sorbents

Sorbents are materials used to remove liquids or gases from a surrounding medium through sorption, a general term that covers adsorption (adhesion of molecules to a surface) and absorption (uptake into the volume of a material). The performance of a sorbent depends on surface area, porosity, chemical affinity, and stability under operating conditions.

Common sorbents fall into several categories. Adsorbents like activated carbon, silica gel, zeolites, alumina, clays, and porous resins rely on high surface area and pore structure to capture contaminants from air or water. Absorbents, including certain hydrogels and polymer beads, take liquids into their internal bulk. Some materials, such as certain resins, can function through both adsorption and absorption depending on the system.

Typical applications are broad. In environmental remediation, sorbents remove oils, solvents, and other contaminants from spills and groundwater. In air and gas purification, they capture volatile organic compounds, moisture, and acid gases, and they enable gas drying and selective separations. In water treatment, sorbents are used for dechlorination, deionization, adsorption of hardness ions, and removal of organic pollutants. In industry, sorbents serve in chromatography as stationary phases and as supports for catalysts.

Regeneration and disposal vary by material. Activated carbon and some other adsorbents can be thermally regenerated or solvent-regenerated for repeated use, though regeneration incurs energy or solvent costs. Single-use sorbents may require proper disposal to prevent secondary contamination. Selection hinges on capacity, selectivity, stability, and economics for the intended application.