Activated carbon an adsorbent, used for the adsorption of odorous compounds. The reverse of adsorption is desorption, the adsorbate splitting from adsorbent. Combining an adsorbent with a refrigerant, adsorption chillers use heat to provide a cooling effect. Activated alumina is an adsorbent that effectively removes arsenic. The bond between the adsorbate and adsorbent in chemisorption is either ionic or covalent. Target proteins are captured on the adsorbent, while particulates and contaminants pass through. Dapsone has been use as a monomer in the design of dye adsorbent polymers. Halloysite is an efficient adsorbent both for cations and anions. Hydrogen densities similar to liquefied hydrogen can be achieved with appropriate adsorbent materials. This process creates a film of the "adsorbate" on the surface of the "adsorbent". The "stationary phase" or "adsorbent" in column chromatography is a solid. Their actions may be broadly categorized as either electrostatic, adsorbent, ionic, or enzymatic. Originally, kaolinite was used as the adsorbent and pectin as the emollient. SEC works by trapping smaller molecules in the pores of the adsorbent ("stationary phase"). This phenomenon is brought about by the gas and adsorbent molecules' interaction.