Vapor adsorption on coal- and wood-based chemically activated carbons

Adsorption of NH3 onto activated carbon prepared from palm shells impregnated with H2SO4

“…However, for the adsorbent samples prepared by H 2 SO 4 activation, the data obtained are dispersed, suggesting that the adsorptive capacity is not solely a function of the BET surface area. A similar observation was also reported by Lee and Reucroft when they studied the adsorption of NH 3 onto wood-base activated carbons prepared by phosphoric acid (H 3 PO 4 ) in the very low relative pressure range [14]. Besides the tests carried out at 323 K, NH 3 adsorption tests for a wide range of temperatures from 303 to 373 K were also carried out for the activated carbons prepared at 973 K for 2 h by thermal activation and chemical activation (20% H 2 SO 4 impregnation).…”

“…Their hydrogen bonding (N-H· · ·O) energy has been reported to be as much as 3 kcal/mol [14]. NH 3 can therefore preferably adsorb onto active adsorption sites provided by oxygen functional groups via hydrogen boding besides on pure carbon sites.…”

Capacity and mechanism of phenol adsorption on lignite

“…However, several works report a decrease in phenol adsorption from water with surface oxidation Mahajan et al, 1980;Leng, 1996;Franz et al, 2000;Terzyk, 2003Terzyk, , 2004Moreno-Castilla, 2004). Since lignites are rich in oxygen surface groups Küçükbayrak et al, 2000), they have a high affinity for water (Allardice and Evans, 1971;Schafer, 1972;Kaji et al, 1986;Müller and Gubbins, 1998;Lee and Reucroft, 1999). Therefore, the decrease in adsorption with oxidation is attributed to the preferential hydration of the surface oxygen groups over the hydrogen-bonding of the -OH of the phenol molecule.…”

On the reactive adsorption of ammonia on activated carbons modified by impregnation with inorganic compounds

“…Those adsorbents include untreated zeolites, carbonaceous materials, and alumina [1,[8][9][10][11][12][13][14][15][16][17][18][19][20]. Ammonia adsorption was studied either from the air filtration standpoint or as a way to characterize the acid-base nature of an adsorbent.…”