1996 Effect of steam and carbon dioxide activation in the micropore size distribution of activated carbon The three series of activated carbons were prepared from a common char, prepared by the carbonization of olive stones (nitrogen flow of 80 ml min -1 ; 850 ℃ ; heating rate, 5 ℃ min -1 ; residence time 2 hours). Activated carbons prepared by carbon dioxide activation exhibit a larger micropore volume and a narrower micropore size distribution than those prepared by steam activation. 2001 Mesoporous high-surface-area activated carbon The shells or seeds were dried at 110 o C, crushed and sieved to a uniform size of 1.0–2.0 mm. Subsequently, ZnCl 2 in the form of a powder and about 10 ml of water were added to the raw material to provide ZnCl 2 -to-shell ratios varying from 0.25 to 3 by weight. The mixtures were dehydrated overnight at 110 o C and pyrolysed under a flow of nitrogen in a quartz tube held in a horizontal furnace (Carbolite). The temperature was ramped at 10 o C/min up to 800 o C. Nitrogen was replaced by CO 2 when the temperature reached 800 o C and the carbon soaked at these conditions for 2–3 h. The activated products were then cooled, washed successively with deionised water, hydrochloric acid (0.1 mol/l) and hot deionised water to remove the zinc and chloride compounds. After overnight drying in air at 110 o C, N 2 adsorption–desorption isotherms of the carbons were measured using a gas sorption analyser (Nova-1000, Quantachrome) to determine surface area and pore volume. At low ZnCl 2 -to-shell ratios, micropore formation is the dominating mechanism; pore widening becomes important as the ratio increases. Pore widening takes place at the expense of micropore formation for high ZnCl 2 -to-shell ratios, thereby reducing the micropore content. 2003 Production of granular activated carbon from fruit stones and nutshells and evaluation of their physical, chemical and adsorption properties Almond, walnut, hazelnut shells and apricot stones were used as starting materials. These raw materials were broken with a Waring commercial blender and sieved to a particle size of 1–1.25 mm in diameter. Granulated raw materials were dried at 110 o C for 24 h. Dried raw materials were mixed with a solution of ZnCl2 (30 wt.%). The mixture was dehydrated at 103 o C for 6–10–18–24 h and subsequently activated at 750–800–850 o C for 2 h in the presence of N 2 (40 ml min -1 flow rate). The activated samples were washed initially with 1.2 M hydrochloric acid solution. Further washing was done with hot distilled water. Products were dried at 110 o C for 24 h in a thermostatically controlled oven.
标签: activated
