Final answer:
TLC utilizes adsorbents such as silica gel, alumina, and cellulose for the separation of compounds. These materials attract molecules to their surfaces, a process known as adsorption, which is distinct from absorption where molecules permeate into the solid.
Step-by-step explanation:
In Thin Layer Chromatography (TLC), several adsorbent layers are employed based on the characteristics of the compounds being separated. Commonly used adsorbents include silica gel, which is highly polar and suitable for separating non-volatile mixtures, alumina (aluminum oxide), which has a high affinity for polar compounds, and cellulose for separating compounds that are soluble in water and organic solvents. These layers function due to a process called adsorption, where molecules adhere to the surface of the solid adsorbent, differentiating it from absorption where the substance is taken up into the material.