New Silica Removal Technique by Vacuum Heating toward High-Performance Cryosorption Pumps Based on Biomass-Based Activated Carbon

Abstract

We developed a new silica (SiO₂) removal technique that can maximize biomass-based activated carbon adsorption performance. SiO₂ 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 SiO₂ by high-temperature vacuum heating. The charcoal made from rice straw was heated at 1800 ℃ for 1 h at approximately 10 Pa in a vacuum furnace. We found that SiO₂ 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 SiO₂. We demonstrated the great potential of activated carbon derived from rice straw as an adsorbent for high-performance cryosorption pumps.