Abstract

We developed a new silica (SiO<inf>2</inf>) removal technique that can maximize biomass-based activated carbon adsorption performance. SiO<inf>2</inf> removal is one of the key processes in making activated carbon suitable for cryosorption pumps in fusion machines. In this study, we employed an evaporation process to remove SiO<inf>2</inf> by high-temperature vacuum heating. The charcoal made from rice straw was heated at 1800^◦C for 1 h at approximately 10 Pa in a vacuum furnace. We found that SiO<inf>2</inf> amount was significantly reduced from 15.8 wt% to 4.20 wt% due to vacuum heating. In addition, the result of surface element mapping analysis using energy-dispersive X-ray spectroscopy (EDX) indicated a considerable decrease in the oxygen content of SiO<inf>2</inf>. We demonstrated the great potential of activated carbon derived from rice straw as an adsorbent for high-performance cryosorption pumps.