Environmental condition effects on radionuclide 64Cu(II) sequestration to a novel composite: polyaniline grafted multiwalled carbon nanotubes

Abstract

This work examines the sequestration of 64Cu(II) by sorption process onto plasma-induced polyaniline (PANI)-grafted multiwalled carbon nanotubes (denoted as MWCNTs/PANI) prepared by an plasma-induced grafting technique. The role of a variety of environmental conditions such as pH, ionic strength, natural organic matter (NOM) in the sorption of 64Cu(II) onto MWCNTs/PANI is studied. The results indicate that the sorption is strongly dependent on pH but independent of ionic strength. A positive effect of NOM on 64Cu(II) sorption is found at pH 7.5. The sorption isotherms in the absence and presence of NOM can be better described by Freundlich model than Langmuir model. Sorption isotherms of 64Cu(II) at higher initial NOM concentrations are higher than those at lower NOM concentrations. The thermodynamic data calculated from temperature-dependent sorption suggest that the sorption is spontaneous and enhanced at higher temperature. Results of this work suggest that MWCNTs/PANI may be a promising candidate for cost-effective treatments of 64Cu(II)-contaminated wastewaters.