APPLIED ENERGY
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2019
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IF 8.426
Haowei Li,Hongwei Ma,Weijie Zhao,Xuehui Li,Jinxing Long
Biofuel production from renewable resources is becoming an increasingly attractive option given the depletion of fossil fuels and the environmental problems caused by the excessive use of unsustainable energy resources. In this study, an efficient approach is provided for high-quality oxygen-containing fuel production from renewable lignin bio-oil. The results demonstrate that the calcination temperature has a remarkable effect on the catalyst structure, surface Ni content and physico-chemical properties of the Ni/MgO material, all of which result in significantly different performances in the upgrading of lignin bio-oil. At 160 °C for 4 h and 3 MPa of hydrogen, a 98% lignin bio-oil model compound of guaiacol is converted with 97% cyclohexanol selectivity in the presence of 15% Ni/MgO-850. Furthermore, the optimized catalytic system is reusable and shows good catalytic performance in the upgrading of both light and heavy lignin bio-oils, indicating that it is a promising strategy for renewable lignocellulosic biomass valorization.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2022
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IF 9.136
Fengchun Gong,Zhen Huang,Xiaolan Wei,Shule Liu,Jianfeng Lu,Jing Ding,Weilong Wang
Rapid and strong CO 2 capture is critical in CO 2 capture and utilization (CCU) techniques to mitigate global warming. Alkali molten salt (AMS) promoted-MgO sorbents with high capacity attracted attention, but their applications suffer from various limitations of low adsorption kinetics and poor stability. Here, AMS-promoted MgO sorbents corporation with Fe 2 O 3 (Mg 100-x Fe x -AMS 10 ) were fabricated via modified methanol evaporation-induced surface precipitation for use in rapid and stable CO 2 capture. Based on characterization of the sorbents, Mg 98 Fe 2 -AMS 10 showed a loose flake structure, with a large surface area and numerous exposed active sites. Therefore, Mg 98 Fe 2 -AMS 10 exhibited a strong CO 2 capacity (14.86 mmol CO2 /g sorbent at 300 °C) and good cyclic durability. Three kinetic models were explored, and the Avrami model provided a good prediction of the CO 2 adsorption behavior, with Mg 98 Fe 2 -AMS 10 exhibiting rapid adsorption kinetics. The adsorption mechanism was investigated using density functional theory (DFT) calculations. The charge transfer and bonding strengths of the surface O atoms on MgO increased, and these atoms preferentially bonded with activated CO 2 (CO 2 ∙− ) under Fe catalysis. This study may provide insights into enhancing the CO 2 capture and kinetics of MgO via combination with 3d transition metals.
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RSC Advances
·
2021
·Vol. 11
·期 25
·15477-15485
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IF 3.361
Fengjiao Li,Liguo Wang,Shuang Xu,Shuting Liang,Ningning Zhang
Developing cost-effective, high-efficiency and heterogeneous catalysts is of prime importance for the green synthesis of diethyl carbonate (DEC) from ethyl carbamate (EC) and ethanol. Herein, a series of MgO/γ-Al2O3 catalysts were readily fabricated by an impregnation method for DEC synthesis from EC and ethanol. The activities of the as-prepared MgO/γ-Al2O3 catalysts as well as the individual MgO or γ-Al2O3 were first tested in the batch reactor. Among the investigated samples, the MgO/γ-Al2O3 with a MgO loading of 10 wt% (denoted as 10% MgO/γ-Al2O3) exhibited the largest amount of stronger basic sites, and the highest activities with EC conversion of 41.8% and DEC yield of 30.4%, respectively. Furthermore, the DEC yield was greatly boosted to 52.1% with a high DEC selectivity of 93.8% over the 10% MgO/γ-Al2O3 catalyst under the optimized reaction conditions in the fixed bed reactor, outperforming most of the reported catalysts.
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PubMed
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JOURNAL OF HAZARDOUS MATERIALS
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2021
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IF 10.588
Tao Chen,Yuanfeng Wei,Weijian Yang,Chengbin Liu
Biochar adsorbents for removing As(III) suffer from the problems of low adsorption capacity and ineffective removal. Herein, a granular MgO-embedded biochar (g-MgO-Bc) adsorbent is fabricated in the form of millimeter-sized particles through a simple gelation-calcination method using chitosan as biochar sources. High-density MgO nanoparticles are evenly dispersed throughout the biochar matrix and can be fully exposed to As(III) through the rich pores in g-MgO-Bc. These features endow the adsorbent with a high adsorption capacity of 249.1 mg/g for As(III). The g-MgO-Bc can efficiently remove As(III) over a wide pH of 3–10. The coexisting carbonate, nitrate, sulfate, silicate, and humic acid exert a negligible influence on As(III) removal. 300 μg/L of As(III) can be purified to far below 10 μg/L using only 0.3 g/L g-MgO-Bc. The spent g-MgO-Bc could be well regenerated by simple calcination . In fixed-bed column experiments, the effective treatment volume of As(III)-spiked groundwater achieves 1500 BV (30 L) (3 g of adsorbent, solution flow rate of 2.0 mL/min, C 0 = 50 μg/L). The Mg(OH) 2 generated in situ in g-MgO-Bc is responsible for the adsorption of As(III) through the inner-sphere complex mechanism. The work would extend the potential applicability of biochar adsorbent for As(III) removal to a great extent.
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CHEMICAL ENGINEERING JOURNAL
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2020
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IF 10.652
Xiaoning Liu,Junyan Fu,Yiwei Tang,Richard L. Smith Jr,Xinhua Qi
MgO-doped ordered mesoporous carbon (OMC-MgO) was synthesized by evaporation-induced self-assembly (EISA) in one-pot with biomass-derived gallic acid instead of phenolics as carbon precursor, metal ion Mg 2+ instead of formaldehyde as cross-linking agent and F127 as template. Mg had dual roles as cross-linking agent to coordinate gallic acid-F127 micelle composites, and as promoter of active sites. With the developed protocol, MgO could be uniformly dispersed throughout the carbon skeleton during calcination at 800 °C without agglomeration. As-prepared OMC-MgO-T800 had a specific surface area of 808 m 2 /g, a perfectly-ordered mesoporous structure centered at (6–8) nm, and exhibited good performance for phosphorus removal from aqueous solutions with a maximum sorption capacity of 107 mg/g. Electrostatic attraction, ligand exchange, and Lewis acid-base interactions are the main phosphate adsorption mechanisms of the developed MgO-doped OMC adsorbents. The as-prepared mesoporous carbon materials are highly selective for phosphorus adsorption from aqueous streams and are reusable and recyclable. This work proposes a green protocol to synthesize OMC-metal oxide composites that is widely applicable to wastewater treatment and technological areas in catalysis and energy storage.
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Environmental Science-Nano
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2020
·Vol. 7
·期 9
·2723-2734
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IF 7.683
Jinzhu Zhu,Jingxiang Sun,Shuanghong Tian,Juan Yang,Jinxi Feng,Ya Xiong
A nano-MgO film supported on 3D nickel mesh was prepared via an electrodeposition–thermolysis process. The film possessed high catalytic activity for the ozonation of toluene, but suffered from deactivation. Interestingly, after fluorination, its breakthrough time was 20 times longer (i.e., from 30 to 600 min) under 50% relative humidity. This significant enhancement was attributed to the formation of a fluorinated MgO film, Mg(OH)F, as confirmed using XRD, XPS, SEM, etc. Mg(OH)F possessed two typical acidic sites (Brønsted and Lewis sites), and they could co-catalyze O3 to generate more highly active ˙OH and O radicals. In particular, its Brønsted acidity could considerably decrease the accumulation of acidic intermediates on the film, suppressing its deactivation. Fluorinated MgO, Mg(OH)F, could be applied as a multifunctional ozonation catalyst for the degradation of other refractory pollutants.
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JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2022
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IF 6.364
Yan Wang,Jin Wang,Junxia Wang,Long Kang,Tongming Zhang,Xusheng Li,Yijie Tang
In this work, the helium irradiation effects were systematically investigated on MgO-Nd 2 Zr 2 O 7 (hereafter M-NZO) composite ceramics used for inert matrix fuel, in which the ion fluences range from 5 × 10 16 to 3 × 10 17 ions/cm 2 at room temperature. It was demonstrated that M-NZO composite ceramic shows superior radiation tolerance after He implantation. Specifically, MgO had almost no phase transition and extensive amorphization . And Nd 2 Zr 2 O 7 phase possessed slightly pyrochlore-fluorite-amorphization structural transformation, while part of Nd 2 Zr 2 O 7 maintained the ordered pyrochlore structure and co-existed with the irradiation-induced disordered fluorite structure. Importantly, GIXRD results indicated that MgO phase presents higher resistance to radiated damage than Nd 2 Zr 2 O 7 phase. Besides, SEM images illustrated that MgO particles have substantially less fragmentation than Nd 2 Zr 2 O 7 particles due to the higher thermal conductivity of MgO. It reconfirmed that MgO phase resists irradiation damage better than Nd 2 Zr 2 O 7 phase in post-irradiated M-NZO composite ceramics.
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ACS Applied Materials & Interfaces
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2017
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IF 7.504
Ying-juan Hao,Bing Liu,Li-gang Tian,Fa-tang Li,Jie Ren,Shao-jia Liu,Ying Liu,Jun Zhao,Xiao-jing Wang
Seeking a simple and moderate route to generate reactive oxygen species (ROS) for antibiosis is of great interest and challenge. This work demonstrates that molecule transition and electron rearrangement processes can directly occur only through chemisorption interaction between the adsorbed O2 and high-energy {111} facet-exposed MgO with abundant surface oxygen vacancies (SOVs), hence producing singlet oxygen and superoxide anion radicals without light irradiation. These ROS were confirmed by electron paramagnetic resonance, in situ Raman, and scavenger experiments. Furthermore, heat plays a crucial role for the electron transfer process to accelerate the formation of ·O2–, which is verified by temperature kinetic experiments of nitro blue tetrazolium reduction in the dark. Therefore, the presence of oxygen vacancy can be considered as an intensification of the activation process. The designed MgO is acquired in one step via constructing a reduction atmosphere during the combustion reaction process, which has an ability similar to that of noble metal Pd to activate molecular oxygen and can be used as an effective bacteriocide in the dark.
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CHINESE JOURNAL OF CATALYSIS
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2017
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IF 2.813
Na Huo,Hong Ma,Xinhong Wang,Tianlong Wang,Gang Wang,Ting Wang,Leilei Hou,Jin Gao,Jie Xu
ABSTRACT From both fundamental and practical perspectives, the production of chemicals from biomass resources using high-efficiency non-precious metal catalysts is important. However, many processes require addition of stoichiometric or excess quantities of base, which leads to high energy consumption, leaching problems, and side reactions. In this study, we investigated the high-efficiency oxidative esterification of furfural to methylfuroate by molecular oxygen with a Co-N-C/MgO catalyst. The catalyst was prepared by direct pyrolysis of a cobalt(II) phenanthroline complex on MgO at 800 °C under N 2 atmosphere. From furfural, 93.0% conversion and 98.5% selectivity toward methylfuroate were achieved under 0.5 MPa O 2 with reaction at 100 °C for 12 h without a basic additive. The conversion and selectivity were much higher than those obtained with cobalt catalysts produced by pyrolysis of a cobalt(II) phenanthroline complex on activated carbon or typical basic supports, including NaX, NaY, and CaO. X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, and experimental results revealed that the high efficiency of Co-N-C/MgO for production of methylfuroate was closely related to the cobalt-nitrogen-doped carbon species and its catalytic ability in hydrogen abstraction. In contrast, Co-N-C(HCl) that synthesized by removing MgO with HCl from Co-N-C/MgO, as the catalyst produced mainly an acetal as a condensation product, and chloride ions had a negative effect on the oxidative esterification. Although the catalytic performance of the cobalt-nitrogen-doped carbon species was greatly affected by HCl treatment, it could be recovered to a great extent by addition of MgO. Moreover, changes in the oxygen pressure hardly affected the oxidative esterification of furfural with Co-N-C/MgO. This study not only provides an effective approach to prepare methylfuroate, but also for designing high-performance non-precious metal catalysts for the oxidative esterification of biomass-derived compounds.
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COMPOSITES SCIENCE AND TECHNOLOGY
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2017
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IF 4.873
Jingxin Zhang,Zhongjie Du,Wei Zou,Hangquan Li,Chen Zhang
A magnesium oxide (MgO) nanoparticles-decorated carbon fiber hybrid (CF MgO) were designed and fabricated as thermal conductive but electric insulating filler for polymer matrix . Carbon fibers (CF) and MgO nanoparticles were firstly treated by the coupling agents with amine groups and epoxy groups , respectively. Then CF MgO was constructed through grafting the nanoparticles onto the surface of the fiber. It was expected that the thermal conductivity of CF would be enhanced but its electrical conductivity would be inhibited by the coating of MgO nanoparticles. The chemical structure and morphology of CF MgO were investigated using Fourier transform infrared spectrometer (FT-IR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM). Finally, the hybrid filler was introduced into Nylon 6. The strong interfacial interaction between the filler and matrix was exhibited, attributed to the existence of the coupling agents and the rough surface of nanoparticles-decorated CF. The highest thermal conductivity reached 0.748 W/m·K at 20 wt % addition of CF MgO. Meanwhile, the insulation of the composite appeared at higher than 10 wt% addition of the hybrid filler. Furthermore, connected by MgO nanoparticles, less CF was necessary for the construction of heat conduction channel, and lower value of percolation threshold was achieved.
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APPLIED THERMAL ENGINEERING
·
2024
·
IF 6.1
Lisheng Deng,Shusen lin,Linfa Xiao,Mitsuhiro Kubota,Hongyu Huang,Jun Li,Dezhen Chen
The application of MgO/Mg(OH) 2 in heat storage technology has been limited due to slow hydration rate and easy agglomeration. In this paper, nanoporous carbon particle (NCP) as a carrier was used to prepare NCP/MgO chemical heat storage composite materials by impregnation and calcination methods, respectively. The microstructure characterization, hydration reaction, and simultaneous thermogravimetric analysis experiments were carried out on the prepared composite materials. The results showed that the internal distribution of MgO in the composite material prepared by calcination method was more uniform, and the particle size of MgO was smaller. Under the conditions of 110 ℃ hydration temperature and 57.8 kPa water vapor partial pressure, the hydration conversion ratio of the composite material prepared by calcination method after 120 min of hydration conversion ratio reached 93 %, which was 17.7 % higher than that of the impregnated composite material and 50 % higher than that of pure MgO. Under the comprehensive influence of specific surface area, pore structure, and active component particle size, compared with pure materials and impregnated composite materials, the dehydration rate of the composite material prepared by calcination method at 300 ℃ was twice that of impregnated method and 6 times that of pure MgO, and the heat storage density reached 1039kJ/kg. After 10 cycles, the heat storage density still maintained an initial state of 95.8 %. Compared with pure materials and impregnated composite materials, NCP/MgO composite materials prepared by calcination method had better heat storage performance and higher cyclic stability.
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CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Shuai Yan,Sen Wang,Gaobin Liu,Qi Yuan,Kuoming Song,He Zhao,Xin Li,Rongzheng Shen
Herein, MgO–12 % TiO 2 (w) ceramics with different contents of Bi 2 O 3 –CuO sintering aid were prepared using a solid-state method. The effects of the sintering aid content on the sintering temperature and the dielectric and mechanical properties of the ceramics were studied. The material was characterized using scanning electron microscopy and X-ray diffraction and Precision LCR tester and universal testing machine and Archimedes drainage method. When the Bi 2 O 3 –CuO content was less than 9 wt%, the ceramic sample has higher dielectric properties. When the Bi 2 O 3 –CuO content was greater than 9 wt%, the dielectric properties will deteriorate. This is because Bi 2 O 3 participates in the chemical reaction between MgO and TiO 2 , forming a high dielectric loss Bi 4 Ti 3 O 7 phase. At high temperatures, Cu 2+ can easily change valence to Cu + , promoting oxygen vacancies and increasing dielectric loss in ceramic samples. The introduction of Bi 2 O 3 –CuO produces new MgTiO 3 , Mg 2 TiO 4 , and Bi 4 Ti 3 O 12 phases in the sample structure, resulting in a structure in which the MgO grains in the sample are surrounded by the new phases that appear around them. This structure fills the pores, increases density, enhances mechanical properties. The dielectric properties of the ceramics were the when the sintering temperature was 1050 °C, and the Bi 2 O 3 –CuO content was 3 wt%. The dielectric constant and dielectric loss were 11.19 and 1.17 × 10 −4 , respectively. The bending strength of the ceramic sample increased from 138.72 MPa to 179.64 MPa when the Bi 2 O 3 –CuO content was increased from 3 wt% to 15 wt%. The Bi 2 O 3 –CuO sintering aid enables MgO to be better applied in ceramic substrates.
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