A sorbent is a material used to absorb or

adsorb Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the ''adsorbate'' on the surface of the ''adsorbent''. This process differs from absorption, in which a f ...

liquids or gases. Examples include: *A material similar to

molecular sieve A molecular sieve is a material with pores (very small holes) of uniform size. These pore diameters are similar in size to small molecules, and thus large molecules cannot enter or be adsorbed, while smaller molecules can. As a mixture of molecu ...

material, which acts by adsorption (attracting molecules to its surface). It has a large internal

surface area The surface area of a solid object is a measure of the total area that the surface of the object occupies. The mathematical definition of surface area in the presence of curved surfaces is considerably more involved than the definition of ...

and good

thermal conductivity The thermal conductivity of a material is a measure of its ability to conduct heat. It is commonly denoted by k, \lambda, or \kappa. Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials of high thermal ...

. It is typically supplied in pellets of 1 mm to 2 mm diameter and roughly 5 mm length or as grains of the order 1 mm. Occasionally as beads up to 5 mm diameter. They are typically made from aluminium oxide with a porous structure. *Materials used to absorb other materials due to their high affinity for doing so. Examples include: **In

composting Compost is a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical and biological properties. It is commonly prepared by decomposing plant, food waste, recycling organic materials and manure. The resulting ...

, dry (brown, high-

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon ma ...

) materials absorb many

odoriferous An odor (American English) or odour (Commonwealth English; see spelling differences) is caused by one or more volatilized chemical compounds that are generally found in low concentrations that humans and animals can perceive via their sen ...

chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., w ...

s, and these chemicals help to decompose these sorbents. **A

sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate throu ...

absorbs many times its own weight in water. **A

polypropylene Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene. Polypropylene belongs to the group of polyolefins a ...

fiber mat may be used to absorb oil. **A

cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wa ...

fiber product may be used to absorb oil. **The granular gel material in a baby

diaper A diaper /ˈdaɪpə(r)/ (American and Canadian English) or a nappy (Australian English, British English, and Hiberno-English) is a type of underwear that allows the wearer to urinate or defecate without using a toilet, by absorbing or cont ...

will absorb several times its original weight in

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellul ...

. **

Desiccant A desiccant is a hygroscopic substance that is used to induce or sustain a state of dryness (desiccation) in its vicinity; it is the opposite of a humectant. Commonly encountered pre-packaged desiccants are solids that absorb water. Desiccants ...

s attract water,

drying Drying is a mass transfer process consisting of the removal of water or another solvent by evaporation from a solid, semi-solid or liquid. This process is often used as a final production step before selling or packaging products. To be consid ...

out (

desiccating Desiccation () is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic (attracts and holds water) substance that induces or sustains such a state in its local vicinity in a moderately sealed container. ...

) the surrounding materials.

Method of action

When used in a chemical spill acting as a sorbent, oil-absorbent pads must attract oil preferentially to water i.e. – it should be oleophilic and hydrophobic. Sorbent materials must act by adsorption or less commonly by absorption. Both adsorb material, as well as absorbents, incorporate the oil or other liquid to be recovered into the body of the material.

References

Desiccants Natural materials Synthetic materials {{Material-stub