Crystals
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2022
·Vol. 12
·期 7
·948
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IF 2.67
Haolong Zhai,Xiaoping Cui,Yuping Gan
Taking the combustion tear gas mixture as the research object, the system formula was optimized by adding a different mass fraction of 5-amino-1H-tetrazole(5AT). TG-DSC, a thermocouple, and a laser smoke test system were used to characterize the characteristic combustion parameters such as combustion temperature and velocity, as well as the end-point effects such as smoke concentration and particle size. Starink’s method, the Flynn–Wall–Ozawa method, and the Coats–Redfern method were used to evaluate the pyrolysis kinetic parameters of the samples. The results show that when the mass fraction of 5-amino-1H-tetrazole in the system is 10%, the maximum combustion temperature of the sample decreases by nearly 70 °C and the smoke concentration increases by 12.81%. The kinetic study also found that with a different mass fraction of 5-amino-1H-tetrazole in the system, the main reaction model of the mixed agent in the first, third, and fourth stages of pyrolysis changed significantly, but for the second stage of sample pyrolysis, the main reaction model (the A4 model) showed a high degree of consistency, which can be considered as the thermal diffusion stage of the tear agent capsicum oleoresin (OC) (the temperature range is 220~350 °C), which is highly consistent with the results of the TG-DSC analysis. It was also confirmed that OC’s thermal diffusion is mainly concentrated in this stage. The results of this study show that adding an appropriate amount of the combustible agent 5-amino-1H-tetrazole to the combustion tear gas mixture can improve its combustion performance and smoking performance, which provides an important, new idea for the development of a new generation of safe, efficient, and environmentally friendly tear gas mixtures.Keywords:5-amino-1H-tetrazole;tear gas mixture;combustible agent;combustion pyrolysis characteristics;dynamics research
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Haochen Qi,Chuang Xing,Weiguo Huang,Mingquan Li,Yujia Jiang,Xu Sun,Heyang Liu,Peng Lu,Jiangang Chen,Shuyao Chen
Fischer-Tropsch (FT) synthesis as a strongly exothermic reaction has diffusely manufactured clean fuels from syngas. However, it is difficult to obtain the concentrated product distributions. Here, we design ZSM-5 encapsulated cobalt particles on the thermal conductivity of the SiC matrix. The Co@NaZSM-5/SiC capsule catalyst with hierarchical structure is ingeniously assembled through a solvent-free synthesis route. Due to the joint functions of acidic zeolite , SiC thermal conductivity and macropores, the olefin selectivity enhances to 32.3% on the Co@NaZSM-5/SiC catalyst. Moreover, the ratio of O 5-11 /C 5-11 approaches 49.1% suggesting the elevated middle olefin proportion. The H + ion-exchanged Co@HZSM-5/SiC capsule catalyst shows a high isoparaffin selectivity of 27.3%, since the olefin isomerization reaction is accelerated over strong acid sites. Besides, Co 2 C phase is readily formed during the FT reaction, which is an activity center for olefin synthesis. The capsule catalyst with the proper acidity, thermal conductivity, and hierarchical structure is a promising prospect for tuning production distribution in FT reaction.
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ELECTROCHIMICA ACTA
·
2022
·
IF 7.336
Yang Huang,Tianyi Gao,Chong Sun,Tingting Han,Mingwu Zang,Daoying Wang,Weimin Xu
In this study, an electrochemical platform based on a novel ternary nanocomposite of advantageously united gold nanoparticles , polypyrrole and graphitic carbon nitride (Au-PPy@ g- C 3 N 4 ) for detection of guanosine-5’-monophosphate (GMP) was designed. Owing to the π-π stacking interaction between the ring structures of the nucleobases in GMP and the hexagonal cells original from g -C 3 N 4 in Au-PPy@ g- C 3 N 4 , the irreversible oxidation of GMP occurred with the potential of 1.08 V (vs. SCE) in phosphate buffer solution (PBS). Under the optimized conditions, the peak currents were linear with the concentration of GMP ranging from 0.05 to 200 μg•mL −1 with a detection limit of 0.028 μg•mL −1 (S/N=3). Meanwhile, the Au-PPy@ g- C 3 N 4 /APTES/GCE sensor exhibited good stability, high reproducibility and acceptable anti-interference ability. Importantly, the results of the detection of GMP with the proposed sensor were well consistent with the data determined by high performance liquid chromatography (HPLC), indicating a promising platform for evaluation of soup quality.
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Applied Sciences-Basel
·
2022
·Vol. 12
·期 8
·3769
·
IF 2.838
Wei Ma,Dong Ye,Haining Wang
Herein, a series of Co-Fe mixed oxide modified ZSM-5 adsorbents were synthesized using the ultrasonic-assisted impregnation method for the capture of elemental mercury. In comparison with other samples, Co4Fe1-ZSM-5 produced a relatively better performance, with the removal efficiency of around 96.6% Hg0and the adsorption capacity of around 901.63 ug/mg Hg0achieved at 120 °C. The interaction between CoOxand FeOximproved the reducibility of oxygen species, thus promoting the oxidation of Hg0. Among a variety of other gas components, O2and NO exerted a positive effect on Hg0, which improved its removal to a certain extent. By contrast, SO2caused an adverse effect on the capture of Hg0, which could be reversed to some degree by the introduction of 5% O2. After five cycles, the mercury removal efficiency of Co4Fe1-ZSM-5 remained above 90%, suggesting excellent recyclability. Finally, XPS analysis was conducted to reveal that Mars–Maessen mechanisms are dominant in the process of mercury adsorption.Keywords:Hg0adsorption;ZSM-5;cobalt oxide;iron oxide;regeneration
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ENVIRONMENTAL RESEARCH
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2022
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IF 8.431
Mingyu Li,Yuhan Ma,Jingjing Jiang,Tianren Li,Chongjun Zhang,Zhonghui Han,Shuangshi Dong
Heterogeneous photo-Fenton technology has drawn tremendous attention for removal of recalcitrant pollutants. Fe-based metal-organic frameworks (Fe-MOFs) are regarded to be superior candidates in wastewater treatment technology . However, the central metal sites of the MOFs are coordinated with the linkers, which reduces active site exposure and decelerates H 2 O 2 activation. In this study, a series of 2, 5-dioxido-1, 4-benzenedicarboxylate (H 2 DOBDC)-functionalized MIL-100(Fe) with enhanced degradation performance was successfully constructed via solvothermal strategy. The modified MIL-100(Fe) displayed an improvement in photo-Fenton behaviors. The photocatalytic rate constant of optimized MIL-100(Fe)-1/2/3 are 2.3, 3.6 and 4.4 times higher compared with the original MIL-100(Fe). The introduced H 2 DOBDC accelerates the separation and transfer in photo-induced charges and promotes Fe(II)/Fe(III) cycle, thus improving the performance. •OH and •O 2 − are main reactive radicals in tetracycline (TCH) degradation. Dealkylation, hydroxylation, dehydration and dealdehyding are the main pathways for TCH degradation.
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高影响因子
CHEMOSPHERE
·
2022
·
IF 8.943
Guohua Li,Xianjin Qi,Nina Yang,Xiaoxu Duan,Aimin Zhang
Molecular sieves have also been used for arsenic adsorption in recent years because of their special structure. In order to solve the problem of arsenic pollution in drinking water and/or industrial wastewater , ZSM-5/Fe adsorbent was prepared by loading iron on ZSM-5 molecular sieve. It is also used as an excellent adsorbent for removing arsenic and other heavy metal ions from industrial wastewater. At room temperature, the concentration of arsenic was reduced from 100 mg/L to 0.006 mg/L after the solution pH was adjusted to the range of weak acid to weak base (4–10) and 0.5 g of ZSM-5/Fe adsorbent was added for reacting 2 h. The adsorption capacity reached 40.00 mg/g, the adsorption efficiency reached 99.99%, reaching the national standard of drinking water. Adsorption thermodynamics, kinetics and isotherms showed that the adsorption mechanism of arsenic is heterogeneous nucleation adsorption (including electrostatic attraction and chemical precipitation). Moreover, ZSM-5/Fe adsorbent can adjust pH spontaneously by using non-skeleton Si–Al phase to achieve effective adsorption from weak acid to weak base. At the same time, ZSM-5/Fe adsorbent showed good reusability and stability in five cycles. This study provides an important idea for the application of ZSM-5 molecular sieve in many fields and the efficient removal of arsenic from drinking water and industrial wastewater.
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2022
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IF 3.898
Qian Zhu,Yan Zhuang,Hongqing Zhao,Peng Zhan,Cong Ren,Changsheng Su,Wenqiang Ren,Jiawen Zhang,Di Cai,Peiyong Qin
The selective oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-diformylfuran (DFF) is an important reaction for renewable biomass building blocks. Compared with thermal catalytic processes, photocatalytic production of DFF from HMF has attracted tremendous attention. Herein, the MoS 2 /CdIn 2 S 4 (MC) flower-like heterojunctions were prepared and considered as photocatalysts for selective oxidation of HMF into DFF under visible-light irradiation in aqueous solution. Results demonstrated MoS 2 in MC heterojunction could promote the separation of photoexcited electron-hole pairs, while the amount of MoS 2 dropping was proved influenced on the photocatalytic performance. 80.93% of DFF selectivity was realized when using 12.5% MC as photocatalyst. In addition, the MC catalyst also showed great potential in transformation of other biomass derived benzyl- and furyl-alcohols. The catalytic mechanism suggested that · O 2 - was the decisive active radical for HMF oxidation. Therefore, the MC heterojunction could be applied in photocatalytic conversion of biomass to valuable chemicals under ambient condition.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2022
·
IF 4.326
Wenhui Li,Jiaxing Zhang,Xiao Jiang,Minchen Mu,Anfeng Zhang,Chunshan Song,Xinwen Guo
Carbon dioxide (CO2) hydrogenation to gasoline through the methanol-mediate route using the metal oxide/ZSM-5 tandem catalyst has attracted considerable attention to reduce the pernicious effect of CO2 on global climate change and to reduce our dependence on fossil fuels. The C5+ molecules are preferred to pass through the straight channels of ZSM-5 zeolite, where side reactions may occur on the acid sites and the catalyst is deactivated due to pore blockage. Thus, the thickness of ZSM-5 along the straight channel, namely the b-axis direction, is crucial to manipulating the product distribution and catalyst lifetime. Here, HZSM-5 nanosheets with different thicknesses (2 nm to 2 μm) along the b-axis were synthesized controllably and composited with In2O3/ZrO2 as tandem catalysts for CO2 hydrogenation to gasoline. In2O3–ZrO2/HZSM-5 with a thickness of 20 nm shows the highest selectivity toward C5+ hydrocarbons under isoconversional conditions and no deactivation after 150 h of reaction with less carbon deposition compared with the 2 μm one. Comparative activity tests and characterization results demonstrate that an appropriate length of straight channels can benefit the production of C5+ hydrocarbons through the polymerization of short-chain molecules while preventing the cracking of long-chain hydrocarbons on acid sites. Adding an appropriate loading of Co into tandem catalysts with optimal composition gives rise to further enhancement in CO2 conversion by 10%, and a slight increase in C5+ selectivity. This can be attributed to the Co-induced hydrogen spillover from metallic Co to support ZrO2, facilitating the formation of the key intermediate and its subsequent hydrogenation steps. This study provides insights into designing effective and anti-carbon deposition tandem catalysts for CO2-to-gasoline by manipulating the channel length–resident time–acidity relationship and the promoter effect.
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ANALYTICA CHIMICA ACTA
·
2022
·
IF 6.911
Yu Wang,Juanjuan Wang,Ming Guan,Parashuram Kallem,Hongdeng Qiu,Jia Chen
In this work, Fe/Ni bimetallic nitrogen-doped porous graphene (Fe/Ni-NPG) nanomaterials with rich pores, strong magnetism and good reusability were successfully prepared by one-step combustion and can be used as magnetic solid phase extraction (MSPE) adsorbents for the determination of 5-nitroimidazoles (5-NDZs) in environmental water samples. The dispersion and active sites of the materials were increased by the introduction of nitrogen. The adsorption behavior of Fe/Ni-NPG for 5-NDZs was investigated, which corresponds to the quasi-second-order kinetics and Langmuir adsorption model. The π-π electron donor-acceptor interaction (π-π EDA), hydrogen bond and electrostatic interaction between Fe/Ni-NPG and 5-NDZs are the main factors that help to obtain excellent adsorption properties. Several important conditions of MSPE are systematically optimized. Under the optimal MSPE conditions, the linear range of DMZ was 0.6–500 μg/L, the linear range of TNZ and ONZ was 0.7–500 μg/L, and the correlation coefficient R 2 ≥ 0.9991. The limit of detection was 0.18–0.2 μg/L, the limit of quantification was 0.6–0.7 μg/L, and the RSDs of intraday and interday precision were 1.58%–4.66% and 3.77–9.69%, respectively. In the three spiked actual environmental water samples, the recovery was 78.05%–107.05% (RSDs<7.82%). The results show that this method based on Fe/Ni-NPG provides an accurate and reliable way to detect 5-NDZs in environmental water.
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ACS Omega
·
2022
·
IF 4.132
Huan Song,Bing Li,Xuezhi Gao,Fenglin Shan,Xiaoxia Ma,Xiaoyan Tian,Xiaoyan Chen
For energetic materials (EMs), the key point of the present research is to improve the energetic property and reduce sensitivity. In this work, two new energetic complexes, Mn(atzc)2(H2O)2·2H2O (1) and Zn(atzc)2(H2O) (2) (Hatzc = 3-amino-1,2,4-triazole-5-carboxylic acid), were synthesized by solvent evaporation and diffusion methods, respectively. The structural analyses illustrate that 1 and 2 exhibit zero-dimensional structural units, which are linked by hydrogen-bonding interactions to give three-dimensional supramolecular architectures. For complexes 1 and 2, the detonation velocities (D) are 10.4 and 10.2 km·s–1 and detonation pressures (P) are 48.7 and 48.6 GPa, respectively. They are higher than most of the reported EMs, which present prominent detonation characteristics. In addition, two complexes can accelerate the thermal decomposition of ammonium perchlorate and exhibit excellent catalytic activity. Therefore, the two complexes can serve as a new class of promising EMs, which have potential application in the design of new high-efficiency solid catalysts.
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MICROPOROUS AND MESOPOROUS MATERIALS
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2022
·
IF 5.876
Kongyan Yang,Feng Zhou,Huixia Ma,Chuntao Liu,Fangwei Ma,Guang Wu
A series of nanocrystalline ZSM-5 zeolites with abundant intercrystalline mesopores was fabricated by a hydrothermal crystallization method without any mesopore template. The ZSM-5 zeolite was characterized by XRD , XRF , N 2 adsorption, NMR, SEM, TEM and NH 3 -TPD and used for the catalytic fast pyrolysis (CFP) of cellulose . The external surface area of the nanocrystalline ZSM-5 zeolite reached 146.6 m 2 /g, larger than the external surface area of conventional ZSM-5 (57.9 m 2 /g). The product yields of the CFP reaction were studied over different Si/Al ratios of nanocrystalline ZSM-5, and the aromatic yield of nanocrystalline ZSM-5 was generally higher than the aromatic yield of conventional ZSM-5. The relationship between the surface area, acid amounts and product yields was established by drawing a linear fitting curve. The results show that both pore structure and acidity have important effects on aromatic yield and coke yield. Aromatics are generated in micropores, and the increase in external surface area caused by reducing the particle size improves the pyrolysis of cellulose to generate bio-oil vapours, which further diffuse into micropores to generate aromatics.
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RESEARCH ON CHEMICAL INTERMEDIATES
·
2022
·Vol. 48
·期 3
·983-1001
·
IF 3.134
Zhang Dawei,Ren Lu,Liu Ailing,Zhang Yumin,Lv Yang,Gu Qiang
Abstract An efficient synthesis of 1,3,5-trisubstituted-1 H -pyrazoles was developed via cyclocondensation in 78–92% yields starting from α , β -unsaturated aldehydes/ketones with substituted phenylhydrazine using vitamin B 1 as a catalyst, and was characterized by HR-MS, FT-IR, 1 H NMR and 13 C NMR spectroscopy. The reaction has simple operation, metal-free catalysis, acid or base free catalysis. As a green catalyst, vitamin B 1 was found to possess favorable catalytic activity and reusability for the condensation reaction. 1,3,5-trisubstituted-1 H -pyrazole shows from orange-red to cyan in different solvents when the electron withdrawing group is attached to acetophenone (taking compound 5i as an example). Compound 5i as a metal ion fluorescent probe has excellent selectivity for Ag + detection. The crystal structure of the compound 3-(4-chlorophenyl)-1,5-diphenyl-4,5-dihydro-1 H -pyrazole ( 5b ) in the orthorhombic space group Pca 21 was presented and formed racemic crystals. Graphical abstract
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