JOURNAL OF CHROMATOGRAPHY A
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2022
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IF 4.601
Haiyan Zhang,Fei Feng,Yangyang Zhao,Bin Zhao,Lei Li,Dan Zheng,Xinxin Li
In this paper, a micro gas chromatographic column (μGCC) was fabricated via the layer-by-layer (LBL) deposition of mesoporous silica (MS) as the stationary phase. The μGCC with embedded elliptical-cylindrical posts was fabricated by typical micro-electro-mechanical system (MEMS) techniques. The MS powder was prepared by a sol-gel method and then deposited inside the microchannels of the μGCC by LBL deposition. This process avoided the high temperature required for the sol-gel method to directly prepare MS inside the microchannel surfaces of the μGCC. Mixtures of light alkanes (C1–C4) could be separated in the μGCC. The separation results showed that the resolution between the components of the sample increased with the number of deposition cycles. When the number of deposition cycles increased from 1 to 8, the resolution of methane and ethane was increased from unseparated to 5.89.
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JOURNAL OF CHROMATOGRAPHY A
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2022
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IF 4.601
Xinrui Wang,Yehong Han,Jiankun Cao,Hongyuan Yan
Polychlorinated naphthalenes (PCNs) are emerging organic pollutants that are harmful to the environment and human health. In this study, a headspace solid-phase-microextraction (HS–SPME)–gas chromatography–tandem mass spectrometry method for the separation and enrichment of PCNs in shrimp was developed and validated. A graphene aerogel was prepared by modifying graphene oxide with a deep eutectic solvent to prevent graphene oxide stacking. As a result, the aerogel had a three-dimensional porous structure, which resulted in easy sorption/desorption for PCNs, and was used as the SPME fiber coating. Next, the experimental parameters for the saponification of the sample matrix and the extraction and desorption of the PCNs were systematically optimized. After optimization, the method showed good linearity ( R 2 ≥0.9968), low limits of detection (0.00983–0.0661 pg g –1 ), and satisfactory recoveries (80.4–108%). Crucially, compared with previously reported methods, this method does not require the use of large amounts of organic reagents or complex operations, giving it the advantages of simplicity, sensitivity, and environmental friendliness. As an example of the practical application of the developed method, the PCNs in river and sea shrimp were quantified.
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Journal of CO2 Utilization
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2022
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IF 8.321
Yichao Wang,Yifan Liu,Qian Su,Yunong Li,Lili Deng,Li Dong,Mengqian Fu,Shuaifei Liu,Weiguo Cheng
Carbon dioxide (CO 2 ) is an important C1 resource, and the preparation of cyclocarbonate by catalyzing CO 2 and epoxides is a nature-friendly route to utilize. In this study, polymer ionic liquid materials (PILMs) were prepared by copolymerizing the vinylimidazole-based ionic liquids (ILs) as monomer with carbonyl-rich copolymer monomer methyl methacrylate (MMA) and crosslinking agent ethylene glycol dimethacrylate (EGDMA), to enhance the affinity of PILMs for CO 2 and PO . Then, epoxides and CO 2 were converted to cyclic carbonates using PILMs by the gas-liquid reaction (GLR) and the gas phase-conversion progress (GCP). Amongst those polymer ionic liquid materials, the PILM containing carboxypropyl group (PILM-VCPImBr) exhibited the performance with the propylene carbonate (PC) yield of 96.7% (at 130 °C, 3 MPa CO 2 , reaction time 3 h) by GLR. And the yield of PC reached 94.2% (at 130 °C, 2 MPa CO 2 , reaction time 3 h) by GCP, which was the same as that of GLR. The excellent catalytic activity can be attributed to the fact that the PILMs fully dispersed the active sites and were rich in pores, which could effectively catalyze propylene oxide (PO) and CO 2 to generate PC. Finally, 1 H NMR spectra showed that VCPImBr and PO formed strong hydrogen bonds to participate the ring-opening process of epoxides, and a possible catalytic mechanism of H-bond synergistic effect was proposed. This article provides a novel strategy for designing both stable and nature-friendly catalysts in the CO 2 transformation, and proposes a new method for cyclic carbonate conversion.
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RSC Advances
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2022
·Vol. 12
·期 11
·6561-6572
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IF 4.036
Chongshan Yin,Xuan Du,Zhi Ding,Qing Zeng,Xi Li,Chunqing He,Bangyun Xiong,Jingjing Li,Yawei Zhou
Nowadays, graphene/polymer composite films with multilayer structure have attracted significant attention for gas barrier application. In this study, a series of reduced graphene oxide/polyethyleneimine (RGO/PEI) composite films were created via recast and layer-by-layer deposition processes. By using the recast process, the myriad PEI molecules in the precursor solution (the PEI : GO feeding ratio is 0.02 : 0.1, 0.05 : 0.1, 0.1 : 0.1, 0.3 : 0.1 and 0.5 : 0.1) ensure more effective reduction and surface modification of the graphene oxide (GO) sheets, while the undesirable free PEI molecules are eventually removed via a filtration process. Then, the RGO/PEI composite films were synthesized on PET substrate using a layer-by-layer assembly. The resulting films show a homogeneous and compact brick-wall structure with excellent gas barrier properties. Barriers against water vapor, nitrogen/oxygen, and carbon dioxide require different content of PEI in the composite film for optimal performance; the ideal values are 19.7, 23.8, and 24.1 wt%, respectively. These values are much lower compared with previously reported studies. Further, the permeability, free volumes, component ratio, morphology, and density of the RGO/PEI composite films have been carefully investigated and discussed. The results revealed that the mechanism behind the excellent gas barrier property of the RGO/PEI composite films is a synergistic effect created by the combination of the brick-wall structure, the small free volume holes, the suitable PEI content (ranging from 19.7 wt% to 24.1 wt%), the high density, and the hydrophobicity.
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JOURNAL OF CHROMATOGRAPHY A
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2022
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IF 4.601
Yanyan Wang,Lili Lian,Xiyue Wang,Boying Yue,Lan Ding,Dawei Lou
In this study, velvet-like carbon nitride (V-g-C 3 N 4 ) was prepared from urea aqueous solutions by one-step thermal polycondensation. The V-g-C 3 N 4 material was then characterized using a scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier transform infrared spectrophotometer (FT-IR), and nitrogen adsorption-desorption isotherms. The specific surface area of V-g-C 3 N 4 (60.66 m 2 /g) was 1.8 times that of the carbon nitride (g-C 3 N 4 ) prepared by the traditional method. V-g-C 3 N 4 was modified on the surface of stainless-steel wire by a sol-gel technique to obtain a solid-phase microextraction (SPME) coating for the extraction of five polycyclic aromatic hydrocarbons (PAHs) from water samples. The chromatography signal of the PAHs extracted using the V-g-C 3 N 4 coating was 1.5 times that when using a g-C 3 N 4 coating, and 5–10 times that when using commercial PDMS. Under the optimized extraction conditions, the linear range of the method developed for the determination of five PAHs was 0.05–100 µg/L, the limits of detection were 0.005–0.012 µg/L, and the recoveries from actual water samples were 85.94–103.47%. Furthermore, the developed SPME device is remarkably durable and can be reused up to 160 times.
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MICROCHEMICAL JOURNAL
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2022
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IF 5.304
Chengyu Zheng,Qin'an Zhou,Wenqing Shao,Jing Zhang,Jun Wang
Platycladus orientalis (L.) is a typical urban greening tree in Asia, but the young leaves of P. orientalis are vulnerable to pathogenic fungi with hidden early signs. In this study, we investigated the volatile organic compounds (VOCs) emissions of the Alternaria alternate infected P. orientalis plants, for the first time, using the gas chromatography-ion mobility spectrometry (GC-IMS) combined with chemometric approaches. Results showed that the A. alternate infection could reduce the VOCs release of P. orientalis leaves. The α-pinene and β-pinene emissions were down to 70% and 55% of controls on day 10, respectively. The destructive inoculated plants responded more to the A. alternate , both in the VOCs emissions and the fungal growth. The (Z)-3-hexenol, n-hexanol, α-pinene, and β-pinene can serve as potential markers for infection discrimination, and their IMS signal intensities were calibrated with corresponding volume concentrations ranging from 0 to 250 μg/L. The PLS-DA model based on GC-IMS fingerprints can correctly classify at least 83% of samples in infection durations after fungal inoculation for the first 10 days. The PLSR model can predict the fungal colony counts in the P. orientalis needles (R c 2 ＞0.97 and R p 2 ＞0.92) with good robustness, whose RMSEP was lower than 0.68 (×10 6 CFU g −1 ) in predict set. In a word, the GC-IMS-based approach had the potential to evaluate A. alternate infection in P. orientalis , and the variation of potential markers can provide reference to its fungal infection monitor with millisecond response in the forest.
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FOOD CHEMISTRY
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2022
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IF 9.231
Long Xu,Hao Cheng,Marco Müller,Andrew J. Sinclair,Weifei Wang,Xuhua Guo,Walter Vetter,Yonghua Wang
Furan fatty acids (FuFAs) have been recognized as beneficial food ingredients to human health. Herein, a targeted quantitation approach by gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC-TQ/MS) was developed for the identification of FuFAs in common marine and other edible oils in multiple reaction monitoring (MRM) mode without any isolation and enrichment. The limit-of-quantitation (LOQ, 0.6 pg) was determined under the optimized parameters in MRM mode. Identification of FuFAs in common edible oils demonstrated that marine fish oils were concentrated sources of 9-(3-methyl-5-pentylfuran-2-yl)nonanoic acid (9M5), 11-(3,4-dimethyl-5-propylfuran-2-yl)undecanoic acid (11D3) and 11-(3,4-dimethyl-5-pentylfuran-2-yl)undecanoic acid (11D5). However, FuFAs were not identified in common plant oils. Additionally, 11D5 was identified in the lipids of Schizochytrium limacinum at a comparable level with that in marine fish oil. We believe that this protocol could facilitate the qualitative and quantitative analysis of FuFAs in food and biological samples.
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PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
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2022
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IF 7.926
Yunfei Ma,Jianbing Wang,Huijiao Wang,Chunrong Wang,Can He,Xian Zhang
How to predict the efficacy of heterogeneous catalytic ozonation reactors in reducing pollutants remains limited by complex multiphase systems . An integrated mathematical model of catalytic ozonation by activated carbon (AC) was developed based on hydrodynamics, mass transfer, adsorption, and reaction kinetics to simulate the performance of gas-liquid continuous flow catalytic ozonation reactors. A novel method was proposed reflecting the catalyst behavior to transform the complex gas-liquid-solid multiphase catalytic system into mass conservation equations for each component in gas and liquid phases. The catalyst activity is assumed to be mainly represented by adsorption and the transformation of ozone to hydroxyl radicals (•OH) by active groups on catalyst surface . A mathematical formulation of •OH generation was derived based on the Langmuir-Hinshelwood (LH) mechanism. The model simulation results obtained the concentration profiles of each component and achieved a satisfactory predictive power with error less than 20%, which in turn justified the modeling process. Sensitivity analysis showed that parameters including gas-liquid mass transfer coefficient, secondary reaction rate constant for indirect oxidation and catalyst capacity transfer coefficient have greater influence on simulation results. The optimal conditions for ozone utilization and pollutant degradation were obtained using the validated model simulations: catalyst dosage of 5 g/L, gas flow rate of 0.05 L/min, and initial ozone concentration of 50 mg/L. The results suggest that this mathematical model can provide useful information for design and optimization of catalytic ozonation reactors during industrial applications.
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JOURNAL OF HAZARDOUS MATERIALS
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2022
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IF 14.224
Senlin Tian,Shanshan Yang,Jianfei Wang,Qiuxian Li,Chen Li,Xiangfen Cui,Ping Ning
Nitrogen and sulfur oxides have been considered as major air pollutants , which has raised concerns. In this study, an integrated strategy is proposed for simultaneous desulfurization and denitrification of simulated flue gas and high value conversion of sulfur and nitrogen resources. The high oxidation capacity of the thermal-electric coactivated (NH 4 ) 2 S 2 O 8 made the process highly effective for SO 2 and NO removal, with efficiencies of 100 % and 98 %, respectively. Mechanistic studies have revealed that highly reactive free radicals were the major participants in promoting oxidation, among which 47.65 % and 27.75 % of NO were oxidized by SO 4 .- and ˙OH, respectively, and 14.3 % and 10.3 % removal were accounted for O 2 .- and 1 O 2 , respectively. The products of desulfurization and denitrification (SO 4 2- and NO 3 - ) were further converted into NH 4 + (maximum conversion efficiency of 83.80 %) and S 2 O 8 2- (maximum conversion efficiency of 70 %) in an electrolytic reactor, and the regenerated (NH 4 ) 2 S 2 O 8 could be recycled for gas purification to extend the service life of the oxidant. Consequently, a complete conversion cycle of S and N species was obtained, and its conversion pathways were proposed. After several cycles, the SO 4 2- and NO 3 - enriched in the solution were post-processed into a compound fertilizer, thereby partially recovering the economic cost.
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ACS Omega
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2022
·
IF 4.132
Bo Zhang,Jing Wang,Qufu Wei,Pingping Yu,Shuai Zhang,Yin Xu,Yue Dong,Yi Ni,Jinping Ao,Yi Xia
Oxygen vacancy (VO) is a kind of primary point defect that extensively exists in semiconductor metal oxides (SMOs). Owing to some of its inherent qualities, an artificial manipulation of VO content in one material has evolved into a hot research field, which is deemed to be capable of modulating band structures and surface characteristics of SMOs. Specific to the gas-sensing area, VO engineering of sensing materials has become an effective means in enhancing sensor response and inducing light-enhanced sensing. In this work, a high-efficiency microwave hydrothermal treatment was utilized to prepare a VO-rich ZnO sample without additional reagents. The X-ray photoelectron spectroscopy test revealed a significant increase in VO proportion, which was from 9.21% in commercial ZnO to 36.27% in synthesized VO-rich ZnO possessing three-dimensional and air-permeable microstructures. The subsequent UV–vis–NIR absorption and photoluminescence spectroscopy indicated an extension absorption in the visible region and band gap reduction of VO-rich ZnO. It turned out that the VO-rich ZnO-based sensor exhibited a considerable response of 63% toward 1 ppm HCHO at room temperature (RT, 25 °C) under visible light irradiation. Particularly, the response/recovery time was only 32/20 s for 1 ppm HCHO and further shortened to 10/5 s for 10 ppm HCHO, which was an excellent performance and comparable to most sensors working at high temperatures. The results in this work strongly suggested the availability of VO engineering and also provided a meaningful candidate for researchers to develop high-performance RT sensors detecting volatile organic compounds.
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ENERGY
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2022
·
IF 8.857
Bing Wei,Jiang Liu,Xiang Zhang,Dianlin Wang,Junyu You,Jun Lu,Jinyu Tang
The objective of this work was to elucidate the mass exchange dynamics (MED) between the tight rock matrix and fractures induced by natural gas ‘dynamic’ soaking (NGDS) during Huff- n -Puff. The equilibrium interfacial tension (IFT) between natural gas (NG) and oil decreased rapidly with an increase in the NG C2/C3 fraction and equilibrium pressure ( P eq ). The IFT curves were separated into two distinct regimes because of the transition of the MED from gas dissolution to oil vaporization. The apparent diffusion coefficient of NG ranged from 4.9 × 10 −11 to 3.35 × 10 −9 m 2 /s. The dissolution of NG into the oil resulted in a linear swelling behavior with P eq . Mass exchange between matrix and fracture took place intensively from the onset of NGDS, driven by gas diffusion, oil swelling, and concentration gradient-driven flow, which stimulated the oil recovery up to 59.3% original oil in place . The NGDS oil recovery curves exhibited three distinctive regions because of the MED evolution over time. The average cutoff pore radius for NGDS-movable oil was less dependent on the operational pressure but was affected by the C2/C3 fraction. We modified a dimensionless number to better correlate the NGDS oil recovery and predict field-scale production.
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JOURNAL OF FOOD SCIENCE
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2022
·Vol. 87
·期 8
·3355-3365
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IF 3.693
Zhipeng Xiao,Wenjun Zhang,Wenli Guo,Lan Zhang,Ai Huang,Meng Tao,Meiqin Li,Rui Su,Zhengquan Liu
Drying is the key process through which the aroma of tencha forms. However, the effects of drying method on volatiles are unknown. We compared tencha-ro drying with regular drying. Volatiles in tencha infusions were extracted using headspace solid-phase microextraction and solvent-assisted flavor evaporation combined with gas chromatography–mass spectrometry. Partial least squares (PLS), odor activity value (OAV), and heat map analyses were performed to identify the optimal drying method for creating a seaweed-like aroma. Changes in the key volatile compounds of the samples were investigated. The tencha infusions contained 125 volatiles with nine chemical structures. According to the sensory evaluation, tencha-ro drying was the optimal method for producing high-quality tencha with an intense and consistent seaweed-like aroma. The PLS model accurately distinguished among the types of tencha. By combining OAVs with screening through multivariate statistical analysis, six volatile compounds were revealed to contribute substantially to tencha's seaweed-like aroma: 2-ethyl-3,5-dimethylpyrazine, 2-ethyl-6-methylpyrazine, 2-ethyl-5-methylpyrazine, dimethyl sulfide, β-ionone, and 2-formyl-1-methylpyrrole. The findings provide a theoretical basis and technical guidance for the processing of high-quality tencha with a strong seaweed-like aroma. Practical Application This study demonstrated that tencha-ro drying contributes to the formation of a seaweed-like aroma in tencha and provides theoretical guidance for tea factories to use the appropriate drying methods for high-quality tencha.
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