Russian Journal of Physical Chemistry A
·
2023
·Vol. 97
·期 7
·1368-1375
·
IF 0.7
Zhang Xueping,Liu Youquan,Zhou Lang,Pu Junhong
Abstract In this work, the isothermal dissolution equilibrium method was used to investigate the solid-liquid equilibrium of the quaternary system NaBr–KBr–CaBr 2 –H 2 O at 273.15 K. The isothermal solubility of three bromides in aqueous solution was measured, and the dry salt phase diagram and water diagram were constructed. The determination results indicate that the system is a simple co-saturation type, and the equilibrium crystals are all simple salts. The isothermal phase diagram of the quaternary system NaBr–KBr–CaBr 2 –H 2 O at 273.15 K contains three isothermal dissolution lines intersecting at an invariant point. The saturated salts at this point are: NaBr⋅2H 2 O, KBr, and CaBr 2 ⋅6H 2 O. The entire phase space of the dry salt phase diagram is divided into three parts by three isotherms, that is, the crystalline region of NaBr⋅2H 2 O that occupies most, the larger crystalline region of KBr and the narrow crystalline region of CaBr 2 ⋅6H 2 O. The invariant point characteristics of the system at different temperatures were compared, and the Pitzer model was used to theoretically predict the isothermal solubility of the quaternary system at 273.15 K. Since the selected parameters in the calculation program come from the temperature correlation equation reported in the literature, the reliability of the parameters is relatively strong. The predicted value of solubility has a small deviation from the experimental value, and the result proves that the reliability of the experimental data is strong. The results of the phase equilibrium study not only reveal the dissolution and crystallization rules of bromine salts in the brine of oil and gas fields in the Sichuan Basin, but also verify the applicability of the Pitzer model in predicting the solubility of low-temperature bromine-containing system.
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ACS Applied Materials & Interfaces
·
2020
·
IF 8.758
Yushan Liu,Haiyue Yang,Chunhui Ma,Sha Luo,Mingcong Xu,Zhenwei Wu,Wei Li,Shouxin Liu
Formaldehyde (FA) is a widespread indoor air pollutant, and its efficient detection is a major industrial challenge. The development of a building material with real-time and visual self-detection of FA gas is highly desirable for meeting both construction and human health demands. Herein, a luminescent transparent wood (LTW) as the building material was developed for dual-channel, real-time, and visual detection of FA gas. It was fabricated by encapsulating multicolor lignin-derived carbon dots (CDs) and poly(vinyl alcohol) (PVA) into a delignified wood framework. It exhibited 85% optical transmittance, tunable room-temperature phosphorescence (RTP), and ratiometric fluorescence (FL) emission. The tunable luminescence was attributed to different CD graphitization and surface functionalization. The color-responsive ratiometric FL and delayed RTP detections of FA were displayed over the range of 20–1500 μM (R2 = 0.966, LOD = 1.08 nM) and 20–2000 μM (R2 = 0.977, LOD = 45.8 nM), respectively. The LTW was also used as an encapsulation film on a UV-emitting InGaN chip to form white light-emitting diodes, indicating the feasibility as an FA-responsive planar light source. The operational notion of functional LTW can expand its applications to new fields such as a stimuli-responsive light-transmitting window or planar light sources while monitoring indoor air pollutants, temperature, and humidity.
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ANALYTICAL LETTERS
·
2018
·
IF 1.206
Zhihong Wang,Chengzhang Wang
Olive waste is a potential resource due to its rich variety of biologically active compounds. To investigate chemical components of olive waste, the selected samples were extracted using ultrasound assisted enzyme hydrolysis and petroleum ether, ethyl acetate and n-butyl alcohol were used to obtain a series of solvent extracts. Gas chromatography–mass spectrometry analysis showed hydrocarbons, esters, acids, alcohols, and ketones present in the extracts. Some fatty acids were considered to be predominant; it is noteworthy that phenolic compounds were detected in the ethyl acetate extract fraction. Furthermore, the primary phenolic compounds were also determined by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. The possible fragmentation patterns have been proposed in positive and negative ion modes; the main fragment ions were observed from the loss of methyl, hydroxyl, or carboxyl groups. The compounds showed different fragmentation ions types in both positive and negative ionization modes and gave structural information on the main phenolic compounds in olive waste. The results of this study may be used to identify valuable active compounds and guide commercial applications of olive waste.
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FOOD CHEMISTRY
·
2020
·
IF 6.306
Yuping Liu,Qingru Li,Wenxi Yang,Baoguo Sun,Ying Zhou,Yang Zheng,Mingquan Huang,Wenjie Yang
Zanthoxylum armatum DC Prodr. pericarp (ZAP) is an important spice because of its unique odor and taste. ZAP oil was obtained by supercritical carbon dioxide extraction. To characterize potent odorants in ZAP oil, volatiles were isolated by headspace solid-phase microextraction and solvent-assisted flavor evaporation. Gas chromatography–mass spectrometry–olfactometry analyses identified a total of 32 odor-active compounds, and their flavor dilution (FD) factors, ranging from 2 to 4096, were measured by aroma extract dilution analysis. To further determine their contributions to the characteristic odor of ZAP oil, 24 odorants with FD factors ≥8 were quantitated, and their odor activity values (OAVs) were calculated. Sixteen compounds with OAVs ≥1 contributed to the characteristic aroma profile of ZAP oil. Linalool had the highest FD factor, concentration and OAV, and its chiral structure was identified as S -(+)-linalool.
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高影响因子
Materials
·
2018
·Vol. 11
·期 1
·111
·
IF 2.467
Hongda Chen,Jihui Wang,Aiqing Ni,Anxin Ding,Xia Han,Ziheng Sun
In order to improve the efficiency of intumescent flame retardants (IFRs), a novel macromolecular charring agent named poly(ethanediamine-1,3,5-triazine-p-4-amino-2,2,6,6-tetramethylpiperidine) (PETAT) with gas phase and condense phase synergistic flame-retardant capability was synthesized and subsequently dispersed into polypropylene (PP) in combination with ammonium polyphosphate (APP) via a melt blending method. The chemical structure of PETAT was investigated by Fourier transform infrared spectroscopy (FTIR), and1H nuclear magnetic resonance (NMR) spectroscopy. Thermal properties of the PETAT and IFR systems were tested by thermogravimetric-derivative thermogravimetric analysis (TGA-DTG) and thermogravimetry–Fourier transform infrared spectroscopy (TG-FTIR). The mechanical properties, thermal stability, flame-retardant properties, water resistance, and structures of char residue in flame-retardant composites were characterized using tensile and flexural strength property tests, TGA, limiting oxygen index (LOI) values before and after soaking, underwritten laboratory-94 (UL-94) vertical burning test, cone calorimetric test (CCT), scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDXS), and FTIR. The results indicated that PETAT was successfully synthesized, and when the ratio of APP to PETAT was 2:1 with 25 wt % loading, the novel IFR system could reduce the deterioration of tensile strength and enhance the flexural strength of composites. Meanwhile, the flame-retardant composite was able to pass the UL-94 V-0 rating with an LOI value of 30.3%, and the peak of heat release rate (PHRR), total heat release (THR), and material fire hazard values were considerably decreased compared with others. In addition, composites also exhibited excellent water resistance properties compared with traditional IFR composites. SEM-EDXS and FTIR analyses of the char residues, as well as TG-FTIR analyses of IFR were used to investigate the flame-retardant mechanism of the APP/PETAT IFR system. The results indicated that the efficient flame retardancy of PP/IFR composites could be attributed to the synergism of the free radical-quenching and char layer-protecting mechanisms in the gas phase and condense phase, respectively.
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JOURNAL OF MEMBRANE SCIENCE
·
2025
·
IF 9
Ao Tang,Huijie Nie,Jialin Zhang,Zhuo Chen,Jie Dong,Xin Zhao,Xiuting Li,Qingsong Xu,Qinghua Zhang
Breaking the trade-off effect between permeability and selectivity and preparing membranes with an excellent comprehensive separation performance is a relentless pursuit in the field of membrane separation technology. Herein, a new series of crosslinked thermally rearranged poly(imide- co -benzoxazole) membranes were successfully synthesized with greatly improved comprehensive gas separation performance. The o rtho -hydroxycopolyimide precursor was synthesized by reacting the newly designed dianhydride bearing the amide structure and thermally crosslinkable benzyl groups, N, N'-(2,4,6-trimethyl-1,3-phenylene)bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxamide) (MPADA), with hexaffuoroisopropylidene diphthalic anhydride (6FDA) and thermally rearrangeable diamine, 2,2-bis(3-amino-4-hydroxyphenyl)- hexafluoropropane (6FAP). Sequential thermal treatment at 375-450 °C under air and at 450-465°C under N 2 resulted in the benzyl-induced crosslinking reaction and thermal rearrangement (TR) reaction of ortho -hydroxyimide, respectively, within the precursor membrane. It demonstrates that the above reactions combined with the inherently existing interchain hydrogen bonding not only effectively expand the chain packing enabling microporous structure for gas transport but also introduce multi-scale microporosity via the unique dual crosslinked network that allows for molecular sieving capability in the resulting membrane. The resulting membranes exhibited a remarkable CO 2 permeability (341.2 Barrer) and ideal CO 2 /CH 4 selectivity (53), which outperformed some typical thermally rearranged polymer membranes and the state-of-the-art 2008 upper bound for CO 2 /CH 4 separation. More importantly, the resulting membranes demonstrated a superior anti-aging and high anti-plasticization property attributed to their highly stable molecular skeleton structure. This work provides a reliable route for constructing polymeric membranes with highly improved gas separation performance and stability.
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产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2021
·
IF 9.028
Bo Zhang,Jing Bai,Yan Zhang,Changhui Zhou,Pengbo Wang,Lina Zha,Jinhua Li,Abdolreza Simchi,Baoxue Zhou
H2S and CO2 are the main impurities in raw natural gas, which needs to be purified before use. However, the comprehensive utilization of H2S and CO2 has been ignored. Herein, we proposed a fully resource-based method to convert toxic gas H2S and greenhouse gas CO2 synchronously into CO and elemental S by using a novel electrochemical reactor. The special designs include that, in the anodic chamber, H2S was oxidized rapidly to S based on the I–/I3– cyclic redox system to avoid anode passivation. On the other hand, in the cathodic chamber, CO2 was rapidly and selectively reduced to CO based on a porous carbon gas diffusion electrode (GDE) modified with polytetrafluoroethylene and cobalt phthalocyanine (CoPc). A high Faraday efficiency (>95%) toward CO was achieved due to the enhanced mass transfer of CO2 on the GDE and the presence of the selective CoPc catalyst. The maximum energy efficiency of the system was more than 72.41% with a current density of over 50 mA/cm2, which was 12.5 times higher than what was previously reported on the H2S treatment system. The yields of S and CO were 24.94 mg·cm–2·h–1 and 19.93 mL·cm–2·h–1, respectively. A model analysis determined that the operation cost of the synchronous utilization of H2S and CO2 method was slightly lower than that of the single utilization of H2S in the existing natural gas purification technology. Overall, this paper provides efficient and simultaneous conversion of H2S and CO2 into S and CO.
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Nature Communications
·
2024
·Vol. 15
·期 1
·1-10
·
IF 14.7
Xu Guangxian,Wang Hong,Zhang Jinyang,Gao Jiao,Guan Jiwen,Xu Qiang,Truhlar Donald G.,Wang Zhandong
Elucidating the formation mechanism of polycyclic aromatic hydrocarbons (PAHs) is crucial to understand processes in the contexts of combustion, environmental science, astrochemistry, and nanomaterials synthesis. An excited electronic-state pathway has been proposed to account for the formation of 14π aromatic anthracene in the benzyl ( b -C 7 H 7 ) self-reaction. Here, to improve our understanding of anthracene formation, we investigate C 7 H 7 bimolecular reactions in a tubular SiC microreactor through an isomer-resolved method that combines in situ synchrotron-radiation VUV photoionization mass spectrometry and ex-situ gas chromatography–mass spectrometry. We observe the formation of o -tolyl ( o -C 7 H 7 ) radical isomer, and identify several C 14 H 10 products (diphenylacetylene, phenanthrene and anthracene) and key C 14 H 14 and C 14 H 12 intermediates. These isomer-specific results support the occurrence of reactions on the electronic ground-state potential energy surface, with no evidence for key intermediates of the proposed excited-state pathway as the key pathway. Furthermore, theoretical calculations unveil new facile reaction pathways that may contribute to the enhanced production of anthracene, and these mechanistic findings are further substantiated by pyrolysis experiments. The results add insight into the molecular formation of PAHs in C 7 H 7 bimolecular reaction, and contribute to establishing accurate models to predict PAH chemistry in diverse laboratory, environmental, and extraterrestrial contexts.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2024
·Vol. 416
·期 6
·1321-1335
·
IF 3.8
Song Yanli,Li Wen,Ba Mengyi,Zhang Yuanyuan,Liu Haixin,Xu Xiang,Su Haoyu,Cai Zhiqiang,Liu Xianming,Sun Tao
This work presents the first example of the utilization of polar ester group functionalized pillar[6]arene (P6A-C10-OAc) as a stationary phase for capillary gas chromatographic (GC) separations. The statically coated P6A-C10-OAc column showed a high column efficiency of 5393 plates/m and moderate polar nature. Its resolving capability and retention behaviors were investigated for a mixture of 20 analytes and more than a dozen isomers from apolar to polar in nature. As evidenced, the P6A-C10-OAc column achieved high-resolution separations of all the analytes and good inertness. Importantly, it exhibited distinctly advantageous performance for high resolution of the challenging isomers of xylenes, diethylbenzenes, ethyltoluenes, and halobenzenes over the commercial HP-5 (5% phenyl dimethyl polysiloxane), HP-35 (25% phenyl dimethyl polysiloxane), and PEG-20M (polyethylene glycol) columns. Graphical Abstract
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Li Lv,Yinglin Wang,Pengfei Cheng,Yue Zhang,Yaoqiong Zhang,Zhaohui Lei,Luping Xu,Zhi Weng
In this study, a one-step chemical vapor deposition (CVD) method was used, utilizing template NaCl and dextrin as the porogen and structural support. The synthesized spinel MFe 2 O 4 (M = Zn, Ni, Cu, Co and Mn) microspheres with multiple cavities structure were applied to the acetone gas sensor detection. Through the characterization of the sensitive materials, the average pore diameter of the microspheres was about 60 nm. Compare with other metal cations , when M = Zn or Ni, the MFe 2 O 4 samples revealed the super gas sensitivity at working temperatures of 250 °C and 175 °C, and the response values to 100 ppm acetone were 25 and 24.3, respectively. In addition, they also exhibited excellent selectivity and long-term stability to acetone. The excellent gas sensitivity of ZnFe 2 O 4 and NiFe 2 O 4 could be attributed to the replacement of Fe with Zn and Ni ions to obtain a higher Fe 3+ /Fe 2+ atomic ratio, thereby increasing the content of adsorbed oxygen. In summary, the gas sensing performance of spinel MFe 2 O 4 oxide had been systematically studied by replacing Fe with other transition metals. The iron-containing spinel oxides are expected to be promising sensing material for gas sensors due to their rich elements and excellent activity.
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JOURNAL OF MEMBRANE SCIENCE
·
2021
·
IF 8.742
Jingjing Kong,Junjie Liu,Peiyu Jia,Ning Qi,Zhiquan Chen,Shan Xu,Nanwen Li
Two kinds of polyimide membranes 6F-AP and 6F-AP/DA (APAF:DABA=3:2) were synthesized and heated between 300–450 °C to study the effect of thermal treatment on the chain structure and gas transport performance of membranes. Fourier Transform Infrared (FI-IR) and X-ray diffraction (XRD) measurements show that heating causes rearrangement of polyimide into rigid polybenzoxazole which prevents the effective stacking of polymer chains leading to the increase of d-spacing and fractional free volume. Positron annihilation results confirm the increase of both size and number of free volume due to the thermal rearrangement. The addition of DABA monomer into 6F-AP causes crosslinking during heating, which results in tightening of the rigid chain spacing of benzoxazole, thus leading to slight decrease in the size and number of free volume. The increase in fraction free volume induced by thermal rearrangement can significantly improve the gas permeability of 6F-AP series membranes, which increases from 16.2 and 3.9 barrer to 271.4 and 200.3 barrer for H 2 and CO 2 , respectively, after increasing the heating temperature from 300 to 450 °C. But this is accompanied by a decrease in gas selectivity due to the increase in free volume size. Finally, by careful tailoring the free volume structure through thermal rearrangement and crosslinking, the 6F-AP/DA polyimide treated at 400 °C exhibits a H 2 permeability of 196.4 barrer and a H 2 /CH 4 ideal selectivity of 90, which is above the 2008 Robeson upper bound. Our results indicate that by designing the functional groups of the reaction monomer plus appropriate thermal treatment, the microstructure of polyimide membrane can be effectively adjusted for high-performance gas separation.
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JOURNAL OF ELECTRONIC MATERIALS
·
2018
·Vol. 47
·期 5
·2545-2556
·
IF 1.566
Yue Lu,Ge Jingjing,Luo Gaixia,Bian Kaiting,Yin Chao,Guan Rongfeng,Zhang Wenhui,Zhou Zheng,Wang
Kaixin,Guo Xiufeng
A facile approach to prepare porous SnO 2 and SnO 2 /C composite with Cu-Sn alloy as raw material by wet chemical reaction strategy has been developed. The prepared porous SnO 2 and its carbon composite showed homogeneous mesoporous structure and high surface area, displayed superior rate performance and high reversible capacity of 625 mAh g −1 and 1185 mAh g −1 over 800 cycles at 0.4 A g −1 , respectively. Compared with commercial SnO 2 , porous SnO 2 sensor presented higher response, faster response/recovery capability, good selectivity and repeatability to ethanol at 180°C.
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危险品化学品经营许可证（带存储）