Adsorption is effective for purifications, e.g. taking a contaminant ranging from 1 ppb to 1000 ppm out of a stream of gas or liquid. In addition, adsorption is good for bulk separations, e.g. taking 1 to 50% out of a stream of gas, or maybe 1 to 10% out of a liquid. Adsorption is also used for recovery of certain constituents (solvents from air), preventing pollution, purifying materials that will react, and so on.
The above by no means represents a comprehensive list of the ways that adsorption can be used. As with any science, adsorption is constantly evolving and research is ongoing.