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  • Author or Editor: Zhiwei Niu x
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Abstract  

The sorption of Pb(II) from aqueous solution using NKF-5 zeolite was investigated by batch technique under ambient conditions. The NKF-5 zeolite sample was characterized by using FTIR and X-ray powder diffraction in detail. The sorption of Pb(II) was investigated as a function of pH, ionic strength, foreign ions, and humic substances. The results indicated that the sorption of Pb(II) on NKF-5 zeolite was strongly dependent on pH. The sorption was dependent on ionic strength at low pH, but independent of ionic strength at high pH. At low pH, the sorption of Pb(II) was dominated by outer-sphere surface complexation and ion exchange with H+ on NKF-5 zeolite surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. From the experimental results, one can conclude that NKF-5 zeolite has good potentialities for cost-effective preconcentration of Pb(II) from large volumes of aqueous solutions.

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Abstract  

The adsorption of Eu(III) on multiwalled carbon nanotubes (MWCNTs) as a function of pH, ionic strength and solid contents are studied by batch technique. The results indicate that the adsorption of Eu(III) on MWCNTs is strongly dependent on pH values, dependent on ionic strength at low pH values and independent of ionic strength at high pH values. Strong surface complexation and ion exchange contribute to the adsorption of Eu(III) on MWCNTs at low pH values, whereas surface complexation and surface precipitation are the main adsorption mechanism of Eu(III) on MWCNTs. The desorption of adsorbed Eu(III) from MWCNTs by adding HCl is also studied and the recycling use of MWCNTs in the removal of Eu(III) is investigated after the desorption of Eu(III) at low pH values. The results indicate that adsorbed Eu(III) can be easily desorbed from MWCNTs at low pH values, and MWCNTs can be repeatedly used to remove Eu(III) from aqueous solutions. MWCNTs are suitable material in the preconcentration and solidification of radionuclides from large volumes of aqueous solutions in nuclear waste management.

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