Searching for methods to remove Zinc out of waste water using oxidation and flotation techniques.
If the zinc is in a dissolved form in water, it means that it has already oxidized and is present in the form of Zn2+ cations (acidic solutions). In an alkaline environment, zinc may be in the form of anions of varying stoichiometry (Gargul et al, Alkaline Leaching of Low Zinc Content Iron-Bearing Sludges). The precipitation of zinc from the alkaline solution must be associated with lowering the pH from the level of zinc anions presence (> 13.5) to the level of appearance of ZnO (pH = 8-12). In none of the cases (acidic or basic solutions) oxidation will lead to the precipitation of zinc in insoluble form.
Thank you very much for the answer, Krzysztof!
Could you tell me also, would oxygenation (simply increasing the oxygen level in the water) under any conditions lead to Zinc precipitation? If not, what reaction could be expected?
What is actually needed, is removing Zn (in both, soluble and solid (very fine particles) forms)) out of wastewater. The question is would oxygenation or flotation help along conventional methods?
In my opinion oxidation will not lead to Zn precipitation. You can do it if you add to wastewater some reagent that will cause zinc precipitation - as a result of the reaction a zinc-insoluble compound will form (e.g. ZnCO3, ZnS, Zn(OH)2). Also, the change of the pH of the solution may affect the possibility of separating zinc in the form of ZnO.
Oxygenation (not oxidation) or aeration of liquid, promotes mixing of chemical agents, for example. There is a device which can also dissolve gases such as air, pure oxygen, ozone and Carbon dioxide into water sources to enable the extraction of dissolved iron, manganese etc.
For instance, in case of removing iron from the water, oxygenation may lead to Iron Hydroxide appearance which precipitate.
I am trying to understand if it is possible to apply this kind of device in case of Zinc. What reagents could be combined with the use of the device?
Do you know an asnwer to that, Krzysztof?
Ok, oxygenation of wastewater, in the case of Zn ions does not lead to Zn precipetation. It could be possible in the case of feeding CO2 gas to the solution and it would be possible to form insoluble zinc carbonate. However, this should be confirmed by laboratory tests or literature reports.
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