The influence of pH, contact time, ionic strength, temperature, and fullerene on the adsorption of Cu(II) onto magnetic multi-walled carbon nanotubes

Abstract

The influences of pH, contact time, absorbent dose, temperature and C₆₀(C(COOH)₂)_n on Cu(II) adsorption onto the magnetic multi-walled carbon nanotubes (MMWCNTs) were studied by batch technique. The dynamic process showed that the adsorption of Cu(II) onto MMWCNTs matched well with the pseudo-second-order kinetics model. The adsorption of Cu(II) onto MMWCNTs was dependent on pH values significantly, the adsorption percentage increased observably at pH 5.0–7.0, and then maintained a steady state with pH increased. Through simulating the adsorption isotherms by Langmuir, Freundlich and Dubini-Radushkevich models, respectively, it could be seen that the adsorption pattern of Cu(II) onto MMWCNTs was mainly surface complexation. The presence of C₆₀(C(COOH)₂)_n could enhance the adsorption content of Cu(II) onto MMWCNTs at low pH, but restrained that at higher pH.

Keywords:

• adsorption
• carbon nanotube
• fullerene

Acknowledgments

The authors gratefully acknowledge support from the Foundation of Heilongjiang Postdoctoral Science Foundation (LBH-Z17050), the National Natural Science Foundation of China (21771045), the Fundamental Research Funds for the Central Universities (HEUCFG201842), and the Decommissioning of Nuclear Facilities and special funds for radioactive waste management ([2017]955).