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

Wang J, Li Z, Li S, Qi W, Liu P, Liu F, Ye Y, Wu L, Wang L, Wu W - PLoS ONE (2013)

Bottom Line: 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 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.

View Article: PubMed Central - PubMed

Affiliation: Radiochemistry Laboratory, School of Nuclear Science and Technology, Lanzhou University, Lanzhou, PR China.

ABSTRACT
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.

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Effect of Cu(II) initial concentrations on Cu(II) adsorption onto oMWCNTs as a function of C60(C(COOH)2)n initial concentrations, m/V  = 0.5 g/L, pH = 5.50±0.10, I = 0.01 mol/L NaCl, T = 25±1°C.
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pone-0072475-g013: Effect of Cu(II) initial concentrations on Cu(II) adsorption onto oMWCNTs as a function of C60(C(COOH)2)n initial concentrations, m/V  = 0.5 g/L, pH = 5.50±0.10, I = 0.01 mol/L NaCl, T = 25±1°C.

Mentions: Likewise, the influence of C60(C(COOH)2)n on Cu(II) adsorption onto oMWCNTs are evaluated at different initial concentrations of Cu(II) and concentration of oMWCNTs at pH 5.5±0.05. The results are shown in Figure 13 and Figure 14. The adsorbed Cu(II) reduces slightly with the increasing concentration of C60(C(COOH)2)n. This shows that the inhibition mode of C60(C(COOH)2)n and C60(OH)n are essentially different. Although C60(C(COOH)2)n and C60(OH)n can be adsorbed to the sidewalls of oMWCNTs by the π-π interaction, the species and the connecting styles of surface functional groups introduced on C60 vary from each other, leading to declining Cu(II) adsorption on the surface of oMWCNTs to varying degrees.


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

Wang J, Li Z, Li S, Qi W, Liu P, Liu F, Ye Y, Wu L, Wang L, Wu W - PLoS ONE (2013)

Effect of Cu(II) initial concentrations on Cu(II) adsorption onto oMWCNTs as a function of C60(C(COOH)2)n initial concentrations, m/V  = 0.5 g/L, pH = 5.50±0.10, I = 0.01 mol/L NaCl, T = 25±1°C.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3756995&req=5

pone-0072475-g013: Effect of Cu(II) initial concentrations on Cu(II) adsorption onto oMWCNTs as a function of C60(C(COOH)2)n initial concentrations, m/V  = 0.5 g/L, pH = 5.50±0.10, I = 0.01 mol/L NaCl, T = 25±1°C.
Mentions: Likewise, the influence of C60(C(COOH)2)n on Cu(II) adsorption onto oMWCNTs are evaluated at different initial concentrations of Cu(II) and concentration of oMWCNTs at pH 5.5±0.05. The results are shown in Figure 13 and Figure 14. The adsorbed Cu(II) reduces slightly with the increasing concentration of C60(C(COOH)2)n. This shows that the inhibition mode of C60(C(COOH)2)n and C60(OH)n are essentially different. Although C60(C(COOH)2)n and C60(OH)n can be adsorbed to the sidewalls of oMWCNTs by the π-π interaction, the species and the connecting styles of surface functional groups introduced on C60 vary from each other, leading to declining Cu(II) adsorption on the surface of oMWCNTs to varying degrees.

Bottom Line: 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 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.

View Article: PubMed Central - PubMed

Affiliation: Radiochemistry Laboratory, School of Nuclear Science and Technology, Lanzhou University, Lanzhou, PR China.

ABSTRACT
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.

Show MeSH
Related in: MedlinePlus