Polymers may also be adsorbed to surfaces through polyelectrolyte adsorption. Activated carbon an adsorbent, used for the adsorption of odorous compounds. The biogeochemistry of arsenic is complex and includes various adsorption and desorption processes. The process is the opposite of sorption (that is, either adsorption or absorption). A more general term is "sorption", which covers absorption, adsorption, and ion exchange. PAINT works by maintaining a balance between the dye adsorption/absorption and photobleaching/desorption rates. Chromatography can be described as a mass transfer process involving adsorption. This hydrophobic nature allows to adsorption of hydrophobic chemicals into surface of MP. Cogeneration systems linked to absorption chillers or adsorption chillers use waste heat for refrigeration. The second mechanism is based on the surface adsorption of electrolyte cations on MnO. Experimentally, there is clear evidence for adsorbate/adsorbate interactions in heat of adsorption data. Infiltration is caused by multiple factors including; gravity, capillary forces, adsorption and osmosis. Two methods in common use are pressure swing adsorption and membrane gas separation. This is often because of ionic adsorption. Impregnated carbons are also used for the adsorption of Hydrogen Sulfide(HS) and thiols.