Akl Zeinab F, Zaki Elsayed G, ElSaeed Shimaa M
Egyptian Atomic Energy Authority (EAEA), P.O. Box 11762 Cairo, Egypt.
Egyptian Petroleum Research Institute (EPRI), P.O. Box 11727 Cairo, Egypt.
ACS Omega. 2021 Dec 8;6(50):34193-34205. doi: 10.1021/acsomega.1c01559. eCollection 2021 Dec 21.
Uranium is the backbone of the nuclear fuel used for energy production but is still a hazardous environmental contaminant; thus, its removal and recovery are important for energy security and environmental protection. So far, the development of biocompatible, efficient, economical, and reusable adsorbents for uranium is still a challenge. In this work, a new orange peel biochar-based hydrogel composite was prepared by graft polymerization using guar gum and acrylamide. The composite's structural, morphological, and thermal characteristics were investigated via Fourier transform infrared (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) methods. The composite's water absorption properties were investigated in different media. The performance of the prepared composite in adsorbing uranium (VI) ions from aqueous media was systematically investigated under varying conditions including solution's acidity and temperature, composite dose, contact time, and starting amount of uranium. The adsorption efficiency increased with solution pH from 2 to 5.5 and composite dose from 15 to 50 mg. The adsorption kinetics, isotherms, and thermodynamics parameters were analyzed to get insights into the process's feasibility and viability. The equilibrium data were better described through a pseudo-second-order mechanism and a Langmuir isotherm model, indicating a homogeneous composite surface with the maximum uranium (VI) adsorption capacity of 263.2 mg/g. The calculated thermodynamic parameters suggested that a spontaneous and endothermic process prevailed. Interference studies showed high selectivity toward uranium (VI) against other competing cations. Desorption and recyclability studies indicated the good recycling performance of the prepared composite. The adsorption mechanism was discussed in view of the kinetics and thermodynamics data. Based on the results, the prepared hydrogel composite can be applied as a promising, cost-effective, eco-friendly, and efficient material for uranium (VI) decontamination.
铀是用于能源生产的核燃料的核心成分，但仍然是一种有害的环境污染物；因此，其去除和回收对于能源安全和环境保护至关重要。到目前为止，开发用于铀的生物相容性好、高效、经济且可重复使用的吸附剂仍然是一项挑战。在这项工作中，使用瓜尔胶和丙烯酰胺通过接枝聚合制备了一种新型的基于橙皮生物炭的水凝胶复合材料。通过傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）、X射线衍射（XRD）和热重分析（TGA）方法研究了该复合材料的结构、形态和热特性。在不同介质中研究了该复合材料的吸水性能。在包括溶液酸度和温度、复合材料剂量、接触时间以及铀的起始量等不同条件下，系统地研究了所制备的复合材料从水介质中吸附铀（VI）离子的性能。吸附效率随着溶液pH值从2增加到5.5以及复合材料剂量从15毫克增加到50毫克而提高。分析了吸附动力学、等温线和热力学参数，以深入了解该过程的可行性和可行性。通过伪二级动力学机制和朗缪尔等温线模型能更好地描述平衡数据，表明复合材料表面均匀，最大铀（VI）吸附容量为263.2毫克/克。计算得到的热力学参数表明该过程是自发的吸热过程。干扰研究表明该材料对铀（VI）相对于其他竞争性阳离子具有高选择性。脱附和可回收性研究表明所制备的复合材料具有良好的回收性能。结合动力学和热力学数据讨论了吸附机理。基于这些结果，所制备的水凝胶复合材料可作为一种有前景、经济高效、环保且高效的材料用于铀（VI）的去污处理。
