This research studies the synthesis of activated carbon from coffee residue for the adsorption of phenol and toluene in a laboratory scale. The experiments comprise three steps which are carbonization, activation and adsorption. The optimum conditions of carbonization are at 500 oC with the heating rate of 10 oC/min for 40 minutes obtaining 21 % yield and 76 % fixed carbon. The physical activation by superheated steam and the chemical activation by zinc chloride solution and phosphoric acid were studied. The optimum conditions of the physical activation are at 900 oC for 1 hour. The total surface area, mesoporous surface area, pore volume and pore diameter are 180 m2/g, 70 m2/g, 0.109 cm3/g and 2.5 nm, respectively. The optimum conditions of the chemical activation are at weight ratio of carbon and chemical of 1:2.5 at 600 oC and 90 minutes. The total surface area, mesoporous surface area, pore volume and pore diameter of the activated carbon activated by zinc chloride solution are 625 m2/g, 171m2/g, 0.358 cm3/g and 2.3 nm, respectively. And those of the activated carbon activated by phosphoric acid are 556 m2/g, 170 m2/g, 0.315 cm3/g and 2.3 nm, respectively. For the adsorption of phenol and toluene, the activated carbons activated by chemicals under the mentioned conditions were used. It was found that the activated carbon activated by phosphoric acid adsorbed phenol better than that activated by zinc chloride solution. The adsorbed values are 58 and 48 mg phenol/gram of activated carbon. In case of toluene, the activated carbon activated by zinc chloride solution adsorbed toluene better than that activated by phosphoric acid. The adsorbed values are 120 and 99 mg toluene/gram of activated carbon.
By
Pongsachai Pecharasangharn
Paisarn Denroungrueng
Wathanapon Boonlerd
