关于化学需氧量测定中化学反应的研究

研究了高氯样品COD测定中的化学反应,发现测定中产生的白色沉淀是AgCl而不是HgCl2,并推断了Cl-在COD测定中的反应机理.讨论了AgNO3、HgSO4加入量对测定结果的影响,重点分析了当AgNO3不足与过量时的数据.当试样体积20.00ml,按0.4g HgSO4络合2000mg/LCl-的比例,投加HgSO4掩蔽10000mg/L Cl-可取得满意结果.

Study on the chemical reaction in the chemical oxygen demand determination

The chemical reaction of samples containing high chloride in COD determination is studied in this paper It is the first time that the white precipitation created in the reaction is found to be AgCl, not HgCl 2 Moreover, the reaction mechanism of Cl - during the COD estimation is proposed The influence of AgNO 3 and HgSO 4 adding amount on the result is discussed Especially the data when the adding amount of AgNO 3 is substoichiometric and superstoichiometric are analysised as a focus According to the proportion that 2000mg/L Cl - can be coordinated by 0 4g HgSO 4, the satisfactory results are achieved after adding HgSO 4 to mask 10000mg/L Cl - when the volume of sample is 20 00ml