Guo Yixuan, Hong Nhung Nguyen Thi, Dai Xiang, He Chunlin, Wang Youbin, Wei Yuezhou, Fujita Toyohisa
School of Resources, Environment and Materials, Guangxi University, Nanning, China.
School of Nuclear Science and Technology, University of South China, Hengyang, China.
Front Bioeng Biotechnol. 2022 Feb 10;10:819407. doi: 10.3389/fbioe.2022.819407. eCollection 2022.
While enjoying the convenience of nuclear energy development, the environmental contamination by radionuclide leakage is of significant concern. Because of its cost-effectiveness and environmental friendliness, biochar has attracted a lot of attention in the field of radioactive water treatment. Herein, a novel teak peel modified biochar (labeled as PMBN3) was prepared and applied to remove strontium from artificial seawater. The characterisation of the prepared PMBN3 showed it contains numerous oxygen-containing functional groups (i.e. carboxyl and hydroxyl groups), laminar morphology, mesoporous structure, large specific surface area. PMBN3 exhibited great advantages in Sr(II) adsorption, such as rapid adsorption kinetics (<1 h for equilibrium) and superior reusability. The adsorption of strontium by biochar is consistent with pseudo-second order and internal diffusion kinetic models. Among the four types of adsorption isotherms, the Freundlich isotherm showed the best fit with R > 0.98. The calculated thermodynamic parameters indicate that strontium adsorption on biochar occurs exothermically and spontaneously. Furthermore, for efficient removal of Sr(II), CO nanobubbles were blown into artificial seawater to precipitate the interfering metal ions, and followed by the adsorption of PMBN3 towards residual metal ions with the removal rate of Sr(II) over 99.7%. Finally, mechanistic studies have shown that the strontium adsorption process by PMBN3 is a multiple adsorption mechanism consisting of ion exchange between H (from -OH and -COOH) and Sr(II), and weak intermolecular forces between Sr(II) and the PMBN3 adsorbent. This study creatively combines chemisorption and nanobubble precipitation for strontium removal, which provides great reference value and guidance for environmental remediation.
在享受核能发展便利的同时，放射性核素泄漏造成的环境污染备受关注。由于生物炭具有成本效益和环境友好性，在放射性水处理领域备受关注。在此，制备了一种新型柚木皮改性生物炭（标记为PMBN3）并将其应用于从人工海水中去除锶。对制备的PMBN3的表征表明，它含有大量含氧官能团（即羧基和羟基）、层状形态、介孔结构和大比表面积。PMBN3在Sr（II）吸附方面表现出巨大优势，如快速吸附动力学（平衡时间<1小时）和优异的可重复使用性。生物炭对锶的吸附符合准二级动力学和内扩散动力学模型。在四种吸附等温线类型中，Freundlich等温线拟合效果最佳，R>0.98。计算得到的热力学参数表明，生物炭对锶的吸附是放热且自发的。此外，为了高效去除Sr（II），将CO纳米气泡吹入人工海水中以沉淀干扰金属离子，然后PMBN3对残留金属离子进行吸附，Sr（II）的去除率超过99.7%。最后，机理研究表明，PMBN3对锶的吸附过程是一种多重吸附机制，包括H（来自-OH和-COOH）与Sr（II）之间的离子交换以及Sr（II）与PMBN3吸附剂之间的弱分子间作用力。本研究创造性地将化学吸附和纳米气泡沉淀相结合用于去除锶，为环境修复提供了重要的参考价值和指导。
