Filter Carbon

[nmonks]

Based on nothing by A-level chemistry, my feeling is that reality will be somewhere between the two extremes that both you gentlemen are advocating. On the one hand, oven temperatures should be ample to drive off volatile organic chemicals, such as light oils, alcohols, etc. On the other hand though the very fact that meat and vegetables don't vaporise in the oven should imply that a lot of organic stuff is perfectly able to survive quite high temperatures without evaporating away. Hence, a hot oven probably gets rid of some stuff, but also leaves a lot behind.

In other words, heating in an oven probably extends the life of carbon, but it surely can't return it to its original pristine condition.

My biggest question is not so much whether it works but whether it is cost effective. Is the cost of heating an oven to 200C and baking the carbon for twenty minutes (or whatever) more expensive than simply replacing with new carbon?

Neale

 

[rdd1952]

My feeling is that if you have to go to that much trouble to reactivate carbon, why use it in the first place unless you definitely need a chemical filter and then, just use new carbon.

 

[raptorrex]

My feeling is that if you have to go to that much trouble to reactivate carbon, why use it in the first place unless you definitely need a chemical filter and then, just use new carbon.

fair point, but if my findings are infact true. you can save much money, and if carbon indeed does get better with age, it could be unesseccery

 

[rdd1952]

The cost of media for a tank is minimal. If you put ceramic rings or a product like Matrix in your filter at setup, you should never have to add anything else. As a matter of fact, you could actually remove some to seed a new tank. With carbon, you either have to find a way to reactivate it or replace it. Why go to the hassle?

 

[nmonks]

This is very much my view of things. Carbon doesn't do anything particularly useful. Skimmers and water changes remove organics more easily, along with other bad things. As a biological filter, carbon is certainly good, but ceramic media is probably better and certainly lasts longer. Add to that its annoyance factor when treating an aquarium with anti-whitespot or whatever, and carbon is simply a pain in the backside you can well do without.

Cheers, NEale

The cost of media for a tank is minimal. If you put ceramic rings or a product like Matrix in your filter at setup, you should never have to add anything else. As a matter of fact, you could actually remove some to seed a new tank. With carbon, you either have to find a way to reactivate it or replace it. Why go to the hassle?

 

[andywg]

with the greatest of respect andy he offers no proof, just his opinion. and it is a link to a commersial site, something we have both stated is often far from reliable. i would never impune this mans reputation. but you pointed out i didnt link to any information backing my comments, though you did, they the comments were not backed up by any science.

His commercial site is discussing him as a speaker and talking of his knowledge and experience. It is not him trying to sell some carbon to anyone, so it is not similar to previous discussions including commercial sites.

Interestingly, I note that the site you link to suggests that filtering through the carbon too fast can cause molecuels to de-adsorb:

the trapped molecules are sometimes held fairly loosely to it, so if you try to filter too fast, they can be washed off the carbon and back into your spirits.

So if you are going to believe the homebrew people over a man that specialises in filter research that you only need an oven to recharge your carbon, you must surely also believe them when they indicate that the molecules can de-adsorb?

And if you read to the bottom of the page they clearly state that the heating performed by the moonshine boys is not reactivation, but merely cleaning:

Note that this is simply a "cleaning" of the dirty carbon - you are not reactivating it fully back to its prior state. Smudge writes ...

GRANULATED CARBON ACTIVATION
Most Carbon is activated using steam. Activation is also accomplished using chemicals. Wood based carbons steam activation involves a two step process, carbonization and activation. Carbonization occurs in an oxygen deficient environment at high temperatures, 700 degree Celsius. Activation of carbon occurs by using steam where temperature of the carbon is raised to 1800 degrees.

REACTIVATED CARBON
Reactivating carbon is a simple process where the spent carbon is thermally reactivated . Reactivation occurs a temperatures between 1400-1700°F where ether volatile organics or oxidized off forming CO2 and water. The non volatile organic compounds are carbonized to form char. In the final phase of the process steam is used to reactivate the carbon. Approximately 80-90% by dry weight of the carbon is recovered in this process. The remainder is made up with virgin carbon. Reactivated carbon performs exactly the same in adsorptive capabilities as virgin carbon.

It is exactly those nasty violatile organic compounds that we want the carbon to adsorb from our tank water.

if my findings are infact true. you can save much money, and if carbon indeed does get better with age, it could be unesseccery

Based on the information above (from my source and yours) I do not see how carbon can get better with age. As to saving money, I personally think that frequent water changes (even including the cost of dechlorinator) are going to be far cheaper than the energy and money costs of heating your oven up, especially considering that most government advice indicates 85% of the energy put into cooking in an oven goes purely to warming up the oven. Not to mention the advantages water changes have over using carbon as detailed by nmonks above.

 

[Bignose]

thats another phalicy like carbon deadsorbing.

But carbon can desorb. Just the fact that you even talk about regenerating your carbon in the exact same sentence means that the carbon can be desorbed. Yes, desorbtion occurs more rapidly at higher temperatures, but the rate of desorbtion is not zero at lower room temperatures. Yes, I agree the rate is small, but it is not zero. Carbon sorbtion is an equilbirum process and the chemicals are always sorbing and desorbing -- and some of the desorbed chemicals will not be immediately resorbed. So, again, the rate of desorbing is probably indeed very small, but it is not zero.

 

[anthony_sydney]

Hi Guys,

thanks for your responses, but now I'm getting confused!!!

Once a tank has been cycled i.e. amonia and nitrate are nil does that mean that I can replace the filter (from my hang on) which is the wool stuff and the carbon and put in another one?

Isn't the whole point of cycling to build up the bacteria which should be stuck in the filter and if I replace the filter cabon and the wool won't it then lose all that good bacteria....

Thanks

 

[rdd1952]

You should only replace the filter when it is too ragged and worn to function any more. You can replace the carbon with some other type of media without changing the cartridge. Simply open the pack and dump out the carbon, replace with whatever you want.

The main reason I stopped using carbon is that you have to wash it to remove all the dust when you put a new bag in. If you do that under tap water with the old filter cartridge, you kill off all your bacteria. Carbon is just too much trouble to use.

 

[anthony_sydney]

Thanks. So I can keep the actual wool part but I just dump out the carbon (rocks) and can replace it with something else.

Thanks

 

[raptorrex]

thats another phalicy like carbon deadsorbing.

But carbon can desorb. Just the fact that you even talk about regenerating your carbon in the exact same sentence means that the carbon can be desorbed. Yes, desorbtion occurs more rapidly at higher temperatures, but the rate of desorbtion is not zero at lower room temperatures. Yes, I agree the rate is small, but it is not zero. Carbon sorbtion is an equilbirum process and the chemicals are always sorbing and desorbing -- and some of the desorbed chemicals will not be immediately resorbed. So, again, the rate of desorbing is probably indeed very small, but it is not zero.

indeed carbon can deadsorb, but at heats of over 160 or so, as that is the temp all organics start to burn.

andy your comment on homebrew, is not quit correct, it is noted that that method of reactivation is used by the suger refining industry. and if you wish you can check.

80 to 90% regenaration, is more than enough to make your carbon, useful again. true the organics that are not removed, may well be the really bad ones, however as they do not deadsorb, in an oven at 700 or so it seems very unlikly that they would suddenly do it in an 80 degree tank! as for the carbon getting better with age, i'm not sure on that, but a litttle knowledge of the thermal forces involved. it is possible to see, the grains of carbon undergoing enormase thermal changes, expansoin and contraction, through the heating and cooling. this may well cause new fishures to appear in the grains them selfs, possibly adding extra surface aria. and using this method you need to replace a small amount of carbon each time, to replace the grains that have crumbled, more evidence if cracking of the carbon!

 

[andywg]

80 to 90% regenaration, is more than enough to make your carbon, useful again. true the organics that are not removed, may well be the really bad ones, however as they do not deadsorb, in an oven at 700 or so it seems very unlikly that they would suddenly do it in an 80 degree tank!

It is not useful to put the carbon in the oven if it is not burning off the very things we want to get rid of. Remember that these boys are looking to take away entirely different compounds. The 80-90% refers to after being used to filter alcohol or sugar. The intention of carbon in an aquarium setting is to remove dissolved organics.

It is likely that there will be a higher loading of dissolved organics on carbon from an aquarium as there will be more of them in the tank water than in an alcohol solution. If the organics are not being burned off then I do not believe that 80-90% regeneration will be observed, probably far lower. Then, each time you re-use the carbon more and more of the carbon will have adsorbed dissolved organics until it is completely full (or so close as to make the effects minimal).

 

[Miss Wiggle]

Thanks. So I can keep the actual wool part but I just dump out the carbon (rocks) and can replace it with something else.

Thanks

yes you can do, as you can see the merits of carbon are highly debated, it's down to you to wade through the facts and decide if you want to use it or not. but it's by no means essential.

 

[raptorrex]

Thanks. So I can keep the actual wool part but I just dump out the carbon (rocks) and can replace it with something else.

Thanks

yes you can do, as you can see the merits of carbon are highly debated, it's down to you to wade through the facts and decide if you want to use it or not. but it's by no means essential.

indeed!!!!

the whole idea of this conversation,IMO is to bring forward the different theorys people hold on carbon. to try and get some form of consensus. there are so many different ideas on how and if it works or so on. facts are on the whole in short supply.

it is not my intention to prove anyone wrong. but it may help if the true facts about how carbon works, if it can deadsorb, in an aquarium and if it can be deadsorbed effectivly at home. may well be of benifit to people who read this later.

i can say that i can find no proveable instances of carbon deadsorbing in the tank, not one!

i can find hundreds of people who do try to deadsorb their carbon, all of which beliave it works, and if it were to be ineffective, surly at least one would have had an instance of deadsorbtion!

i can say that crabon is deadsorbed in a large scale in industry, at the temprutures i have quoted.

i do know one entire aquarculture project that relyse entirly on carbon for its filtration, using a greenwater system to deal with the waste.

what nobody has been able to do yet, is offer any rebutals, that truly stand up, and are more than just expert opinions. and ATM with expert testimony having to be looked at closley in the uk. after so many people being wrongly convicted of crimes through it over the past few years. any comments are to be seen as just that comments.

i have spent tens of hour lookin for information on this subject. and have yet to see anything that would suggest my theory is not correct. atm it is no more than an educated theory, but it stands up. until scinece can be found, that says other wise.

i can say for a fact that my farther, a chemist and metalagist, with a doctrate in both, who lectured in univercity in the early sixtys. built a air filter, for one of the resident of the old folks home we ran during the time. he did deadsorb the carbon he used in that, in the oven at home. and as one of the formost chemist/metalgists in the uk, so much so that in his mid seventes he is still unable to fully retire. my guess is he knew what he was doing.

do we not have a student here, who has access to people who may be able to help?

 

[andywg]

what nobody has been able to do yet, is offer any rebutals, that truly stand up, and are more than just expert opinions. and ATM with expert testimony having to be looked at closley in the uk. after so many people being wrongly convicted of crimes through it over the past few years. any comments are to be seen as just that comments.

i have spent tens of hour lookin for information on this subject. and have yet to see anything that would suggest my theory is not correct. atm it is no more than an educated theory, but it stands up. until scinece can be found, that says other wise.

You are doing science backwards, just like they do with ID. You are saying "this is how I believe it works - you prove me wrong". You will note there is no science to back your theory either.

By the same logic, I can reveal my Pastafarian roots and state my belief that the molecules are not adsorbed, they are merely stored by the Flying Spaghetti Monster in one of His noodly appendages. I don't have any evidence to suggest it is otherwise, so it is a vaild scientific argument until someone proves me wrong.

i can say for a fact that my farther, a chemist and metalagist, with a doctrate in both, who lectured in univercity in the early sixtys. built a air filter, for one of the resident of the old folks home we ran during the time. he did deadsorb the carbon he used in that, in the oven at home. and as one of the formost chemist/metalgists in the uk, so much so that in his mid seventes he is still unable to fully retire. my guess is he knew what he was doing.

But what was that carbon adsorbing? The whole point is that the very things we want removed from the aquarium will not be burnt away in a domestic oven. Even you have admitted that this is likely the case. An air filter has a very different job to an aquarium filter, the cross over is not as simple as "it works in this industry, it will work here".