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931.
932.
Niobium oxide nanowire-deposited carbon fiber (CF) samples were prepared using a hydrothermal method with amorphous Nb2O5·nH2O as precursor. The physical properties of the samples were characterized by means of numerous techniques, including X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), UV–visible spectroscopy (UV–vis), N2 adsorption–desorption, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy. The efficiency for the removal of Cr(VI) was determined. Parameters such as pH value and initial Cr(VI) concentration could influence the Cr(VI) removal efficiency or adsorption capacity of the Nb2O5/carbon fiber sample obtained after hydrothermal treatment at 160°C for 14 hr. The maximal Cr(VI) adsorption capacity of the Nb2O5 nanowire/CF sample was 115 mg/g. This Nb2O5/CF sample also showed excellent photocatalytic activity and stability for the reduction of Cr(VI) under UV-light irradiation: the Cr(VI) removal efficiency reached 99.9% after UV-light irradiation for 1 hr and there was no significant decrease in photocatalytic performance after the use of the sample for 10 repeated cycles. Such excellent Cr(VI) adsorption capacity and photocatalytic performance was related to its high surface area, abundant surface hydroxyl groups, and good UV-light absorption ability. 相似文献
933.
山东省矿产资源特点及其开发利用 总被引:2,自引:0,他引:2
山东矿产资源以能源矿、非金属矿、金矿和铁矿等具优势,常用矿产与优势矿产吻合程度高,主要矿产资源地区匹配关系好,便于综合开发利用。矿产资源开发利用对山东工业发展具有重要导向作用,但也存在加工程度低、综合利用效益差、资源浪费重、对生态环境影响大等问题。在综合分析资源特点和利用现状的基础上,构想了山东主要矿产资源开发基地的布局和发展趋势。 相似文献
934.
Panlai Shi Yuan Wang Hongbin Liang Yaqin Hou Duo Chen Ganye Zhao Peng Dai Yanjie Xia Yin Feng David S. Cram Xiangdong Kong 《黑龙江环境通报》2021,41(10):1332-1342
935.
Cationic organobismuth complex as an effective catalyst for conversion of CO2 into cyclic carbonates
Xiaowen Zhang Weili Dai Shuangfeng Yin Shenglian Luo Chak-Tong Au 《Frontiers of Environmental Science & Engineering in China》2009,3(1):32-37
In order to achieve high-efficiency conversion of CO2 into valuable chemicals, and to exploit new applications of organobismuth compounds, cationic organobismuth complex with
5,6,7,12-tetrahydrodibenz[c,f][1,5] azabismocine framework was examined for the first time for the coupling of CO2 into cyclic carbonates, using terminal epoxides as substrates and tetrabutylammonium halide as co-catalyst in a solvent-free
environment under mild conditions. It is shown that the catalyst exhibited high activity and selectivity for the coupling
reaction of CO2 with a wide range of terminal epoxide. The selectivity of propylene carbonates could reach 100%, and the maximum turnover
frequency was up to 10740 h−1 at 120°C and 3 MPa CO2 pressure when tetrabutylammonium iodide was used as co-catalyst. Moreover, the catalyst is environment friendly, resistant
to air and water, and can be readily reused and recycled without any loss of activity, demonstrating a potential in industrial
application. 相似文献
936.
为减少化工园储罐区多米诺效应发生概率,找出最容易发生多米诺效应、且对事故影响最大的储罐,评估各储罐的脆弱性等级。首先基于不同领域脆弱性的内涵和多米诺效应的特点,提出多米诺效应情况下储罐脆弱性的定义;然后利用熵权物元可拓模型和风险矩阵法的客观性,并结合复杂网络模型和逼近理想排序法(TOPSIS)模型评估事故网络节点重要度,从初始事故的可能性与传播影响力2个方面,构建多米诺效应下储罐脆弱性分级评估模型;最后应用该模型评估某化工园储罐区各罐体脆弱性等级,并将结果与贝叶斯方法的评估结果对比。结果表明: 该模型考虑了储罐自身属性及影响扩展范围,得到的脆弱性分级结果更准确。 相似文献
937.
2012年9月1日至30日利用大气气溶胶OC/EC在线分析仪在线分析了西安PM2.5中的OC、EC,并结合O3和紫外辐射数据(UV)进行了分析。结果表明:PM2.5、OC、EC、及O3的日均值分别为85.22,19.50,7.18,56.69μg/m3。PM2.5及其中OC、EC的日变化规律呈现"双峰"分布,OC、EC的日波动范围较PM2.5小,且OC的波动范围较EC大,OC、EC的相关性较高(R2=0.73)。PM2.5中TCA的平均比重为47.85%,是PM2.5的主要成分之一,TCA以OM为主,OM中SOC的平均比重高达54.76%,PM2.5中SOC的平均比重为21.25%,SOC和O3的相关性较高,表明研究期间西安市有机物光化学反应较重。1 d中10:00至19:00是PM2.5中SOC比重最高的时段且呈上升趋势,而PM2.5中TCA的变化规律则呈"W"型双峰分布。 相似文献
938.
939.
940.
Hongxia Lin Yuxi Liu Jiguang Deng Kunfeng Zhang Xing Zhang Shaohua Xie Xingtian Zhao Jun Yang Zhuo Han Hongxing Dai 《环境科学学报(英文版)》2018,30(8):74-86
Three-dimensionally ordered mesoporous Fe_2O_3(meso-Fe_2O_3) and its supported Au, Pd,and Au-Pd alloy(xA uP dy/meso-Fe_2O_3; x = 0.08–0.72 wt.%; Pd/Au molar ratio(y) = 1.48–1.85)photocatalysts have been prepared via the KIT-6-templating and polyvinyl alcohol-protected reduction routes, respectively. Physical properties of the samples were characterized, and their photocatalytic activities were evaluated for the photocatalytic oxidation of acetone in the presence of a small amount of H_2O_2 under visible-light illumination. It was found that the meso-Fe_2O_3 was rhombohedral in crystal structure. The as-obtained samples displayed a high surface area of 111.0–140.8 m~2/g and a bandgap energy of 1.98–2.12 eV. The Au, Pd and/or Au–Pd alloy nanoparticles(NPs) with a size of 3–4 nm were uniformly dispersed on the surface of the meso-Fe_2O_3 support. The 0.72 wt.% AuP d1.48/meso-Fe_2O_3 sample performed the best in the presence of 0.06 mol/L H_2O_2 aqueous solution, showing a 100% acetone conversion within4 hr of visible-light illumination. It was concluded that the good performance of 0.72 wt.%AuPd_(1.48)/meso-Fe_2O_3 for photocatalytic acetone oxidation was associated with its ordered mesoporous structure, high adsorbed oxygen species concentration, plasmonic resonance effect between AuPd_(1.48) NPs and meso-Fe_2O_3, and effective separation of the photogenerated charge carriers. In addition, the introduction of H_2O_2 and the involvement of the photo-Fenton process also played important roles in enhancing the photocatalytic activity of 0.72 wt.%AuPd_(1.48)/meso-Fe_2O_3. 相似文献