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Lead halide perovskites MAPbX3 (MA = CH3NH3 or Cs; X = I, Br, Cl) are well considered to be potential candidates for photocatalytic reaction due to its excellent photoelectrical properties, but they still suffer from the low charge separation efficiency and slow catalytic reaction dynamics. To tackle the drawbacks, herein, MAPbBr3/carbon sphere (CS) composite photocatalysts using glucose as the carbon source were elaborately designed and fabricated via a dry mechanochemical grinding process. The interfacial interaction Pb-O-C chemical bonds were constructed between MAPbBr3 and the carbon sphere surface containing organic functional groups. By optimizing the content of CSs, the enhanced photocatalytic degradation kinetic rate of Malachite Green (MG) pollutants (92% within 20 min) for MAPbBr3/CSx (x = 17 wt.%) is about 3.6-fold of that for pristine MAPbBr3, which is attributed to the corporative adsorption and enhanced carrier transportation and separation of MAPbBr3/CSx. Furthermore, the possible degradation mechanism was proposed on basis of the electrochemical, mass spectrometry and optical characterization results. Owing to the robust interfacial interaction, effective electron extraction rate (ket = 4.6 × 107 sec?1) from MAPbBr3 to CS can be established, which driven oxygen activation where superoxide radicals (?O2?) played an important role in MG degradation. It is expected that mechanochemistry strategy may provide a new route to design efficient lead halide perovskite-carbon or metal oxide or sulfide composite photocatalysts. 相似文献
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以陶瓷-活性炭球为载体制备载Ru催化剂,用于催化湿式氧化(CWAO)法处理酚醛树脂废水,考察了陶瓷-活性炭球载体、Ru负载量和陶瓷球宏孔孔径等对催化剂的催化活性和稳定性的影响。实验结果表明,催化剂催化活性的顺序为:Ru/KC-120>Ru/KC-80>Ru/KC-60>KC-120>无催化剂。在200℃,氧气分压为1.5 MPa等条件下,催化湿式氧化酚醛树脂废水,3%Ru/KC-120催化剂表现良好的催化活性与稳定性,在120 min内,COD和苯酚去除率分别达到91%和96%。 相似文献
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To evaluate the hazard of combined hydrogen/dust explosions under severe accident conditions in International Thermonuclear Experimental Reactor (ITER), standard method of 20-L-sphere was used to measure the explosion indices of 4-μm fine graphite dust in lean hydrogen/air mixtures. The mixtures were ignited by a weak electric spark. The tested fuel concentrations were 8–18 vol% H2 and 25–250 g/m3 dust. If the hydrogen content is higher than 10 vol%, the dust constituent can be induced to explode by the hydrogen explosion initiated by a weak electric spark. Depending on the fuel component concentrations, the explosions proceed in either one or two stages. In two-stage explosions occurring at low hydrogen and dust concentrations, the mixture ignition initiates first a fast hydrogen explosion followed by a slower phase of the dust explosion. With increasing dust concentration, the dust explodes faster and can overlap the hydrogen-explosion stage. At higher hydrogen concentrations, the hybrid mixtures explode in one stage, with hydrogen and dust reacting at the same time scale. Maximum overpressures of hybrid explosions are higher than those observed with hydrogen alone; maximum rates of pressure rise are lower in two-phase explosions and, generally, higher in one-stage explosions, than those characteristic of the corresponding H2/air mixtures. 相似文献
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针对临近空间大气环境探测需求,介绍了一种可用于30~100 km临近空间大气密度、风场、温度和气压的原位探测技术——探空火箭膨胀落球探测技术,阐述了其探测原理、系统组成和探测过程,采用仿真方法模拟了膨胀落球的探测数据,并利用模拟探测数据成功反演了30~100 km临近空间大气密度、风场、温度和气压等大气产品。该技术具有探测要素多、探测高度范围广、载荷成本低、设备较为简单等特点,对于我国临近空间环境探测和环境研究具有重要意义。 相似文献
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Yonghao Wang Wenqi Wei Yuzhi Lin Mian Zhang Yongjing Wang Minghua Liu 《环境科学学报(英文版)》2020,32(8):111-118
In this work, magnesium silicate-based sulfonated polystyrene sphere composites (SPS/MgSi) were synthesized by one-step (SMD1) and two-step (SMD2) methods. For SMD1, MgSi particles were densely assembled on the surface of SPS, assisted by complexation between Fe3+ and hydroxyl phenol. For SMD2, SPS/SiO2 was firstly obtained by the same method as SMD1, and then SPS/SiO2 was transformed directly to SPS/MgSi under hydrothermal conditions. Therefore, MgSi obtained by the two-step method had an interwoven structure. Compared to SPS, MgSi and SMD1, SMD2 presented a larger specific surface area and more negative surface charges. Therefore, SMD2 showed superior adsorption performance toward CIP with concentrations of 5, 10 and 50 mg/L, and for 50 mg/L, the equilibrium adsorption capacity could reach 329.7 mg/g. The adsorption process is fast and can be described by the pseudo-second-order kinetic model. The relationship between pH value and Zeta potential demonstrated that electrostatic interaction dominated the adsorption process. In addition, competitive adsorption showed that the effect of Na+ was negligible but the effect of Ca2+ was dependent on its concentration. Humid acid (HA) could slightly promote the absorption of CIP by SMD2. After five rounds of adsorption-desorption, the equilibrium adsorption capacity of SMD2 still remained at 288.6 mg/L for 50 mg/L CIP. Notably, SMD2 presented likewise superior adsorption capacity for CIP with concentrations of 10 and 50 mg/L in Minjiang source water. All the results indicated that this synthesis method is universal and that SMD2 has potential as an adsorbent for CIP removal from aquatic environments. 相似文献
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Barbara M. Miller Julie Lellis 《Environmental Communication: A Journal of Nature and Culture》2016,10(2):249-268
A form of issue advocacy, marketplace advocacy campaigns often arise in response to burgeoning societal concerns, especially those faced by energy industries. Although these campaigns may include brief and selective references to corporate activities, most campaigns place a much stronger emphasis on commonly shared societal values. This study examines audience response to values-based environmental marketplace advocacy messages by the fossil fuel industries through a series of focus groups. Four instrumental values were identified in campaign videos (innovation, community, resilience, and patriotism), and the terminal value of pragmatism, especially as it relates to environmental issues, was identified as a result of identification with one or more of the instrumental values. The findings are discussed through the lens of extant research on marketplace advocacy and organizational values as well as Habermas's theory of refuedalization, shedding light on the ways corporations appeal to commonly held societal values in an effort to generate support for a given industry. 相似文献
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In the work presented in this paper, the effect of initial pressure on the lower explosion limit (LEL) of the hybrid nicotinic acid/acetone mixture was investigated through standard explosion tests carried out in the 20 L sphere. From experimental results, the flammability diagram was built in the plane (concentration/minimum explosive concentration) of nicotinic acid versus (concentration/LEL) of acetone. Interestingly, it has been found that, in going from low pressures (P < 1 atm) to high pressures (P > 1 atm), the extension of the flammability region increases. This behavior has been attributed to the fact that the turbulence kinetic energy (and thus the energy dissipation) decreases with increasing initial pressure. Bartknecht's correlation for LEL of hybrid mixtures was modified to take into account the effect of pressure, and two correlations were obtained able to give satisfactory predictions of experimental data at both low pressures and high pressures. 相似文献