Preparation of a novel fluidized bed of recoverable lignin nanospheres with iodine vapor trapping advantage and exploration of its iodine trapping mechanism

The capture of radioiodine plays a crucial role in protecting the environment and safeguarding public health. In this paper, we aim to investigate the iodine trapping properties of lignin with different structural features. Lignin, each with distinct structures and characteristics, was transformed into nanospheres and utilized in a fluidized bed system. The iodine trapping properties and mechanisms of the lignin nanospheres were thoroughly investigated. Notably, the fluidized bed was designed in-house after assessing the practical requirements of different application scenarios, making it both innovative and relevant to real-world applications. The results indicate that the iodine capture capacity of these lignin nanospheres (LNPs) can reach a maximum of 100 mg/g (CELNPs). The capture process is best described by a pseudo-second-order kinetic model. Furthermore, the LNPs remain reusable. The primary mechanism for iodine capture by LNPs involves chemical interactions, while physical interactions serve only as a secondary mechanism. This study evaluated the applicability of lignin in iodine capture and to confirm its feasibility for purifying iodine vapors and subsequent industrial applications. This research provides foundational data for the future development of lignin-based iodine trapping materials and presents a pathway for realizing high-value applications of lignin.