Determination of COD --- Rapid Dissolution Method English versionExperiment Ⅹ the determination of chemical oxygen demand——the Rapid Digested Spectrophotometry methodThe purpose and requirements of th

the abscissa, draw a standard curve and calculate the COD value of the sample wastewater.

3. The influence of Chloridion: add 1mL AgNO3 solution into 12 digester tubes before adding screening agent, then add screening agent, digestive juice and catalyst as usual, and determine the COD value of each tube according to the above steps. Compare the results with those obtained without adding AgNO3 solution to determine the influence of Chloridion.

4. Comparison of advantages and disadvantages: compare the advantages and disadvantages of the Rapid Digested Spectrophotometry method with the Potassium Dichromate Method in terms of accuracy, sensitivity, speed, and environmental impact.

Experimental precautions

1. When adding screening agent, digestive juice and catalyst, the order must be followed, and the amount should be accurate.

2. The digester device must be kept clean and dry, and the temperature and time should be strictly controlled.

3. When preparing the standard solution, the concentration and purity of the reagents should be strictly controlled.

4. The wastewater sample should be fully mixed and representative, and the sample volume should be accurately measured.

5. When using the spectrophotometer, the wavelength, zero adjustment, and calibration should be carefully checked.

6. The waste liquid generated in the experiment should be properly treated to avoid environmental pollution.

Conclusion

Through this experiment, we have learned the Rapid Digested Spectrophotometry method to determinate COD, compared its advantages and disadvantages with the Potassium Dichromate Method, and learned how to eliminate the influence of Chloridion. We should pay attention to experimental precautions and properly handle the waste liquid generated in the experiment to protect the environment