Adsorb vs Absorb
“Adsorption” and “Absorption”– Many have assumed that these terms are similar. However, is that so?
Let’s start out by defining the terms.
Absorption – the process whereby the atoms, molecules and ions enter a solid, gas, or liquid material and are chemically integrated into one another.
On the other hand, adsorb is the process by which the molecules of a fluid stick on the surface of a solid or liquid and are being held by physical bond. It involves adhesion unlike absorption which involve dissolution or diffusion.
Getting a little too technical?
Let’s imagine a scenario where you’re getting a new house and you have decided to apply a new coat of paint. You painted the wall with your new favourite colour, and it sits nicely on the wall. That’s adsorption – a fluid forming a layer on the surface.
While painting, you’ve accidentally toppled the tin of paint, you hurriedly took a piece of towel to wipe it off. The process whereby the paint transferred from the floor to the towel is called absorption – when something penetrates into an object.
Now that we have understand the differences,
Does desiccant adsorb or absorb?
Desiccants is a drying agent that removes excess moisture from the surrounding environment. A common desiccant that is being widely used is silica gel – the sachet of beads that is found in your bags to prevent mould growth.
Many users claim that desiccants absorb moisture, however, there isn’t any chemical reaction being formed between the moisture and desiccant. Instead, moisture simply cling on the surface of the desiccant, forming a physical bond, making it an adsorption process.
Adsorption of moisture is typically a process whereby desorption can happen by introducing heat. Hence, moisture adsorbed can be released back to the environment when the desiccant is heated to a certain temperature.
Therefore, it is always important to understand the type of desiccant you are using to achieve the best result out of it!!
& the next time someone says that desiccant absorbs moisture, tell them otherwise!