Which of the following best characterizes an adsorbent?

An adsorbent is best characterized as a material that adheres to a surface. This process, known as adsorption, involves the accumulation of molecules from a gas, liquid, or dissolved solid onto the surface of the adsorbent, creating a film of the adsorbed substance. This characteristic is essential in various applications, including pollution cleanup, where adsorbents are used to capture and remove pollutants from water and air by adhering to them on their surfaces.

In contrast, materials that get absorbed like a sponge involve a different process where liquids penetrate and dissolve into the material rather than adhering to its surface. Similarly, materials that capture liquids through chemical reactions are typically classified as absorbents or reactive materials, which function through a different mechanism than adsorption. The idea that an adsorbent is not useful in cleanup operations is inaccurate, as many adsorbents play a crucial role in environmental remediation by efficiently capturing harmful substances.