Critical Evaluation of Adsorption-Desorption Hysteresis of Heavy Metal Ions from Carbon Nanotubes: Influence of Wall Number and Surface Functionalization
Critical Evaluation of Adsorption-Desorption Hysteresis of Heavy Metal Ions from Carbon Nanotubes: Influence of Wall Number and Surface Functionalization
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碳纳米管重金属离子吸附-解吸滞后的批判性评估：壁数和表面功能化的影响
DOI：
10.1002/asia.201301475
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发表时间：
2014
影响因子：
4.1
通讯作者：
Wang Xiangke
中科院分区：
文献类型：
--
作者：
Li Jie;Chen Changlun;Zhang Shouwei;Ren Xuemei;Tan Xiaoli;Wang Xiangke
采用单壁、双壁和多壁碳纳米管（SWCNTs、DWCNTs和MWCNTs）以及两种不同氧含量（2.51 wt %和3.5 wt %）的氧化MWCNTs，研究了碳纳米管的壁数和表面功能化对其对重金属离子（Ni II、Cd II和Pb II）的吸附容量和吸附-脱附滞后的影响。 吸附在碳纳米管上的金属离子可以通过降低溶液pH来解吸。当上清液被不含金属离子的电解质溶液取代时，重金属离子的吸附不完全可逆。随着碳纳米管壁数和表面官能团的增加，碳纳米管表面缺陷增多，吸附容量和吸附-脱附滞后指数（HI）值增大。重金属离子在碳纳米管表面的覆盖度、溶液pH值和温度影响金属离子的吸附-脱附滞后。随着吸附在碳纳米管上的金属离子的量增加，可能发生吸附机制从主要不可逆过程到主要可逆过程的可能转变。重金属离子可以不可逆地吸附在缺陷位点上。
Single‐, double‐, and multi‐walled carbon nanotubes (SWCNTs, DWCNTs, and MWCNTs), and two oxidized MWCNTs with different oxygen contents (2.51 wt % and 3.5 wt %) were used to study the effect of the wall number and surface functionalization of CNTs on their adsorption capacity and adsorption–desorption hysteresis for heavy metal ions (NiII, CdII, and PbII). Metal ions adsorbed on CNTs could be desorbed by lowering the solution pH. Adsoprtion of heavy metal ions was not completely reversible when the supernatant was replaced with metal ion‐free electrolyte solution. With increasing wall number and amount of surface functional groups, CNTs had more surface defects and exhibited higher adsorption capacity and higher adsorption–desorption hysteresis index (HI) values. The coverage of heavy metal ions on the surface of CNTs, solution pH, and temperature affect the metal ion adsorption–desorption hysteresis. A possible shift in the adsorption mechanism from mainly irreversible to largely reversible processes may take place, as the amount of metal ions adsorbed on CNTs increases. Heavy metal ions may be irreversibly adsorbed on defect sites.