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首页> 外文期刊>Environmental Science & Technology >Removal and Recovery of Heavy Metal Ions by Two-dimensional MoS_2 Nanosheets: Performance and Mechanisms
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Removal and Recovery of Heavy Metal Ions by Two-dimensional MoS_2 Nanosheets: Performance and Mechanisms

机译：二维MoS_2纳米片去除和回收重金属离子的性能和机理

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摘要

We investigated the removal of heavy metals from water by two-dimensional MoS2 nanosheets suspended in aqueous solution, and restacked as thin film membranes, respectively. From these studies we elucidated a new heavy metal ion removal mechanism that involves a reduction oxidation (redox) reaction between heavy metal ions and MoS2 nanosheets. Ag+ was used as a model species and MoS2 nanosheets were prepared via chemical exfoliation of bulk powder. We found that the Ag+ removal capacity of suspended MoS2 nanosheets was as high as similar to 4000 mg/g and adsorption accounted for less than 20% of removal, suggesting the reduction of Ag+ to metallic silver as a dominant removal mechanism. Furthermore, we demonstrated that MoS2 membranes were able to retain a similar high removal capacity, and attribute this capability to the formation of a conductive, permeable multilayer MoS2 structure, which enables a corrosion-type reaction involving electron transfer from a MoS2 site inside the membrane (anode) to another site on membrane surface (cathode) where heavy metal ions are reduced to metallic particles. The membrane surface remains active to efficiently recover metallic particles, because the primary oxidation products are soluble, nontoxic molybdate and sulfur species, which do not form an insulating oxide layer to passivate the membrane surface. Therefore, MoS2 membranes can be used effectively to remove and recover precious heavy metals from wastewater.
机译：我们研究了通过悬浮在水溶液中的二维MoS2纳米片从水中去除重金属的方法，并分别将其重堆积为薄膜。通过这些研究，我们阐明了一种新的重金属离子去除机理，该机理涉及重金属离子与MoS2纳米片之间的还原氧化（redox）反应。以Ag +为模型物种，通过散装粉末的化学剥落制备MoS2纳米片。我们发现，悬浮的MoS2纳米片的Ag +去除能力高达4000 mg / g，吸附占去除量的20％以下，这表明将Ag +还原为金属银是主要去除机理。此外，我们证明了MoS2膜能够保持类似的高去除能力，并将这种能力归因于导电，可渗透的多层MoS2结构的形成，这使腐蚀型反应涉及从膜内部MoS2位置转移电子（阳极）到膜表面（阴极）上的另一个位置，在那里重金属离子被还原为金属颗粒。膜表面保持活性以有效地回收金属颗粒，因为主要的氧化产物是可溶的，无毒的钼酸盐和硫物质，它们不会形成绝缘氧化物层来钝化膜表面。因此，MoS2膜可以有效地用于去除和回收废水中的贵重金属。

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  • 来源
    《Environmental Science & Technology》 |2018年第17期|9741-9748|共8页
  • 作者

    Wang Zhongying; Sim Alison; Urban Jeffrey J.; Mi Baoxia;

  • 作者单位

    Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA;

    Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA;

    Lawrence Berkeley Natl Lab, Mol Foundry, Berkeley, CA 94720 USA;

    Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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  • 正文语种 eng
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