title: Unveiling the adsorption mechanism of zeolitic imidazolate framework-8 with high efficiency for removal of copper ions from aqueous solutions.
abstract: Among the heavy metal ions, copper(ii) can cause eye and liver damage at high uptake. The existence of copper ions (Cu(2+)) even with an ultralow concentration of less than 0.1 μg g(-1) can be toxic to living organisms. Thus, it is highly desirable to develop efficient adsorbents to remove Cu(2+) from aqueous solutions. In this work, without any surface functionalization or pretreatment, a water-stable zeolitic imidazolate framework (ZIF-8) synthesized at room temperature is directly used as a highly efficient adsorbent for removal of copper ions from aqueous solutions. To experimentally unveil the adsorption mechanism of Cu(2+) by using ZIF-8, we explore various effects from a series of important factors, such as pH value, contact time, temperature and initial Cu(2+) concentration. As a result, ZIF-8 nanocrystals demonstrate an unexpected high adsorption capacity of Cu(2+) and high removal efficiency for both high and low concentrations of Cu(2+) from water. Moreover, ZIF-8 nanocrystals possess fast kinetics for removing Cu(2+) with the adsorption time of less than 30 min. In addition, the pH of the solution ranging from 3 to 6 shows little effect on the adsorption of Cu(2+) by ZIF-8. The adsorption mechanism is proposed for the first time and systematically verified by various characterization techniques, such as TEM, FTIR, XPS, XRD and SEM.
authors.affiliation: Key Laboratory of Magnetic Materials and Devices & Key Laboratory of Additive Manufacturing Materials of Zhejiang Province & Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China. aiguo@nimte.ac.cn.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Mechanical & Industrial Engineering, Louisiana State University, Baton Rouge, LA 70803, USA. ywang@lsu.edu.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Xie
authors.affiliation: Key Laboratory of Magnetic Materials and Devices & Key Laboratory of Additive Manufacturing Materials of Zhejiang Province & Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China. aiguo@nimte.ac.cn and Department of Chemistry, Anqing Normal College, Anqing, China.
authors.forename: Zhuqing
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Chemical & Biological Engineering, Colorado School of Mines, Golden, Colorado 80401, USA.
authors.forename: Xuhui
authors.initials: X
authors.lastname: Feng
authors.affiliation: Department of Mechanical & Industrial Engineering, Louisiana State University, Baton Rouge, LA 70803, USA. ywang@lsu.edu.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key Laboratory of Magnetic Materials and Devices & Key Laboratory of Additive Manufacturing Materials of Zhejiang Province & Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China. aiguo@nimte.ac.cn.
authors.forename: Aiguo
authors.initials: A
authors.lastname: Wu