NEW JOURNAL OF CHEMISTRY
·
2023
·Vol. 47
·期 26
·12279-12286
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IF 3.3
Chaowen Liu,Mudi Xin,Xuejing Zhang,Chunlu Wang,Limei Qiu,Guangtong Xu
As an alternative to conventional cryogenic distillation, LTA zeolites act as cost-effective adsorbents for the adsorptive separation of ethylene and ethane. In this approach, the thermodynamic and kinetic separation of ethylene and ethane by LTA zeolites with regulated particle sizes and pore structures has been studied. Herein, LTA zeolites, with different particle sizes ranging from 0.82 μm to 4.96 μm and a pore diameter distribution concentrated around 4.16–5.07 Å, were prepared using the hydrothermal method followed by an ion-exchange procedure. The results indicated that variation of the zeolitic particle size and the Ca2+ exchange rate has a great influence on the separation process, including the selectivity of C2H4 and the breakthrough time intervals of C2H4 and C2H6. Several issues, including the intracrystalline diffusion, accessibility of active sites, reinforced interaction between adsorbents and adsorbates, and the confined space in the zeolitic channels, were investigated to explain the altered nature of the separation performance. The optimized separation performance was achieved using LTA zeolites with a particle size of 0.82 μm or with an ion-exchange rate of 69.13% and a pore diameter distribution of 4.94 Å.
研究领域:
化学工程
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材料科学
·
吸附分离技术
✓ 已验证
DOI
高影响因子
ACS Applied Energy Materials
·
2024
·
IF 5.4
Shangqing Qu,Guohong Cai,Xianji Qiao,Guobao Li,Junliang Sun
The incorporation of ceramic fillers into polymer electrolytes has proven to be effective in bolstering their mechanical robustness, improving ionic transport efficiency, and ensuring enhanced interface integrity. Nonetheless, the current repertoire of suitable ceramic fillers for such applications is still somewhat limited. Zeolites, renowned for their pronounced adsorption capabilities and potential as sodium-ion conductors, have not been extensively studied regarding their impact on the electrochemical performance of composite electrolytes. In this work, we have developed a novel composite polymer electrolyte (CPE) based on poly(ethylene oxide) (PEO) integrated with LTA zeolite nanoparticles. The cation adsorption on the surface of LTA zeolite particles introduces additional ion migration pathways, while the interaction between hydroxyl groups and ether atoms of the PEO matrix weakens the coordination between Na+ and PEO, thereby promoting sodium-ion mobility within the LTA/PEO CPE. The synergistic effect of cation adsorption and Lewis acid–base action on the zeolite surface yields an impressive sodium-ion transference number of 0.44. The integration of the LTA zeolite into the composite electrolyte diminishes the interfacial resistance against sodium metal electrodes, effectively mitigating sodium dendrite formation. The NVP||PEO-10||Na battery incorporating 10 wt % LTA zeolites exhibits a capacity retention of nearly 88% after 100 cycles at 0.2 C, which is significantly better than those without the zeolite.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2023
·Vol. 47
·期 23
·11051-11062
·
IF 3.3
Chengzhi Hu,Changyan Zhou,Huiping Zhang,Ying Yan
Chemical vapor deposition (CVD) and impregnation (IM) methods were applied in the preparation of novel Fe/LTA (Linde Type A) zeolite membrane/paper-like sintered stainless steel fiber (Fe/LTA/PSSF) catalysts for acetone oxidation. The catalysts were characterized using various techniques, such as actual iron loading (AAS), surface morphology (SEM), phase composition and crystallite size (XRD), specific surface area (BET), valence state (XPS) and reducibility (H2-TPR), to investigate the effects of the calcination process, iron loading, preparation methods and supports on their catalytic activity. The calcined catalysts were more active than the non-calcined catalysts in the catalytic oxidation of acetone due to the different oxidation states of the deposited metal species. The catalysts prepared by CVD with an Fe loading of 2.29% exhibited similar activity to the IM-prepared catalysts with Fe loadings of 4.42% and 9.69%, which may be attributed to the superior dispersion of the active Fe2O3 phases, the smaller size of metal oxide and the increased ability for oxygen storage. Among the IM-prepared catalysts, Fe/LTA/PSSF-IM-2 with an Fe loading of 4.42% exhibited the lowest T90 of 230 °C. Additionally, the catalysts coated on LTA/PSSF showed higher activity and contact efficiency (T90 of 249 °C) compared to those on granular zeolite (T90 of 318 °C).
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Dingcheng Liang,Fengqin Yu,Qiang Xie,Qingping Chen,Yuan Liu,Yuhua Zheng,Keping Zhu,Zhijun Zhang,Jun Liu,Xiao Zhu,Jinchang Liu,Zihan Zhu
Activated carbon (AC) is a broad-spectrum adsorbent but is flammable and has low adsorption capacities for polar and/or high-boiling volatile organic compounds (VOCs), while zeolites exhibit high thermal stability but poor adsorption of macromolecular and nonpolar VOCs. In this study, zeolite/AC composites were synthesized with the aim of obtaining broad-spectrum, efficient, and safe adsorbents for VOCs. Dimethyldiallylammonium chloride (DDA)-modified AC was used as a carrier for an in situ hydrothermal reaction enabling assembly with zeolites due to electrostatic attraction. Interface models were constructed for their phases, which revealed the binding force and simulated the binding process. The adsorption and flame resistance of the composites were evaluated. The results showed that DDA effectively modified AC to give it a long-lasting positive charge in solutions. High-silicon and pure-silicon zeolites exhibited low negative charges or were even neutral; it was difficult to combine with the modified AC via electrostatic attractions. Instead, LTA zeolites with high aluminum contents and negative charges were used, and the seed-induction method was used. Ethanol and ultrasonic dispersion were used to prevent agglomeration of the seeds and modified AC powder, so they were self-assembled electrostatically. Moreover, the crystallization time was extended and composites with high zeolite loadings were successfully prepared. According to the model calculation, the binding energy between the zeolite and AC before and after the DDA modification were 324.97 and 1076.46 kcal mol–1, respectively, and the distance between them was shortened by 2.7 Å after DDA treatment. As a result, AC and zeolite combined more closely and exhibited a stronger binding energy. The adsorption capacity for highly polar dichloromethane was improved by zeolite loading on the AC, and the bed penetration time was doubled. However, impregnation with inorganic sodium enhanced the reactivities of the organic components in the composite, and the ignition point was slightly reduced. Furthermore, the electrostatic self-assembly method can expand to prepare the LTA zeolite/columnar AC composite from shaped AC, greatly improving its application prospects.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
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