Supercritical CO2 regeneration of activated carbon loaded with organic adsorbates

Abstract

Supercritical CO2 regeneration is one of the possibilities for spent carbon regeneration loaded with some organics. Here, adsorption equilibrium and adsorption dynamics were evaluated for some typical organic pollutants under some supercritical CO2 conditions. A supercritical CO2 chromatograph packed with activated carbon (F-400, CAL) was used to detect the pulse responses of organics, which were analyzed by moment analysis. Adsorption equilibrium constants of some organics varied with CO2 density and their boiling points. Possibility of regeneration of each substance was discussed. Cost estimation was necessary and was the key point of this technique.

Decontamination of hazardous substances from solid matrices and liquids using supercritical fluids extraction: A review

“…In their study, the Chihara et al [159], Yeo and Kim [168] regeneration of activated carbon using supercritical process had more satisfactory regeneration result as compared to steam regeneration. The effects of pressure and temperatures on regeneration efficiency were examined as well, of which higher pressure condition was deemed more favorable for regeneration.…”

“…The effects of pressure and temperatures on regeneration efficiency were examined as well, of which higher pressure condition was deemed more favorable for regeneration. Supercritical CO 2 -assisted regeneration of granular activated carbon F-400 filled with several organics compounds was carried out by Chihara et al [159]. They evaluated adsorption equilibrium and dynamics of these organics under supercritical conditions.…”

Supercritical Regeneration of an Activated Carbon Fiber Exhausted with Phenol

“…The process was limited by solubility under the conditions used in this specific study. The solubility of phenol in SCCO 2 increased as the fluid was pressurized and, as a consequence, the extraction pathway was also improved [10,13,17].…”

“…The regeneration of ACs saturated with inorganic compounds is less usual and co-solvents must be used to efficiently extract these adsorbates [16]. The employment of SCCO 2 has also been studied to regenerate ACs saturated with low-volatile organic compounds, e.g., phenol [17][18][19], pesticides [20], herbicides [21], or insecticides [22]. Phenol is the most common model compound in the field of regeneration of ACs [3]: it is a pollutant frequently found in wastewater and drinking water that remains strongly retained on the carbon surface of ACs.…”

Adsorption of organics on MSC5A in supercritical CO2, chromatographic measurements & stop & go simulation

“…Adsorption of organics on adsorbents, such as activated carbon, in supercritical CO 2 could be mild (Shojibara et al 1995;Chihara et al 1997Chihara et al , 2011 compared with adsorption in gas phase (Benkhedda et al 2000). This is because of coadsorption of CO 2 (Tanida et al 1996).…”