Tian Shenglong, Yi Zede, Chen Junqing, Fu Shiyu
State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, Guangdong Province 510640, China.
State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, Guangdong Province 510640, China; South China University of Technology-Zhuhai Institute of Modern Industrial Innovation, Zhuhai 519175, China.
J Hazard Mater. 2023 Feb 5;443(Pt B):130236. doi: 10.1016/j.jhazmat.2022.130236. Epub 2022 Oct 28.
The capture of radioactive iodine is an inevitable requirement in nuclear industry for environmental protection. Metal-organic frameworks (MOFs) are a new generation of sorbents that have wide applications for iodine adsorption and recovery. Although the loading of MOFs on wood can avoid the drawbacks of the powder form of MOFs in implementation, the dense structure of wood results in the lower loading, even after delignification, which limits the adsorption capacity. Herein, a hierarchically porous UiO-66-NH @WCA composite was fabricated by in-situ synthesis of UiO-66-NH in wood-derived cellulose aerogel (WCA) that was further removed hemicellulose from delignified wood. UiO-66-NH @WCA exhibited a high loading (36 wt%) of UiO-66-NH crystals and a high adsorption capacity of 704 mg/g for iodine vapor and 248 mg/g for iodine aqueous solution. The adsorption behavior in iodine aqueous solution was well predicted by the Freundlich isotherm and pseudo-second-order kinetic model. The adsorption capacity of UiO-66-NH @WCA was highest in solution when the pH was 6, while the ionic strength had little effect. The hydroxyl groups on the WCA matrix had a charge transfer effect with iodine, providing additional sites for iodine capture. Furthermore, a packed column system was applied to demonstrate the excellent recyclability and potential for practical application.
捕获放射性碘是核工业环境保护的必然要求。金属有机框架（MOF）是新一代吸附剂，在碘吸附和回收方面有广泛应用。尽管将MOF负载在木材上可避免MOF粉末形式在应用中的缺点，但木材的致密结构导致即使经过脱木质素处理后负载量仍较低，这限制了吸附容量。在此，通过在木材衍生的纤维素气凝胶（WCA）中原位合成UiO-66-NH₂制备了一种分级多孔的UiO-66-NH₂@WCA复合材料，该WCA是从脱木质素木材中进一步去除半纤维素得到的。UiO-66-NH₂@WCA表现出36 wt%的高UiO-66-NH₂晶体负载量，对碘蒸气的吸附容量高达704 mg/g，对碘水溶液的吸附容量为248 mg/g。碘水溶液中的吸附行为可通过Freundlich等温线和准二级动力学模型得到很好的预测。当pH为6时，UiO-66-NH₂@WCA在溶液中的吸附容量最高，而离子强度影响较小。WCA基质上的羟基与碘有电荷转移效应，为碘捕获提供了额外的位点。此外，应用填充柱系统证明了其优异的可回收性和实际应用潜力。
