CELLULOSE
·
2019
·Vol. 26
·期 9
·5211-5226
·
IF 3.917
Jiang Lang,Li Ke,Yang Huiyu,Liu Xin,Xu Weilin,Deng Bo
Flower-shaped hydromagnesite (MgO-P) and magnesium oxide (MgO) micro spheres were synthesized via precipitation-aging method with and without calcination. The disassociated nano flaky petal of around 50 nm (~ 20 nm in thickness) of MgO-P and MgO by sonication were used as flame-retardants for the electrospun cellulose acetate (CA)/MgO-P or CA/MgO nanofiber. SEM, XRD, FTIR, HRTEM were used to characterize all related products. TGA was used to analyze the detailed decomposition procedures of bare, MgO-P, and MgO doped CA nanofiber. Three evaluation methods including broken time after heating, thermography during heating, and combustion observation were adopted to compare the flame-retardancy of composited nanofibers. Doped CA nanofibers showed best flame-retardancy by extending the heat-induced broken time from 0.46 to 12.09 s, which is 26.3 times that of CA nanofiber. The flame of CA/MgO-P and CA/MgO could be self-extinguished once the ignition source was removed. No smoke and size shrinkage could be observed during the combustion of CA/MgO-P or CA/MgO nanofibers. Corresponding flame-retarding mechanism of Mg-based nano flaky petal was proposed.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2020
·
IF 5.647
Jia Liu,Jan Baeyens,Yimin Deng,Tianwei Tan,Huili Zhang
The abatement of CO 2 emitted from combustion is a hot research topic. Current CO 2 capture techniques of adsorption, absorption, membrane separation and cryogenics involve high investment and operation costs. For moderate and high temperature exhaust gas, carbonation/decarbonation cycles offer an attractive alternative. An objective assessment method (screening index) was applied to select the most appropriate chemical reactions, with MgO and Mg(OH) 2 being screened as having the highest potential. Macro-thermogravimetric experiments determined a CO 2 capture yield between 60 and 70% for Mg(OH) 2 at temperatures between 260 and 330 °C, and from 85 to 98% for MgO at temperatures of 400–440 °C. Reaction rates were measured for both MgO–CO 2 and Mg(OH) 2 –CO 2 . The reaction kinetics are best fitted by the Jander 3D-diffusion approach. The Arrhenius equation is applied to the reaction rate constant, and both its activation energy and pre-exponential factor are determined. Integrating the Jander expression in the reaction rate equation enables to predict the CO 2 -capture conversion for any selected temperature and/or contact time.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2021
·Vol. 99
·期 1
·122-131
·
IF 2.326
Liu Shisheng,Wei Xiaohui,Lin Song,Guo Minjie
The preparation of MgO nanoparticles with relatively small sizes and highly active surface areas is still a great challenge nowadays. The principal objective of this work was to investigate and optimize the calcined conditions of MgO with smaller sizes and higher surface areas, which contributed to its better degradation ability towards paraoxon pollutants. Firstly, the aerogel Mg(OH) 2 nanosheets with an increased surface area of 349.0 m 2 /g was prepared via a combined sol–gel-hydrothermal method. Then the calcined MgO nanoparticles with different morphology, size dimensions, and specific surface areas were obtained at different calcination temperatures from 400 to 800 °C. The optimized average grain size of MgO obtained at 600 °C was achieved to 8.7 ± 3.2 nm with a relatively high surface area up to 231.4 m 2 /g. Meanwhile, such as-prepared MgO nanoparticles showed an excellent performance towards paraoxon degradation, and the maximum degradation amount of paraoxon-ethyl was up to 57.8 mg/g@90 min at room temperature. The kinetics of degradation was consistent with the pseudo-second-order model ( R 2 > 0.99). Such excellent degradation capacity was derived from more generations of superoxide radical (•O 2 − ) sites as revealed by using the nitro blue tetrazolium (NBT) as a probe. The results indicated that the MgO nanoparticles reported herein could be an effective candidate for the environmental remediation of organophosphorus toxin pollutants due to their facile scale-up, low cost, eco-friendly characteristic, and high removal efficiency.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2023
·Vol. 16
·期 6
·2445
·
IF 3.4
Run Shi,Yuehan Hao,Deping Chen,Wenxin Liu
Reactive magnesia cement is considered an eco-efficient binder due to its low synthesis temperature and CO2absorption properties. However, the hydration of pure MgO–H2O mixtures cannot produce strong Mg(OH)2pastes. In this study, nesquehonite (Nes, MgCO3·3H2O) was added to the MgO–H2O system to improve its strength properties, and its hydration products and pore structure were analyzed. The experimental results showed that the hydration product changed from small plate-like Mg(OH)2crystals to interlaced sheet-like crystals after the addition of a small amount of Nes. The porosity increased from 36.3% to 64.6%, and the total pore surface area increased from 4.6 to 118.5 m2/g. At the same time, most of the pores decreased in size from the micron scale to the nanometer scale, which indicated that Nes had a positive effect on improving the pore structure and enhancing the compressive strength. Combined with an X-ray diffractometer (XRD), a Fourier transform infrared spectrometer (FTIR), and a simultaneous thermal analyzer (TG/DSC), the hydration product of the sample after Nes addition could be described as xMgCO3·Mg(OH)2·yH2O. When Nes was added at 7.87 and 14.35 wt%, the x-values in the chemical formula of the hydration products were 0.025 and 0.048, respectively. These small x-values resulted in lattice and property parameters of the hydration products that were similar to those of Mg(OH)2.Keywords:nesquehonite;reactive magnesia;Mg(OH)2;magnesium carbonate hydroxide;pore structure;nanopore
研究领域:
材料科学
·
土木工程
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF PHASE EQUILIBRIA AND DIFFUSION
·
2017
·Vol. 38
·期 1
·30-36
·
IF 0.938
Sun W. Z.,Cheng J. G.,Huang Z. K.,Jiang Y.,Wu L. E.,Liu L. M.
The present work determined the phase relations in Si-Al-M-O-C (M = Zr, Mg) systems, involving SiC-Al 2 O 3 -ZrO 2 , SiC-Al 2 O 3 -MgO, SiC-SiO 2 -Al 2 O 3 -ZrO 2 and SiC-SiO 2 -Al 2 O 3 -MgO systems by XRD phase analyses of the solid-state reacted samples from powder mixtures of SiC, Al 2 O 3 , ZrO 2 , MgO and SiO 2 . Within these systems, SiC was respectively compatible with other neighboring phases, forming a set of four-phase compatibility tetrahedrons. The subsolidus phase diagrams of the SiC-SiO 2 -Al 2 O 3 -ZrO 2 and SiC-SiO 2 -Al 2 O 3 -MgO quaternary systems were presented.
研究领域:
材料科学
·
陶瓷学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
·
2017
·
IF 4.52
J. Yan,C.Y. Zhao,Z.H. Pan
Cyclic stability is a key factor in the design of thermochemical heat storage systems . Because carbon dioxide (CO 2 ) may react with heat storage materials and lead to a decrease in energy storage efficiency, the effect of CO 2 on Ca(OH) 2 /CaO and Mg(OH) 2 /MgO systems is investigated in this study. The experimental results show that CO 2 reacts with CaO in the water vapor that appears during the heat release process. Therefore, in the design of Ca(OH) 2 /CaO systems, CO 2 should be cleared from the system. The results from Mg(OH) 2 /MgO systems show that CO 2 only slightly reacts with MgO and Mg(OH) 2 during heat storage and release processes. This study indicates that carbonic acid (H 2 CO 3 ) could easily react with CaO/Ca(OH) 2 to form CaCO 3 during heat release processes. Generally, the remaining CO 2 reduces the reversibility of Ca(OH) 2 /CaO systems but has only a slight influence on Mg(OH) 2 /MgO systems. In addition, the experimental results show that carbonate shell does not exist in rehydration for both of the CaO/MgO samples, but the influence of CO 2 on the entire process increases after each cycle.
研究领域:
材料科学
·
能源工程
✓ 已验证
DOI
高影响因子
Materials
·
2019
·Vol. 12
·期 17
·2649
·
IF 2.972
Wenjing Qin,Mengqing Hong,Yongqiang Wang,Jun Tang,Guangxu Cai,Ran Yin,Xuefeng Ruan,Bing Yang,Changzhong Jiang,Feng Ren
Developing high-radiation-tolerant inert matrix fuel (IMF) with a long lifetime is important for advanced fission nuclear systems. In this work, we combined zirconia (ZrO2) with magnesia (MgO) to form ultrafine-grained ZrO2–MgO composite ceramics. On the one hand, the formation of phase interfaces can stabilize the structure of ZrO2as well as inhibiting excessive coarsening of grains. On the other hand, the grain refinement of the composite ceramics can increase the defect sinks. Two kinds of composite ceramics with different grain sizes were prepared by spark plasma sintering (SPS), and their radiation damage behaviors were evaluated by helium (He) and xenon (Xe) ion irradiation. It was found that these dual-phase composite ceramics had better radiation tolerance than the pure yttria-stabilized ZrO2(YSZ) and MgO. Regarding He+ion irradiation with low displacement damage, the ZrO2–MgO composite ceramic with smaller grain size had a better ability to manage He bubbles than the composite ceramic with larger grain size. However, the ZrO2–MgO composite ceramic with a larger grain size could withstand higher displacement damage in the phase transformation under heavy ion irradiation. Therefore, the balance in managing He bubbles and phase stability should be considered in choosing suitable grain sizes.Keywords:ZrO2–MgO;ultrafine grain;irradiation;He bubble;phase transformation
研究领域:
材料科学
·
核能工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Electronic Materials
·
2025
·
IF 4.7
Tiandong Zhang,Ziqi Jin,Hua Li,Zhaotong Meng,Yue Zhang,Yongquan Zhang,Changhai Zhang,Qingguo Chi,Mengjia Feng
Dielectric capacitors are widely used in electrical engineering due to their excellent insulation, high safety, and high power density. However, under high-temperature conditions, injected electric charges from metal electrodes, along with thermally generated charges, lead to a rapid increase in leakage current and severe degradation of insulation performance in polymer capacitive films, limiting long-term and stable operation. To address this issue, core–shell structured BN@MgO inorganic fillers were prepared using the magnetron sputtering method, with MgO as the core and BN as the shell. Results demonstrate that BN@MgO fillers significantly reduce conduction loss in poly(ether imide) (PEI) films by forming charge traps at interfacial regions between the fillers and the PEI matrix. The built-in electric field between BN and MgO efficiently captures mobile charges, enhancing the electrical insulation properties at elevated temperatures. Optimizing the doping content and BN shell thickness leads to a discharge energy density of 3.9 J/cm3 at 150 °C, with a charge/discharge efficiency of 90% for PEI/BN@MgO-1.5(2.5h) composite films. Additionally, excellent cyclic reliability and performance are maintained after 50,000 charge/discharge cycles. The study presents an efficient method for constructing core–shell BN@MgO fillers and clarifies mechanisms for restricting charge mobility.
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2019
·
IF 3.355
Wenzhuo Deng,Ying Li
The cubic solid solution with dispersed tetragonal precipitates formed in all the investigated Zr 1-x Mg x O 2-x (0.06≤x≤0.2) samples. Upon heating, the Arrhenius curves are broken into three parts, the degradation of cubic solid solution gives rise to a decline in ionic conductivity for MgO partially stabilized ZrO 2 (Mg-PSZ) samples at 1000–1200 °C, whereas a sharp rise at 1400°C suggests the phase transition from a tetragonal to a cubic phase. On cooling, the phase conversion is reflected by a bend in the Arrhenius curve at 1400°C or lower temperatures due to the slow decomposition of the cubic phase. The high activation energies in a low-temperature region are mainly due to the formation of defect complexes, and the partial dissociation of which leads to the low activation energies in a high-temperature region. Additionally, no apparent breaks in the Arrhenius curves for 8mol%Y 2 O 3 -ZrO 2 (8YSZ) are observed at 1000–1600 °C and the ionic conductivities increase monotonically with increasing temperature.
研究领域:
材料科学
·
固体物理
✓ 已验证
产品关联
DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2021
·
IF 9.642
Junjie Weng,Cunhao Cui,Zhongyue Zhou,Yi Zhang,Zhanjun Cheng,Jianfeng Pan
Due to rapid deactivation of catalysts, the effective conversion of biomass with oxygen-rich and hydrogen-deficient characteristics to transportation fuels and high-valued chemicals via catalytic pyrolysis remains a challenge for commercialization. Hydrogen-rich plastic is used as feedstock co-fed with biomass to improve the catalytic pyrolysis process. The present work aims to investigate the co-pyrolysis process of cellulose and polyethylene (PE) over MgO by TG combined with photoionization time-of-flight mass spectrometry (PI-TOF-MS), which features on-line detection of catalytic pyrolysis products in real time. The MgO catalyst could improve the pyrolysis of cellulose and enhance the C C bond breaking of PE, respectively. During catalytic co-pyrolysis, the yields from olefins and furan as well as its derivatives can be enhanced obviously. Further, the formation of additional aromatics can be observed due to the Diels-Alder reaction. This work shows TG coupled to PI-TOF-MS is a powerful setup to study and optimize catalytic co-pyrolysis process.
研究领域:
能源化学
·
催化材料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Thermal Science
·
2025
·
IF 2.6
Li Chuan,Han Li,Li Qi,Du Yanping,Wu Yuting
Cold sintering as a new technology for the fabrication of ceramic composites could overcome the shortcomings of traditional high temperature sintering approach and achieve dense structure in the composite at a relatively low temperature (<200°C). In this work, a shape stabilization phase change composite is fabricated and investigated by dint of such new fabrication approach, in which a mixed nitrate salt of NaNO 3 -KNO 3 is used as phase change material and magnesia powder is acted as structure skeleton. Using of deionized water as sintering additive, the effects of sintering agent content, sintering temperature, uniaxial pressure and time on the composite microstructure characteristics and macroscopic properties are evaluated. The results show that the liquid salt could be effectively accommodated in the magnesia skeleton, forming a dense and stable structure in the composite. There is existence of optimal cold sintering parameters at which a benign combination of mechanical strength and thermal cycling performance could be attained in the composite. Under the sintering temperature of 150°C, duration time of 8 min, uniaxial pressure of 150 MPa, and water mass content of 7%, the fabricated composite exhibits a heat storage density of 610 kJ/kg at its potential utilization temperature range of 30°C–580°C and a compressive strength over 240 MPa with a dense density higher than 98%, demonstrating that it can be a viable alternative used in thermal energy storage domains.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS COMMUNICATIONS
·
2016
·
IF 3.389
Xiaomin Xiang,Bin Zhang,Guoqiang Ding,Jinglei Cui,Hongyan Zheng,Yulei Zhu
The oxidation of furfural in H 2 O 2 and H 2 O 2 –Mg(OH) 2 system were systematically investigated and a rational explanation for the reaction mechanism was proposed. 2-formyloxyfuran, from selective oxidation of HC O group in furfural, was a crucial intermediate. The addition of Mg(OH) 2 suppressed the oxidation of furan ring of furfural and enhanced selectivities of 2(5H)-furanone (44.8%) and succinic acid (38.0%). FT-IR, Gaussian calculation and experimental results indicated that the process of furfural oxidation with H 2 O 2 is homogeneous, and the synergy between dissolved Mg 2 + cations and OH − ions facilitates the HOO − attacking the carbon atom of HC O other than the C C bound of furan ring.
研究领域:
化学工程
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）