Abstract Radiocesium (137Cs) and radiocobalt (60Co) represent main dose-significant radionuclides in low-level radioactive liquid effluents released from commercial nuclear power plants (NPPs). Although pyrogenic carbon-based adsorbents (biochars, BC) have been studied for toxic metal removal, the reports of their use in the adsorption of radionuclides are rare. This article focuses on the competitive removal of Cs+ and Co2+ ions from radioactive solutions to waste biomass derived biochar and the multi-component isotherms. BC exhibited a good affinity to both Cs and Co, and in single-component systems the maximal adsorption capacity Qmaxexp reached 97.4 ± 5.0 (Cs+) and 74.5 ± 0.4 μmol g−1 (Co2+). 3D adsorption surfaces obtained by Sheindorf-Rebuhn-Steintuch (SRS) and extended Freundlich models indicate that the sorption of Cs+ ions from the Cs–Co binary system is significantly affected by Co2+ ions and during the adsorption competitive and interaction effects between Cs+ and Co2+ ions occur. Moreover, mono- and divalent cations present in the solution acted as competing ions, decreasing the Kd values. SEM-EDX maps, FTIR and XPS spectra confirmed that both biochar mineral and carbon fraction participated in Cs and Co immobilization. Beside interactions of Cs+ and Co2+ ions with O-containing moieties on the biochar surface (chemisorption), mineral components and porosity of BC (physisorption) were involved in both Cs and Co removal. Finally, the adsorption loading and fast kinetics for both Cs and Co indicate suitability of biochar to decontaminate low-level radioactive effluents contaminated by 137Cs and 60Co.

中文翻译：

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用于低放射性废水净化的热解碳：同时分离 137Cs 和 60Co

摘要 放射性铯 (137Cs) 和放射性钴 (60Co) 是商业核电站 (NPP) 释放的低放射性液体流出物中的主要剂量显着放射性核素。尽管已经研究了热解碳基吸附剂（生物炭，BC）用于去除有毒金属，但关于它们用于吸附放射性核素的报道很少。本文重点介绍了从放射性溶液中竞争性去除 Cs+ 和 Co2+ 离子到废弃的生物质衍生生物炭和多组分等温线。BC 对 Cs 和 Co 都表现出良好的亲和力，在单组分系统中，最大吸附容量 Qmaxexp 达到 97.4 ± 5.0 (Cs+) 和 74.5 ± 0.4 μmol g-1 (Co2+)。Sheindorf-Rebuhn-Steintuch (SRS) 和扩展的 Freundlich 模型获得的 3D 吸附表面表明，Cs-Co 二元体系中 Cs+ 离子的吸附受到 Co2+ 离子的显着影响，并且在 Cs+ 和 Co2+ 离子之间的吸附竞争和相互作用效应期间发生。此外，溶液中存在的一价和二价阳离子充当竞争离子，降低了 Kd 值。SEM-EDX 图、FTIR 和 XPS 光谱证实生物炭矿物和碳组分都参与了 Cs 和 Co 的固定。除了 Cs+ 和 Co2+ 离子与生物炭表面上的含 O 部分的相互作用（化学吸附）之外，矿物质成分和 BC 的孔隙率（物理吸附）也参与了 Cs 和 Co 的去除。最后，