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Aspects of water treatment – Treatment of active carbon filters
This is a Caldos processed output graphic for a two–channel run showing three successive adsorption/desorption cycles of 0·005M silver nitrate solution from water carrier on 13·2 mg of BPL active carbon. The top trace is the FMC thermal data, the lower trace is the matched refractive–index blank and live traces giving a direct measure of the amount of probe removed from the stream during adsorption or replaced into the stream during desorption. In this case only a small proportion of the AgNO3 was retained by the carbon surface where it is used to prevent bacterial growth in filtration media at the carbon/water interface.
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In the example above, the heat of first exposure of the silver nitrate to the active carbon is considerably larger than the subsequent exposures. By combining the thermal data with the matter transfer data we can calculate the energy yield per unit mass of adsorbed nitrate, weight corrected per gram of active carbon, for each of the three adsorptions above:
Adsorption 1: 17·24 Joules per gram of silver nitrate adsorbed
Adsorption 2: 17·25 Joules per gram of silver nitrate adsorbed
Adsorption 3: 16·93 Joules per gram of silver nitrate adsorbed
The model of Flow Microcalorimeter used for these studies was an FMC–4014
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