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预浓缩-气质联用法测定高山大气中氯氟烃 总被引:1,自引:1,他引:0
建立了预浓缩-气相色谱/质谱联用技术,同时检测高山大气中二氟二氯甲烷、四氟二氯乙烷、一氟三氯甲烷、三氟三氯乙烷的分析方法。4种物质的检出限分别为0.013、0.022、0.021、0.030μg/m~3,相对标准偏差在5.6%以下,标准曲线相关系数大于0.996,加标回收率为93.2%~98.3%。对庐山大气进行监测,结果表明,庐山大气中4种氯氟烃的浓度均高于武夷山和湖北神龙架大气背景点,庐山大气中CFC-11、CFC-113的浓度接近于泰山和贡嘎山的浓度。 相似文献
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针对传统的"厌氧+氧化沟"运行模式对低碳源污水除磷能力不佳的问题,采用耦合回流污泥预浓缩系统的新型氧化沟工艺对其强化除磷进行了中试实验研究。通过采用回流污泥预浓缩系统,调试回流污泥浓缩比,提高系统的除磷能力。研究结果表明,在控制最佳回流污泥浓缩比为55%的情况下,出水TP浓度和去除率分别为0.92 mg/L和67.5%,相比于浓缩比为100%、70%、50%和30%的工况,其去除率分别增加了24.3%、27.3%、8.2%和28.6%,强化了系统的除磷效果。另外,ORP可以预示预缺氧池内无效释磷和反硝化程度,以此作为自动调整最佳回流污泥浓缩比的控制参数。 相似文献
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Herbert Musarurwa Luke Chimuka 《Journal of environmental science and health. Part. B》2013,48(9):770-780
The ever-increasing demand for determining pesticides at low concentration levels in different food matrices requires a preliminary step of pre-concentration which is considered a crucial stage. Recently, the parameter of “greenness” during sample pre-concentration of pesticides in food matrices is as important as selectivity in order to avoid using harmful organic solvents during sample preparation. Developing new green pre-concentration techniques is one of the key subjects. Thus, to reduce the impact on the environment during trace analysis of pesticides in food matrices, new developments in pre-concentration have gone in three separate directions: the search for more environmentally friendly solvents, miniaturization and development of solvent-free pre-concentration techniques. Eco-friendly solvents such as supercritical fluids, ionic liquids and natural deep eutectic solvents have been developed for use as extraction solvents during pre-concentration of pesticides in food matrices. Also, miniaturized pre-concentration techniques such as QuEChERS, dispersive liquid–liquid micro-extraction and hollow-fiber liquid-phase micro-extraction have been used during trace analysis of pesticides in food samples as well as solvent-free techniques such as solid-phase micro-extraction and stir bar sorptive extraction. All these developments which are aimed at ensuring that pesticide pre-concentration in different food matrices is green are critically reviewed in this paper. 相似文献
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老工业区大气中挥发性有机物的分布和组成特征 总被引:1,自引:0,他引:1
以老工业区大气中有机污染物为研究对象,采用预浓缩-GC/MS方法分析了老工业区大气中挥发性有机物(VOCs)的分布和组成特征。结果表明,老工业区内工业行业的复杂性和规划的不合理性,导致有机物分布和组成的差异。混杂区和工业集中区VOCs的浓度大于居住区和对照区,并且有机物的浓度存在垂直分布规律。卤代烃是老工业区大气中含量最高的挥发性有机物,占TVOC的27%,其次是饱和烷烃和芳烃,分别占TVOC的21%和20%。 相似文献
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化学处理活性炭对汞等重金属离子具有良好的吸附特性。通过一系列测试获得了碘化和氯化活性炭预富集水体汞的优化方案。对实验室配制汞标准样品的测试表明,碘化和氯化活性炭对汞具有良好的吸附特性,而采样管的内径、活性炭的填充量以及过滤流速均影响活性炭预富集水体汞的效率。采用600mg的碘化活性炭采样管(内径:0.35cm),在水体过滤流速为10r/min(7mL/min)~25r/min(17mL/min)的条件下,碘化活性炭对水体汞的吸附效率可达到95%以上。增加流速和采样管内径以及减少活性炭填充量均会降低活性炭对水体汞的吸附效率。同时进一步测试了碘化活性炭对高汞(万山汞矿区渗滤水,含量范围:37.68~321.57ng/L)和低汞(贵阳市降水,含量范围:2.76~9.98ng/L)等天然水体汞的预富集效率,其预富集效率的平均值分别为96.74%(n=8)和96.09%(n=8)。该研究为采用化学处理活性炭技术预富集天然水体汞以及开展水体汞同位素测试提供了一种全新方法。 相似文献
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