Highly Efficient Removal and Sequestration of Cr(VI) in Confined MoS2 Interlayer Nanochannels: Performance and Mechanism
Highly Efficient Removal and Sequestration of Cr(VI) in Confined MoS2 Interlayer Nanochannels: Performance and Mechanism
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DOI：
10.1016/j.seppur.2022.121104
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发表时间：
2022-04
影响因子：
8.6
通讯作者：
Qi Han;Julie Yu;Sidney Poon;L. Sun;Minerva Teli;Bei Liu;Hong Chen;Kunkun Wang;Zhongying Wan
中科院分区：
文献类型：
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作者：
Qi Han;Julie Yu;Sidney Poon;L. Sun;Minerva Teli;Bei Liu;Hong Chen;Kunkun Wang;Zhongying Wan
由于Cr（VI）的严重毒性和高流动性，其对环境的污染特别令人关注。在这项研究中，我们采用二维MoS 2纳米片在去除Cr（VI），重点揭示去除机制，以及如何组成和结构的独特性的二维MoS 2纳米材料的内在影响的Cr去除效率。通过分散纳米片的批量实验，我们发现MoS 2纳米片通过相依赖机制表现出高的Cr（VI）去除能力，达到1100 mg/g。特别地，在MoS 2纳米片中的1 T多晶型物通过氧化还原反应机制去除Cr（VI），这与先前报道的MoS 2吸附去除Cr（VI）不同，突出了组分对去除机制和性能的影响。更重要的是，还原产物Cr（III）通过沉淀和吸附同时被去除到MoS 2纳米片上，这可以避免常规处理中通常需要的额外pH升高步骤。MoS 2纳米片独特的二维片状结构使得能够形成对齐的和离子可进入的纳米通道，其中Cr（VI）物种被容纳、还原和螯合。在干燥下的纳米通道的不可逆收缩改性的层堆叠结构的内部到封闭的隔间，防止释放和再氧化的固定化的Cr（III）。汇编的结果突出了MoS 2的组成和结构对Cr去除效率和机制的影响，这对未来的研究具有重大意义，这些独特的功能，二维纳米材料的各种修复方案。
Environmental contamination by Cr(VI) is of particular concern because of its severe toxicity and high mobility. In this study, we employed two-dimensional MoS2nanosheets in the removal of Cr(VI), with an emphasis on revealing the removal mechanisms, and how the compositional and structural uniqueness of 2D MoS2nanomaterials intrinsically impact the Cr removal efficiency. Through batch experiments with dispersed nanosheets, we found that MoS2nanosheets exhibited a high Cr(VI) removal capacity at ∼1100 mg/gviaa phase-dependent mechanism. Particularly, the 1T polymorph in the MoS2nanosheets removed Cr(VI) through a redox-reaction mechanism, which was different from the adsorptive removal of Cr(VI) by MoS2reported previously, highlighting the compositional effects on the removal mechanism and performance. More importantly, the reduced product Cr(III) was concurrently removedviaprecipitation and adsorption onto the MoS2nanosheets, which could avoid the additional pH-elevation step that is typically needed in the conventional treatment. The unique 2D flake-like structure of MoS2nanosheets enabled the formation of aligned and ion-accessible nanochannels, where Cr(VI) species were accommodated, reduced and sequestered. The irreversible shrinking of the nanochannels under drying modified the interior of the layer-stacked structure into confined compartments preventing the release and re-oxidation of the immobilized Cr(III). The compiled results highlight the effects of MoS2composition and structure on the Cr removal efficiency and mechanism, which has substantial implications on future studies tailoring these unique features of 2D nanomaterials for various remediation scenarios.