What is important for the purification of alcohol as

regards carbon pores:

1. The size of the pores in the carbon at the molecule level

2. What use one makes of the different carbon pores

3. How the different types of carbon pores are distributed

Carbon pores consist of:

1. Micro pores with a radius of less than 1 nm (small pores)


2. Meso pores with a radius of 1-25 nm (medium pores)

3. Macro pores with a radius larger than 25 nm (large pores)

Large pores are used for the transport of liquid through the carbon, and absorption occurs in the medium and small pores. Pores are formed during the manufacturing process, when the carbon is activated. The activation basically means that pores are created in a non-porous material by means of chemical reactions.
There are two different methods for this and they produce totally different pore structures:

1. Chemical activation

2. Activation by steam

The large macro pores act as channels through the carbon to the meso- and micro pores

. Granular activated carbon always has macro pores, but in powdered activated carbon often no macro pores are to be found, since after grinding, the carbon consists of very small particles. High and Low activated carbon It has become standard practice to describe the level of activity in the carbon by the quantity of the carbon that has become gaseous and left behind empty spaces (the pores). Thus, a high activated carbon is the one with the most empty space. Such carbon has many meso pores and macro pores. It can have so many large meso pores (12-25 nm) and a large quantity of macro pores that it is not suitable for purification of alcohol. That a carbon is high activated is no guarantee of its quality or a measure of its effectiveness.

© Gert Strand AB, Box 50221, S-202 12 Malmo, Sweden