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摘要
Titanium dioxide nanoparticles (nano-TiO2) were employed for the sorption of Te(IV) ions from aqueous solution. A detailed study of the process was performed by varying the sorption time, pH, and temperature. The sorption was found to be fast, equilibrium was reached within 8 min. When the concentration of Te(IV) was below 40 mg L-1. at least 97% of tellurium was adsorbed by nano-TiO2 in the pH range of 1-2 and 8-9. The sorbed Te(IV) ions were desorbed with 2.0 mL of 0.5 mol L-1 NaOH. The sorption data could be well interpreted by the Langmuir model with the maximum adsorption capacity of 32.75 mg g(-1) (20 +/- 0.1 degrees C) of Te(IV) on nano-TiO2. The kinetics and thermodynamics of the sorption of Te(IV) onto nano-TiO2 were also studied. The kinetic experimental data properly correlated with the second-order kinetic model (k(2) = 0.0368 g mg(-1) min(-1), 293 K). The overall rate process appeared to be influenced by both boundary layer diffusion and intra-particle diffusion. The mean energy of adsorption was calculated to be 17.41 kJ mol(-1) from the Dubinin-Radushkevich (D-R) adsorption isotherm at room temperature. Moreover, the thermodynamic parameters for the sorption were estimated, and the Delta H-0 and Delta G(0) values indicated the exothermic and spontaneous nature of the sorption process, respectively. Finally, Nano-TiO2 as sorbent was successfully applied to the separation of Te(IV) from the environmental samples with satisfactory results (recoveries >95%, relative standard deviations was 2.0%).
- 出版日期2010-12-15
- 单位辽宁大学
