5 replies to this topic

[Ayok]

So, i want to precipitate Fe(OH)3 from my waste water. I hear that the optimum pH for precipitating Fe(OH)3 is about 6,5 - 7,5. So, what happen to my Fe(OH)3 if my waste water ph is about 8,5? I really appreciate anyone helping me. Thanks

[Cheluget]

Ayok:

 

I can give you more info but I cannot paste a word table of EXCEL graph here - do you know how to?

Eric

[kan_gou_lai]

please google "Iron solubility pH". Iron form and solubility will depend on the total iron concentration

 

example : http://www.rpi.edu/d...IBRIUM/iron.htm

[Ayok]

Thank you so Mr kan_gou_lai. Thats quite great help

 

[PingPong]

Solubility of Fe(OH)3 depends on concentration of Fe³⁺ and concentration of OH^- and is determined by the Solubility Product K_sp of Fe(OH)₃

 

Find that via google!

[PingPong]

Fe³⁺ and OH^- not only can form insoluble Fe(OH)₃ but also form various soluble complexes, each with their own equilibrium constant, which complicates calculating the exact solubility of Fe(OH)₃ as it does not only involve its own K_sp but also the equilibrium constants of the various soluble complexes.

 

As a result the solubility of Fe(OH)₃ is lowest at a pH of around 8 as can be seen in the figure below:

 

Edited by PingPong, 14 August 2014 - 06:25 AM.