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Muhammad Sohail Sabir

What is the difference between FeCl2 and FeCl3 for the...

Austin Mccormack  Follow

FeCl2 is not really a coagulant.It is used in water treatment to precipate sulfide and in wastewater treatment plant to precipate phosphate, but it is very ineffective as coagulant.

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David L. Avery  Follow

Dear Henrik Rasmus Andersen,
Thanks for your valuable answer.
Regards.

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Leliz Lampe  Follow

The iron salts most commonly used as coagulants include ferric sulfate, ferric chloride and ferrous sulfate. These compounds often produce good coagulation when conditions are too acid . Sometimes the particles are best removed under acidic conditions, and iron compounds give better results .It was studied many hydrolysis products are cationic and these can interact strongly with negative colloids, producing  coagulation, under the correct conditions of dosage and pH. Excess dosage can give charge reversal and restabilisation of colloid.. At  neutral pH, Fe (III) has limited solubility, because of the precipitation of an amorphous hydroxide, which can play a very important role in practical coagulation and flocculation . At  neutral pH, Fe (III) has limited solubility, because of the precipitation of an amorphous hydroxide, which can play a very important role in practical coagulation and flocculation processes. Positively charged precipitate particles may deposit on contaminant particles  It will possible that surface precipitation of hydroxide could occur, with similar consequences. More importantly in practice, hydroxide precipitation leads to the possibility of sweep flocculation, in which contaminant particles become enmeshed in the growing precipitate and thus are effectively removed.

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David Walters, Ph.D.  Follow

FeCl3 is used as a flocculant while FeCl2 is not a flocculant , however it is used to precipitate sulphide and phosphate.

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