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281.
针对水泥生料开展了氮吸附与SEM测试分析,研究了水泥生料的比表面积,孔径结构和微观表面积。同时,利用管式回转炉和控温立式炉联用装置研究了砷元素在水泥生料上的吸附冷凝特性。结果表明,水泥生料的比表面积很小,微观表面结构致密无孔,砷元素主要是冷凝在生料表面上。进入吸附冷凝炉的重金属可以分为3部分,第1部分冷凝在管壁上,占80%左右;第2部分吸附/冷凝在生料上,占10%左右;第3部分随烟气释放到空气中,不到10%。水泥生料对砷的吸附冷凝量随时间的增加而增加,随温度的升高而降低。水泥生料对砷的吸附冷凝特性可用双常数速率方程拟合,拟合效果较好,计算得表观活化能在6~7 kJ/mol之间。此外,砷的初始浓度对水泥生料的吸附冷凝特性影响很小。 相似文献
282.
H(+)/phenanthrene symporter and aquaglyceroporin are implicated in phenanthrene uptake by wheat (Triticum aestivum L.) roots 总被引:1,自引:0,他引:1
Zhan X Zhang X Yin X Ma H Liang J Zhou L Jiang T Xu G 《Journal of environmental quality》2012,41(1):188-196
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic pollutants that are toxic to human and nonhuman organisms. Dietary intake of PAHs is a dominant route of exposure for the general population because food crops are a major source of dietary PAHs. The mechanism for crop root uptake of PAHs remains unclear. Here we reveal that wheat root uptake of PAHs involves active and passive processes. The passive uptake is mercury and glycerol dependent. Mercury and glycerol inhibit uptake, indicating that aquaglyceroporins sensitive to mercury contribute to passive uptake. Active uptake is mediated by a phenanthrene/H symporter. The electrical response of wheat roots triggered by phenanthrene consists of two sequential phases: depolarization followed by repolarization. The depolarization is phenanthrene concentration dependent, with saturation kinetics that have an apparent of K(m) 10.8 μmol L(-1). As uptake proceeds, external solution pH increase is noticed. Lower pH favors the uptake. Vanadate and 2,4-dinitrophenol suppress the electrical response to phenanthrene and phenanthrene uptake, suggesting that plasma membrane H(+)-ATPase is involved in the establishment of an electrochemical proton gradient acting as a driving force for active uptake. Therefore, it is suggested that aquaglyceroporin and phenanthrene/H symporter are implicated in phenanthrene uptake. Our results provide insight into PAH uptake mechanism in wheat roots that is relevant to strategies for reducing PAH accumulation in wheat for food safety, improving phytoremediation of PAH-contaminated soils or water by agronomic practices and genetic modification to target remedial plants for higher PAH uptake capacity. 相似文献
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285.
建立了利用组合单标多点校正和英蓝超滤单元的离子色谱法测定地表水中F-、C1-、NO3-、S0424—4-种离子的方法,方法操作简便,灵敏度高,线性范围广,抗干扰能力强,可同时快速测定不同数量级浓度的离子,降低了配置标准品和样品前处理的复杂性,减少了因前处理带来的干扰。 相似文献
286.
Effect of inoculation methods on the composting efficiency of municipal solid wastes 总被引:3,自引:0,他引:3
Four types of inoculation methods were studied during the composting of municipal solid wastes and dry grass (MSWG). The methods included a control group as well as initial-stage, two-stage, and multi-stage inoculations. Fulvic acids were extracted from the composting materials and characterized by spectroscopic techniques. The results showed that inoculation of microbes in MSWG enhanced the biodegradation of aliphatics, proteins, and polysaccharides. The inoculation also increased the molecular weight, humic- and fulvic-like compound content, as well as humification degree of the composting products. The inoculation of microbes in MSWG significantly improved composting process and efficiency. The improvement efficiency was in the order of initial-stage < two-stage < multi-stage inoculations. Inoculation of microbes based on composting organic matter composition and temperature enhanced composting efficiency. 相似文献
287.
Phytoavailability and geospeciation of cadmium in contaminated soil remediated by Rhodobacter sphaeroides 总被引:1,自引:0,他引:1
A microorganism was isolated from oil field injection water and identified as Rhodobacter sphaeroides. It was used for the remediation of simulated cadmium-contaminated soil. The phytoavailability of Cd was investigated through wheat seedling method to determine the efficiency of remediation. It was found that after remediation, the accumulation of Cd in wheat roots and leaves decreased by 67% and 53%, respectively. The Cd speciation in soil was determined with Tessier extraction procedure. It was found that the total Cd content in soil did not change during the experiments, but the geo-speciation of Cd changed remarkably. Among the five fractions, the concentration of exchangeable phases decreased by 27-46% and that of the phases bound to Fe-Mn oxides increased by 22-44%. The decrease of Cd accumulation in wheat showed significant positive correlation with the decrease of exchangeable phases. It could be concluded that the remediation of R. sphaeroides was carried out through the conversion of Cd to more stable forms. The decrease of sulfate concentration in supernatant indicated that the R. sphaeroides consumed sulfate. 相似文献
288.
Jiang Y Xu H Zhang W Zhu M Al-Rasheid KA 《Environmental science and pollution research international》2012,19(5):1747-1754
Introduction
In order to reveal the potential relationships between body-size patterns of microzooplankton and environmental status, the spatial patterns in body-size spectra of ciliated zooplanktons were studied based on an annual dataset in a bay of the Yellow Sea, northern China.Materials and methods
A total of 120 samples were collected at a depth of 1?m from each of five sampling sites with a spatial gradient of environmental stress from June 2007 to May 2008. A range of physico-chemical variables were measured synchronously for comparison with biotic parameters.Results
The spatial body-size patterns of ciliated zooplankton represented significant differences among the five sites, and were significantly correlated with the changes of physico-chemical parameters, especially salinity, dissolved oxygen and nutrients. Two paired indices, the average body-size distinctness (AvBSD) and the variation in body-size distinctness (VarBSD), were proposed based on the trait resemblances among ciliate species in body-size pattern. The paired measures showed a clear decreasing trend of departure from the expected body-size spectra in response to water quality status.Conclusion
These results suggest that the body-size pattern of ciliated zooplankton might be used as a potential indicator of marine water quality. 相似文献289.
290.
Heterogeneous photocatalytic degradation of methyl orange in schwertmannite/oxalate suspension under UV irradiation 总被引:1,自引:0,他引:1
Wu Y Guo J Jiang D Zhou P Lan Y Zhou L 《Environmental science and pollution research international》2012,19(6):2313-2320