无机材料学报 ›› 2020, Vol. 35 ›› Issue (3): 293-300.DOI: 10.15541/jim20190381 CSTR: 32189.14.10.15541/jim20190381

所属专题: 2020年环境材料论文精选(二)重金属元素去除

• 研究论文 • 上一篇    下一篇

不同pH条件下硫化钼纳米片吸附Cd(II)的微观机制研究

董丽佳1,郭筱洁2,李雪1,陈朝贵1,金阳1(),AHMED Alsaedi3,TASAWAr Hayat3,4,赵轻舟5,盛国栋6()   

  1. 1. 绍兴文理学院 生命科学院, 绍兴 312000
    2. 杭州电子大学 材料与环境工程学院, 杭州 310018
    3. NAAM Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
    4. Department of Mathematics, Quaid-I-Azam University, Islamabad 44000, Pakistan
    5. 中国科学院大学 资源与环境学院, 北京 100049
    6. 绍兴文理学院 化学与化工学院, 绍兴 312000
  • 收稿日期:2019-07-24 修回日期:2019-09-11 出版日期:2020-03-20 网络出版日期:2019-09-20
  • 作者简介:董丽佳(1984-), 女, 博士. E-mail: Donglijia@126.com

Microscopic Insights into pH-dependent Adsorption of Cd(II) on Molybdenum Disulfide Nanosheets

DONG Lijia1,GUO Xiaojie2,LI Xue1,CHEN Chaogui1,JIN Yang1(),AHMED Alsaedi3,TASAWAR Hayat3,4,ZHAO Qingzhou5,SHENG Guodong6()   

  1. 1. School of Life Science, Shaoxing University, Shaoxing 312000, China
    2. College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
    3. NAAM Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
    4. Department of Mathematics, Quaid-I-Azam University, Islamabad 44000, Pakistan
    5. College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
    6. College of Chemistry and Chemical Engineering, Shaoxing Univeristry, Shaoxing 312000, China
  • Received:2019-07-24 Revised:2019-09-11 Published:2020-03-20 Online:2019-09-20
  • About author:DONG Lijia(1984-), female, PhD. E-mail: Donglijia@126.com
  • Supported by:
    National Natural Science Foundation of China(31700476)

摘要:

本研究结合静态实验和X射线吸收精细结构谱学(EXAFS)评估了硫化钼纳米片对重金属Cd(II)的吸附行为和微观机制。结果表明: Cd(II)在硫化钼纳米片上的吸附受溶液pH、反应时间和温度的显著影响, 但不受离子强度的影响。在pH 3.3~9.6范围内, pH升高显著促进了硫化钼对Cd(II)的吸附量, 但不改变吸收速率、吸附等温线和热力学。二级动力学模型能更好地拟合该吸附平衡, 且内表面颗粒扩散模型显示了吸附过程中的三个典型阶段。等温线和热力学分析说明Cd(II)在硫化钼上的吸附是异质性的、自发的、吸热的和不可逆的过程。EXAFS光谱学分析揭示了该吸附存在两种类型: 在较低的pH(3.56, 6.48)条件下, 内表面络合以Cd-S配位键为主; 在较高的pH(9.57)条件下, 出现Cd(OH)2沉淀, 且配位键以Cd-O和Cd-Cd的形式存在。这些研究结果对于评估重金属离子和硫化钼纳米片在分子水平上的作用机理提供了新的视野。

关键词: 硫化钼纳米片, pH, 微观结构, EXAFS, Cd(II)

Abstract:

Herein, the retention mechanisms and microstructure of Cd(II) on MoS2 nanosheets were evaluated by batch experiments and EXAFS technology. The sorption of Cd(II) on MoS2 was strongly affected by solution pH, contact time, and temperature, but not by the ionic strength. The solution pH could only promote the sorption capacity, but does not improve the sorption rates and change the sorption isotherms and thermodynamics in the pH range of 3.3-9.6. The pseudo-second-order model could fit the equilibrium data better and the intra-particle diffusion model showed three typical stages in the sorption process. The isotherms and thermodynamics analysis indicated that the heterogeneity sorption of Cd(II) onto MoS2 was a spontaneous, endothermic, and irreversible process. The EXAFS spectra revealed the coexistence of two sorption types. The inner-sphere complexation was formed in the form of Cd-S bond at lower pH (3.56, 6.48), while the Cd(OH)2 precipitation occurred in the form of Cd-O and Cd-Cd bonds at higher pH (9.57). These results provide new insights into the interaction mechanisms between metal ions and MoS2 nanosheets.

Key words: MoS2 nanosheets, pH, microstructure, EXAFS, cadmium(II)

中图分类号: