Chinese Journal of Applied Chemistry ›› 2021, Vol. 38 ›› Issue (1): 84-91.DOI: 10.19894/j.issn.1000-0518.200294

• Full Papers • Previous Articles     Next Articles

Size Effect of ZIF-8 on the Adsorption of Uranium

TIAN Long1,4, DOU Wei-Xin2*, YANG Wei-Ting2*, WANG Cheng1,3*   

  1. 1State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China;
    2Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, School of Science, Hainan University, Haikou 570228, China;
    3Institute for New Energy Materials & Low-Carbon, Technologies Tianjin University of Technology, Tianjin, 300384, China;
    4University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2020-09-24 Revised:2020-10-07 Online:2021-01-01 Published:2021-02-01
  • Supported by:
    National Key Research and Development Project (No.2017YFA0700104), the National Natural Science Foundation of China (No.21571170) and the Natural Science Foundation of Tianjin (No.17JCZDJC000)

Abstract: ZIF-8, a classical metal-organic frameworks (MOFs) material, was used as an adsorbent to study the effect of particle size on its uranium adsorption performance. ZIF-8 particles with different sizes were synthesized by three methods, and characterized by scanning electron microscope (SEM), X-ray powder diffraction (XRD), surface area and porosity analyzer. The adsorption of ZIF-8 particles with different sizes for U(VI) from uranyl nitrate solution was tested under the same conditions. The parameters of adsorption isotherm and kinetics were calculated. The results show that ZIF-8 with high crystallinity and high purity is successfully prepared. The morphology of the product is rhombic dodecahedron, and the sizes of the particles are about 50 nm, 150 nm and 2 μm with narrow distributions. The three samples have single uniform micropore structures and their BET surface areas are highly related to the particle size. All the ZIF-8 particles with different sizes can quickly adsorb 90% of U(VI) from the initial concentration of 200 mg/L of U(VI) solution in 70 min (at room temperature, pH=3).The particles with smaller size (about 50 nm) show better adsorption performance, and the saturated adsorption capacity reaches 520.26 mg/g. The adsorption kinetics conforms to the second order kinetic equation, and the adsorption isotherm conforms to the Langmuir model, which indicate that the adsorption for U(VI) of ZIF-8 belongs to chemical monolayer adsorption. After 4 cycles of adsorption and desorption, their removal rates for U(VI) are still above 70%.

Key words: Size effect, ZIF-8, Nanostructures, Uranium adsorption

CLC Number: