Yu, Xin-Yao Luo, Tao Zhang, Yong-Xing Jia, Yong Zhu, Bang-Jing Fu, Xu-Cheng Liu, Jin-Huai Huang, Xing-Jiu Adsorption of Lead(II) on O<sub>2</sub>-Plasma-Oxidized Multiwalled Carbon Nanotubes: Thermodynamics, Kinetics, and Desorption O<sub>2</sub>-plasma-oxidized multiwalled carbon nanotubes (po-MWCNTs) have been used as an adsorbent for adsorption of lead(II) in water. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman spectroscopy measurements show that the bulk properties of MWCNTs were not changed after O<sub>2</sub>-plasma oxidation. The adsorption capacity of MWCNTs for lead(II) was greatly enhanced after plasma oxidation mainly because of the introduction of oxygen-containing functional groups onto the surface of MWCNTs. The removal of lead(II) by po-MWCNTs occurs rather quickly, and the adsorption kinetics can be well described by the pseudo-second-order model. The adsorption isotherm of lead(II) onto MWCNTs fits the Langmuir isotherm model. The adsorption of lead(II) onto MWCNTs is strongly dependent upon the pH values. X-ray photoelectron spectroscopy analysis shows that the adsorption mechanism is mainly due to the chemical interaction between lead(II) and the surface functional groups of po-MWCNTs. The thermodynamic parameters (Δ<i>H</i>°, Δ<i>S</i>°, and Δ<i>G</i>°) calculated from the adsorption isotherms suggest that the adsorption of lead(II) onto MWCNTs is endothermic and spontaneous. The regeneration performance shows that lead(II) can be easily regenerated from po-MWCNTs by altering the pH values of the solution. Raman spectroscopy measurements show;Scanning electron microscopy;MWCNT;Langmuir isotherm model;transmission electron microscopy;adsorption;pH values 2011-07-27
    https://acs.figshare.com/articles/journal_contribution/Adsorption_of_Lead_II_on_O_sub_2_sub_Plasma_Oxidized_Multiwalled_Carbon_Nanotubes_Thermodynamics_Kinetics_and_Desorption/2628184
10.1021/am2004202.s001