Activated carbon, also called activated charcoal, is a form of carbon commonly used to filter contaminants from water and air, among many other uses. It is processed (activated) to have small, low-volume pores that greatly increase the surface area[1][2] available for adsorption or chemical reactions[3] that can be thought of as a microscopic "sponge" structure (adsorption, not to be confused with absorption, is a process where atoms or molecules adhere to a surface). Activation is analogous to making popcorn from dried corn kernels: popcorn is light, fluffy, and its kernels have a high surface-area-to-volume ratio. Activated is sometimes replaced by active.
Because it is so porous on a microscopic scale, one gram of activated carbon has a surface area of over 3,000 square metres (32,000 square feet),[1][2][4] as determined by gas adsorption.[1][2][5] For charcoal, the equivalent figure before activation is about 2–5 square metres (22–54 sq ft).[6][7] A useful activation level may be obtained solely from high surface area. Further chemical treatment often enhances adsorption properties.
Activated carbon is usually derived from waste products such as coconut husks; waste from paper mills has been studied as a source.[8] These bulk sources are converted into charcoal before being activated. When derived from coal,[1][2] it is referred to as activated coal. Activated coke is derived from coke.
- ^ a b c d Chada N, Romanos J, Hilton R, Suppes G, Burress J, Pfeifer P (2012-03-01). "Activated carbon monoliths for methane storage". Bulletin of the American Physical Society. 57 (1): W33.012. Bibcode:2012APS..MARW33012C. Archived from the original on 2018-06-12. Retrieved 2018-05-30.
- ^ a b c d Soo Y, Chada N, Beckner M, Romanos J, Burress J, Pfeifer P (2013-03-20). "Adsorbed Methane Film Properties in Nanoporous Carbon Monoliths". Bulletin of the American Physical Society. 58 (1). M38.001. Bibcode:2013APS..MARM38001S. Archived from the original on 2018-06-12. Retrieved 2018-05-30.
- ^ ""Properties of Activated Carbon", CPL Caron Link, accessed 2008-05-02". Archived from the original on 19 June 2012. Retrieved 13 October 2014.
- ^ Dillon EC, Wilton JH, Barlow JC, Watson WA (1989-05-01). "Large surface area activated charcoal and the inhibition of aspirin absorption". Annals of Emergency Medicine. 18 (5): 547–552. doi:10.1016/S0196-0644(89)80841-8. PMID 2719366.
- ^ P. J. Paul. "Value Added Products from Gasification – Activated Carbon" (PDF). Bangalore: The Combustion, Gasification and Propulsion Laboratory (CGPL) at the Indian Institute of Science (IISc). Archived (PDF) from the original on 2021-09-20. Retrieved 2018-10-10.
- ^ Lehmann JS (2009). "Biochar for environmental management: An introduction. In Biochar for Environmental Management, Science and Technology" (PDF). Archived (PDF) from the original on 2021-07-06.
- ^ "Activated Charcoal". Discover Magazine. Archived from the original on 2022-01-18. Retrieved 2022-01-18.
- ^ Oliveira G, Calisto V, Santos SM, Otero M, Esteves VI (2018-08-01). "Paper pulp-based adsorbents for the removal of pharmaceuticals from wastewater: A novel approach towards diversification". The Science of the Total Environment. 631–632: 1018–1028. Bibcode:2018ScTEn.631.1018O. doi:10.1016/j.scitotenv.2018.03.072. hdl:10773/25013. ISSN 1879-1026. PMID 29727928. S2CID 19141293.