Answer: Adsorption is a phenomenon in which the adsorbate molecules are transferred from one phase to another due to the interaction between the adsorbate and the adsorbent molecules.
Physical adsorption is often used to dry compressed air. When the compressed air to be dried is in full (no time limit) contact with the adsorbent, the water molecules in the air diffuse to the adsorbent and are adsorbed. At the same time, due to the thermal motion of the adsorbed water molecules and the collision of external gaseous molecules, some of them leave the adsorbent surface and return to the gas phase, that is, desorption occurs. When the amount of water molecules adsorbed and desorbed is equal in the same time, a dynamic adsorption equilibrium is reached. At this time, both the adsorption and desorption processes are in progress, but at the same speed. This dynamic adsorption equilibrium is established under certain temperature and pressure conditions. When the temperature and pressure change, the original equilibrium relationship of the system will be broken and a new equilibrium relationship will be established.
