What charcoal does to gases

• Gathers on the surface, as a layer of molecules
• Collects in condensed form
• Causes to condense on a surface
• Holds on a surface, as molecules
• Gathers in a condensed layer
• Condenses on a surface
• Takes up onto the surface

Wiktionary Word definitions in Wiktionary
vb. (en-third-person singular of: adsorb)