Zhang Pengcheng, Wang Lin, Huang Zhiwei, Yu Jipan, Li Zijie, Deng Hao, Yin Taiqi, Yuan Liyong, Gibson John K, Mei Lei, Zheng Lirong, Wang Hongqing, Chai Zhifang, Shi Weiqun
Laboratory of Nuclear Energy Chemistry, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China.
ACS Appl Mater Interfaces. 2020 Apr 1;12(13):15579-15587. doi: 10.1021/acsami.0c00861. Epub 2020 Mar 18.
Despite that two-dimensional transition metal carbides and carbonitrides (MXenes) are burgeoning candidates for remediation of environmental pollutants, the construction of robust functionalized MXene nanosheets with a high affinity for target heavy metal ions and radionuclides remains a challenge. Here we report the successful placement of amidoxime chelating groups on TiCT MXene surface by diazonium salt grafting. The introduction of amidoxime functional groups significantly enhances the selectivity of TiCT nanosheets for uranyl ions and also greatly improves their stability in aqueous solution, enabling efficient, rapid, and recyclable uranium extraction from aqueous solutions containing competitive metal ions. Benefiting from the excellent conductivity of MXenes, the amidoxime functionalized TiCT nanosheets show outstanding electrochemical performance such that when loaded on carbon cloth the application of an electric field increases the uranium adsorption capacity from 294 to 626 mg/g, outperforming all organic electrochemical sorption materials reported previously. The present work provides an effective strategy to functionalize MXene nanosheets with fundamental implications for the design of MXene-based selective electrosorption electrode materials.
尽管二维过渡金属碳化物和碳氮化物（MXenes）是修复环境污染物的新兴候选材料，但构建对目标重金属离子和放射性核素具有高亲和力的稳健功能化MXene纳米片仍然是一项挑战。在此，我们报告了通过重氮盐接枝成功地将偕胺肟螯合基团置于TiCT MXene表面。偕胺肟官能团的引入显著提高了TiCT纳米片对铀酰离子的选择性，也极大地提高了它们在水溶液中的稳定性，从而能够从含有竞争性金属离子的水溶液中高效、快速且可循环地提取铀。受益于MXenes的优异导电性，偕胺肟功能化的TiCT纳米片表现出出色的电化学性能，以至于当负载在碳布上时，施加电场会使铀吸附容量从294 mg/g增加到626 mg/g，优于先前报道的所有有机电化学吸附材料。本工作提供了一种功能化MXene纳米片的有效策略，对基于MXene的选择性电吸附电极材料的设计具有重要意义。
