[hhiitt]

Hello everyone,
I have a mixture of carbon and Fe2(SO4)3. And I want to get pure carbon, but I found that the Fe2(SO4)3 is insoluble in water and difficult to filtrate. So, do you have some good methods to get rid of Fe2(SO4)3?

Thank you in advance!

[Borek]

Hot water? HCl?

[hhiitt]

Hot water? HCl?

I have used 37 wt%  HCl, but it doesn't work better.

Some references say that Fe2(SO4)3 is soluble in water, so I am very confused about this.

[AWK]

Fe2(SO4)3 shows a good solubility in water. Practically all iron compounds are soluble in HCl, even diluted. Your impurity should be completely different one.

[Borek]

Fe2(SO4)3 shows a good solubility in water.

Hmm... my handbook (WNT) lists it as weakly soluble in cold water, but well soluble in hot.

[hhiitt]

Fe2(SO4)3 shows a good solubility in water. Practically all iron compounds are soluble in HCl, even diluted. Your impurity should be completely different one.

In fact, my powder consists of hollow carbon spheres and Fe(NH3)xCl2 which stays in the hollow interiors. Due to the hollow carbon spheres are hydrophobic, I think the HCl solution could not penetrate into the hollow cores and the iron amine complexes could not be eliminated either. So I used 3:1 H2SO4/HNO3 both concentrated to produce the -COOH on the surface of hollow carbon spheres which can improve the hydrophile. When the carbon powder was put into the acids, a yellowish brown smoke generated. After the process, the powder was filtrated, but the color of the solution is brwon even filtrating tens of times.
In the process, I think Fe2(SO4)3 is the only substance should exists in the final powder. Could other substances emerge in the process? Thank you!

[hhiitt]

Fe2(SO4)3 shows a good solubility in water.

Hmm... my handbook (WNT) lists it as weakly soluble in cold water, but well soluble in hot.

Thanks! I will have a try.
By the way, what is the full name of your handbook (WNT)?

[Borek]

WNT stands for Wydawnictwa Naukowo Techniczne (something like Science-Technical Publishing House, see http://www.wnt.com.pl/about.en.php) - AWK is from Poland like me, this was information for him

[AWK]

Fe2(SO4)3 is better soluble at elevated temperatures. Does it mean that at RT its solubility is null?

[Borek]

Fe2(SO4)3 is better soluble at elevated temperatures. Does it mean that at RT its solubility is null?

No. But your statement

Fe2(SO4)3 shows a good solubility in water.

is way too general for substance listed in handbook as "weakly soluble in cold water, well soluble in hot water".

[AWK]

Solubility of Fe2(SO4)3 may be greatly increased it this particular problem by addition some univalent sulfates, eg Na2SO4, K2SO4 or (NH4)2SO4

[Borek]

That's interesting. Do you know anything about the mechanism involved?