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1.
硝酸银沉淀-颗粒物返还法去除COD样品中的氯化物   总被引:1,自引:0,他引:1  
将样品中的颗粒物分离出来后,向样品中加入适量硝酸银,除去生成的氯化银沉淀,再将预先分离的颗粒物合并到水样中,混匀后测定。经过这样处理,既去除了水样中的Cl-,又保留了水样中原来的组份,保证了COD测定结果的准确性。  相似文献   

2.
在日常环境监测工作中,高锰酸盐指数的氧化率可以看作在高锰酸盐指数测定条件下,一定水样消耗氧化剂的量与在COD测定条件下消耗氧化剂的量之比。即:高锰酸盐指数氧化率=高锰酸盐指数COD×100%淮河流域水中有机污染物的组成相对稳定,尤其对COD贡献较大的有机物,从...  相似文献   

3.
二氧化氟是一种具有广阔应用前景的饮用水消毒剂,制备和使用时可能产生一系列氯的不同氧化态物质,其中最主要的是ClO2、ClO2和ClO3,本研究用紫外分光光度法分别测定了ClO2和ClO2的含量,同时用改进的碘量法分别测定溶液中同时存在的ClO2、ClO2和ClO3,并讨论了有关的反应机理,测定的精密度和准确度均满足一般饮用水质分析的需要。  相似文献   

4.
影响COD测定的因素较多 ,今主要对两种水样的保存期进行了验证试验。《水和废水监测分析方法 (第 3版 )》规定 ,测定COD的水样加了固定剂和在冷藏条件下可保存 7d ,但工作中发现即使水样在这样的保存条件下其COD的含量仍在不断下降。为此分别采集了运河王江泾地表水  相似文献   

5.
测定废水中BOD_5技术问题探讨王俊贤(广西柳州地区环境监测站,柳州545002)1.快速测定COD的方法:加大重铬酸钾量(15.0ml),用1:1浓硫酸-浓磷酸混合液作反应介质,使水样中有机物快速氧化,一个水样用3分钟回流时间,无需任何附加条件,与?..  相似文献   

6.
研究了一种测定饮用水中非挥发性有机氯化物(NPOCl)的方法。水样经氮气气提后,以NaNo3溶收抑制Cl-离子干扰,活性炭吸附后高温的烧,用NaOH溶腋作吸收液,氯离子选择电极法测定并换算出NPOCl值。检测限为0.2×10~(-6)mol/L。在1.0×10~(-6)~20.0×10~(-6)mol/L范围内,回收率为75.3%。以本法测定自来水源水和末梢水,结果表明自来水厂氯化消毒引起NPOCl值显著升高。建议NPOCl值作为自来水水质评价的重要参数。  相似文献   

7.
水中二氧化氯,氯,亚氯酸根和氯酸根区分测定法   总被引:7,自引:1,他引:6  
为了保护人类健康制定卫生规范,同时为ClO2的研究和应用提供基础手段,必须要建立一种能准确区分测定水中ClO2,Cl2,ClO^-12,ClO^-3浓度的方法。回顾了现有水中ClO2,Cl2,ClO^-2和ClO^-3的区分测定方法,评述了各种测定方法的优缺点和适用性,指出了目前在区分测定这恨氧化物的方法中存在的问题,提出了解决问题的途径。  相似文献   

8.
石河子市地下水环境背景值   总被引:11,自引:0,他引:11  
采集并测定了石河子市19个地下水背景水样,分别确定了该市潜水和承压—自流水中K+、Na+、Ca2+、Mg2+、Cl-、SO、HCO、NO、F-、总硬度、矿化度、可溶性SiO2、COD、pH、Cu、Pb、Zn、Cd、Mn、V、Li、Mo、Se、Hg、I、As、Cr+5、C6H5OH、CN-、ABS的环境背景值.  相似文献   

9.
将样品中的颗粒物分离出来,向样品加入适量硝酸根,除去生成的氯化银沉淀,再将预先分离的颗粒物合并到水样中,混匀后测定,经过这样处理,既去除了水样中的Cl,以保留了水样中原来的组份,保证了COD测定结果的准确性。  相似文献   

10.
水中微量五氯酚的气相色谱法测定   总被引:1,自引:0,他引:1  
提出GC-FCD分析方法测定水中微量五氯酚残留量。水样经萃取分离、衍生后,采用石油醚提取醋酸五氯酚酯,然后进入色谱柱,柱内填充2%OV-17+2%QF-1/ChromosorbW-HP(80~100目),柱温200℃,N_2流量80mL/min,五氯酚酯3min内出峰,最低检测浓度为0.1μg/L,各种样品回收率均在90%以上,样品测试结果满意,可用于多种水体中微量PCP残留量的测定。  相似文献   

11.
The objective of this paper is to study the hydrological characteristics and origin of the hydrogen sulphide spring water from the Split spa in Southern Croatia in 1987, 1988 and 2003. This paper presents the results of monitoring the content of chlorides and hydrogen sulphide as well as the temperature of the hydrogen sulphide spring water. Since the hydrogen sulphide content during the dry periods significantly differs from the hydrogen sulphide content during rainy periods, this paper also compares the results obtained for those two periods. Under the influence of great quantities of rainfall during cold periods (winter and the beginning of spring) the ratio between seawater and surface water changes and thus the reduction of chlorides and other minerals occurs. The lowered temperature also reduces hydrogen sulphide which can disappear completely. The concentration of 12‰ chlorides (76–94.4% days/year) and 12 mg/L hydrogen sulphide (66.7–88.9% days/year) has been taken as a limit value between water with a normal typical content and water in cold rainy periods. According to the monitoring results it can be concluded that hydrogen sulphide spring water consists of seawater and hydrogencarbonate surface water with a fairly constant content during dry periods while the hydrogencarbonate content increases during rainy periods.  相似文献   

12.
痕量有机氯化合物分析中的样品预处理方法   总被引:3,自引:4,他引:3       下载免费PDF全文
近些年来,痕量有机氯化合物分析中,各种样品预处理技术得到了迅速发展,文章介绍了一些样品预处理方法的原理和最新进展,阐述了索氏提取,超临界流体萃取,微波萃取,固相萃取等几种富集方法的原理,特点,性能及应用,论述了吸附柱层析法,凝胶渗透色谱,高效液相色谱等样品净化技术的特点和应用。  相似文献   

13.
结合某碱渣堆放场的水文地质状况,通过模拟试验,探讨了碱渣堆放场对岩溶地下水的影响。结果表明,碱渣场在冲灰水和大气降水的浸泡、淋滤作用下,其中的氯化物和钙镁盐类大量析出并随碱渣废液一起下渗,石灰岩碎石对氯化物有一定的吸附作用,但能力微弱。据试验数据分析认为,该渣场是焦作市北中部岩溶地下水中氯化物浓度和总硬度持续升高的主要原因。  相似文献   

14.
有机物对环境的污染日益受到各国的关注,尤其是多氯代二苯并-p-二类(PCDDs)、多氯代二苯呋喃(PCDFs)和PCBs等。在我国新修订的“污水综合排放标准”中,也增加了许多有机氯化物项目;本文就二类等有机氯化物的环境监测分析方法作以概括介绍。  相似文献   

15.
结合实验研究了水中苯胺类化合物的测定难点和影响因素,包括样品保存和水样中悬浮物的影响。苯胺类化合物易被氧化,样品不易保存且受悬浮物的影响。研究结果表明:样品中未加入抗氧化剂进行保存时,部分苯胺类化合物迅速降解;当样品中加入80 mg/L硫代硫酸钠进行保存时,部分苯胺类化合物的保存时间可以延迟2~3 d后降解。样品中悬浮物对联苯胺萃取影响较大,回收率偏低,可以通过调节样品pH至酸性后过滤,再将滤液调至中性后进行萃取,回收率明显提高。笔者同时讨论了消除与补偿基质干扰的方法,包括色谱分离条件和检测器条件的选择、优化,内标法、空白基质匹配标准校正法和工作曲线法等定量方法的选择。  相似文献   

16.
Simultaneous analysis of 11 free estrogen hormones and five conjugated estrogens in water and municipal wastewater was studied. The analytical method was developed and tested for different types of solid-phase extraction adsorbents, eluents, sample containers and storage conditions, derivatization, and matrix effects. Varian Bond Elut C-18 solid-phase extraction adsorbent cartridge was selected based on its high recoveries for both free and conjugated estrogens. Sample storage conditions, as well as selection and pretreatment of sample container materials, can affect the trace level analysis of estrogens. Silanization of glassware is observed to provide low relative standard deviation (RSD) in the analysis and less percentage loss due to contacting with sample container materials. Light exposure during the test can significantly impact the results. The derivatized samples stored at −20°C for at least 6 days showed less than 10.5% average RSD in the analysis. The recovery efficiency in clean water varies from 72% to 101% for free estrogens and 78% to 82% for conjugated estrogens. The method detection limits (MDL) for most of the compounds range from 30 to 870 ng/L using a sample volume of 200 mL. With a sample volume of 3 L, the most sensitive compound produces a MDL of 0.03 ng/L. Dilute methanol is used to wash the loaded cartridge as a cleanup step in order to remove interfering species during analysis of wastewater samples. Using the optimized analytical methods, the concentration level of free estrogens in the influent and effluent municipal wastewaters is tested.  相似文献   

17.
应用能量色散X射线荧光光谱法建立了生物质燃料中磷含量的快速测定方法。对比分析压片压力条件、基体效应和干扰元素,明确了能量色散X射线荧光光谱法的测试条件,通过加标回收率实验、标准样品测试、ICP-OES方法对比等获得实验结果。实验结果表明:能量色散X射线荧光光谱法用于生物质燃料样品的分析,标准工作曲线线性相关系数为0.998 3,方法检出限为0.4 mg/kg,平均加标回收率为98.1%,测定值的相对标准偏差为1.36%~4.92%,标准样品磷含量在标准值不确定度内,能量色散X射线荧光光谱法与行业标准ICP-OES方法的准确度和精密度不存在显著性差异,可应用于生物质中磷含量的环境监测。  相似文献   

18.
A Gas Particle Partitioner (GPP) that allows highly efficient separation of gas and particles with no effect on the thermodynamic conditions and substantially no change of the gas composition has been developed. The GPP is a coaxial arrangement with inner and outer electrodes and utilizes a corona discharge to electrically charge the particles and a strong electric field to remove them from the sample flow. Several measures were taken to avoid an influence of the corona discharge on the gas composition. The GPP can be applied for various applications. This paper focuses on the use of the GPP as a pre-filter for gas analyzers, where zero pressure drop and a minimization of the influence of the corona discharge on the gas composition are the main objective. Due to its design, the GPP introduces no changes to the thermodynamic conditions. However, corona discharge is known to produce significant amounts of ozone and oxides of nitrogen. The effect of the corona on the gas composition of the sample flow was determined under various conditions. The gas concentrations strongly depended on several aspects, such as material and diameter of the corona wire and polarity of the corona voltage. Due to the measures taken to minimize an effect on the gas composition, the concentrations of these gases could effectively be reduced. Along with the maximum gas-particle separation efficiency of near 100%, the additional O3 concentration was 42 ppbV and the additional NO2 concentration 15 ppbV. If an efficiency of 95% is acceptable, the added concentrations can be as low as 2.5 ppbV (O3) and 0.5 ppbV (NO2), respectively.  相似文献   

19.
A new strategy for preparing composite samples of special interest and applicability in environmental screening studies is presented. The use of supersaturated experimental design matrices to conduct the sample composition of water sample specimens in screening studies is demonstrated. In contrast to well known conventional sample composition, this strategic approach provides analytical objects allowing the accurate prediction of analyte concentration levels in the original individual sample specimens while fixing the number of experiments to be carried out down to the very number of sample specimens. This will be of special importance when dealing with analytes that require complicated, labour intensive and expensive analytical processes. To reach this goal, two main conditions must be fulfilled. The first one is the sparsity effect (Pareto principle) which holds for the specimens in the sampling campaign. This means that the number of really anomalous or contaminated specimens, as compared to the total number of specimens to be analysed, is low. In environmental screening studies, frequently this situation can be reasonably assumed. The second condition is to have an effective manner to develop and solve the experimental designs required to build-up the composite samples. The challenging problem of screening PCBs in water samples has been tackled to show the usefulness of this strategic approach by combining chemometrically assisted sample composition and rapid analysis using solid-phase microextraction of the composite samples.  相似文献   

20.
气相色谱法测定水和废水中丙烯腈   总被引:2,自引:0,他引:2  
本文通过采用气相色谱法,以GDX-502为固定相,FID为检测器测定水和废水中的丙烯腈,精密度和回收率高.方法简便易行,能满足行业废水和地面水的监队是水和废水中丙烯腈分析的较理想方法。  相似文献   

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