Activated harcoal
So called "activated" charcoal is a powder composed of a processed form of regular charcoal with a particularly large surface area due to microscopic pores on the surface of the particles. This makes it more effective than regular charcoal for most non-fuel uses of charcoal.
Uses
- Pharm: GI treatment on WHO LEM
- Water filtration
Natural occurrence
- Tiny amounts of activated charcoal do occur naturally in regular charcoal.
Hazards
- GRAS
Production
steam activation
In a kiln, push live steam through size-sorted charcoal. The reaction will create additional pores in the charcoal, increasing its surface area.
- C(s) + 2 H2O(g){2 H2(g) + CO2(g)700°C}→
Testing
To the human senses, activated charcoal and regular charcoal are identical. Measurement/estimation of the surface area and pore size are vital to knowing whether or not the production has been successful. This is accomplished through the use of other chemicals, determinism its iodine number[1] and its absorption of methylene blue. [2]
Iodine number
Methylene blue number
See Also
References
- ↑ (2006) "Standard Test Method for Determination of Iodine Number of Activated Carbon" (local copy)
link courtesy ASTM. - ↑ Nunes, Cleiton A (2011) "Estimation of surface area and pore volume of activated carbons by methylene blue and iodine numbers" (local copy)
Química Nova 34(3) Departamento de Química, Universidade Federal de Lavras
DOI:10.1590/S0100-40422011000300020
link courtesy Scientific Electronic Library Online, Brazil.