海岸带水体化学需氧量测定方法的可靠性初步研究

	海岸带水体化学需氧量测定方法的可靠性初步研究
	李兆冉
学位类型	硕士
导师	盛彦清 ; 高彦博
	2016-05-30
学位授予单位	中国科学院大学
学位授予地点	北京
学位专业	环境工程
关键词	化学需氧量海岸带水体溴离子盐度
其他摘要	化学需氧量（COD）是水体中可被氧化的还原性物质的量，用来指示水体的污染程度，是水质监测和评价中最常用的指标之一。在我国，河流的化学需氧量测定主要采用重铬酸盐法，而海洋则多采用高锰酸钾法。河口海岸带是海洋与大陆之间的过渡地带，人类活动十分密集。随着工农业生产的快速发展，河口海岸带水体污染日益严重，而其COD的测定目前仍没有一个统一的方法。因此，对受污染严重的河口海岸带COD测定方法的研究将有助于准确反映该区域水体的污染程度，评价水体水质，在水体污染治理方面有重要意义。本论文首先对溴离子和盐度对COD测定的影响进行了研究，然后选取烟台市三条入海河流，研究不同COD测定方法的差异，从中找出现行监测方法中存在的问题。主要结论如下：（1）溴离子对COD_Cr、酸性COD_Mn测定有明显的影响，对碱性COD_Mn测定的影响不明显。在COD真实值一定时，溴离子与COD_Cr、酸性COD_Mn测量值分别呈良好的线性关系，而与碱性COD_Mn测量值之间几乎无线性关系。在COD_Cr真实值一定时，溴离子浓度越小，单位质量的Br^-对COD_Cr的贡献越大。酸性COD_Mn真实值基本不影响单位质量的Br^-对酸性COD_Mn的贡献。（2）COD_Cr真实值可以根据测定的Br^-浓度、COD_Cr测量值计算得到，但水样中的溴离子浓度超过800 mg/L时，应先稀释后测定。虽然碱性COD_Mn受Br^-浓度的影响较小，但是不能通过碱性COD_Mn、Br^-浓度测量值计算得到碱性COD_Mn真实值。（3）盐度对于COD_Cr和酸性COD_Mn测定的影响明显高于对碱性COD_Mn测定的影响。（4）研究表明以地理位置作为选择COD测定方法的依据是不合理的，应该以盐度为5 PSU作为COD测定方法选择的依据。（5）对于海岸带地区的水体采用传统的经验方法即以COD_Cr值来估算COD_Mn值是不可取的。虽然它们之间可能有一定的线性关系，但估算出来的数值并不能真实反应水体的污染情况。 ; Chemical Oxygen Demand (COD) is one of the important comprehensive indicators to evaluate the degree of water pollution as well as an important item in water-quality monitoring. The K₂Cr₂O₇ method（COD_Cr）is widely used to the determination of river water pollution and the KMnO₄method (COD_Mn) is applicable to the determination of marine water pollution. The coastal zone with the intensive human activities, is the transition zone between ocean and land. With the rapid development of industry and agriculture, the water body have been polluted greatly in the coastal area. However, there is no uniform method for accurate determination of COD. Therefore, the research on the measurement method of COD in the polluted coastal zone will contributed to truly reflect the water pollution situation, and make objective evaluation to the water quality of water body, which is of great significance in the treatment of water pollution. In the present dissertation, the influence of bromide ion and salinity on COD measurements were studied. Besides, we choose the three seagoing rivers in Yantai city as the study areas that are affected seriously by human activities. The differences between different determination methods of COD are systematically studied to find out the problems in the present analytic method of COD. The main conclusions came as follows: (1) Bromine ion has a great influence on the determination of COD_Crand acid COD_Mn, while it has no obvious effect on the determination of alkaline COD_Mn. When the true value of COD_Cr is constant, the bromine ions have good linear relationship with COD_Cr and acid COD_Mn, respectively, and almost no linear relationship with the alkaline COD_Mn. Keeping the same true value of COD_Cr, the contribution of bromine ion per unit mass to COD_Cr is gradually increased with an decrease in concentration of Bromine ion. The contribution of bromine ion per unit mass to acidic COD_Mn was not affected by the true value of acidic COD_Cr. (2) The COD_Cr true value can be obtained by measuring the concentration of bromide ion and the COD_Cr measured value. When the concentration of bromide ion is greater than 800 mg/L, the water sample should be diluted before measurement. Although the concentration of bromide ion has less effect on alkaline COD_Mn, the alkaline COD_Mn true value cannot be obtained by measuring the alkaline COD_Mn measured value and the concentration of bromide ion. (3) The salinity has great effect on the COD_Cr and acidic COD_Mn and the situation is opposite for the alkaline COD_Mn. (4) The geographical location is not suitable to be used as the selection criterion for the determination method of COD. Instead, it is a reasonable choice to take the salinity of 5 PSU as the selection criterion for the determination method of COD. (5) It is not feasible to evaluate the COD_Mn value by COD_Cr value in coastal waters. Although there is a relationship between COD_Mn and COD_Cr, the COD_Mn value estimated by COD_Cr value cannot provide an situation of water pollution.
语种	中文
文献类型	学位论文
条目标识符	http://ir.yic.ac.cn/handle/133337/13906
专题	中国科学院烟台海岸带研究所知识产出_学位论文
作者单位	中国科学院烟台海岸带研究所
第一作者单位	中国科学院烟台海岸带研究所
推荐引用方式 GB/T 7714	李兆冉. 海岸带水体化学需氧量测定方法的可靠性初步研究[D]. 北京. 中国科学院大学,2016.

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