Synthesis Activated Carbon from Coffee Residue by Using Microwave Radiation

Abstract

This research examined synthesis of activated carbon derived from coffee residue by being activated with microwave radiation. The first part of process was to carbonize coffee residue at 400, 500, and 600^๐C respectively. Each carbonization spent 1 hour. The amount of moisture, volatile, ash and fixed carbon were analyzed by following American Society for Testing and Materials (ASTM). It was found that the amount of fixed carbon at temperature 400, 500, and 600 ^๐C were 48, 32, and 27% respectively. Charcoal at 400 ^๐C was immersed in 40%H₃PO₄ solution, ratio of charcoal 1 g. per solution 20 ml. in 24 hrs. After that it was activated by microwave radiation at 200, 500, and 800 Watt respectively in 60 sec. According to characteristic of surface area and total pore volume by BET technique, it was found that at 200, 500, and 800 Watt, surface area were 7.05, 16.50, and 416.10 m²/g and total pore volume were 0.02, 0.03, and 0.24 cm³/g respectively. Microwave powered at 800 Watt, activated carbon consequently gave the most surface area and total pore volume. The microwave radiation at 800 Watt also transmitted high frequency electromagnetic wave which caused the vibration in molecule of the activated carbon. The vibration simultaneously generated heat which was capable of water evaporation and volatility in charcoal.