Tian Hua, Guo Jianrong, Pang Zili, Hu Minghua, He Junhui
Functional Nanomaterials Laboratory, Center for Micro/Nanomaterials and Technology, and Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
Nanoscale. 2020 Aug 21;12(31):16543-16555. doi: 10.1039/d0nr04558f. Epub 2020 Jul 31.
Two-dimensional (2D) porous graphene is attractive as a high-permeability membrane for ionic and molecular separation. Here, we propose a sulfur, nitrogen dual-doped 2D porous graphene (SNPG) nanohybrid by adopting a facile one-step process. The resulting sandwich-like porous nanohybrid features uniform ion-gated nanopores for efficient transport of target heavy metal ions while blocking undesired ions, as well as abundant multi-binding ligands for selectively chelating permeated heavy metal ions. We show from systematic experiments that this SNPG nanohybrid exhibits outstanding selectivity and ability to separate Hg(ii) ions in mixtures with eight other metal ions. An excellent uptake capability (803 mg g) and high removal ability (>99%) within the entire pH range of 2-10 can be obtained. Given the specific 2D porous nanostructure and specific binding ligands, SNPG exhibits an ultrahigh separation factor towards Hg(ii) that is up to four orders of magnitude higher than those of Pb(ii), Cd(ii) and Cu(ii) ions, significantly higher than those of most reported adsorbents. These findings provide a new opportunity to develop selective materials and devices for applications such as efficient recognition, extraction and separation of target metal ions in complex aqueous environments.
二维（2D）多孔石墨烯作为一种用于离子和分子分离的高渗透性膜具有吸引力。在此，我们通过采用简便的一步法制备了一种硫、氮双掺杂二维多孔石墨烯（SNPG）纳米杂化物。所得的三明治状多孔纳米杂化物具有均匀的离子门控纳米孔，可实现目标重金属离子的高效传输，同时阻挡不需要的离子，以及丰富的多结合配体，用于选择性螯合渗透的重金属离子。我们通过系统实验表明，这种SNPG纳米杂化物在与其他八种金属离子的混合物中对Hg(ii)离子表现出出色的选择性和分离能力。在2至10的整个pH范围内可获得优异的吸附能力（803 mg g）和高去除能力（>99%）。鉴于特定的二维多孔纳米结构和特定的结合配体，SNPG对Hg(ii)表现出超高的分离因子，比Pb(ii)、Cd(ii)和Cu(ii)离子的分离因子高出四个数量级，显著高于大多数报道的吸附剂。这些发现为开发用于在复杂水环境中高效识别、提取和分离目标金属离子等应用的选择性材料和装置提供了新机会。
