INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2022
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IF 4.326
Yujia Jiang,Haochen Qi,Jiayuan Wang,Xu Sun,Changjiang Lyu,Peng Lu,Ruiqin Yang,Aqsa Noreen,Chuang Xing,Noritatsu Tsubaki
Zeolites’ great momentum in industrial applications will require an efficient route for their synthesis. The conventional methods for zeolite synthesis normally involve expensive reactor setups, where the crystallization occurs at high-pressure conditions. Herein, we proposed an ambient-pressure synthesis (APS) of the NaA zeolite at 120 °C. The reaction setup simply used a glass tube as a reactor and a low-density liquid as a sealant. The optimum synthesis conditions were obtained by using a methylcellulose template and the polyethylene glycol-400 sealant. Compared with that of the conventional hydrothermal process, the barrier of the sealant over the zeolite gel in the glass tube can significantly reduce the synthesis cost, and it also makes the process much safer than the conventional methods.
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
Materials Research Express
·
2019
·Vol. 6
·期 11
·115504
·
IF 1.449
Peng Wang,Qi Sun,Yujiao Zhang,Jun Cao
The zeolite NaA was successfully synthesized by hydrothermal method using kaolin as a raw material. In order to study the crystallization mechanism, the products and intermediates of different crystallization stages were systematically characterized using x-ray diffraction (XRD), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM)-energy-dispersive spectrometry (EDS). The results show that the metakaolin is completely dissolved during the first hour of the crystallization process, forming a rich crystal nucleus. As the crystallization time increases, the nucleus grows rapidly to form zeolite NaA crystals. When the crystallization time reaches 3 h, the percentage crystallinity of zeolite NaA reaches a maximum. Therefore, it can be concluded that the optimum crystallization time of zeolite NaA is 3 h. Meanwhile, we can come to the conclusion that the synthesis of zeolite NaA from kaolin is a liquid phase transition mechanism. The microstructure of zeolite NaA synthesized at 3 h of crystallization was further investigated by transmission electron microscopy (TEM) technique. The SAED patterns indicate the polycrystallinity of the zeolite NaA structure. The electron diffraction pattern indicates that the crystal structure type of the zeolite NaA belongs to the body center cube (BCC). The textural properties of the zeolite NaA synthesized at 3 h of crystallization were studied by nitrogen adsorption technique. It can be concluded that the BET surface area of the zeolite NaA obtained by the BET method is 21.106 m2·g−1. Meanwhile, from the BJH method, it is found that the microporous surface area and micropore volume of the zeolite NaA are 13.929 m2·g−1 and 0.052 cm3·g−1, respectively.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
Materials
·
2020
·Vol. 13
·期 21
·5047
·
IF 3.057
Jun Cao,Peng Wang,Jie Shen,Qi Sun
Here, using Fe3O4@SiO2as a precursor, a novel core-shell structure magnetic Cu2+adsorbent (Fe3O4@zeolite NaA) was successfully prepared. Several methods, namely X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), Transmission electron microscope (TEM), Brunauer Emmett Teller (BET) and vibrating sample magnetometry (VSM) were used to characterize the adsorbent. A batch experiment was conducted to study the Cu2+adsorption capacity of Fe3O4@zeolite NaA at different pH values, contact time, initial Cu2+concentration and adsorbent does. It is found that the saturated adsorption capacity of Fe3O4@zeolite NaA on Cu2+is 86.54 mg/g. The adsorption isotherm analysis shows that the adsorption process of Fe3O4@zeolite NaA to Cu2+is more consistent with the Langmuir model, suggesting that it is a monolayer adsorption. Adsorption kinetics study found that the adsorption process of Fe3O4@zeolite NaA to Cu2+follows the pseudo-second kinetics model, which means that the combination of Fe3O4@zeolite NaA and Cu2+is the chemical chelating reaction. Thermodynamic analysis shows that the adsorption process of Fe3O4@zeolite NaA to Cu2+is endothermic, with increasing entropy and spontaneous in nature. The above results show that Fe3O4@zeolite NaA is a promising Cu2+adsorbent.
研究领域:
环境科学
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材料科学
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化学工程
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DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2018
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IF 6.578
Xiao-Qing Li,Pei-Yao Zheng,Jia-Kai Wu,Nai-Xin Wang,Shu-Lan Ji,Zhi-hui Yu,Quan-Fu An
Zeolite NaA membranes have been widely used in dehydration of alcohols by pervaporation because of their excellent permeability and selectivity. However, the zeolite NaA membranes were criticized for the poor performance in acidic condition. Herein, we report a simple and effective method to enhance acid stability of zeolite NaA membranes. The key is a positively charged polyelectrolyte complex (PEC) was impregnated on the surface of zeolite NaA membranes. The PEC was synthesized from chitosan (CS) and sodium poly (vinyl sulfonate) (PVS). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) results indicated that the zeolite NaA membranes suffered from severe damage in both morphology and crystal structure after contact with acid, while the PEC/NaA composite membranes remained intact. Accordingly, the PEC/NaA composite membranes（1.5 wt% PEC in solution） exhibited excellent water permeability and selectivity in acid solution. For acidic 90 wt% ethanol/water (pH = 3) mixture separation, the permeate flux was 875 g/(m 2 h), the water content in permeate was as high as 99.8 wt% at 40 °C. Meanwhile, the composite membranes showed a good acid stability for more than 200 h and this was attributed to the barrier effect of PEC layer, as well as the protonation ability of -NH 2 groups in PEC. This method is expected to offer great opportunities for the dehydration of organics under acidic conditions.
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
NEW JOURNAL OF CHEMISTRY
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2018
·Vol. 42
·期 9
·6664-6672
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IF 3.201
Yao-Yi Xu,Xue-Ling Wei,Shuai Liang,Ya-Li Sun,Zi-Sheng Chao
Considering the reliable characteristics and the suitable silica alumina content of kaolin, a new way of synthesizing a ZSM-5/NaA hybrid zeolite membrane on 170 mm length ceramic tubes by employing kaolin as a modification layer using a hydrothermal synthesis process was presented for the first time in this work. Kaolin was filtrated on the surface of the support (not only the ceramic tube, but also the NaA membrane layer) as a modification layer not only promoting the interface interlinkage among the support, NaA membrane and ZSM-5 membrane layer, but also promoting the growth of zeolite membranes. The SEM and XRD results showed that compact and homogeneous NaA and ZSM-5 zeolite layers were both formed with the thicknesses being 7.06 μm and 6.14 μm, respectively, after modification with kaolin. The permeation separation experiments demonstrated that the performance of the ZSM-5/NaA hybrid membrane was better than that of the monolayer zeolite membrane with permselectivities of H2 over CO2, N2, CO and CH4 of 5.40, 4.65, 4.70 and 3.93, respectively, which were higher than the corresponding Knudsen diffusion coefficients. Above all, modifying the support with kaolin and then synthesizing the ZSM-5/NaA hybrid membrane could strengthen the performance of the zeolite membrane effectively, which provided a new approach for the synthesis of high performance zeolite membranes in the field of membrane separation.
研究领域:
材料科学
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膜分离技术
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2019
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IF 5.107
Xuechao Gao,Bing Gao,Hua Liu,Chun Zhang,Yuting Zhang,Ji Jiang,Xuehong Gu
Submicron NaA zeolite seeds were coated on the stainless steel (SS) hollow fiber support by self-assembly method, and then the hydrothermal crystallization and autoclave technique were used to synthesize NaA zeolite membranes. The effects of grafting temperature, grafting time and the size of induction seeds on the membrane performance were extensively investigated. The as-synthesized membranes and zeolite crystals were then characterized by X-ray diffraction, and the morphology and thickness of membranes were examined by scanning electron microscopy. The separation performance of the membrane was evaluated by pervaporation dehydration of 90 wt% ethanol/water mixtures at 75 °C. It was found that the seed-layer should be uniformly coated to induce good continuity for the NaA zeolite membrane layer, where the seeding effect was clearly affected by grafting time, grafting temperature and seed size. The optimal seeding condition was found for a grafting time of 6 h under a temperature of 110 °C, using a seed size of 150 nm. A continuous zeolite membrane layer could be obtained on the surface of the SS hollow fiber, with a separation factor above 10,000 and a permeation flux of 4.22 kg∙m −2 ∙h −1 . The proposed self-assembly method could be readily operated and extended to the seeding process during the preparation of other supported zeolite membranes, providing a good prospect in batch-scale production of SS hollow fiber supported NaA zeolite membranes.
研究领域:
材料科学
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分离技术
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DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2025
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IF 4.7
Wenbin Zhao,Jinhuai Hua,Yi Cao,Rui Yao,Yanshuo Li
A microwave-assisted solvothermal method was developed to achieve La 3+ exchange in NaA zeolite membranes for enhanced ethanol dehydration via pervaporation. Traditional ion-exchange processes are time-consuming and risk structural degradation, whereas the proposed approach utilizes alcohol-based solvents under microwave irradiation to accelerate ion exchange while preserving membrane integrity. By optimizing solvent selection (isopropanol) and La 3+ concentration (0.04–0.05 mol L −1 ), the modified La-LTA membrane exhibited simultaneous improvements in water flux (up to 12.78 % increase) and separation factor (up to 227 % enhancement), particularly in low-water-content systems. Characterization via SEM, XRD, and XPS confirmed retained crystallinity and successful La 3+ incorporation (35.42 % exchange degree). The method's universality was validated by exchanging other ions (Li + , Cu 2+ , Nd 3+ ), with Li-LTA and Nd-LTA membranes also showing dual performance enhancements. This work provides an energy-efficient, scalable strategy to tailor zeolite membranes for industrial dehydration applications.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2022
·
IF 16.744
Xiaoling Chen,Ying Wang,Chan Wang,Jingdong Xu,Tiesen Li,Yuanyuan Yue,Xiaotao Bi,Lilong Jiang,Xiaojun Bao
Deep understanding of the formation mechanism is crucial to the rational design and controllable synthesis of zeolites with desired pore architecture and acidity. Herein, we take the synthesis of NaA zeolite from a submolten salt depolymerized kaolin (SMS-K) as an example to elucidate the formation mechanism of NaA zeolite. By using SMS-K as sole Si and Al sources, a highly pure and crystalline NaA zeolite with superior ion exchange ability was synthesized. By using various ex-situ and in-situ characterizations and studying the crystallization kinetics, a plausible formation mechanism of NaA zeolite via the mesoscale reorganization of SMS-K was proposed. The results indicate that the reorganization of SMS-K into NaA zeolite follows the solid-phase transformation route. Upon being mixed with H 2 O, SMS-K that is mainly composed of silicate monomers and chain/ring microstructures is in-situ transformed rapidly into mesoscale intermediates containing double four-membered rings and β cages, sufficient stirring during aging generates more mesoscale intermediates. During the subsequent crystallization process, the mesoscale intermediates are further self-assembled into NaA nanoparticles when theirs amount reaches a maximum, and finally the nanoparticles grow into well-shaped cubic NaA zeolite particles with smooth surfaces through layer spreading. Our work provides the theoretical foundation for the design and green synthesis of zeolites directly from the natural minerals.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2024
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IF 3.7
Liqin Tang,Xiang Jin,Bing Gao,Xuechao Gao,Xuehong Gu
Due to the low transport resistance, mullite hollow fiber (HF) could be regarded as a promising support for preparation of NaA zeolite membranes. However, insufficient coverage and undesired seed penetration often occur in the seeding step of the mullite support due to the rough surfaces with ultra-large macropores (2–4 μm). This leads to poor intergrowth of the membrane layer. To solve this issue, cationic polyacrylamide (CPAM) was employed to modify the chemical and electrostatic properties of the mullite HF surface, where the electrostatic attraction between the surface and seed crystals could significantly promote the coating effect. In the seeding, the original seeds (3.2 μm) were mixed with the ball-milled seeds (0.3 μm) to improve the seed coverage, i.e., the original seed was used to block the macropores on the support surface to prevent the penetration of small seeds, while the decked ball-milled seed was used to provide sufficient active sites to induce the intergrowth of the zeolite crystals. The effects of the concentration of CPAM, mixed mass ratio of seeds, and seed concentration on the preparation of NaA zeolite membranes were systematically examined, where the separation performances were characterized by pervaporation (PV) dehydration of 90% (mass) ethanol/water mixtures at 75 °C. The results indicated that under a CPAM concentration of 0.7% (mass), an equivalent mass ratio of mixed seeds in a seed concentration of 1.0% (mass), the prepared mullite HF supported NaA zeolite membrane yielded the best PV performance, where the permeation flux and separation factor corresponded to 5.45 kg·m −2 ·h −1 and 10000, respectively, being sufficient for industrial applications.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2019
·
IF 4.175
Juan Liu,Zhujian Huang,Jie Sun,Yixuan Zou,Beini Gong
In this study, thiourea reduced graphene oxide/NaA zeolite composite (tGO-Zeo) was successfully prepared by a facile two-step synthetic route and used as an efficient adsorbent for removal of Cd(II) from aqueous solution. Characterization of the composite material showed that tGO was entrapped within zeolite crystalline particles and intimately interacted with the zeolite framework. Furthermore, the presence of tGO considerably reduced zeolite crystal size and altered crystal morphology, turning cubic zeolite crystals of micrometer size into nanometer irregular particles. Batch adsorption experiment for Cd(II) removal was conducted and the adsorption performance of tGO-Zeo and Zeo (zeolite) were determined. It was shown that doped tGO significantly enhanced the adsorption capacity of zeolite by 31.54%. The adsorption mechanism differs for tGO-Zeo and Zeo, and tGO-Zeo has higher affinity for Cd(II). The adsorption capacity of tGO-Zeo with a tGO doping amount of 1.26% (wt%) was estimated to be 196 mg/g (1.74 mM/g) at 30 °C and superior to most previously reported zeolite based composites, which often contain large amounts of dopants . The effects of pH and ionic strength on adsorption suggest that ion exchange and coordination are responsible for Cd(II) adsorption by tGO-Zeo. Humic acid can slightly increase Cd(II) adsorption performance of tGO-Zeo, which may be due to tGO-Zeo—humic acid—Cd(II) complexes formation. Therefore, tGO-Zeo composite is a cost-effective and eco-friendly adsorbent for efficient removal of Cd(II) ions from aqueous solutions.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
Petroleum Science
·
2019
·Vol. 17
·期 1
·242-254
·
IF 1.846
Yan-feng Ji,Xu-long Cao,Yang-wen Zhu,Hui Xu,Xiu-zhi Sun,Hai-tao Li
Super high molecular weight copolymers of AM/NaA/AMPS were prepared by oxidation–reduction [OR-P(AM/NaA/AMPS)] and controlled radical polymerization [CR-P(AM/NaA/AMPS)]. The resulting copolymers were fully characterized, and the reaction conditions for their preparation were optimized. OR-P(AM/NaA/AMPS), CR-P(AM/NaA/AMPS), and conventional partially hydrolyzed polyacrylamide (HPAM) in brine solution were comprehensively characterized by thermogravimetric analysis, scanning electron microscopy, atomic force microscopy, and dynamic light scattering. OR-P(AM/NaA/AMPS) and CR-P(AM/NaA/AMPS) containing AMPS monomer showed better salt resistance, temperature tolerance, and viscosification property than the conventional HPAM polymer, making them more promising for enhanced oil recovery. Through comprehensive comparison and analysis, it was found that OR-P(AM/NaA/AMPS) was more conducive for high-temperature condition due to the existence of xanthone in OR-P(AM/NaA/AMPS). On the other hand, CR-P(AM/NaA/AMPS) was more suitable for high-mineral atmosphere, which could be attributed to its higher intrinsic viscosity.
研究领域:
化学工程
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材料科学
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石油工程
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DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2026
·Vol. 14
·期 5
·123407
·
IF 7.5
Inam Ullah,Syed Musab Ahmed,Hao Lou,Zeeshan Abbasi,Zubair Ahmad,Muhammad Usman,Wenlong Wu,Zhandong Wang
The practical application of CO 2 methanation is often hindered by water-induced limitations. Conventional sorbent-assisted catalyst systems employ adsorbents merely as passive water scavengers, neglecting their potential role in reaction kinetics. Herein, we report a layer-by-layer catalyst-zeolite architecture that overcomes these limitations by synergistically promoting low-temperature CO 2 activation while enabling effective in-situ water management. This ordered configuration maximizes interfacial contact, allowing the hydrophilic NaA zeolite to actively capture and activate CO 2 at reduced temperatures while continuously removing the water by-product from the Ni/ZrO 2 surface. Consequently, the system achieves 81% CO 2 conversion with 100% CH 4 selectivity at 200 ℃. This work demonstrates that integrating Ni/ZrO 2 catalyst with a functional NaA zeolite provides an energy-efficient and robust strategy for sustained low-temperature CO 2 methanation.
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DOI
高影响因子
危险品化学品经营许可证（带存储）