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Ammonium in Effluents with High COD Value

Prove InstrumentsPhotometric determination using the indophenol blue method

Sample Preparation

Hint
The decomposition with the Crack-Sets 10 or 10C (Potassium peroxodisulfate) fails with strongly organic loaded water (criteria: COD content >300mg/l). In those cases a predecomposition to destroy the organic matrix is advisable.

Evaporate 100 ml of sample and 5 ml of sulfuric acid 95 - 97 % in a 600-ml glass beaker to about 10 ml. Mix this mixture cautiously with 5 ml Perhydrol® 30 % and heat. After the sometimes heavy reaction (gas formation, foaming) has faded, heat until SO3 - formation starts. If the solution turns brown or dark, let it cool down and add again 5 ml Perhydrol® 30 %. Once more heat until beginning SO3-formation. If the solution stays colorless or light yellow, let cool down, dilute with about 50 ml distilled water and neutralise the solution with about 14 - 15 ml sodium hydroxide solution 32 % to pH 4 - 6 using a pH - meter. After cooling transfer the solution into a 100-ml volumetric flask and fill up to volume with distilled water and mix.

Ammonium will be fixed as Ammonium sulfate in the solution and after the oxidation of the digestion can be measured with the above mentioned test kits.

Analysis

Determine with the below mentioned test kits.

Materials

     

Product 114544 is not compatible with Move 100.