Automatic on-line monitor for measuring water body COD (chemical oxygen demand)

Abstract

The invention discloses an automatic on-line monitor for measuring the water body COD. The monitor comprises an ultraviolet transparent electrolytic cell, wherein a reference electrode, a counter electrode and a working electrode made from a TiO2 nanometer material are arranged in the electrolytic cell, the reference electrode and the counter electrode are arranged on the same side of the working electrode in parallel, the reference electrode, the counter electrode and the working electrode are connected to a constant potential rectifier, a liquid inlet is formed in the upper end, located on one side of the working electrode, of the electrolytic cell, a high-power LED ultraviolet lamp is arranged on the outside of the electrolytic cell, and a liquid outlet is formed in the lower end, located on the other side of the working electrode, of the electrolytic cell. According to the automatic on-line monitor for measuring the water body COD, a high-power ultraviolet LED light source and an efficient heat dissipation structure, the nanometer TiO2 working electrode, a peristaltic pump and a miniature electromagnetic valve are adopted, so that light, rapid and automatic on-line monitoring is realized, the volume of test solution required for analysis each time is small, secondary pollution is not caused, and the monitor is suitable for site and on-line monitoring and can be used for laboratory analysis.

Description

technical field [0001] The invention belongs to the field of on-line monitoring of environmental water bodies, in particular to an automatic on-line monitor using a high-power ultraviolet LED lamp as a light source. Background technique [0002] Chemical Oxygen Demand (COD) is the amount of oxidant consumed when a certain oxidant is used to treat water samples under certain conditions, which is converted into the concentration of oxygen required by the water body (mg / L). It is an indicator of the degree of water pollution by reducing substances. It is a must-test indicator for water body monitoring in countries all over the world. [0003] At present, the detection of COD in water bodies at home and abroad is mainly chromium method (GB11914-1989), manganese method (GB11892-1989) and ultraviolet-visible spectrophotometry (HJ / T3992007). The chromium method is mainly used in the detection of highly polluted water and industrial wastewater, and the manganese method and ultravi...

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Problems solved by technology

However, due to the complex and diverse components in the actual water body, the linear range between spectral data and COD is very narrow, and the nonlinear relationship is difficult to describe quantitatively

In addition, limited by the Lambert-Beer's law of solutions, only dilute solutions can be detected, and the detection is affected by multiple factors, such as pH value, colloid, emulsion, and suspension.

Therefore, the accuracy of the COD value measured by UV-visible spectrophotometry is not high, and the range of detectable water bodies is narrow

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