Subject: Re: How is charcoal made?

From: VINAR <S=VINAR%S=VINAR%G=INTEGRATE%P=[email-masked]>
Date: Wed, 12 Apr 1995 08:55:09 GMT

On 11 Apr 1995, John A. Stanley ([email-masked]) wrote:

>In some far, dusty corner of my head I recall that walnut shells
>make good activated charcoal. Can you verify this?

Well, we have never used walnut shell, as it is not abundantly
available here in India. But I suspect that it would be a
good source and in all probability give a granular activated
charcoal just like Coconut shell, or even better in terms of
porosity :-)

Sushil
s=vinar%g=integrate%p=[email-masked]

Re: How is charcoal made?

---

From: [email-masked] (DaveHatunen)
Date: Mon, 10 Apr 1995 14:21:12 GMT

In article <[email-masked]>,
David R. Smith <[email-masked]> wrote:
>I related question is what exactly is meant by "activated"
>charcoal which seems to be the one used in most types of
>filter systems.
>Does it have an electric charge or something, and made from
>only certain woods, etc.

Charcoal is very adsorptive. Simply put, this means molecules of other
substances stick to its surface very easily. Charcoal is also very
porous. Even a very small chunk has a very, very large surface area if
you add up the interior surfaces of all the pores. This means that a
small amount of charcoal can take up a large amount of stuff like
contaminants, such as water impurities. And charcoal is a principle
constituent of gas masks.

Once a chunk of charcoal has adsorbed as much as it can hold, it
becomes inactive at adsorption. You activate it by following the
process used to make it in the first place: raise it to high heat away
from oxygen, driving off all the stuff it adsorbed. It is then
activated charcoal (as is new charcoal fresh out of the kiln).

-- 

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