CHRIS25 - 12-10-2012 at 04:20
I have some Iron 3 Oxide, orange, which I simply acquired by letting some horseshoes rust over many months in good old Irish weather and then emptying
the water into jars and allowing the solution to settle for a few days. The insoluble orange mass is at the bottom of a few jars. I want to increase
the iron content in tap water, (city dwellers apparently have more iron in their water than country folk). As strange as this sounds I need water
with dissolved iron.
Now I understand that I need Iron2 oxide, the ferrous, which dissolves in water. And that lowering the PH of the water perhaps with HCL will turn
ferric into ferrous. The question I have is this is where my understanding ends, because I do not want to make the water too acidic. So how does one
balance this situation? I was thinking that maybe I need to bind the Iron with a sulphate or carbonate, but honestly my chemical knowledge is limited
so perhaps some pointers from someone in the right direction please.
Thankyou.
[Edited on 12-10-2012 by CHRIS25]
ScienceSquirrel - 12-10-2012 at 04:57
Buy some ferrous sulphate at your local garden centre, add to water as desired.
AJKOER - 12-10-2012 at 06:20
Per the attached paper (an interesting fuel cell/CO2 sequestration discussion), one may be able to dissolve some Iron in an Oxygen free water (just
boil it) that is more acidic:
Fe + 2 CO2 + 2 H2O ---> Fe(HCO3)2 + H2 (g) [1]
But in a basic environment, Iron carbonate precipitates:
Fe(HCO3)2 ---Elevated pH--> FeCO3 (s) + CO2 (g) + H2O [2]
Link: http://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/49_1...
So, a practical way of making a Ferrous salt, add Iron to boiling vinegar in the absence of air (to remove O2 and thus avoid forming the basic acetate
salt). To quote Wiki (http://en.wikipedia.org/wiki/Ferrous_acetate ):
"Iron(II) acetate is an off-white or light brown solid ionic compound of iron. It is highly soluble in water and it forms a light green tetrahydrate.
Iron(II) acetate is manufactured from scrap iron and acetic acid, and it is used as a mordant by the dye industry."
However, Iron (III) acetate or basic iron acetate is formed per Wiki (http://en.wikipedia.org/wiki/Basic_iron_acetate ) :
"Materials prepared by heating iron, acetic acid, and air, loosely described as basic iron acetates, are used as dyes and mordants.[3]"
For those interested in Iron in water:
"Iron occurs in many forms in natural water supplies. The most common forms are described below.
1. DISSOLVED IRON: Ferrous bicarbonate [Fe(HCO3)2] is found only in oxygen free water. Dissolved iron is measured in parts per million (ppm). One ppm
is equivalent to approximately 1/4 ounce of iron in 1,900 gallons of water. The recommended limit of iron in drinking water is 0.3 ppm and will begin
staining at 0.5 ppm. The water containing it is clear and colorless when drawn. Upon contact with the air, oxygen is absorbed and reacts with the
dissolved iron to form insoluble ferric hydroxide (commonly known as rust). This clouds the water and colors it in shades of yellow to red-brown.
This reaction produces carbon dioxide as follows
2Fe(HCO3)2 + 1/2O2 + H2O = Fe(OH)3 + 4CO2"
Link: http://www.waterwell.cc/IRON.HTM
[Edited on 12-10-2012 by AJKOER]
CHRIS25 - 12-10-2012 at 10:41
Thanks both of you. i think I will take sciencesquirrel's advice though. No time for new experiments and brain wrangling at the moment.
Though this I find interesting:
Fe + 2 CO2 + 2 H2O ---> Fe(HCO3)2 + H2 (g) [1]
But in a basic environment, Iron carbonate precipitates:
Fe(HCO3)2 ---Elevated pH--> FeCO3 (s) + CO2 (g) + H2O [2] Thankyou ajkoer.
So my orange stuff is ferric hydroxide?
[Edited on 12-10-2012 by CHRIS25]
AJKOER - 16-10-2012 at 12:54
Yes, the red-brown compound is best described as hydrated Ferric oxide (Fe2O3.nH2O).