng,Shisen Xu
The synthesis of structured CO 2 adsorbents with high separation selectivity, strong stability, and low cost to meet industrial needs is very challenging. Here, we synthesized an ultra-stable Zn-MOF (Zn 2 (3-amion-1,2,4-triazolate) 2 (oxalate), Zn 2 (Atz) 2 Ox), and adopted an efficient in-situ growth strategy to produce millimeter-sized spherical Zn 2 (Atz) 2 Ox@AFP (Amino-Functionalization Poly(acrylates), AFP) composite. Due to the heterogeneous crystallization induced by the nanoscale crystal seeds and the confined space of AFP, the three-dimensional (3D) Zn 2 (Atz) 2 Ox bulk crystals transformed into 2D nanosheets with higher CO 2 adsorption efficiency and faster kinetics. Zn 2 (Atz) 2 Ox@AFP has a high affinity for CO 2 (2.05 mmol g −1 at 0.05 bar and 313 K) while exhibiting an inhibitory effect for N 2 (only 0.051 mmol g −1 at 1.0 bar and 313 K), leading to an excellent ideal adsorbed solution theory (IAST) selectivity (2990 for CO 2 /N 2 (5/95, v/v)). Interestingly, Zn 2 (Atz) 2 Ox@AFP exhibits a unique gating effect on CH 4 adsorption, which further extends its application range to natural gas purification. Dynamic breakthrough experiments confirmed that Zn 2 (Atz) 2 Ox@AFP can selectively capture CO 2 in the simulated CO 2 /N 2 (5/95) and CO 2 /CH 4 (5/95) mixed gases.
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JOURNAL OF THE ENERGY INSTITUTE
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2024
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IF 5.6
Xueyu Zan,Shiqi Tao,Chaoyu Zhang,Yixiao Wu,Yongjun Liu,Wei Huang
Direct conversion of methane and carbon dioxide into acetic acid is a dream way to address the two greenhouse gases, but is challenged by their chemical inertness. Cu and Pd are promising candidates both in CH 4 and CO 2 activation as well as the subsequent C-C coupling reactions at low temperature. Herein, we report that acetic acid can be produced by the direct coupling of CH 4 and CO 2 in the presence of H 2 O 2 over Cu-Pd/Al 2 O 3 catalysts at 50 °C. Results show that the acetic acid yield reaches 48.1 μmol·g cat −1 ·h −1 on the optimized reaction condition over Cu 3.8 -Pd 1.6 /Al 2 O 3 catalyst, which is higher than that of either mono-Cu or mono-Pd catalyst. Extensive characterization indicates the higher activity of Cu 3.8 -Pd 1.6 /Al 2 O 3 catalyst is attributed to the strong synergistic effect between Cu and Pd, which results in the formation of CuPdO 2 phase, and thus promoting the electron transfer from Cu to Pd. DRIFTS experiments reveal that acetic acid is produced by the coupling of CH 3 * and COOH* over CuPdO 2 active sites via Langmuir-Hinshelwood mechanism, where CH 3 * is originated from CH 4 dehydrogenation step, and COOH* may formed by the activation of CO 2 by H 2 O 2 . This study provides a new approach for the co-conversion of CH 4 and CO 2 into acetic acid at low temperature.
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高影响因子
AICHE JOURNAL
·
2024
·Vol. 70
·期 7
·e18443
·
IF 3.5
Kang Wang,Yao Jiang,Mingming Xu,Dongdong Zheng,Shaojun Jia,Peng Cui
Separation of CH 4 from natural gas is an essential but extremely challenging process in the petrochemical industry. Here, we tailored a MOF-based adsorbent with partitioned aliphatic pore spaces through the simultaneous incorporation of the aliphatic sites and the symmetrically matched partition agent. The resulting adsorbent demonstrates exceptional adsorption capacity for C 3 H 8 and C 2 H 6 compared to CH 4 , along with remarkably competitive adsorption selectivities for C 3 H 8 /CH 4 and C 2 H 6 /CH 4 . Breakthrough experiments further support the excellent dynamic separation efficiency of the adsorbent for the purification of CH 4 from natural gas. Moreover, detailed density functional theory calculations and molecular simulations elucidate the synergistic interactions between the aliphatic sites and the partitioned pore spaces within the adsorbent, which promote the stronger binding affinities for C 3 H 8 and C 2 H 6 over CH 4 .
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Small
·
2025
·
IF 12.1
Xiang Liu,Yongxin Fu,Ruidong Li,Yurong Yin,Jun Hu,Binran Zhao,Chengyi Dai,Xiaoxun Ma,Chunshan Song
Directly converting methane into high-value-added chemicals presents a significant challenge in catalysis. Nonthermal plasma (NTP) offers an efficient approach for direct methanol synthesis through methane activation. However, theoretical frameworks for designing catalysts under NTP conditions remain underdeveloped. It is quite difficult to control the assembly process of radical species on catalyst surfaces. A boron nitride (BN)-confined Fe single-atom catalysts (Fe-SACs) is synthesized by in situ anchoring in defect sites induced by mechanical ball milling. This catalyst is utilized for NTP-catalyzed direct methane-to-methanol conversion. The results demonstrate that the CH 3 OH yield increases by ≈2.5 times compared to conditions with NTP alone, while selectivity doubles. The experimental results and theoretical calculations indicate that ·OH radicals generated by the dissociation of H 2 O are rapidly adsorbed by Fe-SACs before annihilation. This process facilitates the stabilization of ·CH 3 species and enhances the kinetics of CH 3 OH assembly along the E-R reaction pathway. A design criterion is proposed for plasma-catalyzed radical adsorption intensification-directed assembly catalysts, offering a novel approach for the directional catalytic conversion of reactants through radical pathways.
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