Cleaning and reactivating a carbon filter

[golfnrl]

I have a 6" inline carbon filter that I took out of service a couple of years ago. It's taking up space. I'd like to clean it and reactivate the carbon. Google has not been much help. Neither has youtube. Does anyone have any tips or advice? Base on what I've read and vids watched I'm wondering if the juice is worth the squeeze but I don't want to throw the thing in the land fill either. It's a given the carbon will eventually degrade but I can't find any info on how long that takes other than it depends on the environment.

[Gingerbeard]

This is a shot in the dark since I only know the basics.
If what activates carbon is heat, what about reheating your carbon?
Or, since it's just smelly carbon by this point, why not compost or otherwise return it to nature and recycle/reuse the housing?

[golfnrl]

You're on to something, I've read in a couple of places that heating the charcoal does reactivate it. I might just blow this one out, reheat it and see what happens. Maybe someone has a better method they'll share. And I'm giving this waaaay too much thought.

[MiguelEnfermo]

On a side note, I threw out my SF carbon pellets and replaced them with a new bag yesterday and just searched SF and Amazon for replacement bags and no dice. One would think that the carbon pellets would be a hot seller. Guess not. I got a blooming LSD auto that stinks!

[MiguelEnfermo]

I just got an email back from sales at SF and they do NOT sell activated charcoal refills. A search on Amazon and there are a few places you can get activated charcoal pellets. FYI.

[golfnrl]

Thx for the info about the carbon. I'm still weighing options. It's good to know at least that carbon can still be found.

[Bluey]

You need to wash it first and some add citric acid to the wash. It then needs to be left to dry and then heated.

Activating carbon takes very high temps...from memory north of 800⁰C. So heat it safely as high as you can to complete the drying in an oven.

Humidity kills carbon filters, high humidity that is, so only use them later in flower when the dank is on and RH is low. They will last a long time with that approach in a low RH environment.

Edit. Seal them tightly in plastic in a low RH environment for storage.

[bdeegan]

I have been wondering the same thing and have also struggled to find any information. Something I’ve thought about is automobiles use carbon to trap fuel vapors. When saturated a valve opens that sucks the vapors into the engine using vacuum. What if you put the carbon filter into a vacuum chamber of sort (yeah I know we all have one sitting around lol)? Also, the scientist in me thinks that if high heat is what activates carbon can’t you lower the boiling point by putting something under vacuum? So I theory you could reactive you filter with only 100 degrees (just spitballing) under vacuum vs 800 at normal pressure. What y’all think? Need another hit or have had too many?

[golfnrl]

I think I read that the reheat can be done in an oven but your idea makes sense I think, as I have no way to heat anything to 800 degrees. Another hit may make it more clear, IDK but its worth a try. :>)

[Gingerbeard]

Let's see if'n I can get this right.
The initial process of activating carbon is done in an oxygen free environment at temperatures past 800°C.
The idea is to create surface area.
Once the initial process is done, you can't create more surface area.
'Reactivating' the carbon is more about removing impurities it has picked up.
The scant I have read is all about washing/rinsing (@Bluey's citric acid wash) and reheating it in your oven.
I don't want to post links and junk because, really, this is all stuff I've pieced together.

I read someone in the forum say carbon filters are bad because they are made using mined coal. That is not necessarily true. A carbon filter is just that: a filter that uses carbon. That carbon can be made from any number of renewable resources, including... wait for it... coco coir.

[Bluey]

Early carbon filters were made so they could be easily disassembled and the carbon washed but they don't do that any more. The life of the filter reduces a lot after its first use. I'm not sure its cost/time effective to do this anymore to any but the larger more expensive filters.

Once the activated carbon filter no longer filters the air properly it requires regeneration. It's still activated carbon.

There's a company in Sweden I think it is that makes a huge amount of activated carbon from coco as Ginge said. They are one of the biggest manufacturers of activated carbon globally.

[Bootsy]

To reactivate carbon by heating would take a kiln - oven temps dont get hot enough. I use ozone to regenerate my carbon filters. My first one years ago lasted around 5 grows, and then the smells were getting past - so it's charcoal was dumped in my compost. Bought new ones, but then thought of ozone, which is used to renew carbon filters in some builoding ventilation systems. I Use a cheap offshore plate style with a fan blowing past em in a tent. One on intake and on on discharge of a fan and dose them a few times. I am not sure how many times, but guessing I am into the 8th grow and still no breakout of the smells. I also dose my tents with ozone for awhile after each grow to sanitize. Note that it is a bad things for organics/biologicals so read up on it before trying and dont spend any time breathing it. Super for getting rid of wet-dog smells too. Note that these have no safeties and are pretty high voltage, so be careful if try it - but it works.

[Gingerbeard]

Activating carbon is not the same as reactivating carbon.
There is all sorts of information about home reactivating carbon in your oven. Pretty constant, the temperature I see is 400°F. I also see the big commercial ovens used.
One note I caught was all the odors the carbon picked up in its life will be burned off in reheating. So, you'll get a good miasma when those odors get burned off.

[Gator]

How long do you leave it in the oven??

[Gingerbeard]

Hours is the generic time. I imagine the longer the better.

[golfnrl]

Ginger we must be seeing the same web info about this.
Miasma. That is such a cool word.

[Bluey]

Until it's bone dry. Do not expose to an ignition source.