Formation of active carbons from cokes using potassium hydroxide

Preparation of porous carbons from petroleum coke by different activation methods

“…Nevertheless, the active agents used in the chemical activation method, such as KOH, has dehydrating effect that inhibits the formation of tar [4,5], which helps to enhance the yield of porous carbon and to decrease the activation temperature compared with the physical activation method [6,7]. It is also quite easy for one to prepare high quality porous carbons with well-developed pore structure by chemical activation method.A number of carbon precursors such as coal and coconut shell have been tested to produce porous carbons by physical activation or chemical activation, separately [7][8][9][10][11], however, in spite of a few papers having reported alkali, calcium and magnesium catalyst can increase the rate of reaction in physical activation, there is little work that has been done about the preparation of high quality porous carbons by co-activation with KOH and H 2 O as active agents in the same activation process. Petroleum cokes, which are abundant and cheap (less than $100 per ton and usually be used as burning fuel) in China, have higher carbon content (about 90%) and have been proved to be good starting materials for the preparation of porous carbon.…”

Insight into hydroxides-activated coals: Chemical or physical activation?

“…Interestingly, at temperatures higher than 500 ºC, a high amount of H 2 O is evolved by the two impregnated samples: KOH between 300 ºC and 500 ºC, and above 600 ºC, both, KOH and NaOH. (Figure 3 and 4) indicating that reactions (4) and (7) are taking place, without discard also reaction (8).…”

“…Marsh & Walker 1979 [6]) and there are numerous reports in the literature [7][8][9][10][11][12][13][14][15][16][17], nowadays, it is still unclear and, as consequence, continues being under study [18]. The porosity development is strongly influence by numerous experimental parameters such as coal/KOH weight ratio, maximum treatment temperature, time at the maximum temperature, nitrogen flow and, as consequence, several mechanisms have been proposed.…”

Activated carbons for applications in catalysis: the point of view of a physical-chemist

“…The activation to which the "activated" term is referred is the process that leads to the development of surface area and porosity and the introduction of a variable amount of functional groups. The activation procedure can be divided into 2 main groups (Ahmadpour and Do 1996;Bansal et al 1988;Figueiredo et al 1999;Girgis et al 2002;Illan-Gomez et al 1996;Jagtoyen et al 1992;Laine and Yunes 1992;Marsh and Walker Jr 1979;Marsh et al 1984;Teng et al 1998;Wigmans 1989):…”