The movement of the molecules towards the centre of Activated Carbon Particle
It is by no means easy for the molecules to move inwards as the path along which they travel is not as smooth as is portrayed by the straight line in the diagram above. All along their journey they may be required to climb up a seemingly steep cliff or jump from one bank to another.
The sight of the molecules cramming their way inwards is perhaps analogous to what one can see when a glass filled with sand is tapped on a table: the sand at the bottom of the glass not only becomes compressed but also receives a larger amount of pressure than what it did earlier. Unlike the sand, however, the pressure exerted by the centre-wise condensation of the molecules here is by far stronger. What happens to these molecules can, in a way, be analogous to what happens when a number of people, using ropes tied to a pillar, together try to pull themselves towards the pillar. Eventually, they will find themselves cramped all together at the pillar. (Illustration.3).
With the number of molecules sticking to the walls so overwhelming, and with all of them now cramming inside and forcing their way to the centre of the activated Carbon body at each vibration, one could perhaps only imagine how high the pressure exerted on the centre of the activated Carbon body could be. Now, what could possibly happen next?
Such a phenomenon can occur only to activated Carbon due to the adhesion of the molecules to the walls of the passage—the walls thus serve as a sort of rope to which they cling in their effort to get to the centre.
Nevertheless, it is not unlikely that the presence of other substances such as the different types of Zeolite may also lead to the occurrence of a similar or almost similar phenomenon. Success in this matter is highly dependent on the ability of the activated Carbon particle or of those Zeolite-like substances to hold the molecules throughout their journey to the centre. It is also possible that there exist other waves capable of driving the molecules into moving towards the centre.
But whatever the possibility is, one thing is certain: for such centre-wise condensation to occur, the presence of certain waves capable of driving the molecules into moving towards the centre is inevitable. Apart from that, these molecules need to have something on which they can cling—something like activated Carbon particle, the grasp of which, while it is strong enough to allow the molecules to be transported to the centre, is yet not strong enough to overpower the influence of the waves.
The substances entering the activated Carbon particle will, in combination with other external substances that come along with them, form various compounds, eventually causing the activated Carbon particle to be full of compounds of innumerable varieties. Not only this, with the molecules and the compounds concentrated at the centre of the activated Carbon particle, the centre gets condensed, whereby that part in particular and the whole body in general are subject to a certain amount of pressure, which leaves the body with no choice but to expand.
But, in which direction?
To ease the writer in the process of writing, and unless explained otherwise, from this page onwards what he means by Carbon is Activated Carbon Particles (ACP).