The Development of Chemical Oxygen Demand Monitoring Technology and Instrument in Seawater Based on Spectrum Analysis

摘要

In order to achieve rapid detection of chemical oxygen demand (COD) in seawater, in-situ monitoring technology andinstrument for seawater COD based on spectrum analysis were studied. The influence of chloride ion (Cl~-), bromine ion(Br~-) and turbidity on COD measurement was studied using quantitative method. The results show that the absorptionpeak of Cl~- and Br~- is mainly between 190nm and 225nm. The absorption spectral intensity almost unchanged adding Cl~-and Br~- with different concentrations. The influence of Cl~- and Br~- on ecological parameters measurement was fixed. Theabsorbance at 300-720nm is caused by turbidity. Turbidity compensation can be carried out by the absorbance at300-720nm, the effect of turbidity is eliminated on COD calculation. An absorption spectrum model based on leastsquare method was established using artificial seawater in the laboratory. The model was validated using blind samples,and comparison was done between model calculation and actual value.