A sorbent is a material used to absorb or adsorb liquids or gases. The calculated ability of an adsorbent to preferentially adsorb one gas over another gas. Hydrophobic molecules in the mobile phase tend to adsorb to the relatively hydrophobic stationary phase. It does not readily biodegrade, adsorb, or volatilize. Graphene nanotubes have functional groups that adsorb gases. Unlike amines, solid sorbents can selectively adsorb CO without the formation of chemical bonds (physisorption). The reacting gases adsorb onto active sites on the iron particles. One of the reactants has very high adsorption and the other one doesn't adsorb strongly. Chemical species that adsorb to the surface of nanoparticles are called ligands. Next the water is run through a tank containing activated charcoal to adsorb organic contaminants. They adsorb on the AgCl surface, imparting a negative charge to the particles. Carbons with a combination of macropores and mesopores adsorb tannins. They adsorb to nonbasal planes of ice, inhibiting thermodynamically-favored ice growth. A good collector will adsorb, physically or chemically, with one of the types of particles. Lean traps adsorb the nitrogen oxide and "trap" it.