CERAMICS INTERNATIONAL
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2018
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IF 3.057
Shuang Yin,Senchuan Jiang,Limei Pan,Chao Liu,Yongbao Feng,Tai Qiu,Jian Yang
In this work, Si 3 N 4 ceramics were fabricated through an aqueous gelcasting method using a low–toxic monomer called N, N–dimethylacrylamide (DMAA) followed by gas pressure sintering at 1850 °C for 2 h under 6 MPa N 2 atmosphere. The effect of solid loading on performance of slurries, green and sintered bodies was investigated systematically. The results show that the slurries with a solid loading as high as 50 vol% (viscosity 0.17 Pa.s at 100 s –1 ) were achieved. With the increase of solid loading (30–50 vol%), the green bodies exhibited a monotonically decreased, however high enough in general, flexural strength of 16.50–11.52 MPa, which was comparable to that of widely–used neurovirulent acrylamide (AM) gelling system. In regard to the sintered bodies, increasing solid loading significantly promoted sintering and improved mechanical properties and thermal conductivity as a result of the increased density, bimodal distribution structure, as well as suitable interfacial bonding strength . The best performance parameters of Si 3 N 4 ceramics, bulk density of 3.25 g/cm 3 , apparent porosity of 0.67%, flexural strength of 898.92 MPa, fracture toughness of 6.42 MPa m 1/2 , Vickers hardness of 2.81 GPa, and thermal conductivity of 34.69 W m –1 K –1 , were obtained at 50 vol% solid loading. This work renders low–toxic DMAA gelling system promising prospect in preparation of high–performance Si 3 N 4 ceramics by gelcasting.
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CHEMICAL ENGINEERING JOURNAL
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2018
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IF 6.735
Yuanwu Hu,Hongjie Cui,Zhenmin Cheng,Zhiming Zhou
CO 2 capture and sequestration is one of the viable solutions to reduce the CO 2 emissions from fossil fuel combustion, and sorption-enhanced water gas shift (SEWGS) is a promising technology for pre-combustion CO 2 capture. In this study, a novel alkali metal salt (AMS)-promoted MgO-CaCO 3 sorbent was applied to the SEWGS process, and this sorbent exhibited fast sorption rate, high capacity and good stability in 30 CO 2 capture cycles. Catalyst and sorbent particles were arranged in a layer-by-layer alternating configuration in the reactor. The effects of operating conditions such as temperature, pressure and initial H 2 O/CO molar ratio were investigated, and the thermodynamic equilibrium analyses of the CO 2 sorption on AMS-promoted MgO-CaCO 3 and the SEWGS process in the layered configuration were carried out, based on which the optimization of the reactor configuration was performed. A high-purity H 2 (99.4% in dry basis) was experimentally achieved in the SEWGS process at 573 K, 12 atm and an initial H 2 O/CO molar ratio of 1.5 with a three catalyst/sorbent layered configuration, and the cyclic stability was demonstrated over 10 consecutive SEWGS cycles.
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JOURNAL OF APPLIED POLYMER SCIENCE
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2018
·Vol. 135
·期 46
·46759
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IF 1.901
Mingmin Jia,Yi Feng,Jianhao Qiu,Xiaocheng Lin,Jianfeng Yao
UiO-66-NH 2 nanocrystals were synthesized and embedded into bromomethylated poly(phenylene oxide)/polyethersulfone (BPPO/PES) polymer matrix to form UiO-66-NH 2 /BPPO/PES mixed matrix membranes (MMMs). The crystalline structure, interaction between UiO-66-NH 2 and BPPO, and dispersion of UiO-66-NH 2 were characterized by FTIR, XRD, and SEM. Nanoparticle dispersion was drastically enhanced with the assistance of BPPO, giving an improved adhesion between the polymer and filler particles. Owing to the intrinsic adsorption property of UiO-66-NH 2 and BPPO to CO 2 , the CO 2 permeability was significantly increased. As a result, the UiO-66-NH 2 /BPPO/PES membrane exhibited enhanced gas separation performance, where CO 2 /N 2 and H 2 /N 2 ideal selectivities were increased to 50.2 and 302.4 with a CO 2 permeability of 125.6 Barrer. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46759.
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Journal of Chemistry
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2019
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IF 1.727
Han Zhitao,Gao Yu,Yang Shaolong,Dong Jingming,Pan Xinxiang,Lan Tian,Song Liguo,Yan Zhijun,Sun Deping,Ning Kaixuan
Experiments were conducted to remove NO from simulated flue gas in a rotating packed bed (RPB) reactor with NaClO2 as wet scrubbing oxidant and diesel exhaust gas as carrier gas. The effects of various operating parameters (rotational speed, solution pH, NaClO2 concentration, liquid-gas ratio, and NO and SO2 concentrations) on NO removal performance were investigated preliminarily. The results showed that with the increase of rotational speed, oxidant concentration, and liquid-gas ratio, NO removal efficiency increased obviously. NO removal efficiency increased largely with the decrease of solution pH, and a complete removal of NO could be attained at pH 4. NO concentration imposed little effect on NO removal efficiency while coexisting SO2 in exhaust gas could enhance NOx removal greatly.
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JOURNAL OF CHROMATOGRAPHY A
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2018
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IF 3.716
Xiaohui Yan,Yingying Zhan,Dongdong Zhong,Yanshuo Li,Dapeng Wu
Solid-phase microextraction (SPME) coupled with thermal desorption-gas chromatography (TD-GC) has become a powerful analysis tool for volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) in water samples. However, water adsorption into polar microextraction phase is usually unavoidable during the extraction process, and the burst of large amounts of water vapour during thermal desorption will cause serious problems to GC separation and detectors. Pawliszyn’s group had demonstrated that the tens of micron-thick, defect-free polydimethylsiloxane (PDMS) coating could act as a perfect barrier for water adsorption and offer much better compatibility in complex matrices. However, the PDMS overcoat largely decreased the uptake rate of polar analytes into the inner sorbent. In order to quantify the effect of PDMS coating thickness on water adsorption amount and the extraction kinetics, ultrathin PDMS layer was used to coat the polar extraction phase with polyimide (PI) as a model in this work. It was surprising to find that the PDMS coating with the thickness less than one micron can decrease the water adsorption by 96%, while the extraction efficiency for polar analytes (phenolic compounds and nitroaromatic explosives) was decreased by less than 20% at the extraction time of 30 min. Moreover, the kinetic data showed that the thinner the PDMS coating was, the less the uptake rate of polar analytes into PI extraction phase decreased. Finally, polar poly (phthalazine ether sulfone ketone) (PPESK) extraction phase was also coated with ultrathin PDMS coating to verify the universality of the strategy. Generally, the water adsorption problem in polar SPME was overcome to a great extent, and the extraction efficiency of polar analytes was mainly preserved with this ultrathin PDMS coating, which could broaden the application of SPME in the environmental field.
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JOURNAL OF CHROMATOGRAPHY A
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2018
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IF 3.716
Yinhui Yang,Meiling Qi,Jinliang Wang
This work describes the separation performance of a star-shaped truxene-based material (denoted as EDOTT) as the stationary phase for capillary gas chromatography (GC). The EDOTT capillary column achieved the column efficiency of 5920 plates/m by n -dodecane, 4890 plates/m by naphthalene and 3960 plates/m by 1-octanol at 120 ℃. Its selectivity and retention behaviour were investigated by a number of mixtures of diverse analytes and their isomers. As a result, it showed advantageous performance for separations of apolar to polar analytes, especially phenols and alcohols, over its analogous TTT, TDT and TFT stationary phases. In addition, the EDOTT capillary column was investigated for its column loadability, repeatability and thermal stability, and was finally applied for the determination of isomer impurities in real samples. This work provides an alternative truxene-based stationary phase with high selectivity for polar analytes and demonstrates the key role of structural modification in developing a family of stationary phases with specific selectivity for targeted analytes.
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ChemNanoMat
·
2019
·Vol. 5
·期 9
·1244-1250
·
IF 3.431
Yuxiu Sun,Hongliang Huang,Xiangyu Guo,Zhihua Qiao,Chongli Zhong
Graphical Counter diffusion has been used to drive the in situ formation of mixed metal MOF membranes in a confined space with nanostructure arrays under hydrothermal conditions. Through this approach, a variety of mixed metal ZIF membranes can be synthesized on different kinds of porous substrates. The development of facile, versatile strategies for the fabrication of mixed component metal-organic framework (MOF) membranes is highly desired, but still very challenging due to the difficulty in controlling crystal growth rates of every single component in a specific confined space. It is difficult to adjust the formation of multicomponent MOF membrane in a controlled manner using conventional approaches such as secondary growth methods. Herein, we present a facile strategy that prepares the mixed metal zeolitic imidazolate framework (ZIF) membranes in situ in a confined space with nanostructure arrays under hydrothermal conditions using the counter diffusion mechanism. The counter diffusion of different metal ions from both the homogeneous bulk solution and the solid metal oxide nanostructure grown on substrate leads to the specific effective reaction zone by encountering with linker molecules at the interface. Subsequently, nucleation and crystal growth generate the continuous mixed metal MOF membranes. With this approach, a variety of mixed metal ZIF membranes were synthesized on different kinds of substrates. The prepared membranes exhibited good sieving effect to H 2 and heavier gas molecules during both single and mixed gas permeation tests. This work opens a fresh avenue for the synthesis of mixed component MOF membranes, and the counter diffusion effect can be intentionally adopted to the design and fabrication of selective mixed metal MOF membrane on various supports.
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RARE METALS
·
2025
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IF 11
Wang Ding,Qin Rui-Jie,Yu Jie-Jie,Hu Jin-Wu,Zhang Wen-Hui,Xu Hui,Xu Jing-Cheng,Liao Qiao-Bo,Li Hui-Jun,Wang Xu-Hui
The semiconductor gas sensors used for xylene gas detection in real time has been restricted by the inadequate sensitivity and selectivity. Constructing a bilayer cascade sensor with the catalysis-gas sensitivity synergistic is considered as an effective solution. Herein, the Ag@CeO 2 nanosheets are synthesized by heat treating the Ag@Ce-MOF, which synthesized via solvothermal method. The morphological evolution of cerium metal–organic framework (Ce-MOF), regulated by Ag ions, is investigated, and the transformation mechanism is proposed. The bilayer sensors were constructed by using WO 3 nanofibers, prepared via the electrospinning method, as the sensitive layer and the Ag@CeO 2 nanosheets as the catalytic layer, respectively. The bilayer sensors exhibit remarkable performance in response to xylene. The response value ( R a / R g ) of WO 3 /Ag@CeO 2 sensor to 10 ppm xylene gas reaches 32.13 at the operating temperature of 160 °C. Additionally, the sensor displays an exceptional response to even trace amounts of xylene, as low as parts per billion (ppb). The catalysis-gas sensitivity synergistic mechanism was elucidated by capturing catalytic intermediates using online mass spectrometry. These findings provide a novel strategy for benzene series (BTEX) sensor and offer a novel approach to prepare two-dimensional Ce-MOF and its derived materials with tailored properties. Graphical abstract
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CARBOHYDRATE POLYMERS
·
2025
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IF 12.5
Bingzhen Liu,Kun Wang,Fangfei Sun,Yongliang Zhuang,Hui Li,Lincai Peng
Winter jujube is prone to rapid ripening and deterioration during postharvest storage and transportation. This study developed a multifunctional chitosan (CS) composite film incorporating dialdehyde cellulose nanocrystal (DCNC) and carbon dots (CDs) derived from walnut green husks. DCNC functioned as cross-linking filler, while CDs served as active nanofillers. The CS composite film containing 3 wt% DCNC and 3 wt% CDs (CS/DCNC/CDs-3 %) exhibited significant improvements in UV-blocking, mechanical strength, gas barrier, and thermal stability, attributing to the formation of a dense film structure and synergistic effect of Schiff base and hydrogen bonding interactions among film components. Notably, this composite film demonstrated a high CO 2 /O 2 selectivity of 14.1, facilitating the creation of an ideal atmosphere inside the package. This composite film exhibited remarkable antioxidant activity and displayed potent antibacterial capacity through photocatalytic ROS generation, achieving inhibition rates of 90.8 % against S. aureus and 86.8 % against E. coli . Additionally, this film showed favorable biosafety and biodegradability, addressing food safety and environmental concerns. Postharvest preservation tests confirmed that this film assisted by light exposure effectively regulated physiological metabolism and delayed the ripening of winter jujube, highlighting its potential as an active modified atmosphere packaging material for perishable fruit preservation.
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JOURNAL OF SEPARATION SCIENCE
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2015
·Vol. 38
·期 15
·2700-2707
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IF 2.737
Xiudan Hou,Hui Yu,Yong Guo,Xiaojing Liang,Shuai Wang,Licheng Wang,Xia Liu
A new polyethylene glycol/graphene oxide composite material bonded on the surface of a stainless-steel wire was used for solid-phase microextraction. The layer-by-layer structure increased the adsorption sites of the novel fiber, which could facilitate the extraction of trace compounds. The polyethylene glycol/graphene oxide was characterized by Fourier transform infrared spectroscopy and elemental analysis, which verified that polyethylene glycol was successfully grafted onto the surface of graphene oxide. The performance of the polyethylene glycol/graphene oxide coated fiber was investigated for phenols and phthalate esters coupled with gas chromatography with flame ionization detection under the optimal extraction and desorption conditions, and the proposed method exhibited an excellent extraction capacity and high thermal stability. Wide linear ranges were obtained for the analytes with good correlation coefficients in the range of 0.9966–0.9994, and the detection limits of model compounds ranged from 0.003 to 0.025 μg/L. Furthermore, the as-prepared fiber was used to determine the model compounds in the water and soil samples and satisfactory results were obtained.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Yiran Xiong,Langlang Wang,Ping Ning,Jianfei Luo,Xiang Li,Li Yuan,Yibing Xie,Yixing Ma,Xueqian Wang
The rational design of catalyst structures holds paramount significance for realizing efficient catalytic reactions. In this study, an Fe 3 O 4 @MnO 2 core–shell catalyst was successfully synthesized using a facile one-pot method and applied in the selective oxidation of H 2 S in blast furnace gas. The introduction of the MnO 2 shell suppressed the further growth and aggregation of Fe species, leading to outstanding catalytic stability. Simultaneously, abundant oxygen vacancies facilitated the adsorption and activation of oxygen, thereby enhancing H 2 S oxidation. Experimental results revealed that the Fe 3 O 4 @MnO 2 catalyst (Fe/Mn = 4:1) displayed 100 % H 2 S conversion and 95.7 % sulfur selectivity at 150 °C in a humid gas stream containing O 2 and CO. Remarkably, no discernible decline in catalytic activity was observed after 170 h of operation, indicating the promising industrial prospects of this catalyst. This study provides an effective strategy for designing efficient and stable desulfurization catalysts.
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ACS Applied Materials & Interfaces
·
2017
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IF 7.504
Yu Wu,Pan Jia,Linli Xu,Zhangyan Chen,Linhong Xiao,Jinhua Sun,Jun Zhang,Yong Huang,Christopher W. Bielawski,Jianxin Geng
Here, we describe an in situ approach for growing polyepoxides from the surfaces of graphene oxide (GO) using a surface-initiated polymerization reaction. The polymerization methodology is facile and general as a broad range of epoxides carrying various functional groups have been successfully polymerized by simply adding GO powders in the epoxide monomers. The resultant polyepoxide grafted GO are found to show enhanced dispersibility in various common solvents and to exhibit increased d-spacing between the basal planes. In particular, grafting poly(2,3-epoxy-1-propanol) (PEP) to GO results in a composite (i.e., GO-g-PEP) that is dispersible in water and miscible with polyether block amide, i.e., Pebax MH 1657. Preliminary studies have indicated the membranes prepared using Pebax/GO-g-PEP composites exhibit enhanced CO2 permeabilities and selectivities in comparison to H2, O2, or N2. The excellent performance in gas separation is attributed to the layered structure of the GO-g-PEP sheets with enlarged d-spacing and the functional groups present on the PEP chains grafted to the surfaces of GO sheets.
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