Method for rapidly measuring high-range COD (Chemical Oxygen Demand)

Abstract

The invention discloses a method for rapidly determining high-range COD (Chemical Oxygen Demand). The method comprises the following steps: firstly, preparing a high-range digestion solution, then drawing a working curve, then detecting the content of chloride ions in a water sample, adding mercury sulfate as a masking agent into a clean colorimetric tube, and then adding the high-range digestion solution into the colorimetric tube; adding a water sample or a diluted water sample into the colorimetric tube, tightening a cover, uniformly shaking, and digesting in a digester; cooling after digestion is finished, taking out, shaking uniformly, placing at room temperature, wiping the outer surface of the colorimetric tube, putting into a spectrophotometer, and reading the COD value of the water sample by utilizing a drawn working curve. According to the invention, while the accuracy of an experimental result is ensured, tedious experimental steps are simplified, personal errors are reduced, the discharge amount of waste liquid is also reduced, and the environment is protected. And meanwhile, the flexibility is high, and the working curve range can be adjusted according to the actual application condition.

Description

technical field [0001] The invention relates to the field of sewage treatment, in particular to a method for rapidly measuring high-range COD. Background technique [0002] Chemical oxygen demand (COD) is one of the pollutant indicators in wastewater. It not only reflects the degree of pollution of water by reducing substances, but also is an important comprehensive indicator for evaluating the relative content of pollutants in water and judging the effect of sewage treatment. Items that must be tested. [0003] At present, the main basis for the laboratory determination of (CODcr) value in water is the HJ828-2017 potassium dichromate method and the HJ / T399-2007 spectrophotometric method: [0004] 1. Potassium dichromate determination method: This traditional chemical oxygen demand (CODcr) water quality monitoring method has a long analysis period, and cannot be analyzed in large quantities due to the limitation of reflux equipment, especially the use of heavy metal silver ...

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Problems solved by technology

In this experimental procedure, it is difficult to control the cooling to 60°C. Air circulation, temperature, humidity and other factors will affect the cooling time and cooling effect. It is difficult for laboratory personnel to operate and cannot accurately measure the temperature of the digestion tube. The uncontrollability is too large and the operation is difficult, which is not conducive to daily laboratory use

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