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981.
Herein, we developed the invasive plant-derived biochar (IPB) functionalized with CaAl-LDH at five mass ratios using a physical mixture method, assessed their adsorption perform for Eu(III), and explored the relative mechanisms. Results show that the IPB successfully loaded CaAl-LDH in five composites and their Eu(III) sorption affinities were strongly affected by solution pH, contact time, temperature, and the mass ratio of LDH and IPB. All the sorpiton process for Eu(III) occurred on the heterogeneous surface of five composites and the boundary layer diffusion limited the chemical sorption rate. Interestingly, the CaAl-LDH/IPB composite with high ratio of IPB had higher sorption capacity than the one with high ratio of LDH due to larger porosity of the former. Three mechanisms containing ion exchange between Al and Eu ions, surface complexation with carboxyl- and oxygen-containing functional groups, and precipitation were involved in the Eu(III) sorption, but the dominant sorption mechanism for each CaAl-LDH/IPB composite differed with different mass ratio of CaAl-LDH and IPB. In composite with more IPB (e.g., CaAl-LDH/IPB-13), both ion exchange and surface complexes dominated the sorption process and the intensity of Eu3+ was identified with the one of Eu2O3. Whereas in composites with high LDH, ion exchange dominated the sorption and the intensity of Eu3+ was obviously higher than the one of Eu2O3. This research will provide a new perspective for the application of the LDH/biochar materials. 相似文献
982.
983.
Xue Wang Wenge Cheng Qiuyuan Yang Hongyun Niu Qian Liu Yun Liu Ming Gao Ming Xu An Xu Sijin Liu Xiaoyu Huang Yuguo Du 《环境科学学报(英文版)》2018,30(7):217-226
As well-known persistent organic pollutants(POPs), organofluorine pollutants such as perfluorooctane sulfonate(PFOS) have been proven to be bioaccumulated and harmful to health. However, toxicological assessment of organofluorinated nanoparticles, which have emerged as a novel tool for biomedical and industrial applications, is lacking, to the best of our knowledge. To assess the biological effects and health risk of fluorinated nanoparticles,trifluoroethyl aryl ether-based fluorinated poly(methyl methacrylate) nanoparticles(PTFEPMMA NPs) were synthesized with various fluorine contents(PTFE-PMMA-1 NPs 12.0 wt.%,PTFE-PMMA-2 NPs 6.1 wt.% and PTFE-PMMA-3 NPs 5.0 wt.%), and their cytotoxicity was investigated in this study. The in vitro experimental results indicated that the cytotoxicity of PTFE-PMMA NPs was mild, and was closely related to their fluorine(F) contents and Fcontaining side chains. Specifically, the cytotoxicity of PTFE-PMMA NPs decreased with increasing F content and F-containing side chains. After exposure to PTFE-PMMA NPs at a sublethal dose(50 μg/m L) for 24 hr, the phospholipid bilayer was damaged, accompanied by increasing permeability of the cell membrane. Meanwhile, the intracellular accumulation of reactive oxygen species(ROS) occurred, resulting in the increase of DNA damage, cell cycle arrest and cell death. Overall, the PTFE-PMMA NPs were found to be relatively safe compared with typical engineered nanomaterials(ENMs), such as silver nanoparticles and graphene oxide, for biomedical and industrial applications. 相似文献
984.
The influence of a single water molecule on the reaction mechanism and kinetics of hydrogen abstraction from methanol(CH_3OH) by the ClO radical has been investigated using ab initio calculations. The reaction proceeds through two channels: abstraction of the hydroxyl H-atom and methyl H-atom of CH_3OH by ClO, leading to the formation of CH_3O + HOCl(+H_2O) and CH_2OH + HOCl(+H_2O), respectively. In both cases, pre-and post-reactive complexes were located at the entrance and exit channel on the potential energy surfaces. Results indicate that the formation of CH_2OH + HOCl(+H_2O) is predominant over the formation of CH_3O + HOCl(+H_2O),with ambient rate constants of 3.07 × 10-19 and 3.01 × 10~(-23) cm~3/(molecule·sec), respectively, for the reaction without water. Over the temperature range 216.7–298.2K, the presence of water is seen to effectively lower the rate constants for the most favorable pathways by 4–6 orders of magnitude in both cases. It is therefore concluded that water plays an inhibitive role on the CH_3OH + ClO reaction under tropospheric conditions. 相似文献
985.
法布里-珀罗光纤传感器在桥梁健康监测中的应用 总被引:1,自引:2,他引:1
对桥梁实施监测 ,是诊断桥梁健康状况的主要手段 ,现代传感技术和计算机技术的发展 ,使桥梁健康状态的实时监测变为可能。笔者分析了法布里 -珀罗光纤传感器的基本原理和特性 ,设计了一种法布里 -珀罗应变测试系统 ,并在预应力混凝土连续桥梁上与电阻式应变传感器进行了应变对比测试试验。试验结果表明 ,法布里 -珀罗光纤传感器对环境温度不敏感 ,易与钢筋、混凝土复合 ,适用于桥梁结构的应变测试 ,可用于桥梁健康状态的在线监测 相似文献
986.
987.
Microbial polyhydroxyalkanoates (PHAs) have been extensively studied as environmentally friendly biodegradable thermoplastics. The major obstacle to wide acceptance of PHAs is their high price, mainly attributed to the costs of raw materials and polymer recovery. A large amount of organic solids are discarded from food production and consumption and may be used as carbonaceous raw materials for production of PHAs. A novel technology was investigated at bench-top scale to produce PHAs from food scraps. The harvested cell mass had a high PHA content (72.6% of dry cell mass), the same as obtained from pure glucose and organic acids. The organic solid was first digested in an acidogenic reactor in which about 60% solid was converted to fermentative products, including short-chain fatty acids. The four major acids were acetic, propionic, butyric, and lactic acids at concentrations of 6, 2, 27, and 33 g/L, respectively. The acids were transported through a membrane barrier via molecular diffusion to an airlift bioreactor, where the acids were utilized by an enriched culture of Ralstonia eutropha for PHA synthesis. Purification of fermentative acids was not performed in this molecular diffusion–based integration of acidogenesis and polymerization. By using a dialysis membrane as the barrier, the dry cell mass concentration and PHA content reached 22.7 g/L and 72.6%, respectively. The PHA was a copolymer of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with 2.8 mole % of hydroxyvalerate. 相似文献
988.
高州水库水体富营养化评价与控制对策研究 总被引:1,自引:0,他引:1
采用综合营养状态指数法(TLI))和卡森指数评分法对高州水库2004年到2008年的水质进行了评价,结果显示,近年来高州水库两库区3月份的综合营养状态指数值TLI(∑)近年来呈上升趋势。石骨库区和良德库区2008年3月份的综合营养状态指数值分别达到了40.32和48.07。两库区3月份都呈现出即将突破中营养化状态达到富营养化的趋势。卡森指数评分法得出水库2004-2008年的分值在45.0-68.2之间,自2005年以后,每年3月份的富营养程度要高于9月份,且三月份呈明显的上升趋势。表明了2-3月份是高州水库水华爆发的危险期。在实地调研的基础上,分析了主要的污染原因,并提出了针对高州水库的富营养化控制措施和建议。 相似文献
989.
990.
伴随着沿海人口的递增和养殖业的发展,粪便污染已成为近岸海域污染的一个重要污染源,日益威胁着人类的生存和经济发展。抗生素抗性分析法(Antibiotic Resistance Analysis,ARA)凭借对不同物种粪便源中相同示踪因子特异性抗生素抗性的检测,可以达到识别粪便污染源的目的。作为一种经济有效的粪便污染源示踪工具,ARA研究在欧美等国已开展并得到了应用。简要介绍了ARA原理、着重阐述了ARA的应用方法学,并概括了目前ARA在国内外发展现状。以期为同领域专家学者提供参考,促进中国利用ARA法在识别粪便源技术中的应用。 相似文献