sorption

Imagine a sponge taking in water or a filter trapping a gas. That is sorption. It is a general word for two related processes: absorption, where something goes into a material, and adsorption, where something sticks to the surface of a material. In simple terms, it means one substance is taken up by another, either inside it or on it.

You will often see this word in science. People use it when talking about pollutants being held by soil, gases sticking to charcoal, or substances being taken up by living tissue. If something is being taken into or onto another material, sorption is often the right word.

Sorption is a general term for the process in which atoms, ions, or molecules from one substance are taken up by another. It is an umbrella term that includes two related but different processes: *absorption and adsorption*. Both involve one substance being held by another, but the place where it ends up is what matters.

*Absorption happens when a substance moves into* the bulk of a material. Imagine a paper towel soaking up spilled juice. The liquid does not stay only on the outside; it goes into the fibers.

*Adsorption happens when a substance attaches to the surface* of a material. Imagine a gas sticking to activated carbon or dust clinging to glass. In this case, the material is held on the outside rather than moving deeply inside.

Scientists use sorption when they want a broader word that can cover either process, or sometimes both at once. The term appears often in environmental science, chemistry, materials science, and biology. It is useful when talking about soil holding pollutants, filters removing chemicals from water or air, gases attaching to solid surfaces, or living tissue taking in certain substances.

You may also come across "sorption isotherms," which describe how much of a substance is taken up by a material at a given temperature. Whether the topic is water cleaning, air filtration, drug delivery, or the behavior of industrial materials, sorption helps describe how one substance is taken into or onto another.