5664Re: Activated Carbon
- Aug 6, 2002--- In Distillers@y..., "Mike Nixon" <mike@s...> wrote:
> Grant Dunn wrote:follow the pack.
> Subject: Re: [Distillers] Activated Carbon
> Hi Mike,
> Its nice to meet somewhere who does some research and doesn't just
>acts in three ways:
> We don't entirely disagree. From what I have read, activated carbon
>attractive "force" forms relatively weak bonds between the carbon and
> Adsorption - relying on electrostatic Van der Walls forces. This
adsorbate. In theory activated carbon could release or desorb what it
removed at some point, but from practical experience desorption rarely
>porous network where a chemical reaction or physical entrapment take
> Absorption - refers to the diffusion of a gas or compound into the
place. Ozone for example is absorbed into activated carbon where it
oxidizes a portion of the carbon's surface. Ozone (O3) is reduced to
oxygen (O2) thus "detoxified". Ozone does not accumulate or build-up
in the carbon structure.
>surface and the adsorbate. Pollutants are tightly bound to the
> Chemisorption - an irreversible chemical bond between the carbon
>and the carbon used to remove these compounds is generally not
> Chemisorption is associated with the removal of inorganic chemicals
regenerated. The filtering of alcohol primarily involves the removal
of organics via adsorption. After the activated carbon has reached
exhaustion and all the adsorptive sites are filled, it can be
>don't have the equipment to prove it either way, everything I have
> Where we differ is on what is required to regenerate it. While I
read suggests that this requires temperatures above 800 degrees. I
would be very interested to see any documented reports that indicate
>its adsorption of nitrogen gas. This clearly demonstrates the need to
> The surface area of activated carbon is calculated from measuring
keep activated carbon in an airtight container. How then does rinsing
it in water affect its reactivity? What are the impurities you are
trying to remove? Do you know that rinsing removes them? Activated
carbon is available in food grade so why don't you just use that?
>about the difference between 'physiosorption' and 'chemisorption', as
> Hi Grant,
> I really didn't want to confuse matters on the List by rabbiting on
the only activity we are really interested in getting clean booze.
Specifically, we are interested in removing compounds that have taste
or odor and which, like those that contribute color, tend to bind
strongly. With these, the only bonding is by weak Van der Waals
forces. There is no significant redistribution of electron density in
either the molecule or at the substrate surface, and subsequent
release of the molecules by heating is easy. Heating in an oven to 160
deg C is quite sufficient to clean used carbon to the extent that it
can be used again, particularly when the carbon is first soaked in
water to provide active flushing with steam as it boils. Of course,
this will not release all the adsorbed molecules . heating to a much
higher temperature in an inert atmosphere is needed to do that
thoroughly . but 90+% efficiency is good enough for all practical
purposes, and has been used as a cost-effective recovery process by
sugar refineries ever since 'white' sugar was processed.
>nitrogen. Thus, an asphyxiation hazard exists inside enclosed spaces
> Wet activated carbon primarily removes oxygen from air, not
containing wet activated carbon. Dry activated carbon requires no
special precautions. Rinsing activated carbon before first use is a
sensible procedure as many carbons, particularly the 'stone' carbons,
are produced using chemical etchants which may still linger in the
final product (eg. zinc chloride and phosphoric acid). Those are the
impurities you want to remove before letting newly procured carbon
anywhere near liquids that you are later going to drink.
>gained during my time at Farnborough where I was engaged in work
> As an aside, not that it matters much, knowledge of all this was
relating to purification of liquid coolants. Bottom line however, for
anyone wanting to check on all this, is to leave aside all 'theory'
and the boring ravings of idjits like me, and to simply go ahead and
try it. If it works for you, then wear a happy smile. If it doesn't,
then just blame me and still wear a happy smile!!
>I regenerate my charcoal using steam from my boiler. Have done it 5
> All the best,
or 6 times now with no appreciable change to the effectiveness of the
charcoal. I get a huge pong for about 3 hours then no smell. If the
smell is anything to go by, I have no problem reactivating. The smell
coming off,is just the like shit you are trying to remove from your
distillate only concentrated...green apples spring to mind.
No science here but if it works.....
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