Product Overview:

Add a known amount of potassium dichromate solution and mercury solution to the water sample, and use silver as a catalyst in a strong acid medium. After boiling and refluxing for 2 hours, use 1, 10Using ortho phenanthroline as an indicator, titrate unreduced potassium dichromate in water samples with ammonium ferrous sulfate, converted from the amount of consumed ammonium ferrous sulfateThe mass concentration of oxygen consumption is the apparent COD. Export the gas formed by the oxidized chloride ions in the water sample that have not been complexed, and then use hydrogenAfter absorption of sodium oxide solution, potassium iodide is added and the pH is adjusted to about 3-2. Starch is used as an indicator and titrated with standard sodium thiosulfate titration solutionThe amount of sodium thiosulfate is converted to the mass concentration of oxygen consumed,It is the chloride ion correction value. The difference between the apparent COD and the chloride ion correction value is the true COD of the measured water sample.

Technical parameters:

Measurement range: 0-700mg/L, 0-7000mg/L (diluted water sample), chloride ion less than 20000mg/L;
Measurement time: no more than 2 hours
Measurement error: Potassium hydrogen phthalate standard solution (500mg/L), relative standard deviation not exceeding 5.0%
Industrial organic wastewater (500mg/L), with a relative standard deviation not exceeding 8.0%
Environmental temperature: 5-40 ℃
Heating power: 1300W (AC 220V ± 22V, 50HZ)
Cooling method: air-cooled, fan power greater than 80W
Flow range: 0-60ml

Application scope:
This method is applicable for the determination of chemical oxygen demand (COD) in high chloride wastewater with chloride ion content less than 20000mg/L. The detection limit of the method is 30mg/L. Suitable for the determination of COD in wastewater such as oil fields, coastal refineries, oil depots, chlor alkali plants, and deep-sea wastewater discharge.
The instrument adopts a glass burr reflux tube instead of a spherical reflux tube, and uses air cooling technology instead of tap water cooling, which can save water and make the instrument more efficient

Standardization, while making instrument use more reassuring. The instrument is also equipped with an air pressure sampling device and an automatic zeroing burette, which simplifies the titration operation procedures in the later stage,

Improved the reliability of the method.