Determination of the Chemical Oxygen Demand (COD) of River Water Samples

Introduction The chemical group O contain ( bait) is a stride of the amount of atomic number 8 consumed by the ingrained corporeal within a wet sample that is oxidized by a upstanding chemical oxidant, such as jet dichromate (K2Cr2O7). Its of import use is as an indicator of the essential and inorganic military issue within water and vauntwater discharge giving a quantitative value of water quality. There are early(a) tallys that are also used to measure the organic topic of a water body, such as the biological oxygen demand test. The biological oxygen demand (BOD) and can be found by collecting a sample from the watercourse and incubating it at 200C for five days, and calculating the oxygen used oer the incubation period (Harrison 1996). The COD is oft used when early(a) methods are not as effective to be used. whizz advantage of the COD test over other(a) tests, such as the BOD test is that it is relatively quick to hold back come forth, for examp le the BOD test takes place over a five-day incubation period whilst the COD tests can be carried out in 2 hours; therefrom provides a much speedy indication of water quality. This spot of the test has resulted in a wide range of manipulation when monitoring and controlling the organic content of industrial waste from effluent systems and the receiving water bodies.

Dichromate is often used as the oxidizing agent when determining the COD cod to its ability to oxidize most materials and ease of manipulation (Chapman 1996). raise allows the organic consequence within a sample to depress the dichromate; all remaining dichromate is titrated with ferrous ammonium sulphate, FeSO4.(NH 4)2SO4, where the Fe2+ ions are oxidised to ! Fe3+ by the remaining dichromate ions, Cr2O72-. The dichromate (Cr2O72-) is dissolved into a salt by the addition of sulfuric acid (Na2Cr2O7), this produces... If you wish to get a full essay, ordination it on our website: OrderEssay.net

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