JOURNAL OF MEMBRANE SCIENCE
·
2021
·
IF 8.742
Ye Zhang,Yong Gao,Peng Wang,Yichen Xu,Zhenming Yang,Jinsong Zhang
Membrane contactors have received considerable attention for extraction due to non-dispersive mass transfer through porous membranes. The past decades have seen the rapid development of organic hollow fiber membrane contactors, but very few studies have explored the applications of inorganic membranes in extraction, possibly due to their high costs. In this work, a novel SiC foam material with a hollow skeleton and microporous strut wall was used as a ceramic membrane contactor (HS-FCMC) for rare earths extraction. The foam's structure was characterized by scanning electron microscopy (SEM), X-ray micro-computed tomography (micro-CT), and mercury intrusion porosimetry (MIP). The flow and concentration fields inside and outside the foam cell were simulated by computational fluid dynamics (CFD), and the mass transfer through the ceramic membrane was analyzed. Based on the nitric acid–Ce 3+ /Pr 3+ –P507–kerosene chemical system, the extraction efficiency of Pr 3+ and Ce 3+ using the HS-FCMC reached 96.13% and 92.86%, respectively. A comparison study with poly tetra fluoroethylene (PTFE) hollow fibers was also conducted. The results indicate that the HS-FCMC is suitable for rare earths extraction due to the multiscale porous structure and chemical stability of the hollow-skeleton SiC foam. This research advances the knowledge of inorganic membrane extraction methods.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2021
·
IF 3.712
Ye Zhang,Yong Gao,Peng Wang,Duo Na,Zhenming Yang,Jinsong Zhang
Extraction reactor is a major research area of interest within the field of rare earths extraction and separation. SiC foam offers excellent material characteristics as well as three-dimensional (3-D) reticulated structure; however, very little research has been carried out on its application in extraction reactor so far. In this work, a static mixer reactor based on SiC foam was designed and demonstrated to extract and separate Ce(III) and Pr(III) from nitric acid media by using 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (P507) as extractant. The structure–performance relationship between SiC foam and extraction performance was studied by experiment combined with computational fluid dynamics (CFD) simulation. The experiment data are in good agreement with the simulation results. Contrast experiment by using a Kenics mixer was carried out, and SiC foam shows better extraction and mass transfer performance. Using the optimal structural SiC foam (pore size D = 2.3 mm, open porosity ε = 85%, foam length L = 80 mm), high extraction efficiency η (Pr(III): 94.6%, Ce(III): 88.5%) and separation factor β (2.27) between Ce(III) and Pr(III) is achieved at a high total throughput of 200 mL/min. Besides, overall volumetric mass transfer coefficient K L a of Pr(III) and Ce(III) are 0.519 and 0.378 s −1 at the residence time τ of 3.6 s, respectively, which reach the high level of microchannel reactors and are better than conventional extractors and other static mixers. SiC foam is found to be applicable as a static mixer for efficient and high-throughput extraction and separation of rare earths.
研究领域:
稀土提取
·
分离工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Coatings
·
2022
·Vol. 12
·期 5
·585
·
IF 3.236
Wen Sun,Xuankun Li,Jingtao Zou,Han Guo
TiO2is widely used for the photocatalytic degradation of organic pollutants in wastewater, but the practical applications of the photocatalyst are limited due to its poor visible light absorption and low recovery rate. In this study, high production of nitrogen-doped TiO2was achieved by a hydrolysis precipitation method; the obtained N-TiO2had a small crystallite size and good dispersibility. The effect of calcining temperature on the photocatalytic performance of N-TiO2was evaluated through the degradation of methylene blue (MB) in a blue light LED irradiation cylinder, it was found the N-TiO2calcined at 400 °C showed the best photocatalytic activity. Then the N-TiO2was immobilized on SiC ceramic foam by dip-coating with PVA as the binder. The prepared N-TiO2/SiC foam showed excellent photocatalytic activity under blue light LED irradiation; as high as 96.3% of MB was degraded at optimum conditions. After five cycles of MB photodegradation, the photocatalytic activity of N-TiO2/SiC foam only changed slightly, which makes it a promising photocatalytic material for wastewater treatment.Keywords:nitrogen-doped TiO2;SiC foam;LED irradiation;photodegradation;methylene blue
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2021
·
IF 5.062
Zhige Zhang,Guofeng Zhao,Bing Han,Jiawei Zhong,Jun Xie
Sustainable transformation of methane into methanol feedstock syngas is a promising direction in future energy generation. A monolithic SiC-foam (SiC-foam, denoted as SCf) supported structured Ni-SrO composite nanomaterial was prepared via reducing the SrNiO 3 perovskite. The Ni-SrO/SCf displays a stronger resistance to Ni-sintering/coke-deposition than the unmodified Ni/SCf due to its uniform Ni distribution as well as the strong Ni-SrO interaction. In the presence of Ni-SrO/SCf sample at a gas hourly space velocity (GHSV) of 24,000 mL CH4 CO2 g Cat −1 h − 1 and an operating temperature of 850 °C, the initial conversion rate of biogas (CH 4 /CO 2 ) was 70/94%, which gradually dropped to 55/72% within 40 h, but its activity remained stable for the next 60 h. By contrast, the conversion rate of biogas (CH 4 /CO 2 ) in the presence of Ni/SCf sample was decreased rapidly from 60/80 to 50/65% within 20 h, due to the severe coke deposition and Ni-sintering.
研究领域:
能源化学
·
催化材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2017
·
IF 3.133
Haibo Wu,Yinsheng Li,Xuejian Liu,Zhengren Huang,Dongliang Jiang
In order to improve the connectivity between pores of gelcasted and solid-state-sintered SiC (S-SiC) foams, we utilized the synergetic poring mechanism of direct foaming and sacrificial solid template through introducing organic micro-beads into aqueous foamed SiC-B 4 C-C suspensions. The addition of micro-beads accelerated the formation of more bubble-derived pores in S-SiC foams, and generated abundant bead-derived pores in the bubble-derived-pore struts and partial-sintering-derived pores between SiC grains as well. This multiple pore microstructures induced excellent connectivity between pores and an ultrahigh porosity of 89.5%. Consequently, an outstanding nitrogen gas permeability of 9.2 × 10 −11 m 2 was acquired under the condition of a superior compressive strength of 2.2 ± 0.4 MPa.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Communications
·
2024
·
IF 3.7
Jie You,Yang Wang,Hongwei Wang,Jian Yang,Quan Li,Jian Gu
In this paper, a new process for preparing porous SiC foam with three-dimensional network structure is presented. A certain thickness of SiC coating is deposited on the surface of ultra-light carbon skeleton by CVD process, so as to achieve effective control of its structure and mechanical properties. The effects of CVD deposition time on the density, porosity and skeleton thickness rates of SiC foams were explored. By increasing the CVD deposition time, the structure of SiC foams can be effectively regulated, and the mechanical properties of SiC foams can be significantly improved. The porosity of the prepared SiC foam can be adjusted in a wide range (26.9%∼94.68%). When the density of SiC foam increases from 0.67 g/cm 3 to 2.36 g/cm 3 , its bending strength increases from 27.4 MPa to 136.9 MPa, which is significantly improved. After high temperature oxidation treatment (800–1200 °C), the mechanical properties of SiC foam will be further improved. However, when the oxidation temperature reaches 1400 °C, its mechanical properties will be reduced. This research provides a new idea for the preparation of high-performance porous SiC ceramics, and lays a foundation for its structural design, manufacture and application.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Kai Su,Yang Wang,Kexuan Hu,Xia Fang,Jie Yao,Quan Li,Jian Yang
An ultralight and high-strength SiCnw@SiC foam with highly efficient microwave absorption and heat insulation properties was successfully synthesized using the template sacrifice method and chemical vapor deposition process. The microstructure is a novel double network structure, which is formed by the coupling of the morphology-controlled SiCnw and the SiC skeleton. The introduction of SiCnw can not only provide more interface polarization and dielectric loss to the SiC foam, which greatly enhances the microwave absorption capacity of the composite foam, but also can enable it to act as an excellent radiation absorbent, which can effectively reduce the thermal conductivity of the foam, especially at high temperatures. In this study, a minimum reflection loss (RLmin) of −52.49 dB was achieved at 2.82 mm thickness with an effective absorption bandwidth of 5.6 GHz. As the length/diameter ratio of SiCnw decreases, the composite foam exhibits excellent high-temperature thermal insulation and mechanical properties. For the SiCnw@SiC foam, the thermal conductivity is only 0.304 W/mK at 1200 °C and the compressive strength reaches 1.53 MPa. This multifunctional SiCnw@SiC foam is an outstanding material, which has potential applications in microwave absorption and high-temperature heat insulation in harsh environments.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
PubMed
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2022
·
IF 3.898
Ye Zhang,Yong Gao,Peng Wang,Duo Na,Zhenming Yang,Jinsong Zhang
Recently, there has been considerable interest in the use of microchannel reactors for hydrometallurgy of rare earths (REs). Here, a novel integrated microchannel reactor based on the hollow-strut SiC foam material is presented and demonstrated to extract Ce 3+ and Pr 3+ using 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (P507) as the extractant. The typical three-dimensional reticulated structure of the hollow-strut SiC foam was characterized by scanning electron microscopy and X-ray micro computed tomography. Since the reactor’s structure plays a key role in fluid mixing and mass diffusion during the extraction process, the structure-performance relationship of the foam was studied by extraction experiments combined with numerical simulations. Using the foam with the optimal structure, the influence of the flow rate Q 0 of the two liquid phases on the extraction efficiency η and overall volume mass transfer coefficient K L a was discussed. For both RE ions, with increasing Q 0 , η decreases while K L a increases. For the total flow rate of the two phases of 4 ml⋅min −1 , the η values of Pr 3+ and Ce 3+ reached 98.7% and 97.0%, respectively. For the total flow rate of 36 ml⋅min −1 which was much higher than that of many other microchannel reactors reported in the literatures, the η values of Pr 3+ and Ce 3+ still reached 92.2% and 86.9%, respectively, and the K L a values of Pr 3+ and Ce 3+ were 0.198 and 0.161 s −1 , respectively, similar to the high values reported for other microchannel reactors studied in previous work. These findings indicate that the hollow-strut SiC foam microchannel reactor is suitable for use in REs extraction.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
RENEWABLE ENERGY
·
2024
·
IF 9
Qiang Chen,Yixuan Dong,Jing Ding,Weilong Wang,Jianfeng Lu
Solar energy is an abundant renewable energy source, and the use of solar energy for carbon dioxide reforming of methane (CRM) is a promising thermochemical energy storage scheme, but the reactor using the traditional powder catalyst has the disadvantages of complex encapsulation and low energy storage efficiency. In this paper, porous SiC-foam with high thermal conductivity is used to prepare Ni/CeO 2 –Al 2 O 3 /SiC catalyst, and then is loaded into a cavity reactor to achieve highly efficient and stable CRM under solar simulator. After a period of reaction, methane conversion rate remains high. As inlet flow rate decreases and incident energy flux rises, methane conversion rate is improved, and thermochemical energy storage efficiency first rises and then drops with maximum 31.4%. The numerical model of the cavity reactor under concentrated heat flux is established, and the simulation results are in good agreement with the experimental data. The structure of catalyst bed directly influences the heat storage performance, and the optimal bed thickness, radius and porosity are obtained. For thick bed, the reverse reaction appears in the end region of the bed, and then this region expands with bed thickness rising, so the reaction rate first increases and then decreases.
研究领域:
能源科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Qiuyan Ding,Hengyu Shen,Zongliang Kou,Hong Li,Xiaolei Fan,Xiaoxia Ou,Yilai Jiao,Xin Gao
Rational design of catalytic packing is crucial in developing reactive distillation (RD) processes as efficient in-situ coupling of reaction and separation is required. Structured catalytic packings are advantageous than the conventional packings (e.g., inert packing + catalyst ‘tea bags’), due to the integration of the catalysis and separation function in one unit, mitigating mass/heat transfer limits. Herein, we present one of the latest developments in the field of structured catalytic packings, which was applied to a pilot-scale RD process of ethyl lactate (EL) synthesis via acid-catalyzed esterification and showed the advantages. The tungstophosphoric acid and hierarchical Y zeolite were uniformly decorated on corrugated silicon carbide (SiC) foam sheets via new preparation method (of ultrasound-assisted impregnation and microwave-assisted drying). The activity of the resulting materials was first assessed in a batch reactor, then the best candidate was employed by the pilot process. Findings from the pilot-scale RD experiments show that the developed structured SiC foam catalytic packing (SSFCP) exhibited an excellent performance (with the normalized conversion of 0.155 mol/g catalyst ), outperforming the conventional seepage catalytic packing internal (0.002 mol/g catalyst ). The influence of various variables (including molar feed ratio, feed position and reflux ratio) on the process performance of the pilot RD rig was also investigated and optimized, achieving a lactic acid conversion of 46.9 % and EL purity of 44.9 % (bottom). The good performance was attributed to the improved mass transfer thanks to SiC foam corrugated sheet (which encourage the vortex formation), thereby enabling more efficient coupling with the reaction. The SSFCP demonstrated reasonable stability, making it a promising candidate for relevant practical RD applications.
研究领域:
化学工程
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Zhige Zhang,Guofeng Zhao,Wenyang Li,Jiawei Zhong,Jun Xie
The efficient conversion of renewable biogas has attracted ever-increasing interest in past decades. Ni-CeO 2 -Al 2 O 3 supported on monolithic SiC-foam (denoted as Ni/CeO 2 -Al 2 O 3 /SCF) is designed and applied in biogas reforming. The monolithic Ni/CeO 2 -Al 2 O 3 /SCF catalysts were deeply characterized by XRD, ICP-AES, SEM, HR-TEM, CO 2 -TPD, etc. The cycle between CeO 2 -Al 2 O 3 and CeAlO 3 was verified by in-situ CH 4 /CO 2 -TPSR, and the catalytic role of CeAlO 3 in coke elimination and CO 2 activation was further confirmed. Due to the uniform distribution of Ni nanoparticles (NP S ) and the activation of CO 2 by CeAlO 3 , Ni/CeAlO 3 -Al 2 O 3 /SCF shows excellent catalytic stability to inhibit sintering and eliminate carbon deposition. At 900 °C and a gas hourly space velocity (GSHV) of 24000 mL g Cat -1 h −1 , excellent CH 4 /CO 2 conversion of 86/99% are initially achieved over Ni/CeAlO 3 -Al 2 O 3 /SCF catalyst, followed by slight decrease after 140 h, and remain basically stable for the next 260 h.
研究领域:
化学工程
·
能源科学
·
催化材料
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2015
·
IF 2.605
Haibo Wu,Jie Yin,Yinsheng Li,Yunzhou Zhu,Xuejian Liu,Sea-Hoon Lee,Yiquan Wu,Zhengren Huang
ZrB 2 –SiC foams were prepared from composite poring mechanisms of foaming and solid poring (PAA beads) by the application of a gelcasting technique. The porosities and microstructures of sintered bulks were tailored through changing the solids loading of slurries and the amount of added PAA beads. The increase in solid loading caused high viscosities of slurries, and thus resulted in the reduction of porosity and a tendency to form close pores. With increasing the amount of PAA beads, high porosities (up to 91.4%) and obvious connectivity improvement between bubble-derived pores emerged owing to efficient foaming and presence of bead-derived pores. As the porosity increased, the compressive strength (0.4–8.2 MPa) decreased, and the gas permeability (9.7–62.1×10 −12 m 2 ) augmented because of the effects of bead-derived pores and the increase in window number and size of bubble-bead pores.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）