海岸带水体化学需氧量测定方法的可靠性初步研究

发布时间：2018-06-24 04:00

本文选题：化学需氧量 + 海岸带水体　；参考：《中国科学院烟台海岸带研究所》2016年硕士论文

【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CODMn测定有明显的影响,对碱性CODMn测定的影响不明显。在COD真实值一定时,溴离子与COD_(Cr)、酸性CODMn测量值分别呈良好的线性关系,而与碱性CODMn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CODMn真实值基本不影响单位质量的Br-对酸性CODMn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CODMn受Br-浓度的影响较小,但是不能通过碱性CODMn、Br-浓度测量值计算得到碱性CODMn真实值。(3)盐度对于COD_(Cr)和酸性CODMn测定的影响明显高于对碱性CODMn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CODMn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。
[Abstract]:Chemical oxygen demand (COD) is the amount of redoable and redoable substances in water, which is used to indicate the degree of water pollution, and is one of the most commonly used indexes in water quality monitoring and evaluation. In China, the chemical oxygen demand of rivers is mainly determined by dichromate method, while in the ocean potassium permanganate method is used. Estuarine and coastal zone is a transitional zone between ocean and continent, and human activities are very dense. With the rapid development of industrial and agricultural production, the water pollution in estuarine and coastal zone is becoming more and more serious. However, there is still no uniform method to determine COD in estuarine and coastal zone. Therefore, the study of COD determination method in the seriously polluted estuarine and coastal zone will be helpful to accurately reflect the pollution degree of the water body in this area and evaluate the water quality, which is of great significance in the treatment of water pollution. In this paper, the influence of bromine ion and salinity on COD determination was studied, then three rivers in Yantai city were selected to study the differences of COD determination methods, and to find out the existing problems in the current monitoring methods. The main conclusions are as follows: (1) Bromine ions have obvious influence on the determination of COD _ (Cr) and acid COD _ (mn), but not on the determination of basic COD _ (mn). When COD is true, there is a good linear relationship between bromine ion and COD _ (Cr) and acid COD _ (mn), but there is almost no linear relationship between bromine ion and alkaline COD _ (mn). When the true value of COD _ (Cr) is constant, the smaller the concentration of bromine ion, the greater the contribution of Br- to COD _ (Cr). (2) the true value of COD _ (Cr) can be calculated according to the measured value of Br-concentration and COD _ (Cr), but when the concentration of bromine ion in water exceeds 800 mg / L, it should be diluted first and then determined. Although alkaline CODMn is less affected by Br-concentration, However, the true value of alkaline COD mn can not be obtained by calculating the Br-concentration of alkaline COD DMn. (3) the effect of salinity on the determination of COD _ (Cr) and acid COD _ (mn) is obviously higher than that on the determination of basic COD _ (mn). (4) the study shows that geographical location is the choice for COD determination. The basis of the law is unreasonable. The salinity of 5PSU should be used as the basis for the determination of COD. (5) it is not advisable to use the traditional empirical method to estimate COD _ (Cr) in coastal waters. Although there may be a linear relationship between them, the estimated values do not reflect the pollution of the water.
【学位授予单位】：中国科学院烟台海岸带研究所
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X832

【参考文献】