연소 조건과 수종을 달리한 블랙카본의 물리화학적 성질 및 세슘의 흡착 특성

This study was carried out to investigate the physicochemical and adsorptive characteristics of black carbon (BC) materials for cesium in case of severe nuclear accidents. The BC was prepared with a xylem of oak and pine trees incompletely combusted with different ramp rate and final temperature. Carbon (C), hydrogen (H) and oxygen (O) atomic ratios, BET, pore structure, and zeta potential were characterized for the produced BC. A low cesium concentration (Cw?10-7 M) was used for sorption batch experiments. The H/C and O/C ratios of BC decreased with the increase of final temperature, which indicates a carbonization of the wood materials regardless of ramp rate and tree species. However, SEM images showed different pore structures depending on tree species such as steric and plate-like for oak-BC and pine-BC, respectively. The greatest sorption distribution coefficients of Kd,Cs?1,200~1,800 L kg-1 were observed for the oak-BC produced at 400°C, while comparatively low Kd,Cs<100 L kg-1 for pine-BC. In addition, the sorption capabilities of BC declined with the increase of combustion temperature up to 600°C, because high temperature destroyed surface functionalities with the rise of ash components in the BC. Therefore, the sorption processes of BC for radioactive cesium are predominantly controlled by final production temperature of BC as well as raw materials (e.g., tree species).