JOURNAL OF ALLOYS AND COMPOUNDS
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2022
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IF 6.371
Fengjiao Chen,Yong Zhang,Dongyue Wang,Tian Wang,Jianhua Zhang,Dongzhi Zhang
This paper introduces a room temperature NH 3 gas sensor with excellent performance based on cobalt trioxide and molybdenum telluride (Co 3 O 4 -MoTe 2 ) nanocomposite. Co 3 O 4 nanofiber was synthesized by electrospinning, and MoTe 2 nano particle was synthesized by simple hydrothermal method . MoTe 2 , Co 3 O 4 and Co 3 O 4 -MoTe 2 film sensors were prepared on interdigital electrode substrate by drop coating method. X-ray photoelectron spectroscopy (XPS), dispersive spectrometer (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to observe the morphology, microstructure, and composition of the prepared nano-materials. The gas sensing performance of the pristine Co 3 O 4 , MoTe 2 and Co 3 O 4 -MoTe 2 composite film sensors were tested at room temperature. The results of experimental research show that the Co 3 O 4 -MoTe 2 gas sensor has better sensing performance for ammonia than the pure sensor, such as high response (56.20%@1ppm), excellent selectivity, good stability, short response/recovery time (7s/7s@1ppm) and low detection limit (26 ppb). The performance enhancement of the Co 3 O 4 -MoTe 2 film sensor was mainly attributed to the p-n heterojunction formed between MoTe 2 and Co 3 O 4 .
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SENSORS AND ACTUATORS B-CHEMICAL
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2022
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IF 9.221
Liu-Xin Cai,Li Chen,Xi-Qian Sun,Jing Geng,Chen-Chen Liu,Yue Wang,Zheng Guo
One-dimensional hetero-structured nanofibers (NFs) have recently received great attention because of their rich architectures and potential applications in the field of gas sensors. Polyoxometalate (POM) is a unique nanosized transition metal-oxygen cluster used as a molecular platform to prepare metal oxide nanomaterials and accompanied by high negative charges that readily combine with various metal oxide precursors to form metal oxide complexes. Herein, with the assistance of POM, ZnWO 4 /ZnO hetero-structured NFs were prepared by combining facile electrospinning with thermal oxidation . Adjusting the molar ratio of POM (H 3 PW 12 O 40 ·xH 2 O, denoted as PW 12 ) and Zn(NO 3 ) 2 ·6H 2 O (denoted as Zn 2+ ) in the precursor solution , a series of ZnWO 4 /ZnO hetero-structured NFs were obtained. Compared with pure ZnO NFs, the optimized ZnWO 4 /ZnO hetero-structured NFs demonstrate more excellent sensing performance. A high relative response of 108.5 was achieved for 50 ppm triethylamine (TEA) and with a low detection limit about 150 ppb. Furthermore, the ZnWO 4 /ZnO hetero-structured NFs exhibited remarkable TEA selectivity and outstanding reproducibility. The enhanced sensing mechanism toward TEA could be attributed to n-n heterojunctions with the obvious barrier-control electron transfer effect at the interface between ZnWO 4 and ZnO.
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Energies
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2022
·Vol. 15
·期 16
·5851
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IF 3.252
Yong Yao,Shizhu Li,Chuangting Chen,Dongchen Zheng,Zhichao Wu,Chi Yu,Shuying Pu,Fa-Qian Liu
MIL-53(Fe) was prepared and modified with benzoic acid to prepare MIL-53(Fe)-BA additive, which was used to improve the catalytic oxidation rate of sulfite, prevent the scaling of the desulfurization tower, and improve the desulfurization efficiency during the wet flue gas desulfurization (WFGD) process of power plants. MIL-53(Fe)-BA exhibits abundant Lewis acid sites because of the appearance of coordination unsaturated Fe atoms. Due to the excellent sorption capacity, Ca(OH)2was used as the main SO2desulfurizer. The composite desulfurizers were prepared by mixing MIL-53(Fe)-based additives and Ca(OH)2, and were characterized by SEM, XRD, and FT-IR. A desulfurization unit was set up at laboratory scale to study the effect of catalytic oxidation additives on sulfite oxidation and desulfurization efficiency. The results showed that the addition of MIL-53(Fe)-BA can increase the oxidation capacity of sulfite by 159%, and greatly improve the desulfurization efficiency. These composite desulfurizers broaden the adaptability of the desulfurizing system to high-sulfur coals, and provide support for improving the desulfurizing efficiency of power plants.Keywords:catalytic oxidation;oxidative desulfurization;wet flue gas desulfurization;calcium hydroxide;MIL-53(Fe);Lewis acid sites
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REACTIVE & FUNCTIONAL POLYMERS
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2022
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IF 4.966
Xiaona Huang,Yinchuan Wang,Xuguang Wang,Xiutian Yang,Hao Zhang,Fan Zhang,Chao Wang,Yungang Bai,Ying Liu,Jiarui Wang,Xinyue Wang,Hui Chi,Chao Zhou,Kun Xu,Pixin Wang
During the completion of a natural gas well , the annular gas migration of the cement paste significantly damages the cement quality. Thus, the cement with self-repairing property has great significance in oil well applications. In this work, chemically cross-linked hydrogels were synthesized by the solution polymerization of acrylamide , acrylic acid , and 2-(dimethylamino)ethyl methacrylate (DMAEMA) with NMBA as cross linker to plug the CO 2 -triggered microcracks in the cement paste. The mechanical strength of the hydrogel (Cu-PMAD) was significantly enhanced by complexation between Cu 2+ and the carboxyl group of the hydrogel network. As a self-healing plugging material, Cu-PMAD hydrogel powder was mixed with cement to prepare self-repairing cement slurry. The amphoteric structure of hydrogel was triggered by CO 2 due to the DMAEMA unit of the hydrogel was protonated, and the hydrogel can swell further by the anti-polyelectrolyte effect under CO 2 of nature gas and formation salt-bearing fluid. The good swelling ability and mechanical properties endowed the Cu-PMAD hydrogel with excellent plugging ability for cement microcracks triggered by CO 2 .
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Inorganic Chemistry Frontiers
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2021
·Vol. 8
·期 23
·5016-5023
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IF 6.569
Mengqi Bu,Yang Feng,Qingxun Li,Yiran Wang,Shou Feng,Kai Zhang,Yujie Jiang,Lili Fan,Zixi Kang,Daofeng Sun
Metal–organic framework (MOF) membranes with an ultra-small pore size (<4 Å) have shown great prospects in the highly selective separation of small gas molecules such as hydrogen, but their narrow channels may result in a low gas permeance. To improve the gas permeance of ultra-microporous MOF membranes, a stable covalent organic framework (COF) with large and uniform pores is doped to construct a binary COF/MOF all-nanoporous composite (ANC) membrane, equivalent to reducing the effective membrane thickness but avoiding the challenging ultra-thin membrane preparation. The COF synthesized by ball milling is combined with a metal gel to form a precursor membrane, which was then transformed to a COF/MOF ANC membrane by treatment with the MOF ligand vapor. A very small amount of solvent has been applied, offering an environmentally-friendly preparation process. Compared with the pristine MOF membrane, the COF/MOF ANC membranes possess a highly improved gas permeance from 22 GPU to 551 GPU with a slight sacrifice of selectivity; this introduces a new strategy to optimize the separation performance of MOF membranes.
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CHEMICAL ENGINEERING JOURNAL
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2021
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IF 13.273
Qingli Qu,Xiaoli Zhang,Hossein Ravanbakhsh,Guosheng Tang,Jian Zhang,Yankang Deng,Kevin Braeckmans,Stefaan C. De Smedt,Ranhua Xiong,Chaobo Huang
Core-shell multicompartmental microparticles have gained increasing attention as their architecture resembles the multicompartmental composition of eukaryotic cells. However, challenges remain in the fabrication of biocompatible multicompartmental microparticles at a sufficiently high scale. Herein, all-aqueous ‘mangosteen-like’ core–shell multicompartmental microparticles were created by an oil-free gas-shearing fabrication approach. Both the shell thickness and core size of thus obtained mangosteen-like microparticles can be easily finetuned. Mangosteen-like particles have well segregated (up to eight) compartments which are attractive to precisely control enzymatic cascade reactions. To illustrate the application potential, insulin releasing mangosteen-like microparticles (‘artificial pancreatic beta cells’) were developed.
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COMPOSITES SCIENCE AND TECHNOLOGY
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2021
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IF 8.528
Zhaofeng Wu,Shuai Cao,Qihua Sun,Furu Zhong,Min Zhang,Haiming Duan
The uniform dispersion of multi-wall carbon nanotubes (MWNTs) in waterborne polyurethane (WPU) matrix was achieved by in-situ polymerization and latex particles assisted dispersion, endowing the MWNT/WPU composite film with the enhanced tensile strength , elongation at break and thermal stability. Compared with pure WPU, the breaking strength , elongation at break and initial decomposition temperature of the MWNT/WPU composite were increased by 69.6%, 16.4% and 130 °C, respectively. The decomposition amount at 400 °C of MWNT/WPU composite is only about half that of pure WPU. The latex particles assisted dispersion also effectively improved the exposure rate of MWNTs, making it easier for MWNTs to contact the target gas molecules. Increased exposure rate and uniform dispersion of MWNTs, and rich functional groups of WPU improved the gas sensing performance, making the response of the flexible MWNT/WPU to O 3 be 4.1 times of the responses of pure MWNTs. The limit of detection for O 3 reached 38.4 ppb. The enhanced mechanical properties endowed the flexible MWNT/WPU composite with the high bending stability and long-term stability. After one month, the response of the MWNT/WPU was changed by 3% and the responses decreased by no more than 10% after bending 5000 times.
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INTERNATIONAL JOURNAL OF ENVIRONMENTAL ANALYTICAL CHEMISTRY
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2021
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IF 2.826
Xuan Luo,Xiang-Dong Qing,Xu-Chang Miao,Sen Xiang,Hong-Jun Chen,Xiao-Hua Zhang,Min He
In this study, PM10 samples at four locations of Loudi, China were collected from January 2017 to March 2017 and December 2017 to February 2018 at first. Then, a new analytical strategy of second-order calibration based on the alternating trilinear decomposition (ATLD) coupled with gas chromatography-mass spectrometry (GC-MS) was firstly developed for quantitative analysis of seven polycyclic aromatic hydrocarbons (PAHs) in these samples. This strategy is more sensitive and efficient than traditional chromatography not only, but also it can resolve the problems of baseline drift and peaks overlapping in chromatographic analysis. Without the need for intricate pretreatment process and any derivation reactions, useful qualitative and quantitative information of seven PAHs was quickly extracted from the GC-MS-Sample data array by replacing chemical or physical separation with mathematical separation. In validation samples, the average recoveries of seven PAHs ranged from (96.7 ± 4.8) % to (107.9 ± 4.2) %, and the root-mean-square errors of prediction (RMSEPs) were within the range of 0.03–0.35 μg mL−1. The highest concentrations of individual PAHs in these samples were for phenanthrene (1.34 μg mL−1 in monitoring station), acenaphthylene (0.79 μg mL−1 in municipal government) and chrysene (0.53 μg mL−1 in monitoring station). Identified by component analysis, coal combustion and vehicle exhaust were the most possible sources of Loudi, China. These results demonstrated that the proposed method is characterised as a more precise, simple and promising analytical strategy to identify and quantify PAHs in actual aerosol.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2021
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IF 7.312
Wei Xie,Yang Jiao,Zhili Cai,Hongyan Liu,Lili Gong,Wei Lai,Linglong Shan,Shuangjiang Luo
This paper reports two new series of benzimidazole functionalized polyimides and ionic polyimides for highly selective membranes with great potential for natural gas sweetening. It has been demonstrated that both the –NH groups in the benzimidazole moieties and the corresponding ionic groups after N -quaternization tighten the microporous structure and restrict polymer chain mobility through hydrogen bonding and electrostatic interaction. The BET surface areas and d -spacing values decrease with benzimidazole molar content or the degree of ionization. Consequently, a linear correlation between CO 2 permeability coefficients with benzimidazole molar content or degree of ionization was observed due to the decrease of CO 2 diffusivity, and the monotonic increase of CO 2 /CH 4 selectivities is ascribed to the increase of both diffusivity selectivity and solubility selectivity. The benzimidazole-based copolyimide and the ionic copolyimide membranes exhibited high CO 2 /CH 4 selectivity under high-pressure mixed-gas conditions. In particular, the copolyimide PI-0.75 membrane displayed a mixed-gas CO 2 permeability of 27 Barrer and CO 2 /CH 4 selectivity of 47 at 20 bar total pressure. The performance was much higher than those of the state-of-the-art commercial cellulose triacetate membranes for natural gas upgrading. The facile polymer synthesis and microporosity tunability, as well as the excellent mixed-gas separation performance, render the copolyimide membranes in this study promising towards economic membrane-mediated natural gas upgrading.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2021
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IF 7.312
Peiyu Jia,Junjie Liu,Jingjing Kong,Mingming Hu,Ning Qi,Zhiquan Chen,Shan Xu,Nanwen Li
Two series of 6FDA-based co-polyimide membranes were synthesized by adding different diamine monomer containing special functional groups: APAF (containing OH) and DABA (containing -COOH). The ODA/APAF and ODA/DABA series were heat treated at 450 °C and 350 °C, respectively. Thermal rearrangement of polymer chain segments is confirmed in ODA/APAF membranes by infrared spectroscopy, while addition of DABA in ODA/DABA membranes causes decarboxylation crosslinking. Positron lifetime measurements reveal existence of ultramicropores in polyimides. The thermal rearrangement in ODA/APAF membranes induces remarkable increase in both size and number of ultramicropores and therefore increase in fractional free volume (FFV), but the crosslinking in ODA/DABA causes significant decrease in both size and number of ultramicropores. The increase in FFV is favorable for gas permeation, but too large size of the micropore drastically deteriorates the gas selectivity. Finally, the ODA/APAF(3:7) shows a high CO 2 permeability of 127.4 Barrer with CO 2 /CH 4 selectivity of 34.2, which surpasses the 1991 Robeson upper bound. Besides, the ODA/DABA(3:7) exhibits a H 2 permeability of 22.6 Barrer with H 2 /CH 4 selectivity of 256.8, which also exceeds the 1991 Robeson upper bound. Our results indicate that the gas permeability and selectivity of polymer membranes can be effectively adjusted by tailoring the ultramicropore structures, and positron can provide precise information about micropores.
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JOURNAL OF MEMBRANE SCIENCE
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2021
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IF 8.742
Yanjiao Wang,Ge Yang,Hailing Guo,Xianglong Meng,Guodong Kong,Zixi Kang,Rémy Guillet-Nicolas,Svetlana Mintova
HKUST-1 nanocrystals (50–80 nm) were homogeneously dispersed in a polyetherimide (PEI) polymer matrix . The use of a capping agent (sodium formate) prevented the agglomeration of HKUST-1 nanocrystals in the casting solution. The highly dispersed HKUST-1 nanocrystals were found to strengthen the interactions with the PEI and minimize the interfacial holes by providing more accessible Cu unsaturated metal sites for the C O bonds on the five-membered rings of the PEI matrix. The PEI membrane loaded with 30 wt % HKUST-1 nanocrystals (30-N-HKUST-1/PEI) showed a high H 2 permeability (193.3 Barrer at 25 °C under 1.5 bar) and good ideal H 2 /CH 4 and H 2 /CO 2 selectivity factor of 101.7 and 20.6 in a single gas test, respectively. In the gas mixture test, it also showed a good separation performance, i.e., a H 2 /CH 4 and H 2 /CO 2 selectivity factor of 82.4 and 16.5 was measured, respectively. The 30-N-HKUST/PEI membrane was tested in a gas mixture at different temperatures (25–100 °C), different pressures (0–3 bar) and various time (5–72 h) to study the performance in more realistic conditions thus to be further considered in the separation of syngas.
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JOURNAL OF MEMBRANE SCIENCE
·
2021
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IF 8.742
Caijin Zhou,Bingqi Xie,Junxin Chen,Yiwei Fan,Jisong Zhang
The generation of Dean vortices in the membrane contactor is regarded as one of the critical technologies for gas-liquid mass transfer enhancement at low liquid Reynolds number. In this work, the gas-liquid mass transfer enhancement by Dean vortices in the curved hollow fiber membrane contactors is rapidly characterized based on the flux balance of gas across the membrane and dissolved in liquid. The effects of Reynolds number, curved diameter, liquid viscosity and rheology on the gas-liquid mass transfer enhancement with different curved shapes are systematically determined. The gas-liquid mass transfer correlations are proposed to describe the enhancement effect of Dean vortices on gas-liquid system with different viscosities. At the helical diameter of 6 mm and Reynolds number of 308, the enhancement factor is up to around 2.5. Furthermore, the trade-off relation between gas-liquid mass transfer intensification and energy consumption across the curved membrane contactors is investigated. The liquid velocity profile is also obtained by the finite element numerical simulation with COMSOL Multiphysics software to evaluate the Dean vortices intensity generated in different curved shapes, which agrees well with the experimental results.
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