What Does Activated Carbon Actually Do?

[catxx]

??

 

[juwelfan]

It Adsorbs (no typo its with a 'd' not the 'b') chemicals / impurities taking them out of the water. But once its surface is saturated (full) no more can 'stick' on to it. Then the chemicals just stay in the water as normal.

 

[kniesh]

another words, nothing after about 48 hours.

 

[catxx]

so is it worth having it in the tank and replacing it if the tank is getting weekly water changes anyway?

this isn't for my tanks, for one of my colleagues daughters goldfish tank. apparently she always put new carbon in.

 

[juwelfan]

another words, nothing after about 48 hours.

LOL!

I understand that every gram of activated carbon has a surface area of about 500 m2, which is pretty big. The fact is has such a huge surface area makes it different from just plain old unactivated carbon.

 

[celaeno]

my main concern is after those 48 hours, are the absorbed substances released into the water again?

 

[juwelfan]

my main concern is after those 48 hours, are the absorbed substances released into the water again?

No, not totally. Its all about concentration gradients, if the carbon surface is saturated (which i would have thought would take more than 48 hrs, but i have to figures to back that up) then no more substances would be picked up. Then if fresh low chemical/impuritie water were passed over the carbon some of the adsobed substances may go back into the water as the water would be have a lower conc. of chemicals (everything in the universe likes to be equal if it can). However, most would just stay 'stuck' to the carbon until you throw it away.