Molecular Catalysis
·
2020
·
IF 3.687
Ning Xiang,Xiaojin Han,Yarong Bai,Qiaoyan Li,Jianfeng Zheng,Yulin Li,Yaqin Hou,Zhanggen Huang
Supported noble metal catalysts have been widely utilized for HCHO catalytic oxidation. When the active components are fixed, the altering and regulation of the supports would have a huge effect on catalytic performance. Here, two types of Pd/γ-Al 2 O 3 catalysts with different support size (micro-γ-Al 2 O 3 and nano-γ-Al 2 O 3 , respectively) were fabricated and used for HCHO oxidation. Compared with the micro-sized counterpart, the Pd/nano-γ-Al 2 O 3 catalyst exhibited much superior HCHO oxidation performance which could totally oxidize 160 ppm of HCHO into harmless CO 2 under a WHSV of 100,000 mL g cat −1 h −1 at room temperature. Multiple characterizations including XRD, BET, TEM, CO chemisorption, FT-IR, O 2 -TPD, XPS and in situ DRIFTS were implemented to study the effect of γ-Al 2 O 3 support size on physicochemical properties of Pd/γ-Al 2 O 3 catalysts and elucidate the structure-activity relationship. The results revealed that large specific surface area, rich surface OH groups as well as high curvature of nano-γ-Al 2 O 3 not only facilitated HCHO adsorption, but also stabilized highly dispersed Pd species which then promoted the activation of oxygen and boosted formate species decomposition, and consequently leading to the enhanced HCHO oxidation performance of Pd/nano-γ-Al 2 O 3 . This work deepens the comprehension of support size-dependent activity of Pd/γ-Al 2 O 3 catalysts for HCHO oxidation and provides an alternative method to prepare high-performance Pd catalysts for HCHO oxidation.
研究领域:
催化化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
Solid Fuel Chemistry
·
2022
·Vol. 56
·期 1
·37-44
·
IF 0.829
Wang Ruiyu,Sun Bingkang,Zhu Jiliang,Fan Xing
Abstract Nano γ-Al 2 O 3 support was prepared by sol-gel method, and the Mg 2 Si/γ-Al 2 O 3 catalyst was prepared by impregnation method from Mg 2 Si and the γ-Al 2 O 3 support. The catalyst was characterized by X-ray diffraction, N 2 adsorption-desorption, scanning electron microscopy and CO 2 temperature-programmed desorption analysis. The catalytic hydrocracking of lignite-related modelcompounds, 1-methoxynaphthalene (1-MON) and bibenzyl ether (BE), was investigated. Mg 2 Si was well distributed on the surface and in the voids of γ-Al 2 O 3 support. The Mg 2 Si/γ-Al 2 O 3 catalyst had high specific surface area, large amount of mesopores, strong basicity, and exhibited high catalytic efficiency in hydrocracking of 1-MON and BE due to the synergic effect between Mg 2 Si and γ-Al 2 O 3 . Under an initial hydrogen pressure of 3 MPa and reaction time of 60 min, the conversion of 1-MON and BE reached 100% when the reaction temperatures were 225 and 175°C, respectively. The selectivities for naphthalene and toluene were close to 100%, only traces of the hydrogenated products were detected. After 4 cycle tests, the catalytic activity of Mg 2 Si/γ-Al 2 O 3 catalystdropped to 50%.
研究领域:
化学工程
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催化材料
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2016
·Vol. 7
·期 2
·466-480
·
IF 5.287
Sijia Liu,Xin Liang,Jie Zhang,Biaohua Chen
Two different kinds of γ-Al2O3 precursors: stick-like ammonium aluminum carbonate hydroxide and willow leaf-like boehmite could be selectively synthesized via a facile hydrothermal method by just adjusting reaction temperature. After heat treatment, γ-Al2O3 with two different morphologies (stick-like and willow leaf-like) were synthesized and used as supports for CoMo hydrodesulfurization catalysts. Fourier transform infrared spectroscopy of pyridine adsorption and NH3-temperature-programmed desorption showed that stick-like γ-Al2O3 (ACH) and willow leaf-like γ-Al2O3 (AOH) exhibited a lower Lewis acidity than commercial γ-Al2O3. X-ray diffraction indicated that CoMo oxidic catalysts supported on ACH and AOH contained more β-CoMoO4 phase. X-ray photoelectron spectroscopy and high resolution transmission electron microscopy revealed that after presulfurization, more CoMoS active sites and multilayered (Co)MoS2 slabs formed on ACH and AOH supports, thereby creating catalysts with a higher hydrodesulfurization activity in the hydrodesulfurization of thiophene and 4,6-dimethyldibenzothiophene.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
Asia-Pacific Journal of Chemical Engineering
·
2023
·
IF 1.8
Kai Fei,Zhuo Yi Dong,Li Shi,Xuan Meng,Naiwang Liu
Transformer oil plays a critical role in ensuring the insulation and normal operation of power transformers. However, during operation, the transformer oil would undergo oxidation and degradation, leading to the formation of acids and polar compounds that increase its acidity and degrade its performance. Hence, the recycling and regeneration of aged transformer oil is an essential practice in transformer maintenance, contributing significantly to the extension of a transformer's operational lifespan and the reduction of potential risks. Adsorption separation is a preferred method for regeneration, offering simplicity and high efficiency. This study focuses on impregnated γ-Al 2 O 3 as an adsorbent for acidity removal in waste transformer oil. We conducted static adsorption experiments to investigate the optimal loading amount of the active component and the best calcination temperature for acid removal. XRD technique is employed to monitor the phase changes of the carrier during the calcination process. BET analysis is used to observe variations in the specific surface area and pore volume of the adsorbent during the modification process. DTG-TGA is utilized to assess the weight loss during the calcination process. FTIR is employed to observe changes in functional groups during modification and adsorption processes. Along with these investigations, a study is also carried out to assess the dynamic acid removal performance of the acid-removing adsorbent loaded into a fixed bed. The findings contribute to the development of sustainable methods for regenerating transformer oil, ensuring efficient and environmentally friendly operations.
研究领域:
化学工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2023
·Vol. 13
·期 36
·24944-24954
·
IF 3.9
Lin Li,Tao Zeng,Hongyu Huang,Jun Li,Noriyuki Kobayshi,Xiaohu Yang
In this study, the influences of nano γ-Al2O3 on the thermal storage performance of LiCl were experimentally investigated. The XRD results show that a complex of lithium aluminium oxychloride (LiAlOCl2) was formed through the LiCl·H2O and γ-Al2O3 composites preparation process. The in situ diffuse reflectance infrared Fourier transform spectroscopy measurement reveals that the addition of γ-Al2O3 accelerated the hydration rate of LiCl composites, concentrated the spectrum utilization range, and promoted the desorption rate of physical adsorbed H2O and low-frequency structural –OH in the materials. The highest specific surface area of the composite is 34.5 times higher than that of pure LiCl. The addition of γ-Al2O3 can increase the conversion rate of LiCl·H2O to approximately 100% at the hydration time of 1 h and the addition content of γ-Al2O3 at 15 wt%. A maximum heat storage density (HSD) for the LiCl·H2O-γ-Al2O3 composite can reach 714.7 kJ kgLiCl·H2O−1 in 1 h when the addition content of γ-Al2O3 was 15%wt and its water uptake can reach 0.26 g g−1 in 1 h. It also can be found that the addition of Al2O3 in LiCl resulted in a decrease of the activation energy from 90.89 kJ mol−1 to 79.76 kJ mol−1. However, the thermal conductivity of the LiCl·H2O-γ-Al2O3 composite slightly decreased with the increase of nano γ-Al2O3 content.
研究领域:
材料科学
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能源存储
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Atmosphere
·
2022
·Vol. 13
·期 2
·333
·
IF 3.11
Chao Wang,Lingdong Kong,Shengyan Jin,Lianghai Xia,Jie Tan,Yuwen Wang
Soot and aged soot are often found to be mixed with atmospheric particles, which inevitably affect various atmospheric heterogeneous reactions and secondary aerosol formation. Previous studies have investigated the heterogeneous reaction of NO2with different types of soot, but there are few studies on the heterogeneous reaction of NO2with mixtures containing diesel soot (DS) or aged DS and mineral dust particles. In this study, the effects of DS and aged DS on the heterogeneous reaction of NO2on the surface of γ-Al2O3were investigated via in-situ diffuse reflectance infrared Fourier transform spectrometry (DRIFTS). The results showed that the DS or DS n-hexane extract significantly inhibited the formation of nitrate on γ-Al2O3particles and promoted the formation of nitrite. At 58% RH, with the increase of DS or DS n-hexane extract loading amount, the effect of DS or DS n-hexane extract on the formation of nitrate changed from promotion to inhibition, but DS or DS n-hexane extract always promoted the formation of nitrite. The results also showed that light was conducive to the formation of nitrate on the DS-γ-Al2O3or DS-n-hexane extract-γ-Al2O3particles. Furthermore, the influence of soot aging on the heterogeneous reaction of NO2was investigated under light and no light. In the dark, O3-aged DS-γ-Al2O3or O3-aged DS-n-hexane extract-γ-Al2O3firstly inhibited the formation of nitrate on the mixed particles and then promoted it, while the effect of aged DS on nitrite formation was complex. Under light, the O3-aged DS-γ-Al2O3firstly promoted the formation of nitrate on the mixed particles and then inhibited it, while the O3-aged DS-n-hexane extract-γ-Al2O3promoted the formation of nitrate on the mixed particles. Our results further showed that the production of nitrate on the O3-aged particles under light or no light was greater than that of the UV-nitrate-aged particles. This study is helpful to deeply understand the atmospheric chemical behavior of soot and the heterogeneous conversion of atmospheric NO2.Keywords:soot;NO2;heterogeneous reaction;aged soot;γ-Al2O3
研究领域:
大气化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2023
·Vol. 30
·期 28
·72354-72367
·
IF 5.8
Zhou Tao,Lu Linghong,Tao Suwan,Ma Yi
In this work, we synthesized activated alumina biochar composites (γ-Al 2 O 3 /BC) by sol–gel method, which improved the problem that the surface charge of γ-Al 2 O 3 was not conducive to the removal of heavy metal cation in a neutral solution, and then explored the feasibility of removing Pb(II) by γ-Al 2 O 3 /BC as well as reusing Pb-laden waste sludge to remove phosphorus (P) and its micro-adsorption mechanisms. The results show that the maximum adsorption capacity of γ-Al 2 O 3 /BC for Pb(II) is 182.48 mg/g, and the removing capacity of recycled Pb-laden slag for P also reaches 87.13 mg/g. It was found that the presence of Pb in the slag makes P removal more effective. In addition, in the process of P removal, the Pb in the slag will not be released, which will not cause secondary pollution to the water. The micro-adsorption mechanism of Pb(II) and P on the composites was investigated by XPS, XRD, and FTIR. It demonstrates that special functional groups such as hydroxy-aluminum, hydroxyl, and carboxyl groups can remove Pb(II) through strong surface complexation and electrostatic attraction. Furthermore, the removal mechanism of P from Pb-laden sludge includes chemisorption and complexation, and the precipitation of P and Pb on the adsorbent surface is the main reason for the removal of P. Therefore, it is feasible to further effectively remove P by using the waste biochar containing Pb. The idea of this paper provides a potential method for the reuse of waste adsorbent.
研究领域:
环境科学
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材料科学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF SOILS AND SEDIMENTS
·
2024
·Vol. 24
·期 6
·2309-2317
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IF 2.8
Mi Na,Yang Min,Wang Xiaohan,Sun Qian,He Jianzhou,Deng Shaopo,Fan Tingting
Purpose The application of silicon could effectively alleviate Cd contamination in the soil. However, the interaction between silicon and Cd in soils is not well understood. Our research aims to investigate the mechanism of the impact of silicate on the sorption of Cd on metal oxides in soils. Materials and methods Sodium silicate and Cd(II) co-sorption on γ-Al 2 O 3 and goethite at pH 5.5 and 7.5 was studied using a combination of batch sorption experiments, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Results and discussion Silicate enhanced the sorption of Cd(II) onto γ-Al 2 O 3 at pH 5.5 and 7.5. However, the sorption of Cd(II) on goethite at pH 5.5 and 7.5 was only promoted when the silicate concentration reached 1 mmol L −1 . Cadmium(II) enhanced silicate sorption on γ-Al 2 O 3 at pH 5.5 and on goethite at pH 7.5, while it decreased silicate sorption on γ-Al 2 O 3 at pH 7.5 and had no significant effect on goethite at pH 5.5. At pH 5.5, Cd(II) reacted with silicate to generate Cd 2 SiO 4 , and Cd-Si-Al ternary complexes were formed on γ-Al 2 O 3 . At pH 7.5, silicate promoted the formation of Cd(OH) 2 on γ-Al 2 O 3 , which ultimately transformed into CdCO 3 . When silicate concentration reached 1 mmol L −1 , more silicate complexes were formed through the Fe-O-Si bound on goethite at both pH 5.5 and 7.5 to promote the adsorption of Cd(II) owing to its electronegative functional group on the surface of the complex. Conclusions The type of clay minerals, pH, and the presence of silicate all significantly affected Cd sorption. Furthermore, the sorption mechanism of Cd on γ-Al 2 O 3 and goethite in the presence of silicate has been elucidated. The above findings improve our understanding of the mechanism for immobilizing Cd in soils using silicon-containing materials.
研究领域:
土壤科学
·
环境化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2022
·
IF 6.437
Koïta Djakaria,Ziyue Tang,Jingai Shao,Xu Chen,Haoyu Xiao,Joseph Smith,Haiping Yang,Hanping Chen
Furfural is one of the top valuable building block chemicals, the selective production of furfural from biomass has attracted increasing concerns in recent years. In this work, a novel method for the selective production of furfural through cellulose catalytic pyrolysis with WO 3 /γ-Al 2 O 3 was reported, and the synergistic effect between γ-Al 2 O 3 and WO 3 was explored. Compared with cellulose pyrolysis alone, the addition of γ-Al 2 O 3 improved the selectivity of furans and greatly inhibited the formation of sugars; while, WO 3 addition promoted the formation of levoglucosenone . When (20–40%) WO 3 /γ-Al 2 O 3 were added, the amount of sugars was further reduced, and the yields of furans (furfural and 2-methylfuran, in particular) were further increased at the same time. Under the optimum conditions (temperature = 600 °C, residence time = 15 s, and catalyst to cellulose mass ratio of 4), 30%WO 3 /γ-Al 2 O 3 showed the best performance, and the selectivity and yield of furfural were improved by nearly 100% and 300%, respectively, as compared with cellulose pyrolysis alone. In addition, compared with γ-Al 2 O 3 , the addition of 30%WO 3 /γ-Al 2 O 3 further increased the yield of furfural and 2-methylfuran to about 50% and 200%, respectively. The high selectivity and yields of furans with WO 3 /γ-Al 2 O 3 addition might be due to that WO 3 crystals in the composite promote the formation of levoglucosenone, which is further converted to additional furans through the Lewis acid sites of γ-Al 2 O 3 . The study may provide some meaningful advices for improving the production of furfural from green catalytic pyrolysis of cellulose.
研究领域:
化学工程
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
Journal of Water Process Engineering
·
2020
·
IF 3.465
Yu Li,Luchao Wu,Yun Wang,Peng Ke,Jie Xu,Baohong Guan
Ozone decomposition into free radicals, which can be facilitated by enhancing electron transfer between ozone and catalyst, is an important segment in catalytic ozonation. We doped cerium uniformly on γ-Al 2 O 3 with an impregnation–calcination method to enhance electron transfer in catalytic ozonation of phenol in aqueous solution. The removal efficiency of phenol is raised from 39.7% by ozonation alone to 46.3% by catalytic ozonation with Ce/Al 2 O 3 in 50 min reaction. A higher Ce 3+ /Ce 4+ ratio in Ce/Al 2 O 3 witnesses a higher electron transfer rate in catalytic ozonation and thus a higher degradation efficiency of phenol, illustrating that the activity of Ce/Al 2 O 3 depends on the valence state of Ce. The electron transfer cycle is formed by the electron donation from Ce 3+ to ozone molecule and the electron acceptance of Ce 4+ from adjacent lattice oxygen. After getting the electron, the ozone molecule is decomposed to generate free radical of ·OH on the surface of Ce/Al 2 O 3 . The continuous flow experiments exhibit a stable and high catalytic activity of Ce/Al 2 O 3 for catalytic ozonation, implying the feasibility in practical application.
研究领域:
环境科学
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2020
·Vol. 150
·期 11
·3174-3183
·
IF 2.482
Wang Xun-Qiang,Li He,Yuan Qi-Yue,Liu Xiao-Qin,Liu Ding-Hua
Abstract Polycarbonate diols (PCDLs) are intermediates used in the synthesis of polyurethanes (PU), and therefore their efficient and green synthesis is a necessity. In this work, KOH/K 2 CO 3 @ γ -Al 2 O 3 catalysts were prepared and employed in the synthesis of PCDLs. A 4 wt% KOH/40 wt% K 2 CO 3 @ γ -Al 2 O 3 catalyst and a DMC: 1,4-BDO molar ratio of 1.25:1 exhibited the best activity for the reaction and gave a PCDL yield of 95% with a molecular weight of 4527 g·mol −1 . Moreover, the catalyst could be reused 4 times without a significant loss of the catalytic activity in transesterification. The effects of the catalyst composition and reaction conditions on the synthesis of PCDLs were investigated. The results indicate that the catalyst amount and the molar ratio of DMC: 1,4-BDO can influence the purity of PCDLs. Graphic Abstract The reaction equation
Catalyst preparation
The synthesis of PCDLs using DMC and 1,4-BDO
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
CARBOHYDRATE RESEARCH
·
2012
·
IF 2.332
Liqiang Wu,Zhikui Yin
A simple and clean synthesis of per- O -acetylation carbohydrate derivatives has been accomplished by treatment of sugars with a stoichiometric quantity of acetic anhydride under solvent-free conditions in the presence of sulfonic acid functionalized nano γ-Al 2 O 3 as an efficient and environmentally benign catalyst.
研究领域:
有机化学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）