International Journal of Applied Ceramic Technology
·
2018
·Vol. 15
·期 6
·1490-1501
·
IF 1.165
Xiangli Kong,Minghui Qiu,Anran Wang,Lu Yang,Rongfei Zhou,Yiqun Fan,Deshuang Kong,Changjun Gu
The adhesion and cohesion between the coating layers and the ceramic honeycombs are usually one of the key issues in the preparation of high-performance zeolite-based/Monolith catalysts. In this work, we investigate the deposition of high-efficiency Cu-SAPO-34 catalyst on a cordierite monolith with special focus on the impact of alumina binders on the structure, mechanical adhesion and cohesion, and catalytic performance of the monolithic catalyst. Two kinds of alumina nanoparticles, α-alumina and γ-alumina, have no significant impacts on the Cu-SAPO-34 crystal structure, micropore morphology and catalytic activity. But washcoating experiments showed that the mass loss rate of the coating was less and the loading of the catalyst was higher when α-alumina was used as the binder. The reason of improving the adhesion and cohesion strength is the suitable thermal shrinkage, the uniform distribution and densification structure of α-alumina. Furthermore, optimization of the coating formulation with α-alumina as the binder has been performed. Finally, the catalyst prepared under the optimal conditions was tested by SCR and a maximum conversion rate of 97.4% was obtained. It was concluded that the use of the washcoating method with α-alumina does not affect catalytic performance while it increases bonding strength between substrate and catalysts.
研究领域:
化学工程
·
催化材料科学
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DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2022
·Vol. 19
·期 5
·2675-2685
·
IF 2.328
Qingliang Shan,Qian Ma,Jiawei Lian,Caiyu Yao,Anze Shui
In this research, for studying the influence of size and heat treatment temperature of initial Al(OH) 3 on the physical properties of porous mullite ceramics, porous mullite ceramics were prepared by in situ reaction sintering of amorphous silica and treated Al(OH) 3 . The transition phases χ-Al 2 O 3 , к-Al 2 O 3 , and stable phase α-Al 2 O 3 can be obtained in turn when the treatment temperature of raw Al(OH) 3 is 500, 1000, and 1500°C, respectively. The coarser the raw Al(OH) 3 , the higher the strength of porous mullite ceramics. When the sintering temperature is 1500°C, the bending strengths of PS500-C, PS1000-C, and PS1500-C (PS x -C represents that the specimen was prepared by the coarse grade Al(OH) 3, which was previously treated at x °C) are 40.3 ± 2.1, 54.9 ± 5.2, and 64.8 ± 4.8 MPa, respectively. In addition, although the activated Al 2 O 3 can decrease the formation temperature (∼100°C) of porous mullite ceramics, the strength and density of porous mullite ceramics prepared by activated Al 2 O 3 will decrease at the same sintering temperature. It is believed that the increase of defects and pores during the phase transformation should be responsible for this phenomenon.
研究领域:
材料科学
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陶瓷工程
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·Vol. 47
·期 19
·26869-26876
·
IF 4.527
Shao-Min Lin,Ya-Ling Yu,Ming-Feng Zhong,Huan Yang,Chen-Yang Zhang,Zhi-Jie Zhang,Wei Xu,Jiong-Yan Xie,Yu-Chun Qiu
Converting the γ phase into the α phase completely is necessary in the presintering stage of industrial alumina (Al 2 O 3 ), which requires high temperature and energy consumption. To reduce the presintering temperature, γ-Al 2 O 3 was activated by oxalic acid . XRD , 27 Al-MAS-NMR and TG-DSC were used to characterize the γ - alumina before and after activation, and the phase transformation was studied. The formation temperature of α-Al 2 O 3 decreased to 1029 °C for oxalic acid activated γ-Al 2 O 3 , and the α-fraction was 100% for activated γ-Al 2 O 3 at 1300 °C. After oxalic acid activation , the diffraction peak intensity of γ-Al 2 O 3 decreased significantly; the results of 27 Al-MAS-NMR suggested that octahedral [AlO 6 ] in γ-Al 2 O 3 was easier than tetrahedral [AlO 4 ] to be attacked by oxalic acid , and the formation of pentavalent [AlO 5 ] with higher reaction activity, which was in favour of the lowering formation temperature of α-Al 2 O 3 . The dissolution concentration of Al increased after oxalic acid activation, and the dissolution process was controlled by surface reactions. Oxalic acid mainly attacked the octahedral aluminium in γ-Al 2 O 3 and extracted Al as three complexes of [Al(C 2 O 4 )] + , [Al(C 2 O 4 ) 2 ] - and [Al(C 2 O 4 ) 3 ] 3- . Oxalic acid activated γ - Al 2 O 3 with a lower phase transformation temperature has broad application prospects in the alumina industry.
研究领域:
材料化学
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无机化学
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固态化学
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工业催化
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陶瓷材料
✓ 已验证
DOI
高影响因子
SOFT MATERIALS
·
2019
·
IF 0.973
Zhiqiang Zou,Wei Wu,Yi Wang,Liang Wang
Rapidly increasing demands for higher integration density and stability of electronic devices embrace higher requirements for thermally conductive silicone rubber, which is promisingly used in ultra-thin components. In this work, alumina whiskers (AWs) and alumina flakes (AFs) are used to modify liquid silicone rubber (LSR) by fabricating binary (AFs/LSR) or ternary (AWs/AFs/LSR) composites. The thermal conductivity and mechanical strength of the binary and ternary composites were investigated. Thermal conductivity of the binary AFs/LSR composite (25AFs/LSR) was 0.1990 W m−1 K−1, while the thermal conductivity of the ternary AFs/AWs/LSR composite (20AFs/5AWs/LSR) was 0.2655 W m−1 K−1. Furthermore, the tensile strength of the ternary AWs/AFs/LSR composites increased by 180.9% as compared with the binary system, increased to 7.81 MPa from 2.78 MPa due to the introduction of 1 wt% AWs. As a reason, a significant synergistic effect of AWs and AFs in the enhancement of both thermal and mechanical properties of the LSR was proved. Furthermore, the dielectric property measurements demonstrated that the ternary composites exhibited a lower dielectric constant and dielectric loss, indicating that the AWs/AFs/LSR composites were qualified to be applied in the field of electronic devices.
研究领域:
材料科学
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电子工程
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产品关联
DOI
高影响因子
Materials Research Express
·
2019
·Vol. 6
·期 4
·045207
·
IF 1.449
Jing Liu,Yunzhu Ma,Wensheng Liu,Xiaolei Song,Shuwei Yao,Juan Wang,Ming Cheng,Chunlan Li
Precursor sol with a high solid content is significant for alumina fiber synthesis. In the present work, alumina precursor sols used for preparing alumina fibers were synthesized by dissolving aluminum powder (AP) into a mixture of formic acid, acetic acid and deionized water. The effects of preparation temperatures on solubility of AP, structure of the synthesized sols and gels were investigated. The reaction mechanism of hydrolysis and polymerization was also studied. Based on the reaction mechanism, alumina precursor sol with a high solid content was acquired through the adjustment of temperature. The results revealed that all the sols synthesized at the temperature from 85 °C to 115 °C consisted of polymers, linear oligomers and monomeric species. Colloidal particles presented spherical shape with a uniform size. However, AP cannot dissolve entirely at 85 °C and white precipitates (HO)Al(CH3COO)2 was produced at 105 °C and 115 °C. AP had the highest dissolution degree at 95 °C. A colorless and transparent alumina sol with the highest solid content was acquired at this temperature. The structure of concentrated gels was also discussed. It was revealed that network polymers increased when using sols synthesized at temperature above 105 °C, which were negative for spinning. Continuous green fibers were obtained successfully using the alumina sol prepared at 95 °C.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF PHASE EQUILIBRIA AND DIFFUSION
·
2017
·Vol. 38
·期 1
·30-36
·
IF 0.938
Sun W. Z.,Cheng J. G.,Huang Z. K.,Jiang Y.,Wu L. E.,Liu L. M.
The present work determined the phase relations in Si-Al-M-O-C (M = Zr, Mg) systems, involving SiC-Al 2 O 3 -ZrO 2 , SiC-Al 2 O 3 -MgO, SiC-SiO 2 -Al 2 O 3 -ZrO 2 and SiC-SiO 2 -Al 2 O 3 -MgO systems by XRD phase analyses of the solid-state reacted samples from powder mixtures of SiC, Al 2 O 3 , ZrO 2 , MgO and SiO 2 . Within these systems, SiC was respectively compatible with other neighboring phases, forming a set of four-phase compatibility tetrahedrons. The subsolidus phase diagrams of the SiC-SiO 2 -Al 2 O 3 -ZrO 2 and SiC-SiO 2 -Al 2 O 3 -MgO quaternary systems were presented.
研究领域:
材料科学
·
陶瓷学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2023
·Vol. 107
·期 1
·132-143
·
IF 3.9
Milad Kermani,Jinghua Wu,Zexiao Liu,Fei Zuo,Hua-Tay Lin,Chunfeng Hu,Salvatore Grasso
This work examines the impact of sintering thermal history on kinetics of grain growth for 1264 ppm (0.1 wt%) MgO-doped alumina. Results suggest that sintering with a high heating rate in the order of ∼10 3 °C min −1 retards grain growth rate. By contrast, a slow heating rate of 5°C min −1 resulted in an increase in grain growth constant by a factor of ∼4. The segregation of Mg to grain boundaries, favored by short sintering duration, is considered to be one of the possible factors contributing to the retarded grain growth rate for the rapidly heated compacts. Furthermore, it is proposed that the simultaneous combination of retarded grain boundary migration rate and limited surface-diffusion-driven grain coarsening, promoted by rapid heating, enables pressure-less fabrication of translucent alumina without a need for vacuum or hydrogen atmosphere. In fact, it is demonstrated that weakly translucent alumina can be produced at relatively low temperatures of 1475–1550°C by sintering with a high heating rate (herein, ∼10 3 °C min −1 ) in ambient atmosphere.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2025
·
IF 11.3
Qiuyu Chen,Yongyi Zhang,Haiwang Liu,Peng Liu,Xinxin Ye,Xing Xia,Xiangwei Wu
Straw-derived dissolved organic matter (DOM) is widespread in farmland soils, but the relationship between straw-derived DOM and As in their co-sorption on minerals and the underlying mechanisms remain unclear. Here, batch experiments and spectroscopic analyses were employed to investigate the co-sorption of straw-derived DOM and As(III/V) on γ-Al 2 O 3 . Results showed a trade-off between the As(III/V) and DOM immobilization on γ-Al 2 O 3 under different pH levels, which was caused by competitive sorption. The rape straw-derived DOM (DOM_Ra) exhibited a stronger inhibition on As(III/V) sorption than rice straw-derived DOM (DOM_Ri). This could be due to more aromatic fractions in the DOM_Ra and DOM_Ri, which were preferentially sorbed by γ-Al 2 O 3 . In turn, the preferential sorption of aromatic DOM components was weakened by As(V) sorption, which, however, was not found in As(III) and DOM co-sorption. Furthermore, spectral results indicated that carboxylic groups on the sorbed DOM could provide additional binding sites for As(III/V) to form ternary complexes, but its role was overwhelmed by the DOM competitive sorption, which ultimately exhibited the inhibitory effect of DOM on As(III/V) sorption. These findings enhance the fundamental understanding of the co-sorption of As(III/V) and DOM on soil minerals and contribute to predicting As mobility and OM stability in As-contaminated farmlands with straw return.
研究领域:
环境科学
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土壤化学
·
农业生态学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Long Li,Jibran Iqbal,Ying Zhu,Fang Wang,Feiyu Zhang,Wanchao Chen,Ting Wu,Yiping Du
Alumina, as a support material, was loaded together with chitosan and hydroxyapatite to form chitosan/Al 2 O 3 -HA composite beads and was used for estradiol and chrysoidin removal from aqueous solution in the present work. The physicochemical properties of the beads were studied with Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectrometry (FTIR), thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) surface area analysis. FTIR spectra confirmed that the chitosan was loaded successfully on Al 2 O 3 -HA, and functional groups were immobilized onto the surface of the beads after the synthesis. The adsorption condition including pH, the amount of adsorbent, initial concentration and time were evaluated during the batch experiments. Isotherm data best matched the Langmuir model and the pseudo-second-order model best described the adsorption kinetics . The maximum adsorption capacity was found to be 39.78 mg/g and 23.26 mg/g for estradiol and chrysoidine, respectively. The adsorbed estradiol and chrysoidin were completely eluted from the composite beads with the eluent of 0.1 M H 2 SO 4 /MeOH and the regenerated material was used in several cycles without deterioration in its initial performances. This study suggests that the developed composite beads have high potential for the efficient removal estradiol and chrysoidin from aqueous solution.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Zhenhao Yang,Guihua Liu,Tiangui Qi,Qiusheng Zhou,Zhihong Peng,Leiting Shen,Yilin Wang,Xiaobin Li
The quality of alumina ceramics generally depends on alumina powder. High-density alumina ceramics were prepared from industrial coarse gibbsite. Near-spheric α-Al 2 O 3 with particles smaller than 500 nm was produced via the synergy of B and F from NH 4 BF 4 . The near-spheric α-Al 2 O 3 calcined at low temperature generated alumina ceramics with high density and low porosity. Meanwhile, the wet pretreatment yielded smaller particles with structural distortion and high microstrain and aluminum hydroxide, notably increasing the relative density of alumina ceramics. 99.18 % relative density, 0.017 % porosity, and 27.54 GPa Vickers hardness of alumina ceramics were achieved at 1650 °C for 2 h without additives and pressed sintering. In addition, the early stage of sintering of alumina green body followed particle boundary diffusion with reduced activation energy in the sintering process. The close packing of the spheric α-Al 2 O 3 , high microstrain of α-Al 2 O 3 , structural defects with considerable AlO 4 units calcined at low temperature, structural distortion in the alumina, and activated alumina on the α-Al 2 O 3 surface collectively promoted the densification of alumina ceramics, achieving remarkable hardness, high density, and tiny porosity.
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
·
2024
·
IF 8.3
Chen Zhou,Changhui Fu,Guangyi Tian,Feifan He,Shaolong Huang,Zhiguang Guo
Passive daytime radiative cooling is receiving more and more attention as a cooling method that does not consume energy to cool objects. However, most radiative cooling materials require the mixing of multiple particles, which increases the manufacturing process requirements. Most radiative cooling materials are susceptible to outdoor abrasion, pollution, and UV exposure, which leads to decreased performance. In this paper, the biomimetic film with both radiative cooling and self-cleaning functions was prepared by a simple evaporation-induced self-assembly process and spraying process using Al2O3 as the main radiatively cooling raw material, poly(vinylidene fluoride-co-hexafluoropropylene) [P(VDF-HFP)] as the additive, and polydimethylsiloxane as the binder. Therefore, we can get a biomimetic-Al2O3–P(VDF-HFP)-PDMS film (BAPPF). The BAPPF was spectrally selective. Specifically, the reflectance of BAPPF in the solar spectrum (0.45–0.89 μm) exceeded 100%, and the average reflectance in the main thermal effect of the solar spectrum (0.78–1.10 μm) was 99.92%. In addition, the BAPPF had 96.97% reflectance in the solar spectrum (0.3–2.5 μm) and 90.55% mid-infrared emissivity in the atmospheric window (8–13 μm). The combined performance enabled BAPPF to reduce temperature by up to 8.4 °C over air temperature in outdoor tests. What’s more, BAPPF had excellent superhydrophobic properties, with a water contact angle of up to 159°. The self-cleaning of the BAPPF prevented contamination and maintained cooling even when working outdoors for long periods of time. Furthermore, the BAPPF maintained high performance after mechanical friction, chemical corrosion, UV aging, and water impact, which has broad reference value and application prospects.
研究领域:
材料科学
·
环境科学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2025
·
IF 5.4
Quanyun Ye,Junfei Li,Dong Zeng,Ronghui He,Peiran Li,Jie Pan,Wencheng Wu,Dechun He
Nanoplastics experience complex aging processes when exposed to the environment, leading to substantial modifications in their physicochemical properties. These transformations significantly influence their interaction with mineral colloids, consequently altering their migration and fate. This study systematically investigated the homoaggregation of pristine and UV irradiation aged polystyrene nanoplastics (PSNP), as well as the heteroaggregation with alumina (Al 2 O 3 ) minerals under different water chemical conditions. The results showed that photoaging not only altered the surface morphology of PSNP, but also increased their surface negative charge and generated oxygen-containing functional groups, thereby improving the stability of the aged PSNP. Al₂O₃ heteroaggregated with PSNP, leading to a decrease in stability. The interaction between Al₂O₃ and aged PSNP was more pronounced compared to pristine PSNP. The pH value and ionic strength significantly influenced heteroaggregation, with acidic conditions and low ionic strength promoting heteroaggregation through stronger electrostatic attraction. Bivalent electrolytes (Ca 2+ ) were more effective than monovalent electrolytes (Na + ) in inducing PSNP heteroaggregation, as more carboxyl groups of PSNP were generated after photoaging, which combined with Ca 2+ through the bridging effect and enhanced the heteroaggregation. Furthermore, the heteroaggregation behaviors of both pristine/aged PSNP and Al 2 O 3 followed the DLVO theory. The findings revealed the important controlling effect and mechanism of UV irradiation and Al 2 O 3 on the fate of nanoplastics in aquatic environments.
研究领域:
环境科学
·
胶体化学
✓ 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）