Application of oxidized multi-wall carbon nanotubes for Th(IV) adsorption

Th(IV) adsorption onto oxidized multi-wall carbon nanotubes (MWCNTs) was carried out at 293±2K. The effects of MWCNT concentration, pH, and ionic strength were studied. The results showed that Th(IV) adsorption onto oxidized MWCNTs strongly depended on MWCNT concentration and pH, and was weakly dependent on ionic strength. Oxidized MWCNTs showed a higher Th(IV) adsorption capacity than as-grown MWCNTs. The adsorption process followed pseudo second order kinetics. The Freundlich isotherm model described the data better than the Langmuir model. The adsorption mechanism of Th(IV) may be surface complexation. Oxidized MWCNTs may be a promising candidate for the concentration of Th(IV), or its analogue actinides from large volumes.