Efficient removal of heavy metal ions from aqueous systems with the assembly of anisotropic layered double hydroxide nanocrystals@carbon nanosphere

Environ Sci Technol. 2011 Jul 15;45(14):6181-7. doi: 10.1021/es200668q. Epub 2011 Jun 21.

Abstract

We report on the efficient removal of heavy metal ions from simulated wastewater with a nanostructured assembly. The nanoassembly was obtained via direct assembling the performed anisotropic layered double hydroxide nanocrystals (LDH-NCs) onto the surface of carbon nanospheres (labeled as LDH-NCs@CNs). It was found that the maximum adsorption capacity of the nanoassembly toward Cu(2+) was ∼ 19.93 mg g(-1) when the initial Cu(2+) concentration was 10.0 mg L(-1), displaying a high efficiency for the removal of heavy metal ions. The Freundlich adsorption isotherm was applicable to describe the removal processes. Kinetics of the Cu(2+) removal was found to follow pseudo-second-order rate equation. Furthermore, the as-prepared building unit of the assembly, including LDH-NCs, CNs, and the assembly, as well as Cu(2+)-adsorbed assembly, were carefully examined by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), nitrogen sorption measurements, and X-ray photoelectron spectroscopy (XPS). Based on the characterization results, a possible mechanism of Cu(2+) removal with the assembly of LDH-NCs@CNs was proposed. Comparison experiments show that the adsorption capacity of the resulting LDH-NCs@CNs assembly was much higher than its any building unit alone (CNs or LDH-NCs), exhibiting the deliberation of the assembly on water decontamination. This work provides a very efficient, fast and convenient approach for exploring promising nanoassembly materials for water treatment.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adsorption
  • Anisotropy
  • Hydroxides / chemistry*
  • Kinetics
  • Metals, Heavy / analysis
  • Metals, Heavy / isolation & purification*
  • Microscopy, Electron, Transmission
  • Models, Chemical
  • Nanoparticles / chemistry*
  • Nanospheres / chemistry*
  • Photoelectron Spectroscopy
  • Spectroscopy, Fourier Transform Infrared
  • Waste Disposal, Fluid / methods*
  • Water Pollutants, Chemical / analysis
  • Water Pollutants, Chemical / isolation & purification*
  • Water Purification / methods*

Substances

  • Hydroxides
  • Metals, Heavy
  • Water Pollutants, Chemical