Comparison of the effect of various carbon-based nanomaterials for the removal of Cu2+ ions from aqueous solutions

Water pollution caused by heavy metals is one of the most important issues threatening the environment. The study, presented here was focused on the removal of heavy metal Cu2+ ions from aqueous solution by using pristine multi-walled carbon nanotubes (p-MWCNT), acid treated MWCNTs (a-MWCNTs) and unzipped MWCNTs (u-MWCNTs). The size dependency of MWCNTs on the adsorption of Cu2+ ions was evaluated. Moreover, pH, adsorbent dosage, initial metal ion concentration and temperature effects on the adsorption process were explored. The maximum adsorption efficiency was found to be 98.5% for u-MWCNTs that is fabricated from the layered MWCNTs having an outer diameter of 50-80 nm and an inner diameter of 10-20 nm at 0.5 g L-1 adsorbent mass. The absorption kinetic data fitted best to the pseudo-second-order model. The thermodynamic assessments indicated that the adsorption was endothermic and randomness process. [GRAPHICS]