SENSORS AND ACTUATORS B-CHEMICAL
·
2022
·
IF 9.221
Yue Song,Bing Yang,Ziyu Ma,Yang Song,Jianbo Sun
Development research as a NO 2 gas sensor has attracted extensive attention recently. However, how to improve the electrical conductivity of materials, adjust the band structure of materials through photoexcitation and improve the carrier lifetime is still a challenge. In this work, an S-doped In 2 O 3 structure (S x /In 2 O 3−x ) was synthesized by enforcing the simple hydrothermal method . Doping directly controls the distribution of structural defects and oxygen vacancies in the material structure, and the response to NO 2 increases by orders of magnitude under photoexcitation. Various structural characterization techniques examined the properties of the S x /In 2 O 3−x -based material. More specifically, its electro-optical properties and the impact of S doping on its energy band structure were thoroughly analyzed to investigate the origins of the enhanced responsivity .
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ATMOSPHERIC ENVIRONMENT
·
2022
·
IF 5.755
Jixing Liu,Shuping Zhu,Teng Guo,Bin Jia,Li Xu,Jun Chen,Ping Cheng
Naphthalene (Nap), one of the most abundant PAHs in the atmosphere, has been shown to be an important secondary organic aerosol (SOA) precursor. In this study, the gas- and particle-phases (Suspended Nap-coated polystyrene latex spheres (PSLs) generated by vaporization condensation) Nap ozonolysis were investigated in a 1000 L volume cubic Teflon smog chamber. Gas-phase products and Nap-SOAs were observed from the gas- and particle-phase Nap ozonolysis via homogeneous and heterogeneous reactions, respectively. The time-dependent size distribution and mass concentration of Nap-SOAs were analyzed using a scanning mobility particle sizer and a laboratory-developed single-particle aerosol mass spectrometry (SPAMS) instrument. The chemical components of the homogeneous and heterogeneous reaction products were analyzed on-line by single photo ionization mass spectrometry (SPIMS), SPAMS, as well as by thermal desorption gas chromatograph-mass spectrometry. The results showed that the chemical components of the gas-and particle-phase Nap ozonolysis were essentially the same, with the dominant products being phthalaldehyde, phthalic anhydride, 2-carboxybenzaldehyde, and benzoic acid ; Nap-SOA formation was attributed to the formation of new particles as well as the uptake of homogeneous and heterogeneous Nap oxidation products on the gas-phase or/and the particle surface. Based on the online measurement results, the reaction mechanism of Nap-ozonolysis also exhibits an initial carbon atom or double-bond attacks by O 3 , and kinetic analysis of Nap-coated PSLs ozonolysis shows a heterogeneous reaction rate constant of 2.55E-4 s −1 with R 2 = 0.984. This study provides a systematic approach to characterize the chemical and physical properties of the gas- and particle-phase Nap ozonolysis in real time, which will deepen our understanding of the migration and transformation of PAHs in the atmosphere.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2022
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IF 4.326
Lu Liu,Qi Wu,Shunli Wang,Wei Lai,Peijun Zheng,Can Wang,Xin Wei,Shuangjiang Luo
The recovery of helium from natural gas using membranes has attracted substantial attention, while very limited polymers were spun into hollow fibers and evaluated for realistic helium recovery. This work demonstrates the successful preparation of asymmetric and highly helium-selective hollow fiber membranes for the enrichment of helium from natural gas. A novel, aromatic copolyimide was designed and fabricated into hollow fiber membranes (HFMs) via the dry-jet/wet-quench spinning approach. The as-prepared HFMs display a He permeance of 85 GPU and high He-related gas selectivities of 140, 204, 448, and 609 for He/N2, He/CH4, He/C2H6, and He/C3H8 gas pairs, respectively. Particularly, ternary and quaternary mixed-gas permeation results reveal excellent light and heavy hydrocarbon resistance due to the competition between plasticization and gas sorption. The HFMs also demonstrated superior low-temperature gas separation performance and outstanding membrane gas separation stability, rendering them attractive for helium recovery.
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JOURNAL OF MEMBRANE SCIENCE
·
2022
·
IF 10.53
Ke Chen,Linhan Ni,Hao Zhang,Li Li,Xin Guo,Junwen Qi,Yujun Zhou,Zhigao Zhu,Xiuyun Sun,Jiansheng Li
The performance of mixed matrix membranes (MMMs) is significantly determined by the inherent structure and composition of incorporated nanofillers. In this work, the core-shell ZIF-8@RF nanofillers were prepared through a kinetically-controlled growth of zeolitic imidazolate framework-8 (ZIF-8) and polymerization of resorcinol and formaldehyde (RF), followed by being incorporated into the glassy 6FDA-Durene and rubbery Pebax 1657 via a physical blending approach to form MMMs. Benefiting from the enhanced interfacial compatibility, CO 2 affinity, and the intrinsic characteristics of porous ZIF-8, the resultant MMMs demonstrated outstanding performance for CO 2 /CH 4 separation. The CO 2 permeability and CO 2 /CH 4 selectivity of the ZIF-8@RF/6FDA-Durene (ZIF-8@RF/Pebax 1657) MMMs increased up to 1332.1/363 Barrer and 28.6/29.6, corresponding to an improvement of 65.4/116.3% of the CO 2 permeability and 49.7/53.4% of the CO 2 /CH 4 selectivity compared to the pristine membrane. Meanwhile, CO 2 /CH 4 selectivity of ZIF-8@RF MMMs increases by up to 33.0% and 28.1% in comparison to the ZIF-8 without RF layer MMMs, respectively. More importantly, both MMMs can maintain their extraordinary separation performance after stabilized in the existence of moisture. These results demonstrate that the separation performance of the MMMs was remarkably improved with the addition of ZIF-8@RF.
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Advanced Intelligent Systems
·
2022
·Vol. 4
·期 12
·2200169
·
IF 7.298
Wenjie Ren,Changhui Zhao,Gaoqiang Niu,Yi Zhuang,Fei Wang
Artificial senses like electronic nose, which ameliorates the problem of poor selectivity from single gas sensor, have elicited keen research interest to monitor hazardous gases. Herein, the doping effects of gallium on In 2 O 3 nanotubes (NTs) are investigated and a four-component sensor array for the detection of trimethylamine (TMA) is reported. All-gallium-doped/alloyed In 2 O 3 (Ga-In 2 O 3 ) sensors show improved sensitivity and selectivity to TMA at an operating temperature of 240 °C, with 5 mol% Ga-doped/alloyed one displaying the highest response in the range of 0.5–100 ppm and the lowest detection limit of 13.83 ppb. Based on the gas-sensing properties, a four-component sensor array is fabricated, which shows unique response patterns in variable-gas backgrounds. Herein, back propagation neural network (BPNN), radial basis function neural network (RBFNN), and principal component analysis-based linear regression (PCA-LR) are trained with the gas-sensing data to discriminate different gases with high accuracy, as well as to predict the concentrations of target gases in different gases and gas mixtures. Furthermore, accuracies of 92.85% and 99.14% can be achieved for the classification of six gases (three single gases and three binary gas mixtures) and for the prediction of TMA concentrations in the presence of different concentrations of TMA and acetone, respectively.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2023
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IF 4.4
Shangjun Lin,Wentao Liu,Xuehe Hou,Zhenyun Peng,Zhencheng Chen,Fangrong Hu
As an organic substance, n -propanol gas has been paid attention to in environmental monitoring and exhalation of lung cancer patient. In this paper a rapid detection method for n -propanol gas is developed based on molecularly imprinted polymers (MIP) and terahertz (THz) metasurface sensors. We first prepared a MIP suitable for detecting the n -propanol gas. And then the n -propanol MIP was modified to the THz metasurface sensor for detecting the n -propanol gas. Since the MIP adsorbed with n -propanol changes the dielectric environment of the sensor, the resonance frequency of the sensor also change. So we based on the n -propanol concentration was analyzed according to the change in resonance frequency. The experimental results showed that the sensor can effectively detect the n -propanol concentration in the range of 50–500 ppm (parts per million). In addition, we also verified the specificity and repeatability of the sensor. This work provides a new idea and method for the sensitive and specific detection of n -propanol gas.
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CHEMICAL ENGINEERING RESEARCH & DESIGN
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2022
·
IF 4.119
Mingyang Chen,Rui Yang,Pei Li
Since PMDA-ODA polyimide is insoluble, its soluble precursor PMDA-ODA poly (amic acid) (PAA) is used to prepare hollow fiber membranes (HFMs). Due to the existence of –CO–NH– and –COOH groups, PAA is subject to form hydrogen bonds with water and consequently leads to a very slow phase inversion rate during the non-solvent induced phase inversion process. Therefore, the hollow fiber spinning has to be carried out with a low take-up speed that limits the productivity. In this paper, we increased the take-up speed of PAA hollow fiber to 60 m/min by simply adding LiCl into polymer dope. Moreover, an integrally skinned defect-free PMDA-ODA hollow fiber membrane was obtained at the high take-up speed where the gas permeances were 6.8 ± 0.7, 2.2 ± 0.2, 0.4 ± 0.04 and 0.07 ± 0.01 GPU for H 2 , CO 2 , O 2 and N 2 , respectively, with an ideal selectivity of 3.1 ± 0.3, 31 ± 3.0 and 5.7 ± 0.6 for H 2 /CO 2 , CO 2 /N 2 and O 2 /N 2 , respectively. These results indicated a dense PMDA-ODA layer of 1 μm. To our best knowledge, this is the first time that a defect-free hollow fiber membrane for gas separation is prepared based on PMDA-ODA.
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ENERGY
·
2022
·
IF 8.857
Xiaoya Zang,Jing Wang,Yong He,Xuebing Zhou,Deqing Liang
Tetrabutylammonium bromide (TBAB) is a typical thermodynamic additive that can enhance the hydrate equilibrium temperature . Additionally, semi-clathrate hydrates formed from TBAB solutions exhibit reasonable CO 2 adsorption performance. In this study, TBAB hydrates were synthesized to determine their carbon capture capacity from a ternary gas mixture of CH 4 /CO 2 /N 2 (0.5/0.4/0.1). We measured the effect of temperature, pressure, and TBAB mass fractions (0.05–0.2) on the formation of gas hydrates, which were analyzed using Raman spectroscopy, powder X-ray diffraction (PXRD), and cryo-scanning electron microscopy (Cryo-SEM). With a 0.05 TBAB aqueous solution, the maximum recovery factor of CH 4 was 1.646 at 290.1 K and 7.0 MPa, whereas the maximum CO 2 split ratio was 0.454 at a pressure of 7.0 MPa and temperature of 280.1 K. Furthermore, the cryo-SEM images revealed that the addition of TBAB significantly increased the specific surface area of the hydrate crystals compared with the pure water system. PXRD and Raman spectroscopy showed that the hydrate structure transformed from a SI to a semi-clathrate hydrate. The hydrate samples formed from the 0.05 TBAB solution were found to be type A and B, leading to greater gas consumption. These results are expected to provide support for hydrate gas separation technology.
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AICHE JOURNAL
·
2022
·Vol. 68
·期 7
·e17662
·
IF 4.167
Guoxuan Li,Qinghua Liu,Chengmin Gui,Zhigang Lei
Deep eutectic solvents (DESs) as promising green drying agents were first proposed to natural gas (NG) dehydration. In this work, choline chloride (ChCl)-based DESs were prepared using ChCl as hydrogen bond acceptor (HBA) and triethylene glycol (TEG), ethylene glycol (EG) or Urea as hydrogen bond donors (HBDs). To explore the potential application, methane (CH 4 ) dehydration experiment was conducted to verify the dehydration performance using prepared DESs. The thermodynamic properties were predicted by COSMO-RS model (Conductor-like screening model for real solvents). The quantum chemistry calculation was applied to understand the separation mechanism at the molecular level. The absorption performance of H 2 O in DESs depends on the weak interaction between Cl atom (or N and O atom) of ChCl and H atom of H 2 O as well as the free volume of DESs. Molecular dynamics (MD) simulation discloses the intermolecular interaction between HBA and HBD. This work makes the first multi-scale analysis on NG dehydration using DESs.
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HIGH PERFORMANCE POLYMERS
·
2022
·
IF 1.73
Rui Yang,Ming Yang Chen,Pei Li
Carbon molecular sieve (CMS) membranes have excellent gas separation property over conventional polymeric membranes and superior anti-swelling property. PMDA-ODA polyimide has high thermal stability and good mechanical property. It has been extensively adopted as the precursor of CMS membrane. However, due to the insoluble nature, PMDA-ODA CMS membranes are limited to configurations like dense symmetric films or composite membranes using porous inorganic or metal substrates. In this work, CMS hollow fiber composite membranes based on an asymmetric PMDA-ODA hollow fiber were successfully prepared for the first time. The neat PMDA-ODA hollow fiber membrane was crosslinked by polyethyleneimine to alleviate pore collapsing during carbonization and then dip-coated by a PMDA-ODA PAA solution to seal the surface defects. The PDMA-ODA CMS composite hollow fiber membranes showed gas permeances of 93.4 GPU, 19.6 GPU, 6.5 GPU, and 4.7 GPU for CO2, O2, N2, and CH4, respectively, with an ideal selectivity of 14.4, 3.0, and 19.8 for CO2/N2, O2/N2, and CO2/CH4 gas pairs, respectively. The attractive gas separation property shows a great potential for industrial application.
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JOURNAL OF CHROMATOGRAPHY A
·
2022
·
IF 4.601
Tao Sun,Qiuchen Huang,Wei Zhang,Ruonan Chen,Wei Li,Haipeng Chen,Shaoqiang Hu,Zhiqiang Cai
Pillar[ n ]arenes possess highly symmetrical and rigid pillar-shaped architecture with π -electron rich cavity that afford their reliable host-guest recognition interactions towards matched guests. In this work, a novel amphiphilic pillar[5]arene (P5A-C10-2NH 2 ) was designed, synthesized and employed as the stationary phase for capillary gas chromatography. To date, they have not been reported in the field of chromatography. The P5A-C10-2NH 2 capillary column (10 m × 0.25 mm i.d.) was prepared by static coating method. Its capillary column exhibited moderate polarity and column efficiency of 2265 plates/m determined by naphthalene at 120 °C. As evidenced, the P5A-C10-2NH 2 column achieved advantageous separation performance for a mixture of 24 analytes of diverse types and exhibited different chromatographic selectivity from two pillar[5]arene derivatives columns and commercial HP-35 column with 35%-phenyl-methylpolysiloxane. Moreover, the P5A-C10-2NH 2 column baseline resolved more than a dozen positional and cis - trans isomers. Furthermore, the separation mechanism of P5A-C10-2NH 2 column was discussed by quantum chemical calculations. In addition, the P5A-C10-2NH 2 column had high thermal stability and excellent separation repeatability 0.01–0.04% for run-to-run, 0.03–0.17% for day-to-day and 3.2–3.9% for column-to-column. The special amphiphilic structure and high resolution for various analytes reveal the good potential of pillararenes as a new class of stationary phases for chromatographic analyses. Moreover, the TPG column achieved improved thermal stability over the GIL column and excellent repeatability.
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高影响因子
ELECTROANALYSIS
·
2022
·Vol. 34
·期 10
·1656-1665
·
IF 3.077
Xiaohui Zhang,Ping Li,Ziwei Zhang,Jinghan Guo,Zhongying Fang,Shemsu Ligani Fereja,Kaifan Liu,Xinjie Tong,Yue Zheng,Zongjun Li,Wei Chen
In this work, fabrication of Cu 2 O@Cu 1.75 S core-shell octahedrons was achieved through a facile water bath stirring process. Compared with pure Cu 2 O, the composite showed enhanced sensing performance for NO 2 . The response value of Cu 2 O@Cu 1.75 S to 5 ppm NO 2 at 40 °C is seven times that of Cu 2 O to 5 ppm NO 2 at 75 °C. Moreover, Cu 2 O@Cu 1.75 S has the ability to detect 100 ppb NO 2 and has good NO 2 sensing selectivity and long-term stability. This study shows that Cu 2 O@Cu 1.75 S hybrid is a type of outstanding NO 2 gas sensing material on account of its low working temperature and high sensing sensitivity.
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