A low-concentration cod measuring device based on spectrometry

Abstract

The invention provides a low-concentration COD measuring device based on spectrometry. The device comprises a light source, a collimation system, a sample cell, a converging system and a light signaldetection system, a first optical reflection end face and a second optical reflection end face which are opposite are arranged on the inner wall of the sample cell, a first quartz light window and a first plane mirror are sequentially arranged on the first optical reflection end face, the first quartz light window is a light source incident plane, a second plane mirror and a second quartz light window are sequentially arranged on the second optical reflection end face, and the second quartz light window is a light source emergent plane. Light emitted by the light source becomes parallel lightthrough the collimation system, and the parallel light enters the sample cell through the incident plane of the same, is emitted from the emergent plane of the sample cell after being repeatedly reflected by the first plane mirror and the second plane mirror and absorbed by to-be-measured liquid and then enters the light signal detection system after passing the converging system. Compared with devices applying conventional straight line measuring light paths, the low-concentration COD measuring device has the advantage that detection limit of COD concentration is lowered greatly.

Description

technical field [0001] The invention relates to the field of water quality detection and analysis, in particular to a COD detection method and the technical field of environmental optical detection, in particular to a low-concentration COD measurement device based on a spectrum method. Background technique [0002] Chemical oxygen demand (COD) refers to the amount of oxidant consumed when reducing substances in water are oxidized by strong oxidants under certain conditions. sexual indicators. In recent years, my country's national economy has developed rapidly, but at the same time the problem of environmental pollution has become increasingly serious. Especially the problem of water pollution. COD can be used to judge the relative content of organic matter in water, and is one of the most important comprehensive indicators of organic pollution in environmental monitoring. At present, the main method for measuring COD in water is the alkaline potassium permanganate colori...

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Problems solved by technology

[0004] At present, the detection limit of COD measured by ultraviolet absorption spectroscopy is generally greater than 10 mg / L, and the COD content in drinking water and seawater is low, generally 3 mg / L, which is lower than the detection limit of COD measured by ultraviolet absorption spectroscopy. Therefore, these waters The COD in the environment can only use the alkaline potassium permanganate colorimetric method, which restricts the on-site / on-line monitoring and control of COD in seawater and drinking water in my country

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