Abstract One of the crucial aspect of nuclear waste management is the radioactive waste stream released from the nuclear fuel cycle. In radioactive waste treatment, adsorption is one of the most powerful methods for the pre-concentration process. In this study, functionalization of multiwalled carbon nanotubes (MWCNTs) using potassium permanganate (KMnO4) and citric acid (C6H8O7) as oxidizing agents was investigated for adsorption of thorium from aqueous solutions named PPM-MWCNTs and CA-MWCNTs, respectively. The central composite design technique was used to examine the initial thorium concentration, pH, and temperature as the adsorption parameters. The thermodynamic parameters (standard enthalpy (ΔH°), entropy (ΔS°), and free energy (ΔG°)) were determined and the results indicated that both adsorption systems were endothermic processes. The adsorption isotherms of modified MWCNTs were investigated using the Langmuir, Freundlich and Dubinin-Radushkevich isotherm models for characterizing the process. According to the high correlation coefficients, the Langmuir model described well the adsorption of thorium on PPM-MWCNTs and CA-MWCNTs and adsorption capacities were found to be 105.28 and 50.67 mg g−1, respectively. In addition, molecular dynamics simulations were successfully performed on the Th bonded modified MWCTNs.

中文翻译：

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通过改性多壁碳纳米管去除钍：优化、热力学、动力学和分子动力学观点

摘要 核废物管理的关键方面之一是核燃料循环释放的放射性废物流。在放射性废物处理中，吸附是预浓缩过程中最有效的方法之一。在这项研究中，研究了使用高锰酸钾 (KMnO4) 和柠檬酸 (C6H8O7) 作为氧化剂对多壁碳纳米管 (MWCNTs) 进行功能化，以分别从名为 PPM-MWCNTs 和 CA-MWCNTs 的水溶液中吸附钍。中心复合设计技术用于检查作为吸附参数的初始钍浓度、pH 值和温度。测定了热力学参数（标准焓（ΔH°）、熵（ΔS°）和自由能（ΔG°）），结果表明两种吸附系统都是吸热过程。使用 Langmuir、Freundlich 和 Dubinin-Radushkevich 等温线模型研究了改性 MWCNT 的吸附等温线，以表征该过程。根据高相关系数，Langmuir 模型很好地描述了钍在 PPM-MWCNTs 和 CA-MWCNTs 上的吸附，吸附容量分别为 105.28 和 50.67 mg g-1。此外，还成功地对 Th 键合的改性 MWCTN 进行了分子动力学模拟。分别。此外，还成功地对 Th 键合的改性 MWCTN 进行了分子动力学模拟。分别。此外，还成功地对 Th 键合的改性 MWCTN 进行了分子动力学模拟。