[Simultaneous Removal of Cd (II) and Phenol by Titanium Dioxide-Titanate Nanotubes Composite Nanomaterial Synthesized Through Alkaline-Acid Hydrothermal Method].
A composite nanomaterial, TiO2/TNTs, was synthesized by TiO2 (P25) through alkaline and acid hydrothermal reaction, which possessed both titanate nanotubes (TNTs) and TiO2 phase. It was found that the adsorption kinetics of Cd(II) onto TiO2/TNTs was very quick, and the adsorption could reach the equilibrium within 30 min. In addition, the maximum adsorption capacity of Cd(II) was as large as 120. 34 mg.g-1 calculated from Langmuir isotherm model. The adsorption mechanism of Cd(II) was ion-exchange between Cd2+ and Na+/H+ located in the interlayers of TNTs. However, the adsorption capacity of phenol on TiO2/TNTs was so small that the photocatalysis for phenol degradation was needed. In the adsorption-photocatalysis system, the removal efficiencies of Cd(II) and phenol could reach up to 99. 6% and 99.7%, respectively. Especially, removal of Cd(II) was attributed to adsorption by TNTs of the composite nanomaterial, while removal of phenol was resulted from photocatalytic reaction by the TiO2 phase. Moreover, the co-existing Cd(II) enhanced the photocatalytic degradation of phenol due to the enhancement on photocatalytic activity of TiO2/TNTs after Cd(II) was adsorbed. Co-existing Na+ did not show obvious effect on the co-removal of Cd(II) and phenol by TiO2/TNTs, but adsorption of Cd(II) was inhibited in the presence of Ca2+ as it could compete for the adsorption sites and enhance the aggregation of the material. Furthermore, TiO2/TNTs could be efficiently reused after desorption via HNO3 and regeneration via NaOH, and the removal efficiencies of Cd(II) and phenol were still as high as 91. 7% and 98. 1% even after three cycles. This study proposed a method to synthesize a material which had both adsorptive and photocatalytic performance, and it was of great importance for application of nanomaterials in the simultaneous removal of heavy metals and organic pollutants.
Li
L
Lei
Yin-jia
YJ
Jin
Ting
T
Wang
Xiao
X
Zhao
You
Y
Yan
Wen
W
Liu
D000327:Adsorption; D002104:Cadmium / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007474:Ion Exchange; D043942:Nanotubes / Q000737:chemistry*; D010636:Phenols / Q000302:isolation & purification*; D014025:Titanium / Q000737:chemistry*
D010636:Phenols; D002104:Cadmium; C009495:titanium dioxide; D014025:Titanium