排序方式: 共有35条查询结果,搜索用时 31 毫秒
21.
测定空气中甲醇的毛细管气相色谱方法研究 总被引:3,自引:0,他引:3
使用HP—Wax毛细管柱进行水样分析,甲醇和乙醇分离效果好,该方法的精密度和准确度高,每0.2μL的最低检出限为0.7ng。此法利用了化学工作站,使得分析更简单、方便。 相似文献
22.
Endalkachew Sahle-Demessie Catherine B. Almquist Sridara Chandra Sehker 《Water, Air, & Soil Pollution: Focus》2008,8(3-4):297-309
Oxidation of methanol over V2O5 catalysts supported on anatase TiO2 that were prepared using sol-gel formation and impregnation procedures were investigated. The effects of incorporating Mg
in sol-gel to influence the properties of the catalyst were also studied. The process provides an alternative low temperature
reaction pathway for reducing emissions of hazardous air pollutant (HAPs) such as methanol and total reduced sulfur compounds
(TRS) from pulp and paper mills. The bulk and surface composition of the catalysts were determined by XRD and SEM-EDAX, respectively.
The X-ray diffraction patterns of the vanadia–titania catalysts showed mainly the anatase phase of TiO2. Temperature programmed desorption of methanol from the different catalyst showed that the α and β peaks differ significantly
with V content and addition of Mg. The combination of gas phase and surface reactions on the V/TiO2 catalysts reduced the amount of ozone required for high degradation of methanol to mainly CO
x
with small quantities of methyl formate. In the absence of ozone the catalysts showed very low activity. It is hypothesized
that the ozone is directly influencing the V4+ and V5+ redox cycle of the catalyst. Oxidation of methanol is influenced by the operation variables and catalyst properties. The
results of this study revealed that the V content has significant influence on the catalyst activity, and the optimum vanadia
loading of about 6 wt%. Higher turnover frequencies were observed over sol-gel catalysts than with catalysts prepared by the
impregnation method. 相似文献
23.
We present an overview of possible biotechnological applications for using carbon dioxide for the synthesis of chemicals.
These approaches are very appealing as they contribute to the implementation of new synthetic methodologies that reduce waste
and make a better use of carbon and energy. Several synthetic approaches will be considered including both the incorporation
of the whole COO moiety or its reduction to other C1 molecules. Each option will be discussed making a comparison between the natural and artificial process in order to highlight
the possibility to learn from Nature and develop useful mimetic or enzymatic systems. 相似文献
24.
吴珉 《环境监测管理与技术》1997,9(2):36-37
对变色酸光度法测定空气中甲醇的方法进行了改进,在比色波长,显色时间和试剂用量等方面均作了重新选定,使精密度和准确度都有所提高,与气相色谱法比较,分析结果一致。 相似文献
25.
26.
毛细管气相色谱法测定水和废水中的丙烯酰胺 总被引:2,自引:0,他引:2
本文采用毛细管色谱法建立了水和废水中丙烯酰胺的测定程序。在此,以活性炭柱吸附,浓缩样品中的丙烯酰胺,用甲醇洗脱,洗脱液用FID测定,方法回收率为831~990%,相对标准偏差为534%,检出限为0016mg/L。 相似文献
27.
吹脱捕集-热解析-气相色谱法测定水中苯系物含量的探讨 总被引:4,自引:0,他引:4
职克利 《石油化工环境保护》2005,28(1):i002-i003
建立了吹脱捕集-热解析的方法对样品进行浓缩,提高了方法的灵敏度,降低了方法的检出限。用微量的甲醇作中间溶剂,使水中苯系物这一分散体系,变为均匀稳定的单液相状态,方法的准确度和精密度较高。当进样量为3mL时,苯系物的各组分检出限在0 1~1 0 μg/L之间,浓度与峰高线性关系良好(r >0 998) ,线性范围在10 3~10 4 μg/L之间,方法的变异系数在1 0~6 5 %之间,回收率在92 7%~10 5 3%之间,该方法操作简单实用性强,能够充分满足生产要求 相似文献
28.
We studied the photocatalytic activity of Ti-montmorillonite. The highest activity was found for a Ti/bentonite ratio of 10 mmol/g, prepared using HCl and calcined by microwaves. This mixture is less active than TiO2 P-25 for 4-chlorophenol removal in water, but more active for methanol removal in air. 相似文献
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30.
顶空毛细管气相色谱法同时测定水中丙酮甲醇乙腈 总被引:1,自引:0,他引:1
采用顶空毛细管气相色谱法同时测定水中丙酮、甲醇和乙腈,确定顶空平衡温度为95 ℃,平衡时间为30 min,氯化钠质量浓度为200 g/L。丙酮、甲醇和乙腈在0.500 mg/L~5.00 mg/L范围内线性良好,检出限分别为0.02 mg/L、0.10 mg/L和0.04 mg/L,标准溶液平行测定的RSD≤3.0%,两个质量浓度水平的空白加标回收率范围为90%~108%。苯系物对测定不产生影响,吡啶会影响甲醇的测定。 相似文献