Has someone got it muddled up? Or is there a difference between adsorb and absorb? There certainly is a difference!
Adsorb is the word that is correctly used to describe what silica gel does with moisture. Adsorption is the process by which a substance adheres to the surface of the adsorbent. In this case the moisture (water molecules) adhere to the surface of the silica gel. The moisture does not actually penetrate in to the silica gel. So, the terminology is as follows: the silica gel is the adsorbent, and the water molecules are called the adsorbate. Remember, if silica gel, e.g. e-Gel, is re-generated the water molecules are removed from the e-Gel surface; however, the silica gel loses approximately 20% of its capacity as a number of the pores do not re-open. Some companies view best practice as not to re-generate silica gel, but simply dispose of it.
Absorption is the process in which the absorbent, (which could be a liquid or a solid) dissolves a fluid. An example of absorption would be when a towel is used to soak up a drink that has been spilled. Another example, is that of a sponge that absorbs not adsorbs moisture.