Synthesis of activated carbon from rice chaff by microwave hydrothermal method

Rice chaff can be converted into activated carbon by alkaline treatment at high temperature. In this study, we tried to synthesize activated carbon from rice chaff by microwave hydrothermal treatment with NaOH solution. Rice chaff was heated at 700°C for 1 h in N ₂ after HCl treatment to remove impurity, such as alkali metals, resulting in the formation of charcoal. The charcoal was mixed with NaOH aqueous solution, and then heated at 100°C under microwave irradiation. After heating, the product was separated by filtration, washed with deionized water and dried at 50 °C. The specific surface area of product was 1060 m ²/g under microwave irradiation and 690 m ²/g by conventional heating with autoclave, which indicates that microwave hydrothermal treatment is effective for activation of charcoal.