Why potassium dichromate is used in COD?

Currently, most COD tests use potassium dichromate as the oxidant. Potassium dichromate is a hexavalent chromium salt that is bright orange in color and is a very strong oxidant. Between 95-100% of organic material can be oxidized by dichromate.

Which method is used for COD?

The traditional chemical oxygen demand (COD) analysis method is the wet chemistry method. This involves a two hour digestion at high heat under acidic conditions in which potassium dichromate acts as the oxidant for any organic material present in a water sample.

What is the objective of COD test?

The COD test is often used to monitor water treatment plant efficiency. This test is based on the fact that a strong oxidizing agent, under acidic conditions, can fully oxidize almost any organic compound to carbon dioxide.

What is dichromate method?

The Dichromate Chemical Oxygen Demand (COD) test measures the oxygen equivalent of the amount of organic matter oxidizable by potassium dichromate in a 50% sulfuric acid solution.

Why sulphuric acid is used in COD?

Chemical Oxygen Demand (COD) 1% Silver Sulphate in Sulphuric Acid (conc.) provides the primary and secondary digestion catalysts for oxidation of carbon during chemical oxidation.

Which indicator is used in COD?

Most commonly, a 0.25 N solution of potassium dichromate is used for COD determination, although for samples with COD below 50 mg/L, a lower concentration of potassium dichromate is preferred.

What is the ratio of BOD and COD?

In domestic waste the ratio between BOD/COD is 1:2. The COD/BOD ratio is useful for assessing the amount of sewage available for biological treatment.

Why do we use h2so4 in COD?

What is the principle of COD?

OBJECTIVE: To measure Chemical Oxygen Demand. BACKGROUND AND PRINCIPLE: The chemical oxygen demand (COD) determines the amount of oxygen required for chemical oxidation of organic matter using a strong chemical oxidant, such as, potassium dichromate under reflux conditions.

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