College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, 610066, China; Key Laboratory of Treatment for Special Wastewater of Sichuan Province Higher Education System, Sichuan, Chengdu, 610066, China.
College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, 610066, China.
Chemosphere. 2019 Jul;226:405-412. doi: 10.1016/j.chemosphere.2019.03.154. Epub 2019 Mar 27.
In this study, a novel adsorbent thiol functionalized magnetic carbon nanotubes (CNTs-SH@FeO) was synthesized to overcome somewhat existing difficulties during the Hg(II) adsorption process, including low efficiency and selectivity, narrow feasible pH range and difficult to separate and reuse. The Hg(II) adsorption performance of CNTs-SH@FeO was evaluated using batch experiment and its physiochemical properties were investigated by characterization techniques. The batch experiment results showed that the prepared CNTs-SH@FeO maintained high Hg(II) adsorption efficiency (>98%) over wide pH range from 3 to 11. The selective adsorption of Hg(II) by CNTs-SH@FeO was achieved with the coexistence of Cu(II), Mg(II) or Zn(II) ions, in which adsorbate matrix Hg(II) removal efficiency of 81.39%, 89.36% and 95.52% was obtained, respectively. CNTs-SH@FeO kept high Hg(II) removal efficiency (>80%) and good magnetic property (Ms value > 21 emg g) after five cycles of adsorption/regeneration. The Hg(II) adsorption kinetics could be better described by pseudo-second-order kinetic model. Freundlich model showed higher correlation coefficient in adsorption isotherms study, and the calculated maximum adsorption capacity was 172.4 mg g. Thermodynamic study suggested that the adsorption process was exothermic in nature. Surface adsorption, complex adsorption and reduction adsorption were all contributed to the removal of Hg(II) using CNTs-SH@FeO.
在这项研究中，合成了一种新型的吸附剂巯基功能化磁性碳纳米管（CNTs-SH@FeO），以克服汞（II）吸附过程中存在的一些困难，包括效率低、选择性差、可行的 pH 范围窄以及难以分离和再利用。通过批量实验评价了 CNTs-SH@FeO 的 Hg(II)吸附性能，并通过表征技术研究了其物理化学性质。批量实验结果表明，所制备的 CNTs-SH@FeO 在 pH 值为 3 至 11 的宽范围内保持了较高的 Hg(II)吸附效率（>98%）。通过 CNTs-SH@FeO 实现了 Hg(II)的选择性吸附，同时共存 Cu(II)、Mg(II)或 Zn(II)离子，其中吸附剂基质 Hg(II)的去除效率分别为 81.39%、89.36%和 95.52%。CNTs-SH@FeO 在五次吸附/再生循环后仍保持较高的 Hg(II)去除效率（>80%）和良好的磁性（Ms 值>21 emg g）。Hg(II)吸附动力学可以更好地用准二级动力学模型描述。在吸附等温线研究中，Freundlich 模型显示出更高的相关性系数，计算出的最大吸附容量为 172.4 mg g。热力学研究表明，吸附过程本质上是放热的。表面吸附、络合吸附和还原吸附都有助于使用 CNTs-SH@FeO 去除 Hg(II)。
