sorbens

Sorbents are materials that remove, separate, or stabilize substances through sorption, the combined processes of adsorption (surface accumulation) and absorption (bulk uptake). They are used to collect contaminants or separate components from liquids and gases. The performance of a sorbent depends on surface area, pore structure, chemistry, and compatibility with the target phase. In practice, the term covers a wide range of solids and gels designed to interact with specific sorbates, and the plural form sorbents is commonly used.

Common sorbents include activated carbon, silica gel, alumina, zeolites, and porous polymers that mainly function by adsorption, as well as desiccants and hydrogels that operate by absorption. Some materials can act as both, depending on conditions and the sorbate.

Important properties include total surface area (often > 500 m2/g for effective adsorbents), pore size distribution, hydrophobic/hydrophilic balance, thermal and chemical stability, and regenerability. The selectivity is influenced by pore size, surface functional groups, and solvent polarity.

Applications span environmental and industrial uses: air and water purification, spill cleanup, gas separations, fragrance and decolorization, chromatography, and catalysis supports; desiccants in packaging; moisture control in electronics and pharmaceuticals.

Manufacture varies by type: activated carbon by carbonization and activation; silica gel and alumina by hydrolysis and dehydration; zeolites by hydrothermal synthesis; polymers by polymerization. Regeneration can be thermal desorption, solvent washing, or chemical treatment, depending on sorbate and material. Disposal considerations are important for sorbed hazardous substances.