Korea Biochar Research Center, APRU Sustainable Waste Management & Division of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, South Korea; State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China.
Decontamination Technology Research Division, Korea Atomic Energy Research Institute, Daejeon, 34057, Republic of Korea.
Environ Res. 2022 Nov;214(Pt 4):114072. doi: 10.1016/j.envres.2022.114072. Epub 2022 Aug 18.
Radioactive elements released into the environment by accidental discharge constitute serious health hazards to humans and other organisms. In this study, three gasified biochars prepared from feedstock mixtures of wood, chicken manure, and food waste, and a KOH-activated biochar (40% food waste + 60% wood biochar (WFWK)) were used to remove cesium (Cs) and strontium (Sr) ions from water. The physicochemical properties of the biochars before and after adsorbing Cs and Sr were determined using X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, extended X-Ray absorption fine structure (EXAFS) spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX). The WFWK exhibited the highest adsorption capacity for Cs (62.7 mg/g) and Sr (43.0 mg/g) among the biochars tested herein. The removal of radioactive Cs and Sr exceeded 80% and 47%, respectively, in the presence of competing ions like Na and Ca. The functional groups present in biochar, including -OH, -NH, and -COOH, facilitated the adsorption of Cs and Sr. The Cs K-edge EXAFS spectra revealed that a single coordination shell was assigned to the Cs-O bonding at 3.11 Å, corresponding to an outer-sphere complex formed between Cs and the biochar. The designer biochar WFWK may be used as an effective adsorbent to treat radioactive Cs- and Sr-contaminated water generated during the operation of nuclear power plants and/or unintentional release, owing to the enrichment effect of the functional groups in biochar via alkaline activation.
环境中意外排放的放射性元素对人类和其他生物构成了严重的健康危害。在这项研究中，使用了三种由木材、鸡粪和食物垃圾混合物制成的气化生物炭，以及一种 KOH 活化生物炭（40%食物垃圾+60%木材生物炭（WFWK）），从水中去除铯（Cs）和锶（Sr）离子。使用 X 射线衍射（XRD）、傅里叶变换红外（FT-IR）光谱、扩展 X 射线吸收精细结构（EXAFS）光谱、X 射线光电子能谱（XPS）和扫描电子显微镜-能量色散 X 射线光谱（SEM-EDX）测定了生物炭在吸附 Cs 和 Sr 前后的物理化学性质。在测试的生物炭中，WFWK 对 Cs（62.7 mg/g）和 Sr（43.0 mg/g）的吸附容量最高。在存在 Na 和 Ca 等竞争离子的情况下，放射性 Cs 和 Sr 的去除率分别超过 80%和 47%。生物炭中存在的官能团，包括-OH、-NH 和-COOH，促进了 Cs 和 Sr 的吸附。Cs K 边 EXAFS 光谱表明，3.11 Å处的 Cs-O 键归属于单个配位壳，对应于 Cs 与生物炭之间形成的外球络合物。由于碱性活化使生物炭中的官能团富集，设计的生物炭 WFWK 可用作处理核电站运行过程中产生的放射性 Cs 和 Sr 污染水和/或意外释放的有效吸附剂。
