查找使用阿拉丁产品的科研文献

Dual-Site Synergistic Modulation of La0.9Fe0.8Co0.2O3 Perovskite Oxide for High-Performance Methane Sensing in Oil and Gas Pipelines

Lichao Dong,Zhenzhu Xi,Lu Hu,Jiangang Zheng

Methane (CH 4 ), the primary constituent of natural gas, is a colorless, odorless, combustible gas prevalent in petroleum and natural gas transmission pipelines as well as coal mines. However, conventional n-type semiconductor sensors face significant challenges in real-time CH 4 leak monitoring within these environments due to severe signal drift induced by synergistic interference from high humidity and volatile organic compounds (VOCs). To address this, we synthesized La 0.9 Fe 0.8 Co 0.2 O 3 nanomaterials via a facile one-pot hydrothermal method. A dual-site synergistic modulation strategy, involving the co-introduction of self-induced defects and Co dopants, endows the sensor with exceptional sensitivity toward CH 4 at markedly lowered operating temperatures. At the optimal temperature of 125 °C, the tailored sensor exhibited a remarkable sensitivity of 17.55 toward 100 ppm CH 4 , representing an order-of-magnitude improvement over pristine LaFeO 3 . Furthermore, the device demonstrated excellent dynamic performance, with a rapid response time of 9.9 s and a recovery time of 7.2 s, enabling reliable detection across diverse environmental matrices. Notably, the sensor maintained a stable response value of approximately 15 even under extreme humidity (95% relative humidity) and exhibited outstanding repeatability. The exceptional performance originates predominantly from A-site-induced lattice strain coupled with the proliferation of active sites triggered by B-site substitution. The insights gained and the established mechanism herein enable the advancement of advanced methane sensing technologies geared towards industrial safety applications.

Green and Efficient Extraction Approach for Polyphenol Recovery from Lotus Seedpods (Receptaculum Nelumbinis): Gas-Assisted Combined with Glycerol

Nina Bao,Marwan M. A. Rashed,Bianling Jiang,Kefeng Zhai,Zisheng Luo

In this paper, the gas-assisted combined with glycerol extraction (GAGE) for polyphenol recovery from lotus seedpods (LSPs) was modeled and optimized. Box–Behnken design was applied to optimize the total polyphenol content (TPC) of LSP along with enhancing antioxidant activities using response surface methodology based on the TPC extraction yield (%), which was affected by glycerol concentration, time, temperature, and glycerol-to-solid ratio. The optimal conditions for the LSP extract were glycerol-to-solid ratio, 42 mL/g; time, 50 min; concentration of glycerol, 45%; and temperature, 70 °C. Ultra-high-pressure liquid chromatography integrated with triple-time-of-flight mass spectrophotometry (UPLC-Triple-TOF/MS) analysis revealed nine biologically active polyphenols. Furthermore, Fourier-transform infrared spectroscopy and scanning electron microscopy results demonstrated the effect and influence during extraction. The findings suggested that GAGE is a potential, green, and high-efficiency alternative that could be used to recover polyphenols from plant source byproducts.

Gas Chromaotography-Mass Spectrometry Analysis of Insecticidal Essential Oil Derived from Chinese Ainsliaea fragrans Champ ex Benth (Compositae)

MP Zhao,XC Liu,QZ Liu,ZL Liu

Tannic Acid/Polyvinyl Alcohol as a Wellbore Strengthener for Water-Based Drilling Fluid in Natural Gas Hydrate Reservoir

Xing Xing Wang,Guan Cheng Jiang,Guo Shuai Wang,Li Li Yang,Yin Bo He,Xiao Ya Wu

In South China Sea, the natural gas hydrates are usually reserved in argillaceous siltstones. These argillaceous siltstones are weakly cemented and incorporated with the solid hydrates. During the drilling process, the natural gas hydrates may decompose unexpectedly, resulting in the wellbore collapse. To improve the stability of the wellbore, this study develops a wellbore strengthener for water-based drilling fluids used in argillaceous siltstones. Tannic acid/polyvinyl (TA/PVA) alcohol has been adopted for preparing the wellbore stabilizer. A series of experiments have been conducted to investigate the effects of newly developed wellbore strengthener on the mechanical properties of the argillaceous siltstones as well as its mechanisms on the wellbore stability. The experimental results show that the wellbore strengthener developed in this study can significantly improve the compressive strengths of the argillaceous siltstone cores. The AFM characterizations indicate that the adhesion force between the silica (the major compound in argillaceous siltstones) microspheres and the wellbore strengthener can reach up to 2138 nN. Moreover, the SEM images visually show good cementation of the argillaceous siltstones after being treated by the wellbore strengthener. In addition, the wellbore strengthener can also assist in reducing the fluid losses of water-based drilling fluids. It is hopeful that the wellbore strengthener provided in this study help the development of underwater natural gas hydrates.

Removal of bromoamine acid in dye wastewater by gas-liquid plasma: The role of ozone and hydroxyl radical

Yi-Ying Xin,Lyu Zhou,Ke-ke Ma,Joono Lee,H.I.A. Qazi,He-Ping Li,Cheng-Yu Bao,Yue-Xi Zhou

As a widely used anthraquinone dye intermediate, bromoamine acid (BAA) exists extensively in dye wastewater. In this study, the gas-liquid discharge non-thermal plasma technology was employed to degrade BAA. Efficient removal was achieved by the system within 15 min treatment. Besides, the effects of input power, working gas flow rate and solution pH value on BAA removal efficiency were investigated. BAA removal rate increased with higher input power and lower pH value, while too high or too low working gas flow rate could lead to the decrease of BAA removal. The existence of BAA caused significant decline of aqueous ozone concentration while enhanced the production of H 2 O 2 , indicating that the aqueous ozone participated in BAA degradation. The contributions of main active species were investigated. H 2 O 2 and UV produced by discharges showed little effects on BAA degradation individually, however led to synergistic effect by producing OH. Over 60 % removal of BAA was attributed to OH oxidation, while direct molecular ozone contributed around 20 % degradation. The second-order rate constants of BAA reacting with ozone and OH were determined to be 1.22 × 10 3 M −1 s −1 and 4.06 × 10 9 M −1 s −1 , respectively. A kinetic model was established to predict BAA degradation. 12 degradation intermediates were detected by HPLC-Q-ToF-MS, GC–MS and HPLC-UV. The degradation was mainly caused by hydroxylation, bond cleavage and addition of OH on double bonds.

Effect of {010} crystal facets of Bi2MoO6 and 1D/2D heterostructures for conductometric room temperature NH3 gas sensors

Kaidi Wu,Hongfeng Chai,Kaichun Xu,Marc Debliquy,Chao Zhang

High working temperature and the insufficient limits of detection limit the broad applications of semiconductor chemiresistive gas sensors. Herein, pure Bi 2 MoO 6 nanosheets and a series of one-dimensional/two-dimensional (1D/2D) multi-walled CNTs/Bi 2 MoO 6 nanocomposites were developed via a facile hydrothermal route for room-temperature ammonia monitoring. The as-synthesized samples were characterized by various analytical techniques. 0.5 wt% MWCNTs/Bi 2 MoO 6 nanocomposites showed the best sensing properties to 10–50 ppm NH 3 , including low limit of detection (157 ppb), high response (R a /R g = 44.2 @ 50 ppm), good selectivity, reproductivity, and anti-humidity sensing ability. The enhanced gas sensing mechanism was proposed based on the synergetic effect of high-energy crystal facets, modified surface characteristics and p-n heterojunction . Density functional theory (DFT) studies were also carried out to further clarify the gas sensing mechanisms. This work provides a practical approach to design and fabricate high-precision gas sensors working at room temperature .

Monodisperse ZnFe2O4 nanospheres synthesized by a nonaqueous route for a highly slective low-ppm-level toluene gas sensor

Chengjun Dong,Xu Liu,Xuechun Xiao,Shangfeng Du,Yude Wang

Monodisperse ZnFe 2 O 4 nanospheres were succesuffully synthesized via a nonaqueous route in benzyl alcohol at low temperaure of 200   °C. It was found that the ZnFe 2 O 4 is 7–16   nm in diameter with a large surface area of 87.40   m 2 /g. The gas sensor based on ZnFe 2 O 4 nanospheres shows a high pontential for detecting low-ppm-level toluene, exhibiting a good linearity ranging from 1 to 100   ppm with a high response (100   ppm:9.98) and excellent selectivity.

Lead-Free CsCu2I3 Perovskite Nanostructured Networks Gas Sensor for Selective Detection of Trace Nitrogen Dioxide at Room Temperature

Xia Sun,Jie Yang,Zhilin Wu,Gang Meng,Xuezheng Guo,Delin Kuang,Lian Xiong,Weijie Qu,Xiaodong Fang,Xi Yang,Xiaosheng Tang,Yong He

A Facile Method for the Synthesis of Porous ZnO Hollow Microspheres and Their Gas Sensing Properties for Acetone

Xiang Di,Lin Huiming,Ma Jie,Chen Xiang,Jiang Jingjie,Qu Fengyu

In order to enrich the variety of zinc oxide (ZnO), well-defined porous ZnO hollow microspheres (PZHM) by a mass of nanoparticles were successfully synthesized through a simple solvothermal method. Zinc acetate and 1,2-propylene glycol was used as zinc source and solvent respectively to fabricate PZHM without the assistance of any surfactant. Upon changing the amount of zinc acetate and 1,2-propylene glycol, the morphology of the samples could be adjusted. PZHM, with 1–2 μm in diameter and 200–300 nm in wall thickness, were found to be composed of nanoparticles that assembles to form the large surface area and highly porous samples. Gas sensing performances of the ZnO hollow spheres have been investigated, showing high sensitivity (S = 180 at 1000 ppm), low detection limit (1 ppm), fast response/recovery (8/9 s), and very good selectivity.

Heterogeneous electro-Fenton catalysis with self-supporting CFP@MnO2-Fe3O4/C cathode for shale gas fracturing flowback wastewater

Pei Dong,Xi Chen,Meiting Guo,Zhiyuan Wu,Haolong Wang,Feifei Lin,Jinqiang Zhang,Shuaijun Wang,Chaocheng Zhao,Hongqi Sun

Self-supporting electrodes have triggered great interests in improving electro-Fenton (EF) system for degradation of refractory organic pollutants . In this work, a novel self-supporting carbon fiber paper (CFP) electrode modified by transition metals, e.g. Fe and Mn, was fabricated and employed as a heterogeneous EF cathode. The prepared electrode exhibited excellent degradation for a number of typical organic pollutants along with superior stability. Remarkably, a high removal efficiency was achieved in the EF treatment of shale gas fracturing flowback wastewater. Results indicated that 65.2% TOC and 74.8% COD were eliminated after 4 h degradation. The residual COD value of the real wastewater was 80 mg L −1 , meeting the emission requirement of the integrated wastewater discharge standard (COD   ＜   100 mg L −1 ) with a low specific energy consumption of 6.9   kWh   kg −1   COD −1 . This work demonstrates a competing alternative for efficient decontamination of real wastewater using an electro-Fenton strategy with a low-cost electrode.

Molecularly imprinted solid-phase extraction coupled with gas chromatography for the determination of four chloroacetamide herbicides in soil

Yan Wang,Xiaoyang Jin,Dan Zhao,Xiaohong Guo,Ranhong Li

A molecularly imprinted solid phase extraction (MISPE) coupled with gas chromatography (GC) for the simultaneous separation and determination of four chloroacetamide herbicides, alachlor, acetochlor, pretilachlor and metolachlor, in soil was developed. Molecularly imprinted polymers (MIPs) with butachlor as the dummy template were synthesized via precipitation polymerization, where methacrylic acid (MAA) was used as the functional monomer, ethylene glycol dimethacrylate (EDMA) as the crosslinker and acetonitrile as the porogen. Fourier-transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM) were used to characterize the polymers. Under the optimum SPE conditions, the polymer sorbents can selectively extract and enrich alachlor, acetochlor, pretilachlor and metolachlor. A comparison experiment also showed that the MISPE cartridges were better than the nonimprinted and C18 cartridges in terms of recovery. The mean recoveries of the four chloroacetamide herbicides from blank soil spiked at 0.1, 0.5, and 1 μg mL−1 ranged between 80.6 and 90.2% with relative standard deviations (RSD) of less than 8% (n = 5). The limit of detection (LOD) and the limit of quantification (LOQ) of the four analytes were in the range of 1.0 × 10−12 to 5 × 10−11 g and 0.0005–0.025 mg kg−1, respectively. The presented MISPE-GC method exhibited highly selective separation and enrichment of trace chloroacetamide herbicides and could be potentially applied to the determination of chloroacetamide herbicides in soil.

Fabrication and property evaluation of calcium-oxide-loaded microcapsules during supplemental heat-based exploitation of natural gas hydrates

Jintang Wang,Zihua Shao,Yujing Bai,Guolei He,Xudong Wang,Lei Liu,Bo Liao,Xiaohui Sun,Kaihe Lv,Jinsheng Sun

The exploitation of natural gas hydrates (NGHs) by traditional methods is far lower than the commercial target. Calcium oxide (CaO)-based in situ supplemental heat combined with depressurization is a novel method for effectively exploiting NGHs. In this study, we propose an in situ supplemental heat method with the sustained-release CaO-loaded microcapsules coated with polysaccharide film. The modified CaO-loaded microcapsules were coated with polysaccharide films using covalent layer-by-layer self-assembly and wet modification process, with (3-aminopropyl) trimethoxysilane as the coupling agent and modified cellulose and chitosan as the shell materials. Microstructural characterization and elemental analysis of the microcapsules verified the change in the surface composition during the fabrication process. We found that the overall particle size distribution was within the range of 1–100 μm, corresponding to the particle size distribution in the reservoir. Furthermore, the sustained-release microcapsules exhibit controllable exothermic behavior. The decomposition rates of the NGHs under the effect of CaO and CaO-loaded microcapsules coated with one and three layers of polysaccharide films were 36.2, 17.7, and 11.1 mmol h−1, respectively, while the exothermic time values were 0.16, 1.18, and 6.68 h, respectively. Finally, we propose an application method based on sustained-release CaO-loaded microcapsules used for the supplemental heat-based exploitation of NGHs.