COD 2000 KMnO4
Measurement of Chemical Oxygen Demand by Permanganate Index Method

principle
Potassium permanganate index:
Measure the oxidizing properties of potassium permanganate (permanganate index) in acidic media at high temperatures. This method is based on the ISO 8467 international standard
Accurate, applicable to drinking water and surface water with permanganate index between 0.5-10mg/l and chloride ion concentration below 300 mg/l.

Water with a permanganate index above 10mg/l can be measured after automatic dilution, and the dilution ratio will depend on the higher concentration of chloride ions
In terms of quantity (at the same ratio), the permanganate index corresponds to the mg/l of oxygen corresponding to the amount of permanganate ions consumed.

main features
Meets the technical requirements of Chinese Hj/T100-2003
Automatically perform benchmark control loop
Can continuously detect 6 water samples
Short titration time
Low maintenance volume and high fault free rate

Application scope
This method is mainly used to monitor the water quality of drinking water and surface water. Due to the fact that some organic compounds cannot be oxidized or completely oxidized,
Therefore, the potassium permanganate index method is not suitable for determining the chemical oxygen demand of pollution sources.

method
Heat the sample containing sulfuric acid and a known concentration of potassium permanganate to 96-98 ℃ within 10 minutes
Due to the oxidation of substances in the water sample, the amount of permanganate is reduced
- Use excessive sodium oxalate to reduce excess potassium permanganate
- Use potassium permanganate corresponding to the excess oxalate for back titration. If the permanganate index is above 10 mg/l, dilute the sample automatically with distilled water