查找使用阿拉丁产品的科研文献

Impregnation of PEI in Novel Porous MgCO3 for Carbon Dioxide Capture from Flue Gas

Xia Wan,Xiaojuan Lu,Jie Liu,Yuanfeng Pan,Huining Xiao

CO2 emission has caused serious environmental problems, and the reduction of CO2 has become a global issue. The use of amine-impregnated solid adsorbents for CO2 capture from flue gas has been an effective approach. Herein, a novel porous MgCO3 was synthesized by a facile and template-free method and further impregnated with polyethylenimine (PEI) to prepare porous adsorbent for highly efficient CO2 capture. Moreover, during the synthesis of MgCO3, CO2 was used as one of the reactants in an attempt to improve the potential utilization of CO2. The effects of PEI loading, temperature, and coexisting gases (H2O, NO, and SO2) on CO2 adsorption performance were identified in a fixed bed. The results indicated that the adsorption capacity of the adsorbent toward CO2 was increased significantly after PEI impregnation. With the increase of temperature, the capture capacity of CO2 decreased because of the dominated thermodynamic control on the low PEI-loaded adsorbents, however, increased due to the governed kinetic control on the high PEI-loaded adsorbents. In addition, the adsorbent loaded with 20 wt % PEI showed the highest CO2 capture capacity, up to 1.07 mmol/g at 75 °C, and exhibited a 19.6% increase by introducing 10 vol % of water vapor. Meanwhile, the CO2 capture capacity was almost unaffected by NO; however, SO2 in flue gas could have some negative effects on CO2 adsorption due to the stronger acidity. Finally, the cyclic adsorption/desorption tests demonstrated excellent regenerability and stability of adsorbent. The results indicated that the PEI-modified porous MgCO3 is a very promising adsorbent for CO2 capture.

Manganese leaching in high concentration flue gas desulfurization process with semi-oxidized manganese ore

Dong Sun,Guangzhi Xin,Lu Yao,Lin Yang,Xia Jiang,Wenju Jiang

Manganese leaching during high concentration flue gas desulfurization process with semi-oxidized manganese ore was studied in this paper. It was found that there were different reaction pathways among which MnO 2, Mn 2 O 3 and MnCO 3 in semi-oxidized manganese ore during flue gas desulphurization and manganese leaching. High SO 2 concentration facilitated redox reaction between MnO 2 and SO 2 , and high concentration of H 2 SO 4 accelerated MnCO 3 /Mn 2 O 3 leaching from semi-oxidized ore. Kinetics study showed that manganese leaching in flue gas desulfurization process with semi-oxidized ore was controlled by a mixed-control model, that is the surface chemical reaction and mass diffusion dominated both the oxidation of SO 2 and manganese leaching process. The apparent activation energy was 13.05 kJ·mol −1 and the reaction orders with respect to SO 2 and H 2 SO 4 concentration were 1.38 and 0.10, respectively. Finally, a semi-empirical rate equation based on shrinking core model was derived to describe the process.

Preparation and Characterization of Fe3O4@SiO2 Nanoparticles Incorporated Polymer Monolithic Column for Gas Chromatography

Zhao Aixia,Xu Zhiqiang,Ma Liyi,Tian Zhenfeng,Gan Wuer

We report on the synthesis of Fe 3 O 4 @SiO 2 nanoparticles incorporated poly(divinylbenzene) monolithic column via in situ polymerization. The monolith had larger specific surface area and relatively uniform porous structure and was characterized by scanning electron microscopy, nitrogen adsorption–desorption, and Fourier transform infrared spectroscopy. The monolith was then applied for the evaluation of gas chromatography separation properties. Here, an electromagnetic induction heating technique was employed to control the column temperature with the thermal effect of eddy current in ferromagnetic materials Fe 3 O 4 . The monolith offered good separation efficiency for benzene and toluene and a higher column efficiency was obtained up to 4481 and 9216 plates per meter, respectively. In addition, the injection volume and column capacity of the proposed system are as much as 5 µL and 100 ng. This makes it possible to use a UV detector. The fabricated Fe 3 O 4 @SiO 2 nanoparticles incorporated poly(divinylbenzene) monolithic column has been shown to be very promising for gas chromatography separation. Graphical Abstract

Pore structure characterization and gas transport property of the penetrating layer in composite membranes

Shichun Li,Haobin Zhang,Shuwen Yu,Jingwei Hou,Shiliang Huang,Yu Liu

Polymeric composite membranes have emerged as the leading technology in industrial gas separation fields for decades, but there are still several unsolved fundamental problems on the interface between layers in composite membranes, which hinders the development of membranes with better performance. The penetrating layer locating between the selective layer and the supporting layer of composite membranes could strongly affect both gas separation performance and durability of membranes, the understanding of the penetrating layer is however limited. The bottleneck in studying penetrating layer is structure characterization, as the penetrating layer is hard to be distinguished from the selective layer and the supporting layer by an electronic microscope. Here, the nanoporous structure of the penetrating layer in the polydimethylsiloxane (PDMS)/polysulfone (PSf) composite membrane was characterized by small angle X-ray scattering (SAXS) that measures variations of nano-pore size distribution of membranes. The penetration degree was quantitatively described as a relative reduction in gyration radius of pores measured by SAXS. In the penetration process, the repeated cycles of penetration and drying of PDMS solution in pores occurred, which filled the small pores and divided the big pore into smaller ones. Moreover, the effects of penetrating layers on the gas transport property of composite membranes were estimated by using restriction factor in which the restriction effect of the supporting layer was also considered, and high correlation between penetration degree and restriction factor was presented.

Graphene Oxide-Doped Conducting Polymer Nanowires Fabricated by Soft Lithography for Gas Sensing Applications

Ning Tang,Yang Jiang,Hemi Qu,Xuexin Duan

Fabrication, characterization and excellent formaldehyde gas sensing of Tb-doped In2O3 beaded-porous nanotubes

Duan Haojie,He Yue,Li Shouchun,Liu Li,Xu Suyang,Li Yu,Li Haiying,Gong Yimin,Liang Qingcheng,Cheng Yali

The pure and Tb-doped In 2 O 3 beaded-porous nanotubes (BPNTs) are fabricated by simple electrospinning method. The crystal phase, morphology and chemical composition of the obtained samples were analyzed by characteristic techniques (XRD, FE-SEM, TEM, EDS, XPS, etc.). The mechanism of forming BPNTs structure was studied, and phase separation plays a key role in the process of formation. A series of sensing tests toward formaldehyde gas showed that 6 mol% Tb-doped In 2 O 3 BPNTs exhibited the best sensing performance: high response (75–50 ppm), shorter response and recovery times (2 s and 12 s), low limit of detection (LOD, 1.27–100 ppb), good selectivity and long-term stability, etc. The significantly improved gas sensing properties were mainly resulted from their high surface basicity, enriched defects (oxygen vacancies), small crystallite size and complex porous structures.

Poly(3-hexylthiophene) stationary phase for gas chromatographic separations of aliphatic and aromatic isomers

Jianlin Peng,Meiling Qi

This work describes the investigation of utilizing a chain-typed thiophene-based π-conjugated polymer, i . e ., poly(3-hexylthiophene) (P3HT), as the stationary phase for gas chromatography (GC). The P3HT column was statically prepared and investigated for its column efficiency, polarity, separation performance, repeatability and thermal stability. As a result, it showed moderate polarity and column efficiencies of 3260, 3310 and 3790 plates/m for 1-octanol, naphthalene and n -dodecane, respectively. As evidenced, it exhibited high-resolution performance for aliphatic and aromatic isomers, including those critical pairs such as phenanthrene/anthracene and p -/ m -benzenediol isomers. Moreover, it displayed stronger retention for alkanes, alcohols and phenols in comparison to the polysiloxane stationary phase with close polarity. Also, the P3HT column had good repeatability and reproducibility with the RSD values less than 0.05% for run-to-run, 0.17–0.54% for day-to-day and 2.7–5.2% for column-to-column, and good thermal stability up to 260 °C. This work demonstrates the promising future of the thiophene-based polymer and its derivatives in separation science.

Efficient degradation of evaporative condensing liquid of shale gas wastewater using O3/UV process

Tao Lu,Ying Chen,Min Liu,Wenju Jiang

In this study, a batch experiment was used to investigate the degradation of real evaporative condensing liquid of shale gas wastewater (ECLSGW). We showed that compared to the O 3 , ultraviolet (UV), UV/TiO 2 , and O 3 /UV/TiO 2 processes, the O 3 /UV process has better performance in removing the chemical oxygen demand (COD) and total organic carbon (TOC) of ECLSGW under the same conditions. The effects of initial pH (3–12), ozone flow rate (0.1–0.5 L/min), UV power (15–50 W), and reaction time (0–60 min) on the degradation of ECLSGW via the O 3 /UV process were investigated using a single-factor experiment. Moreover, the optimal experimental conditions were obtained using a quadratic polynomial prediction model (R Adj 2 =0.9961) that was obtained from the central composite design (CCD) of the response surface methodology (RSM). Under optimal experimental conditions, the COD and TOC removal efficiency reached 93.12 and 95.5%, respectively. In addition, gas chromatography–mass spectrometry analysis showed that the O 3 /UV process could nearly completely mineralize organic pollutants in the ECLSGW. Hydrogen peroxide (H 2 O 2 ) and hydroxyl radical ( OH) were identified by manganese dioxide (MnO 2 ) and tert-butanol (TBA). The mechanism research showed that OH plays an important role in the degradation of organic pollutants. In summary, the O 3 /UV process is an effective method to degrade ECLSGW.

Solvent-free route for metal–organic framework membranes growth aiming for efficient gas separation

Jiamin Hou,Xilu Hong,Sheng Zhou,Yanying Wei,Haihui Wang

Industrial applications of membranes based on metal–organic frameworks (MOFs) are challenged by their complex fabrication procedures and poor processability, despite their huge potential for efficient gas separation. Especially, the consumption of a large amount of toxic, expensive solvent, and harsh operation by conventional solvothermal growth also make it less attractive for industrial production. Herein, a solvent-free method is proposed to fabricate continuous defect-free MOF membranes on commercial porous stainless steel substrates, where the metal precursors are electrodeposited on the support followed by a heat treatment with the ligand powder via solid-state reaction without using any solvent. This strategy is proven to be applicable for various MOF membranes and it is expected to be a facile, cheap, and environmental friendly way for future large-scale production. © 2018 American Institute of Chemical Engineers AIChE J , 65: 712–722, 2019

CdS QDs-chitosan microcapsules with stimuli-responsive property generated by gas–liquid microfluidic technique

Yanjun Chen,Rongyi Yao,Yifeng Wang,Ming Chen,Tong Qiu,Chaocan Zhang

This article describes a straightforward gas–liquid microfluidic approach to generate uniform-sized chitosan microcapsules containing CdS quantum dots (QDs). CdS QDs are encapsulated into the liquid–core of the microcapsules. The sizes of the microcapsules can be conveniently controlled by gas flow rate. QDs-chitosan microcapsules show good fluorescent stability in water, and exhibit fluorescent responses to chemical environmental stimuli. α-Cyclodextrin (α-CD) causes the microcapsules to deform and even collapse. More interestingly, α-CD induces obvious changes on the fluorescent color of the microcapsules. However, β-cyclodextrin (β-CD) has little influence on the shape and fluorescent color of the microcapsules. Based on the results of scanning electron microscopy, the possible mechanism about the effects of α-CD on the chitosan microcapsules is analyzed. These stimuli-responsive microcapsules are low-cost and easy to be prepared by gas–liquid microfluidic technique, and can be applied as a potential micro-detector to chemicals, such as CDs.

Experimental study of TiO2 hollow microspheres removal on elemental mercury in simulated flue gas

Jiang Wu,Xian Li,Jianxing Ren,Xuemei Qi,Ping He,Bu Ni,Chong Zhang,Chengzhen Hu,Jun Zhou

TiO 2 hollow sphere was synthesized by hydrothermal method using trifluoroacetic acid (TFA) and Ti(SO 4 ) 2 as raw materials, and it was applied to photocatalytic oxidization of elemental mercury (Hg 0 ) in the simulated flue gas. The prepared samples were well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra (UV-vis DRS) and nitrogen adsorption/desorption. The results showed that only anatase phase TiO 2 hollow sphere was obtained. The average diameter of TiO 2 hollow spheres was about 800   nm and the shell thickness was about 200–400   nm. When M , the molar ratio of TFA to Ti(SO 4 ) 2 , was higher than a certain value, the photocatalytic activity of prepared TiO 2 hollow spheres began to reduce. When M   =   2, addition TFA content was the best quantity, which got the best TiO 2 hollow spheres and provided the most appropriate F − decomposed from TFA during the sample preparation, which was helpful to its photocatalytic ability. In the experimental temperature range, the photocatalytic oxidation efficiency decreased with the increasing of reaction temperature, and the intensity of UV irradiation had an important effect on the photocatalytic reaction. When UV irradiation intensity was 303.45   μW   cm −2 and reaction temperature was 55   °C, TiO 2 hollow sphere sample prepared at M   =   2 had the highest photocatalytic ability and the mercury removal efficiency reached up to 82.75%.

Determination of phthalate esters in teas and tea infusions by gas chromatography–mass spectrometry

Liping Du,Lijuan Ma,Yang Qiao,Yan Lu,Dongguang Xiao

Phthalate esters (PAEs), a group of environmental pollutants which are carcinogenic to human body, have been detected in teas. In this work, five PAEs in teas and tea infusions were quantitatively determined by a modified simultaneous distillation extraction (SDE) coupled with gas chromatography–mass spectrometry. After the optimization of SDE, the proposed method afforded a wide range of linearity and high linear regression coefficients with the limits of detection range of 0.24–3.72   μg/kg. The average recoveries were 79.83–116.67% for tea samples and 78.22–101.64% for tea infusions with all the relative standard deviations below 20%. The total content of five PAEs in teas was 1.135–3.734   mg/kg and the total dissolving ratio of five PAEs from tea to infusion was 19.05–28.07% for the selected tea samples. The risk assessment result of all the selected tea samples demonstrated that the population with the habit of drinking tea won’t cause risk to human health.