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IRON AS A REAGENT
Elemental Iron (Fe0) from the electrode plate is driven into solution by the electric current as ferrous iron (Fe++) without any anionic species attached. Chemical reactions with ferrous iron begin immediately and as ferrous iron hydrolyzes through its different oxidation states to ferric iron (Fe+++) and eventually to its amorphous, oxyhydroxide form, subsequent reactions continue to occur with these different forms of iron and it’s subsequent by products. Iron is a powerful, inexpensive reducing agent utilized in many water and wastewater applications.
REAGENT IS INTRODUCED IN ITS CATIONIC FORM
Anionic species present in common water treating chemicals (sulfate, carbonate, sulfide, chloride, etc.) are not present to interfere with reactions. This results in less sludge, lower TDS, a better quality precipitate (sludge) for further disposition, better quality effluent water for subsequent polishing and beneficial reuse processes.
DISSOLVED METALS PRECIPITATE VIA DIRECT CHEMICAL REPLACEMENT OR CO-PRCIPITATE WITH THE AMORPHOUS IRON OXYHYDROXIDE.
The process of electrolysis results in an alkaline pH shift and the pH is maintained between 8.5 to 9.0 exiting the reactor, therefore; dissolved metals may react to form a metallic hydroxide. The process of electrolysis liberates Oxygen gas which results in precipitation of metals as an acid resistant oxide that will pass USEPA TCLP. Any dissolved or suspended contaminants that have not reacted at this point will be adsorbed and occluded within the precipitate of the iron oxyhydroxide and are co-precipitated.
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