ADSORPTION-JOURNAL OF THE INTERNATIONAL ADSORPTION SOCIETY
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2016
·Vol. 23
·期 1
·113-120
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IF 1.87
Chen Hongyin,Ding Jing,Wang Weilong,Wei Xiaolan,Lu Jianfeng
Post modification methods were used to synthesis MCM-41 with different pore sizes, modified by Al grafting and cation doping. Water adsorption characteristics were measured by dynamic water vapor adsorption and analyzed regarding equilibrium and kinetics. Results showed that Al grafting and cations doping modifications on MCM-41 changed water adsorption characteristics. Doped cations strengthened the water adsorption capacity at low RH following the order of Al–C12–Mg > Al–C12–Li > Al–C12–Na. Kinetics analysis indicated that capillary condensation process developed slowly due to low diffusion constant. But the adsorption transient uptake rates in capillary condensation sections were larger compared to other sections, Larger RH step not only resulted in larger uptake rate, but also promoted capillary condensation. Instead of calculating or measuring isotherms and diffusion coefficients respectively, parameters like transient uptake rate corresponding to the effects of both transport ability and adsorption capacity should be considered.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2021
·
IF 5.541
Xiaohua Li,Shengnan Ge,Shanshan Shao,Zhichao Lv,Xianliang Xiang,Yixi Cai
In order to promote the production of hydrocarbons in the catalytic pyrolysis of rape straw, a core-shell catalyst fabricated by external recrystallization method was employed. The composite catalyst HZSM-5@MCM-41 was prepared by varying the mass ratio of template and HZSM-5 (THR), and the effect of zeolite acidity and mesoporosity on the production of hydrocarbons was analyzed. A final pyrolysis temperature of 500 °C was suitable to obtain high yield of hydrocarbons over composite catalysts. Compared with ZSM-5 with a favorable pyrolysis temperature of 550 °C, a lower pyrolysis temperature meant a more efficient process, which may be related closely to the good diffusion of large-sized pyrolysis vapors over HZSM-5@MCM-41 catalysts. In addition, the highest yield of monocyclic aromatic hydrocarbons obtained over HZSM-5@MCM-41 with THR of 1 was 11.43 wt.%, which was boosted by 2.5 times compared with HZSM-5. A proper THR was suitable to fabricate a core-shell catalyst with excellent crystallinity, acidity and mesoporosity, and resulting in a high yield of hydrocarbons. Furthermore, the core-shell catalyst presents less formation of graphite-like coke, which indicated the easier removal of coke. Therefore, the composite HZSM-5@MCM-41 catalysts were more appropriate for upgrading of pyrolysis vapors for hydrocarbons.
研究领域:
能源与环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2024
·Vol. 14
·期 2
·142
·
IF 3.8
Dengke Li,Qinghao Shi,Fengbing Liang,Dexin Feng
Biodiesel is a non-toxic and environmentally friendly fuel that is made from renewable biological sources. It can replace petrochemical diesel and has very broad application prospects. However, the main raw materials in biodiesel are animal and plant oils, which present the problems of high costs and a lack of resources. The current research primarily emphasizes the transesterification process, with comparatively less focus on the esterification of fatty acids. In this paper, a series of phosphotungstic acid (PTA)-functionalized hydrophobic MCM–41 catalysts, OTS–PTA–MCM–41(Cx), were synthesized and used to catalyze the esterification of long-chain fatty acids with methanol in water. The experimental results show that the yield of esterification reached a maximum when catalyzed by OTS–PTA–MCM–41(Cx) and synthesized with a template agent with two carbon atoms less than the number of carbon atoms of a fatty acid. The effects of different reaction variables were investigated to optimize the reaction conditions for the maximum conversion. The stability of the catalyst was also verified. Finally, a mixed catalyst was used to catalyze in situ the esterification of fatty acids in a fermentation broth, which reached a high level (close to 90%). This paper provides references for the synthesis of a hydrophobic solid acid catalyst and green synthesis by esterification reactions in an aqueous solution and a fermentation broth system.
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
·
2017
·Vol. 7
·期 82
·52321-52326
·
IF 3.108
Zhenzhen Wu,Juan Li,Xian-Ming Zhang
In this study, we introduced 1H-1,2,4-triazole into the ordered nanochannels of propyl amino functioned MCM-41 and then investigated the hybrids' proton conducting performance. A high proton conductivity of 8.34 × 10−3 S cm−1 has been obtained at 120 °C, with 5 mol% mole ratio of dangling propyl amino and fully loaded 1H-1,2,4-triazole in the silica. The activation energy is 0.55 eV and 1.303 eV in the temperature range below and above 80 °C respectively, indicating that the charge transfer mechanism of the material involved both vehicle and Grotthuss process. The above results showed that loading of 1-H-1,2,4-triazole molecules into silica's ordered mesopores is a good strategy for excellent proton conductivity under intermediate temperature.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY
·
2018
·Vol. 120
·期 7
·1700415
·
IF 2.2
Meizhen Lu,Libo Peng,Qinglong Xie,Yong Nie,Xuejun Liu,Xianghong Lu,Jianbing Ji
At present, the utilization of grease has attracted more and more attention. This article presents a simple method that efficiently cleaves methyl oleate-derived methyl 9,10-epoxystearate ( a ) to give high yields of methyl 9-oxononanoate ( d ) with nonanal ( c ) as co-product. A WO 3 /MCM-41 catalyst is prepared via direct mixed-gel synthesis. The catalyst is tested in the oxidative cleavage of a to produce d which can be used as a polymer precursor or an important feedstock. The effects of WO 3 loading, temperature, time, H 2 O 2 / a molar ratio, catalyst/ a weight ratio, and t -BuOH/ a weight ratio on the a conversion and d yield are examined using single-factor experiments. The optimal reaction conditions are determined by orthogonal experiments. The optimal WO 3 loading, temperature, time, H 2 O 2 / a molar ratio, catalyst/ a weight ratio, and t -BuOH/ a weight ratio are 35%, 80 °C, 20 min, 1.3, 0.04, and 0.5, respectively. Under these conditions, the a conversion and d yield reach 99.4 and 78.4%, respectively. In addition, the catalyst shows no significant decrease in activity after being reused three times. Moreover, the reaction mechanism is studied based on the product distribution over time. Practical Applications : Few studies on methyl 9,10-epoxystearate used as the raw material to give methyl 9-oxononanoate and nonanal are found. Because the ethylene oxide bond is more unstable than the carbon–carbon double bond, the oxidative cleavage of methyl 9,10-epoxystearate is easier than cleavage of methyl oleate that allows the oxidative cleavage to be done under milder conditions. Methyl 9-oxononanoate can be converted to a monomer of high-value polymers and is also an important feedstock in the production of chemicals. The co-product nonanal is a natural spice which can be used in the fragrance industry. The results show that the reaction time is short and methyl 9-oxononanoate yield is high under mild reaction conditions. The method in this study can also be widely used in other oxidative cleavage reactions of epoxides. Methyl 9,10-epoxystearate is used as the raw material to produce methyl 9-oxononanoate with nonanal as co-product using WO 3 /MCM-41 as catalyst and H 2 O 2 as oxidant.
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
Catalysis Science & Technology
·
2018
·Vol. 8
·期 21
·5526-5534
·
IF 5.365
Songyan Jia,Xinjun He,Jiao Ma,Kangjun Wang,Zhanwei Xu,Z. Conrad Zhang
The synthesis of furan compounds by renewable carbohydrates has emerged as an important path toward biomass utilization. 5-Hydroxymethylfurfural (5-HMF) and furfural are two typical furan products from cellulosic and hemicellulosic materials, of which the primary components (hexoses and pentoses) undergo selective dehydration. It is worth noting that hemicellulose is rich in not only pentoses but also hexoses, indicating the feasibility of producing 5-HMF and furfural simultaneously. However, research on the production of 5-HMF from hemicellulose-derived hexoses remains lacking. Mannose, a major hexose component of hemicellulose, has been previously found to be a suitable feedstock for 5-HMF production in the presence of homogeneous catalysts, such as metal salts. In this work, Cr-, Al- and Sn/MCM-41 catalysts were prepared by a simple impregnation method and characterized. The conversion of mannose into 5-HMF was evaluated in dimethyl sulfoxide (DMSO) solvent. It was found that the as-synthesized Sn/MCM-41 catalyst showed a superior activity to Cr/MCM-41 and Al/MCM-41. Mannose could be effectively converted into 5-HMF with a yield of ∼45% and ∼88% conversion at 150 °C after 60 min, which were comparable to reported results over heterogeneous catalysts. The as-synthesized Sn/MCM-41 catalyst was also efficient for the conversion of glucose and fructose with reasonable 5-HMF yields. The Sn/MCM-41 catalyst could be reused for eight consecutive cycles without significant loss of catalytic activity.
研究领域:
生物化学
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催化化学
·
生物质利用
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2022
·
IF 4.171
Zhaoping Chen,Qin Wang,Ziyao He,Jiaming Li,Enrou Mei,Xiaojuan Liang,Weidong Xiang
CsPbX 3 (X = Cl, Br, I) perovskites have emerged as promising candidate lasing materials due to their high optical gain , low defect state density, and high absorption coefficient. Unfortunately, they suffer from poor stability, particularly with respect to temperature, moisture, and light exposure, preventing their use in practical optoelectronic applications , such as for amplified spontaneous emission (ASE) with an ultralow laser threshold. Herein, CsPbBr 3 @MCM-41 molecular sieve (CMM) composites are controllably prepared by different ultrasonication and stirring treatments. In addition, different perovskite concentrations and heat-treatment conditions are also considered to demonstrate the ASE behaviors. In addition, CMM@PS (CMMP) and CMM@AB (CMMA) composites were fabricated successfully by further optimizing the mixing ratio of CMM and the polymer. More excitingly, the stability of the CMM@polymer films with respect to the external environment is greatly improved after the polymer coating . To our surprise, the CMM@ploymer thin films demonstrated ASE at room-temperature, with an ASE threshold as low as 0.136 mJ/cm 2 and 0.049 mJ/cm 2 for CMMA and CMMP, respectively. These results clearly shed light upon the control and optimization of CsPbBr 3 perovskite composite films , paving the way for their widespread use in optoelectronic applications .
研究领域:
光学材料
·
纳米复合材料
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光电子学
·
激光物理
·
功能薄膜
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Zekai Miao,Rui Wu,Qinggong Liu,Xinran Han,Hao Ge,Runhao Suo,Jia Xue,Zongyun Jiang,Shengping Wang
Coal gasification fine slag (FS) containing residual carbon (RC) and slag particles (SP) can serve as carbon and silica precursor to prepare porous materials. This study reports the high performance porous carbon/mesoporous silica from gasification fine slag for CO 2 capture. Herein, FS was treated by chemical activation followed by hydrothermal treatment to prepare porous carbon/mesoporous MCM-41. The resulting material exhibited a high surface area of 1309 m 2 /g and pore volume of 1.03 cm 3 /g. After hydrothermal treatment, the mesoporous silica exhibited well-ordered hexagonal arrays of mesoporous channels. The physiochemical properties of the mesoporous silica remained nearly unchanged with the variation of hydrothermal parameters in the presence of porous carbon. The porous carbon facilitated the adsorption of dissolved silica, which promoted a second nucleation step, leading to the formation of additional nanoparticles. Those interaction weakened the effect of reaction conditions on the interaction between the precursor silica and surfactant. The porous composite showed excellent CO 2 capture performance, with a breakthrough time of 75 min in the fixed bed and a CO 2 adsorption capacity of 3.016 mmol/g. The CO 2 adsorption kinetics of the composite were consistent with the Avrami kinetic models for porous composites. This work realized the utilization of full-component fine slag to synthesize porous carbon/mesoporous MCM-41 material which was suitable for CO 2 capture.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Renewable and Sustainable Energy
·
2016
·Vol. 8
·期 5
·
IF 0.961
Lu Meizhen,Liu Xuejun,Li Yongqiang,Nie Yong,Lu Xianghong,Deng Dongshun,Xie Qinglong,Ji Jianbing
Bi-functional catalysts consisting of platinum on aluminosilicate MCM-41 materials with Si/Al ratios between 10 and 30 were prepared via direct mixed-gel synthesis. The catalysts were tested in the hydrocracking of bio-alkanes, produced from biodiesel hydrodeoxygenation and composed of n-hexadecane and n-octadecane, for the production of bio-jet fuel. The effects of temperature, pressure, weight hourly space velocity (WHSV), and H 2 /n-paraffin weight ratio on bio-alkanes conversion and product distribution were examined. The conversion was found to be dependent on the acid strength of the catalyst supports which were proportional to the Al content. However, the catalyst selectivity decreased with the increasing Al content. The optimal Si/Al ratio, temperature, pressure, WHSV, and H 2 /n-paraffin weight ratio were determined to be 20, 330 °C, 2 MPa, 1 h −1 , and 0.20, respectively. Under these conditions, the bio-alkanes conversion and kerosene/gasoline ratio in the product reached 65.62% and 1.96, respectively.
研究领域:
能源化学
·
催化材料科学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Ruoxin Hu,Zhenbo Cai,Lijun Ji,Yanyang Wu,Xiaohua Ma
Recovery of valuable aromatic compounds from tobacco waste is important, and efficient separation methods remain highly demanding. This work proposed a hybrid PDMS membrane for high flux aromatic compounds recovery. MCM-41, a silicone-based molecular sieve, was selected to fabricate the membrane to improve the pervaporation performance. The prepared MCM-41/PDMS membrane was investigated in model aqueous solution at different concentrations and temperatures. The optimal pervaporation fluxes of the MCM-41/PDMS membrane achieved 0.95 g/(m 2 ·h), 0.51 g/(m 2 ·h), and 0.26 g/(m 2 ·h) for 2-phenylethanol, β-ionone, and dihydroactinidiolide, respectively, exhibiting superior performance to the PDMS membrane. Moreover, the long-term stability of the hybrid membrane was examined with practical tobacco extract. The average fluxes were 41.20 mg/(m 2 ·h), 20.57 mg/(m 2 ·h), and 9.73 mg/(m 2 ·h), respectively. The hybrid PDMS membrane in this study, with high permeate flux and selectivity, is promising for recovery of aromatic compounds particularly from tobacco waste.
研究领域:
化学工程
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POROUS MATERIALS
·
2024
·Vol. 31
·期 3
·897-912
·
IF 2.5
Lu Qing,Wang Shougui,Ji Cailin,Chen Guanghui,Dong Jipeng,Gao Fei
Ionic liquid immobilization is an effective means for preparing metal-free heterogeneous catalysts for the CO 2 conversion. Herein, a series of quaternary ammonium ionic liquids functionalized MCM-41 heterogeneous catalysts, integrating hydrogen bond donors and nucleophilic ion sites, were prepared by a post-synthetic modification method for the CO 2 cycloaddition reaction. The physicochemical properties of the catalysts were analyzed by XRD, EA, SEM, TEM, BET, FT-IR, TGA, NMR and XPS. The results show that the quaternary ammonium ionic liquids are successfully immobilized onto the MCM-41 molecular sieves. The obtained catalysts maintain an excellent pore structure and have the good thermal stability. The effects of catalytic conditions on the catalytic performance, the recyclability of the catalysts and their generalizability to epoxide substrates were systematically investigated. In addition, the catalytic performance was evaluated for low concentrations of CO 2 (20% CO 2 , 80% N 2 ). The synergy of multifunctional active sites makes the obtained materials exhibit the high catalytic activity without metals, co-catalysts and solvents. Furthermore, a possible mechanism for the conversion of CO 2 to cyclic carbonate catalyzed by the MCM-41-N/CH 3 (1:3) was proposed.
研究领域:
化学工程
·
催化科学
·
材料科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2015
·
IF 4.321
Yixiang Bao,Xiaomin Yan,Wei Du,Xiaoni Xie,Zhaoqi Pan,Jialu Zhou,Laisheng Li
A thin-film composite ultrafiltration (UF) membrane grafted with amine-functionalized MCM-41 was prepared and used for removing heavy metals from aqueous solution. The porous NH 2 -MCM-41 nano-particles formed a uniform hydrophilic and adsorptive layer on the thin-film which endowed the composite membrane with affinity to heavy metals and better anti-fouling performance. The adsorption capacity of Cr (VI) and Cu (II) on membrane were 2.8 mg Cr/g and 3.7 mg Cu/g, respectively, and their adsorption processes reached equilibrium around 5 min. The continuous UF experiments demonstrated that the membrane can be used as an effective filter medium to purify the water containing trace heavy metals. The metals concentration in filtrates was maintained below initial concentration of 1 mg/L (Cu) and 0.5 mg/L (Cr) during the 7-hour filtration. The membrane’s adsorption capacity could be regenerated by being immersed in 0.5 M HNO 3 . Besides, to examine its anti-fouling performance, the model NOM (natural organic matter) water was used as a feed solution. The composite membrane showed not only slower irreversible fouling evolution but also higher rejection of NOM compared with that without grafting NH 2 -MCM-41. The method reported in this study was efficient to enhance the rejection and anti-fouling performance of UF membrane, what’s more, endowed the membrane with affinity to heavy metals.
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
危险品化学品经营许可证（带存储）