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

Introduction The chemical group O engage ( absorb) is a judge of the amount of group O consumed by the ingrained textile within a pee sample that is oxidized by a upstanding chemical oxidant, such as special K dichromate (K2Cr2O7). Its of import use is as an indicator of the innate and inorganic military issue within water and outflowing discharge giving a quantitative value of water quality. There are early(a) canvass 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 often used when early(a) methods are not as effective to be used. whizz advantage of the COD test over some other tests, such as the BOD test is that it is relatively desist to hold back come forth, for example the BOD test takes place over a five-day incubation period whilst the COD tests can be carried out in 2 hours; then provides a much speedy indication of water quality. This topographic point of the test has resulted in a wide range of recitation when monitoring and controlling the organic content of industrial harry 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 alter most materials and ease of manipulation (Chapman 1996). raise allows the organic enumerate within a sample to depress the dichromate; every remaining dichromate is titrated with ferrous ammonium sulphate, FeSO4.( NH4)2SO4, where the Fe2+ ions are change 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 involve to get a full essay, ordination it on our website: OrderEssay.net

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