Adsorption of Cu(II) on oxidized multi-walled carbon nanotubes in the presence of hydroxylated and carboxylated fullerenes

• Published in: PloS one Vol. 8; no. 8; p. e72475
• Main Authors: Wang, Jing, Li, Zhan, Li, Shicheng, Qi, Wei, Liu, Peng, Liu, Fuqiang, Ye, Yuanlv, Wu, Liansheng, Wang, Lei, Wu, Wangsuo
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 29.08.2013; Public Library of Science (PLoS)
• Subjects: Adsorption; Buckminsterfullerene; Carbon; Carbon nanotubes; Chemical engineering; Chemistry; Composite materials; Computer simulation; Copper; Copper - chemistry; Earth Sciences; Endothermic reactions; Environmental science; Fullerenes; Fullerenes - chemistry; Functional groups; Hazardous materials; Hazardous substances; Heavy metals; Hydrogen ions; Hydrogen-Ion Concentration; Ionic strength; Isotherms; Laboratories; Materials Science; Multi wall carbon nanotubes; Nanomaterials; Nanoparticles; Nanotechnology; Nanotubes; Nanotubes, Carbon - chemistry; Nanotubes, Carbon - ultrastructure; Nickel; NUCLEAR PHYSICS AND RADIATION PHYSICS; Osmolar Concentration; Oxidation-Reduction; pH effects; Physics; Pollutants; Porosity; Researchers; Sorption; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman; Studies; Temperature; Thermodynamics; Zinc; China
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0072475

The adsorption of Cu(II) on oxidized multi-walled carbon nanotubes (oMWCNTs) as a function of contact time, pH, ionic strength, temperature, and hydroxylated fullerene (C60(OH)n) and carboxylated fullerene (C60(C(COOH)2)n) were studied under ambient conditions using batch techniques. The results showed that the adsorption of Cu(II) had rapidly reached equilibrium and the kinetic process was well described by a pseudo-second-order rate model. Cu(II) adsorption on oMWCNTs was dependent on pH but independent of ionic strength. Compared with the Freundlich model, the Langmuir model was more suitable for analyzing the adsorption isotherms. The thermodynamic parameters calculated from temperature-dependent adsorption isotherms suggested that Cu(II) adsorption on oMWCNTs was spontaneous and endothermic. The effect of C60(OH)n on Cu(II) adsorption of oMWCNTs was not significant at low C60(OH)n concentration, whereas a negative effect was observed at higher concentration. The adsorption of Cu(II) on oMWCNTs was enhanced with increasing pH values at pH < 5, but decreased at pH ≥ 5. The presence of C60(C(COOH)2)n inhibited the adsorption of Cu(II) onto oMWCNTs at pH 4-6. The double sorption site model was applied to simulate the adsorption isotherms of Cu(II) in the presence of C60(OH)n and fitted the experimental data well.