Pseudo Continuous Reactor with Microwave-plasma for Preparation of High Surface Area Activated Carbon

Abstract

A new activation method using a pseudo continuous reactor with microwave-induced plasma is examined to prepare activated carbon. Carbonized carbon gel is mixed with potassium hydroxide before being activated by microwave irradiation. The specific surface area of the product is investigated by varying microwave-retention time. The results show that the activated carbon with specific surface area of 3,054 m 2 g -1 and total pore volume of 1.35 cm 3 g -1 can be obtained within 510 s, although hour-level time is necessary to obtain similar activated carbon if conventional methods are used. Temperature change of the carbon precursor caused by microwave irradiation was measured in batch mode to estimate the temperature at pseudo continuous system based on the retention time. It was found that the retention time to reach 700 ° C of the carbon precursor can be essential factor to achieve high surface area and large pore volume. In addition, the activated carbon synthesized by the proposed method can show an average mass yield percentage of 24.2%, which is much higher than that from conventional methods, 4.5-5.0%. Based on the influence of the microwave retention time, reaction mechanism is discussed. The fast rate and high yield shown here should contribute to energy-saving process.