PROPELLANTS EXPLOSIVES PYROTECHNICS
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2022
·Vol. 48
·期 1
·e202200102
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IF 2.134
Jie Li,Jinjiang Xu,Shiliang Huang,Shichun Li,Yu Liu
Many superfine processing techniques have been applied on desensitization of HMX. However, large-scale production of superfine HMX is still a big challenge due to the overloaded parameters, poor stability and capacity issue. Here, we developed a novel and facile gas-solid method to prepare superfine HMX, based on a process of solvent vapor permeation and removal. Superfine HMX with structure of stacking microcrystalline particles was achieved conveniently. Compared to pristine HMX, the characteristic height for impact initiation of the resultant superfine HMX increased from 23.30 cm to 112.20 cm. Moreover, the largely increased surface area of superfine HMX enhanced the interfacial interaction between HMX and binder, which remarkably enhanced the comprehensive mechanical performance of HMX-based polymer bonded explosives (PBXs). The compressive and tensile strength of the superfine HMX based PBXs were improved by 57.14 % and 120.27 %, respectively. This simple and reliable method can shed light on the design and preparation of energetic materials with better safety performance and optimized mechanical performance.
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JOURNAL OF CHROMATOGRAPHY A
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2022
·
IF 4.601
Ziqi Sun,Meiling Qi
This work presents the investigation of a novel CO 2 -based poly(ether-carbonate) copolymer, namely poly(propylene ether-carbonate)diol (PPCD), for gas chromatographic (GC) analyses. The PPCD column exhibited column efficiency of 4000 plates/m determined by naphthalene at 120 ℃ with the retention factor 6.23. Its separation performance was investigated by adopting a wide variety of analytes and isomers, including the isomer mixtures of alkanes, substituted benzene isomers with diverse groups, phenols and anilines, and the mixtures of organic solvents of high volatility, aliphatic amines and N-heterocycles. As a result, the PPCD column displayed distinctly higher resolving capability than the commercial columns described herein and achieved high column inertness towards acidic/basic analytes without involving any deactivation procedure. Additionally, it displayed excellent separation repeatability and reproducibility with the relative standard deviation (RSD) values less than 0.01% for within-day and in the range of 0.26% – 0.36% for between-day and 3.0% – 4.1% for between-column ( n = 4). Further, the PPCD column (30 m) was used to GC–MS analysis of the lemongrass essential oil and resolved more components well than the indicated commercial columns, evidencing its outstanding separation performance for analyses of complex samples. Up to date, the CO 2 -based poly(ether-carbonate) copolymers are not reported in the field of chromatography. This work demonstrates their promising future as a new type of selective and inert stationary phases for practical GC analyses.
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JOURNAL OF MEMBRANE SCIENCE
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2022
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IF 10.53
Can Wang,Zhili Cai,Wei Xie,Yang Jiao,Lu Liu,Lili Gong,Qi-Wei Zhang,Xiaohua Ma,Hongjun Zhang,Shuangjiang Luo
Thermally induced chemical crosslinking has attracted substantial attention for fabricating plasticization resistant membranes due to the facile structure tunability that enables the construction of robust and well-defined architecture for gas separation. In this study, we report a new series of dual thermally crosslinkable polyimides derived from 4,4′-diamino-2,2′-biphenyldicarboxylic acid (DCB) containing two carboxyl groups, and a systematic investigation of the thermal treatment above and below T g demonstrated the decarboxylation-induced crosslinking. The dual thermally crosslinked membranes were insoluble in common organic solvents and maintained excellent mechanical properties . Due to the evolution of CO 2 and collapse of chain segments during thermal treatment, the crosslinked membranes exhibited hierarchical microcavity size distribution featuring ultra-micropore size in the range of 2.0–6.0 Å and micropore size in the range of 6.5–10.0 Å. Gas transport properties of the crosslinked membranes were feasibly tuned through the chemical compositions and thermal treatment procedures. For instance, the CO 2 permeability of crosslinked 6FDA-DAM 0.7 -TFMB 0.1 -DCB 0.2 increased almost three-fold with only a slight decrease in CO 2 /CH 4 selectivity. The crosslinked membranes also demonstrated superior plasticization resistance with mixed-gas feed pressure up to 40 bar and excellent low-temperature gas separation performance at −30 °C, making them attractive for aggressive gas separations.
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APPLIED SURFACE SCIENCE
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2022
·
IF 7.392
Li-Wen Mao,Li-Yuan Zhu,Tao Tao Wu,Lei Xu,Xuan-Hong Jin,Hong-Liang Lu
Heterostructured Nb 2 O 5 /SnO 2 core-shell nanorods are synthesized by a facile hydrothermal strategy and atomic layer deposition (ALD). The SnO 2 shell thicknesses varying from 7 to 34 nm exhibit a significant impact on sensing performance. The response enhancement mechanism of the Nb 2 O 5 /SnO 2 core-shell nanorods is illustrated based on the electron-depletion model. The Nb 2 O 5 /SnO 2 core-shell nanorods gas sensors were synthesized based on the micro-electromechanical systems (MEMS), which could provide variable operating temperatures for the gas sensors with highly integrated design and low power consumption. The response of the Nb 2 O 5 /SnO 2 core-shell nanorods gas sensor deposited with 20 nm SnO 2 shell towards 20 ppm H 2 S at 275 °C was 4.0, which showed a 3.8-fold of improvement compared with pristine Nb 2 O 5 nanorods. Furthermore, the well-structured core-shell nanorods gas sensors maintained stable performance after three months, presenting long-term stability and repeatability. The proposed Nb 2 O 5 /SnO 2 core-shell nanorods gas sensors demonstrate a potential strategy for the practical application in oil and gas drilling platforms and other industrial fields.
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POLYMER
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2022
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IF 4.432
Weilian Wu,Hongchao Niu,Shiqing Lai,Chanjuan Liu,Li Zhou,Xiaohua Huang
A series of random 6FDA-MFPAP/BAMF co-polyimides with different MFPAP:BAMF molar ratios (2:1, 1:1, 1:2, and 1:3) were synthesized from a novel diamine, 4-(3-methoxy-4-(difluoromethoxy)-phenyl)-2,6-bis(4-aminophenyl)pyridine (MFPAP); a commercial fluorene diamine (BAMF); and a dianhydride, 4,4'-(hexafluoroiso-propyl)diphthalic anhydride (6FDA). The prepared co-polyimides exhibited outstanding thermal performances ( T g > 345 °C, T d > 509 °C), good optical properties (λ cut-off > 342 nm, λ 80% > 410 nm), and hydrophobic properties (contact angle >91.8°). They also showed excellent solubility in both high and low boiling point organic solvents . The pure gas (He, CO 2 , O 2, and N 2 ) permeability of the co-polyimide membranes was measured using the constant volume-variable pressure method. The gas permeabilities of the membranes were superior to those of the commercial Kapton, Matrimid and P84, where the He permeability coefficient of 6FDA-MFPAP/BAMF (2:1) was 55.39 barrer. This can be reasonably explained and supported by the fractional free volume and molecular chain spacing of the polyimides . In addition, the gas transport performances of the copolymers have significantly improved over their corresponding homopolymers (6FDA-MFPAP and 6FDA-BAMF). And the 6FDA-MFPAP/BAMF co-polyimides with 2:1 and 1:1 M ratios of MFPAP/BAMF had the best gas separation performance for the gas pairs He/CO 2 and O 2 /N 2 , respectively, which was close to the Robeson upper limit in 1991.
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SENSORS AND ACTUATORS B-CHEMICAL
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2022
·
IF 9.221
Jingfeng Weng,Junzhe Zhang,Chunyu Zhang,Jin Lv,Jinhui Liu,Chengqian Zhou,Jun Yuan,Min Wang,Dongqing Xu,Yun Zhong,Wenli Chen
Citrus Huanglongbing (HLB) is incurable, so it is necessary to develop an accurate and timely detection method for citrus HLB. Volatile organic compounds (VOCs) of plants can be used as an indicator of their health status. Based on the difference of VOCs between healthy and HLB citrus leaves, we designed the polyethyleneimine (PEI)-modified carboxylic multi-walled carbon nanotubes (CNT-COOH) gas sensor and used it in the diagnosis of citrus HLB. Our PEI/CNT-COOH sensor showed significant impedance responses to four citrus HLB biomarkers VOCs (ethylhexanol, phenylacetaldehyde , linalool and methyl salicylate) with sensitivity up to single-digit ppm. We then used the sensor to detect the VOCs in citrus leaves, and found that the diseased citrus can be distinguished from the healthy citrus according to the different response values of the sensor, successfully identified HLB-infected citrus. Compared with the conventional qPCR method, PEI/CNT-COOH sensor not only has higher accuracy, but also can be used in real time field detection of citrus leaves due to its less stringent operating condition and portability.
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SENSORS AND ACTUATORS A-PHYSICAL
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2022
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IF 4.291
Hang Liu,Bing Liu,Peihua Li,Wenlong Kang,Yuhong Zhang
In this paper, the SnO 2 and Ce/SnO 2 nanomaterials are synthesized through a simple hydrothermal route and used for detecting NO 2 gas . The SnO 2 materials exhibit a good linearity for NO 2 detection, and the limit of detection is calculated to be as low as about 5 ppb at 10% humidity. The humidity dependence of the gas sensing characteristics of metal oxide semiconductors has been one of the greatest obstacles for gas sensor applications . The NO 2 gas sensing response of SnO 2 and Ce/SnO 2 also are investigated at 50% humidity. The Ce/SnO 2 materials show higher response than pure SnO 2 . The gas sensing mechanism of Ce/SnO 2 material is discussed in detailed. The reach results provide a new way for increasing the anti-humidity of the metal oxide semiconductor gas sensor.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 33
·e52810
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IF 3.057
Zhirong Hu,Jiayu Miu,Xiong-Fei Zhang,Mingmin Jia,Jianfeng Yao
UiO-66-NH 2 (Zr-based metal organic framework) is integrated into cellulose acetate (CA) to fabricate mixed matrix membranes (MMMs) through solvent-casting approach. To regulate the interfacial compatibility and suppress the non-selective voids, UiO-66-NH 2 with different particle sizes are investigated. The introduction of UiO-66-NH 2 provides additional pathways for gas molecules and renders the membrane with high CO 2 affinity, substantially augmenting the separation efficiency of UiO-66-NH 2 @CA composite membrane. By optimizing the particle size of UiO-66-NH 2 , the non-selective voids and the particle agglomeration can be effectively restricted. The optimum separation performance is obtained by U-100@CA membrane (UiO-66-NH 2 : 200 nm in size), exhibiting a CO 2 permeability of 168.8 Barrer with CO 2 /N 2 and CO 2 /CH 4 ideal selectivities of 40.2 and 51.3, respectively. The separation mechanism is ascribed to the presence of sufficient amine groups, the high CO 2 solubility of CA matrix, and superior inorganic–organic interfacial property.
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SENSORS AND ACTUATORS B-CHEMICAL
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2022
·
IF 9.221
Qin’an Zhou,Chengyu Zheng,Luyi Zhu,Jun Wang
P-type SnS and n-type SnS 2 can form SnS x heterostructure and the unique structure has been proved to possess better sensing properties. In this work, a series of SnS x was synthesized by a one-step hydrothermal method at different S/Sn molar ratios . And the QCM transducer provided a platform for SnS x samples to realize high sensitivity detection of TMA gas at low concentration (below 10 ppm threshold limit). The TMA sensing sensitivity improved as the content of SnS x heterostructure increased in 40 % RH at 25 ℃. The SnS x prepared in the S/Sn ration of 6 exhibited the best sensitivity (−22.29 Hz/ppm), good selectivity and stability with the limit of detection (LOD) of 770 ppb, suggesting the TMA sensing enhancement of SnS x heterostructure. Density functional theory (DFT) simulations verified the improved sensing response of SnS x heterostructure was ascribed to the p-n junction and weak hydrogen bonds . This heterostructure may contribute to the further development of QCM gas sensors for TMA sensing in the monitoring of food freshness and environment.
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PLASMA SCIENCE & TECHNOLOGY
·
2021
·Vol. 23
·期 11
·115503
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IF 1.567
Xinghao LIU,Cheng CHENG,Zimu XU,Shuheng HU,Jie SHEN,Yan LAN,Paul K CHU
Tetracycline (TC) is an antibiotic mainly used in livestock production and respiratory infection. Traditional methods are not effective in removing TC from solution. In this study, TC was degraded by gas–liquid plasma in the presence of rGO-TiO2 in solution. The rGO-TiO2 was prepared by modified hummers and hydrothermal method. The electrical and optical properties of the gas–liquid discharge plasma were studied and the produced long-lived reactive species were analyzed by spectrophotometer. The degradation efficiency of TC was improved by 41.4% after plasma treatment for 12 min in presence of 30 mg l−1 rGO-TiO2 compared to that with plasma alone. The degradation efficiency increased with increasing discharge power, but as the initial concentration was increased from 20 to 80 mg l−1, the degradation efficiency of TC decreased. The initial pH had no significant effect on the degradation of TC. The intermediate products were determined by UV–vis spectrophotometry and ESI (+)–MS, and the degradation mechanism was analyzed. The reactive species, including O3, ·OH, and H2O2, etc., produced in the plasma/catalyst system attracted electron-rich functional groups (amino group, aromatic ring, and double bond). Therefore, the gas–liquid plasma/catalyst system could be an effective and promising method for pharmaceutical wastewater treatment in future.
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CHEMICAL ENGINEERING JOURNAL
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2021
·
IF 13.273
Zepeng Rao,Guanhong Lu,Lu Chen,Asad Mahmood,Gansheng Shi,Zixia Tang,Xiaofeng Xie,Jing Sun
To identify the distinctive role of reactive oxygen species (ROS) and trace the intermediates not only help to decompose the pollutants in high efficiency but also for avoiding more harmful intermediates formed. Here, we developed a new method to generate different ROSs by controlling the atmosphere to distinguish their role in the degradation of flowing gas-phase VOCs, including o -xylene, styrene, and acetaldehyde. This method is in good agreement with the traditional sacrificial agent capture experiment. The results show that • OH radicals play a dominant role in the degradation of o -xylene and styrene, while • O 2 − radicals primarily take part in the acetaldehyde degradation. Additionally, we distinguish the role of holes, • OH and • O 2 − played during the VOCs photo-oxidation through the radical trapping, in situ DRIFTS, and GC-MS analysis. Under the attack of • O 2 − radicals, aromatic VOCs were photo-oxidized to intermediates containing benzene rings and ketones (i.e., toluene and butanone), while carbon chain compounds (i.e., 3-methylfuran and ethanol) tend to form under the action of • OH and holes. This can be associated with the different reaction paths initiated by ROS. For acetaldehyde removal, •O 2 − species facilitate the formation of acids (i.e., acetic acid) while the •OH species and holes lead to the production of ketones (i.e., acetone). This work provides deep understanding on the role of various ROS in the photocatalytic oxidation of VOCs, which can guide the design of efficient photocatalysts, selective formation of intermediates to be easily decomposed or as raw materials for further application.
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JOURNAL OF HAZARDOUS MATERIALS
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2021
·
IF 10.588
Shangbo Zhou,Shuchan Peng,Zhiqiang Li,Daijun Zhang,Yantao Zhu,Xingquan Li,Mingyu Hong,Weichang Li,Peili Lu
As hydraulic fracturing (HF) practices keep expanding in China, a comparative understanding of biological characteristics of flowback and produced waters (FPW) and sludge in impoundments for FPW reserve will help propose appropriate treatment strategies. Therefore, in this study, the microbial communities and functions in impoundments that collected wastewaters from dozens of wells were characterized. The results showed that microbial richness and diversity were significantly increased in sludge compared with those in FPW. The vast majority of microorganisms found in FPW and sludge are organic degraders, providing the possibility of using these indigenous microorganisms to biodegrade organic compounds. Our laboratory findings first show that wastewater pretreatment using these microorganisms was effective, and organic compounds in FPW from different shale formations were removed by 35–68% within 72 h in a wide temperature range (8 – 30 ℃). Meanwhile, highly toxic compounds such as phthalate esters (PAEs), polycyclic aromatic hydrocarbons (PAHs), and petroleum hydrocarbons were effectively eliminated in reactors. The main microorganisms, key functional genes, and putative pathways for alkanes, PAHs, and PAEs degradation were also identified.
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