Sulfate Reactor

[reefcrazy93]

I have found the idea of using sulphur to reduce nitrate in the reef aquarium. I begun to think of using pyrite instead of sulphur in a reactor. The pyrite would produce sulfate but would also produce excessive amounts of iron.What would be the advantages and disadvantages of using pyrite instead of sulphur.

[Randy Holmes-Farley]

I would not expect pyrite (iron sulfide) to do anything in seawater. Do you have reason to think it will?

[reefcrazy93]

The saltwater wouldn't do anything to the pyrite. Its the bacteria along with the addititon of some CO2

[reefcrazy93]

The only problem I can think of is how to remove all that iron. (Just to let you know this is and idea for my science fair project. I might use this idea if I can figure out an answer to the iron.)

[Randy Holmes-Farley]

I think you need to work out the chemistry. If you somehow dissolved pyrite with CO2 (acid) (very unlikely in seawater plus CO2, IMO), the product is highly toxic hydrogen sulfide (not sulfur).

I'd stick to other known ways to reduce nitrate:

Nitrate in the Reef Aquarium
http://www.advancedaquarist.com/issues/august2003/chem.htm

Hydrogen Sulfide and the Reef Aquarium
http://reefkeeping.com/issues/2005-12/rhf/index.php

[reefcrazy93]

Its not just the CO2. Its also the bacteria that. When the pyrite produces hydrogen sulfide the bacteria would use the sulfide. Then the sulfide becomes sulfate.

[reefcrazy93]

The bacteria is the most important factor in this reactor.

[Randy Holmes-Farley]

Its not just the CO2. Its also the bacteria that. When the pyrite produces hydrogen sulfide the bacteria would use the sulfide. Then the sulfide becomes sulfate.

Well, I first do not believe that CO2 plus seawater (in the pH range of 5-8) will dissolve pyrite (although I could be mistaken on that), but adding hydrogen sulfide in any way would be a terrible plan, IMO. It is one of the biggest risks when disturbing anoxic regions in sand beds. It is very toxic.