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持久性有机污染物(POPs)具有环境稳定性、蓄积性等特点。在城市地表径流中,其迁移能力与径流中的颗粒物的性质与POPs本身性质、土地利用情况、排水条件、管理方式和降水条件等因素密切相关。针对国内外的研究结果总结了影响POPs在城市地表径流迁移中的受影响因素,分析了不同径流粒子的影响情况、城市绿地净化作用、管理方式以及降水过程对POPs的迁移影响。 相似文献
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疏水性离子液体用于萃取酚类物质 总被引:36,自引:4,他引:32
测定了苯酚、苯基酚、苯二酚等几种不同取代基的酚类物质在疏水性离子液体[bmim]PF6(1-丁基-3-甲基咪唑六氟磷酸盐)和[dmim]PF6(1-癸基-3-甲基咪唑六氟磷酸盐)与水两相中的分配系数. 实验结果表明,萃取过程很快可以达到平衡. 与传统有机溶剂相比,分配系数处在同一个数量级. 分配系数随温度升高而降低,离子液体对不同取代基的酚类萃取能力有很大差异,咪唑基团上取代烷基链的长度对不同酚类物质的分配系数有很大影响,因此可以通过调节离子液体结构使其适用于不同成分的含酚废水. 相似文献
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The n‐butane/water distribution constant is one of the key parameters in determining the extraction efficiency. Experimental results on 34 organic compounds illustrated that a fundamental linear relationship exists between the distribution constant and the aqueous solubility of the solute. The relationship can be broadly applied to many different classes of chemical compounds as well as to many different solvent extraction systems. The linear equation obtained by a regression method allows one to estimate the distribution constant and predict the result of butane extraction if the aqueous solubility of certain solute is available. 相似文献
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利用疏水性离子液体1-丁基-3-甲基咪唑六氟磷酸盐[Bmim][PF6]、1-丁基-3-乙基咪唑六氟磷酸盐[Beim][PF6]、1-丁基-3-甲基咪唑双三氟甲磺酰亚胺盐[Bmim][Tf2N]对水溶液中的9种芳香化合物进行萃取,以苯胺为代表对萃取工艺进行了优化,考察了乙醚、正丁醇等低极性溶剂对离子液体的再生情况. 结果表明,在室温下,当相比O/A=0.2、时间为10 min时,[Bmim][PF6]对苯胺的萃取率达87.2%,分配系数为34.1,效果明显高于甲苯、正辛醇等传统有机溶剂. 芳香化合物的分子结构对萃取有较大影响,萃取率及分配系数随溶质疏水性增加而增加. 用乙醚作为反萃剂效果较好,苯胺和离子液体的回收率分别为93.1%和95.2%,溶质及离子液体均能实现资源化回收利用. 相似文献
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H. Garivait C. Polprasert K. Yoshizumi L. Baetz Reutergardh 《Polycyclic Aromatic Compounds》2013,33(3):325-350
The gas-particle partitioning and particle size distributions of airborne PAH in Bangkok urban air were investigated using an 8 stage size fractionating cascade impactor (Andersen “low volume” sampler) and a downstream XAD-2 adsorbent tube for sample collection. Nine PAH classified as carcinogenic and co-carcinogenic compounds-Pyrene (PYR), Benz(a)Anthracene (BaA), Benzo(e)Pyrene (BeP), Dibenz(a,c)Anthracene (DBacA), Benzo(k)Fluoranthene (BkF), Benzo(a)Pyrene (BaP), Dibenz(a,h)Anthracene (DBahA), Benzo(ghi)Perylene (BghiP) and Trimethylcholanthrene (3MC) - were quantified. The lower molecular weight (MW) PAH such as PYR, BeP and BaA were present mainly in the gaseous phase (80%, 40% and 24%, respectively) while higher MW compounds were present almost totally in the particulate fraction. The results show that 30%–60% of each PAH by mass were found on particles smaller than 0.43 μm and more than 70% on particles with diameter less than 2.1 μm. In addition, the relationship between the particle/gas partition coefficient (K p ) and the sub-cooled liquid vapor pressure (p°L) was also determined to describe the gas-particle partitioning of those PAH compounds in a tropical atmosphere. 相似文献
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持久性有机污染物现状及处理方法的研究 总被引:1,自引:0,他引:1
持久性有机污染物(POPs)是一类具有环境持久性、生物累积性、长距离迁移能力和高生物毒性的特殊污染物.本文介绍了持久性有机污染物的定义,来源,特性.概述持久性有机污染物在我国的污染现状,并探讨我国持久性有机污染物处理方法的研究进展. 相似文献
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提出了以最密堆积作为评价水煤膏粒度配比优劣的指标并研究了煤粉颗粒在不同粗细比下的自然堆积体积和析水率,得出了徐州混煤和贾汪烟煤(粒度0~5mm)的最佳配比,该结果在我所水煤膏流动试验台上得到验证。 相似文献
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Direct-contact vaporization heat transfer is investigated by analyzing the heat transfer coefficient with the area of liquid-liquid direct-contact interface. The interface areas of liquid-liquid heat transfer are determined by stroboscopic images. At higher temperature, the heat transfer area per unit volume decreases. The water temperature has no significant influence on the heat transfer coefficient. The effects on droplet size distributions of operating variables including inlet water temperature, n-pentane flow rate, and test position with packing and without packing are compared. 相似文献
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Octanol-water partition coefficients (K ow s) of substituted polycyclic aromatic compounds (PACs), anthracene-, pyrene- and quinoline-derivatives, have been determined using HPLC. The determined K ow s have been compared with results from theoretical fragment methods, developed by Rekker and Mannhold [1] and by Hansch and Leo [2]. The results showed that if these theoretical methods are to be useful with simple substituted PAHs they must be applied differently than normally supposed, due to intramolecular steric conditions. Comparison of the determined K ow s with measured K oc values showed that the relationship between K oc and K ow is not straightforward, and that prediction of K oc from K ow alone will not give results applicable for substituted polycyclic aromatic compounds. 相似文献
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介绍了弛张筛的工作原理,说明其具有维护量小、运行可靠、筛孔不易堵塞、适于难筛物料等特点。论述了伯特利弛张筛和宾得弛张筛的性质,并分别对其进行了工业化筛分试验,根据结果绘制各筛面分配曲线,对比了筛分效率和平均分配误差。结果表明:伯特利弛张筛的上层筛分效率为92.35%,高于宾得弛张筛的86.01%,筛分效果优于宾得弛张筛,而伯特利弛张筛的下层筛分效率仅为55.70%,低于宾得下层的76.53%,筛分效果不如宾得弛张筛;伯特利弛张筛的分配粒度均小于分级粒度,而宾得弛张筛的分配粒度均大于分级粒度;宾得弛张筛上下层筛板的平均分配误差均小于伯特利弛张筛。综合对比后说明宾得弛张筛在红柳选煤厂的应用效果更佳。 相似文献
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