The removal of U(VI) from aqueous solution by oxidized multiwalled carbon nanotubes.
Multiwalled carbon nanotubes (MWCNTs) have exhibited high sorption capacity for radionuclides due to the unique hollow structure and large surface area. In this study, surface properties of oxidized MWCNTs were characterized by using XRD, SEM, FTIR and potentiometric acid-base titration. The sorption of U(VI) on oxidized MWCNTs as a function of contact time, U(VI) concentration, pH, ionic strength, humic acid/fulvic acid (HA/FA) and carbonate was investigated by using batch technique. The removal of U(VI) by oxidized MWCNTs was strongly dependent on pH and ionic strength. The presence of HA/FA enhanced U(VI) removal on oxidized MWCNTs at low pH while inhibited U(VI) sorption at high pH. The mechanism of U(VI) sorption on oxidized MWCNTs was assumed to be cation exchange/outer-sphere surface complexation in acidic pH and to form precipitation under circum neutral conditions. The oxidized MWCNTs exhibit higher sorption capacity and stronger chemical affinity than pristine MWCNTs.
Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, 230031 Hefei, PR China. sunyubing@126.com
Yubing
Y
Sun
Shitong
S
Yang
Guodong
G
Sheng
Zhiqiang
Z
Guo
Xiangke
X
Wang
D001578:Benzopyrans / Q000737:chemistry; D002254:Carbonates / Q000737:chemistry; D006812:Humic Substances; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D011199:Potentiometry; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013997:Time Factors; D014501:Uranium / Q000737:chemistry* / Q000302:isolation & purification; D018505:Waste Management
D001578:Benzopyrans; D002254:Carbonates; D006812:Humic Substances; D037742:Nanotubes, Carbon; D012996:Solutions; D014501:Uranium; C005023:fulvic acid