硫酸消解-可见光谱法快速测定化学需氧量

通过在442nm处测定废水样品消解后剩余Cr2O^2-7的吸光度，采用计算机拟合发现当化学需氧量在65～650mg／L时，剩余Cr2O^2-7的吸光度与COD浓度呈线性关系，用此法和国标法(重铬酸钾法)分别测定人工模拟废水和工业废水的COD，二者相对误差低于5．0％，表明该法具有较好的可信度和适应性，适于COD的快速准确测定。

Rapid Determination of Chemical Oxygen Demand By Sulfuric-Acid Digestion and Visible Spectrometry

A rapid and simple method based on visible spectrometric procedure is proposed for the determination of COD in wastewater treatment system. It is an improvement of standard method to determine COD, I.e. Determination of excess dichromate (Cr2O2-7) by visible spectrometry at 442 nm. The absorbance value (A) of Cr2O2-7 and the concentration of COD have linear relation by computer analogy, so COD is determined indirectly in this way. Some influencing factors, such as the refluxing time, the amount of wastewater sample and potassium dichromate, sulfuric acid concentration are investigated, respectively. The result shows that when the concentration of COD in wastewater sample is in the range of 65～650 mg·L-1, the results obtained by using the method presented exhibit good agreement with those given by the standard method of COD determination, and the relative error is less than 5.0%. The viability of this method is demonstrated by analyzing two kinds of synthetic wastewater and five kinds of industrial wastewater, and it proves to be a rapid and accurate method for COD determination.