Copper removal using bio-inspired polydopamine coated natural zeolites

J Hazard Mater. 2014 May 30:273:174-82. doi: 10.1016/j.jhazmat.2014.03.048. Epub 2014 Mar 29.


Herein, for the first time, natural clinoptilolite-rich zeolite powders modified with a bio-inspired adhesive, polydopamine (PDA), have been systematically studied as an adsorbent for copper cations (Cu(II)) from aqueous solution. Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) revealed successful grafting of PDA onto the zeolite surface. The effects of pH (2-5.5), PDA treatment time (3-24h), contact time (0 to 24h) and initial Cu(II) ion concentrations (1 to 500mgdm(-3)) on the adsorption of Cu(II) ions were studied using atomic absorption spectroscopy (AAS) and neutron activation analysis (NAA). The adsorption behavior was fitted to a Langmuir isotherm and shown to follow a pseudo-second-order reaction model. The maximum adsorption capacities of Cu(II) were shown to be 14.93mgg(-1) for pristine natural zeolite and 28.58mgg(-1) for PDA treated zeolite powders. This impressive 91.4% increase in Cu(II) ion adsorption capacity is attributed to the chelating ability of the PDA on the zeolite surface. Furthermore studies of recyclability using NAA showed that over 50% of the adsorbed copper could be removed in mild concentrations (0.01M or 0.1M) of either acid or base.

Keywords: Copper adsorption; Natural zeolites; Neutron activation analysis; Polydopamine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adsorption
  • Copper / chemistry*
  • Indoles / chemistry*
  • Particle Size
  • Polymers / chemistry*
  • Porosity
  • Surface Properties
  • Waste Disposal, Fluid / methods
  • Water Pollutants, Chemical / chemistry*
  • Zeolites / chemistry*


  • Indoles
  • Polymers
  • Water Pollutants, Chemical
  • polydopamine
  • Zeolites
  • Copper