State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha, Hunan 410082, China.
Brook Byers Institute for Sustainable Systems, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Environ Sci Technol. 2020 Dec 15;54(24):16212-16220. doi: 10.1021/acs.est.0c05532. Epub 2020 Dec 1.
Mercury (Hg) removal is crucial to the safety of water resources, yet it lacks an effective removal technology, especially for emergency on-site remediation. Herein, multilayered oxygen-functionalized TiC (TiCO) (abbreviated as M-TiC) nanosheets were prepared to remove Hg(II) from water. The M-TiC has demonstrated ultrafast adsorption kinetics (the concentration decreased from 10 400 to 33 μg L in 10 s), impressively high capacity (4806 mg g), high selectivity, and broad working pH range (3-12). The density functional theory (DFT) calculations and experimental characterizations unveil that this exceptional Hg(II) removal is owing to the distinct interaction (., adsorption coupled with catalytic reduction). Specifically, Ti atoms on the {001} facets of M-TiC prefer to adsorb Hg(II) in the form of HgClOH, which subsequently undergoes homolytic cleavage to form radical species (., OH and HgCl). Immediately, the HgCl radicals dimerize and form crystalline HgCl on the edges of M-TiC. Up to ∼95% of dimeric HgCl can be efficiently recovered via facile thermal treatment. Notably, owing to the adsorbed OH and energy released during the distinct interaction, M-TiC has been oxidized to TiO/C nanocomposites. And the TiO/C nanocomposites have shown to have better performance on the photocatalytic degradation of organic pollutants than Degussa P25. These exceptional features coupled with mercuric recyclable nature make M-TiC an outstanding candidate for rapid/urgent Hg(II) removal and recovery.
汞（Hg）的去除对于水资源的安全至关重要，但目前缺乏有效的去除技术，尤其是在紧急现场修复方面。在此，我们制备了多层含氧功能化碳化钛（TiC）（简称 M-TiC）纳米片，用于从水中去除 Hg(II)。M-TiC 表现出超快的吸附动力学（浓度在 10 秒内从 10400 降至 33 μg/L）、令人印象深刻的高容量（4806 mg/g）、高选择性和较宽的工作 pH 范围（3-12）。密度泛函理论（DFT）计算和实验表征揭示了这种出色的 Hg(II)去除是由于独特的相互作用（吸附与催化还原偶联）。具体而言，M-TiC 的{001}面的 Ti 原子以 HgClOH 的形式优先吸附 Hg(II)，随后发生均裂，形成自由基物种（OH 和 HgCl）。立即，HgCl 自由基在 M-TiC 的边缘二聚化并形成结晶态 HgCl。高达约 95%的二聚 HgCl 可以通过简便的热处理有效地回收。值得注意的是，由于独特相互作用过程中吸附的 OH 和释放的能量，M-TiC 被氧化为 TiO/C 纳米复合材料。并且，与 Degussa P25 相比，TiO/C 纳米复合材料在光催化降解有机污染物方面表现出更好的性能。这些独特的特性以及汞的可回收性使 M-TiC 成为快速/紧急去除和回收 Hg(II)的优秀候选材料。
