纳米TiO_2花式分层微球的合成及其对Pb(Ⅱ)的吸附性能

Synthesis of flower-like TiO_2 hierarchical spheres and its adsorption properties of Pb(Ⅱ)

利用仿生合成的方法,以甘氨酸为模板剂、钛酸正四丁酯作钛源,水热合成一种新型纳米TiO2花式微球,并对其进行了表征。通过考察pH值、温度和Pb(Ⅱ)溶液的初始浓度对吸附效果的影响,研究了TiO2花式微球对水溶液中Pb(Ⅱ)的吸附性能及其吸附动力学特性。结果表明,纳米TiO2花式微球直径约2μm,平均孔径约56 nm,比表面积约是270.3 m2/g;当pH值为4.0时TiO2花式微球对溶液中Pb(Ⅱ)吸附率达到最高,210 min时基本达到吸附平衡,20、30和40℃的最大吸附量分别为75.64、76.34和77.52 mg/g。吸附过程遵循准二级速率方程,与Langmuir等温式拟合更好。

Based on the principle of biomimetic synthesis, flower-like TiO2 hierarchical spheres assem- bled by nanosheets were synthesized by glycine assistant via a simple hydrothermal approach. Furthermore, the adsorption properties of flower-like TiO2 spheres on Pb（ Ⅱ） were studied, and the factors affecting the adsorption rate such pH, temperature, initial concentration of Pb（ II ） and reaction time were investigated. All the results showed that these flower-like spheres are about 2 μm in diameter with sheet thickness about 20 nm. The adsorption-desorption isotherms can be as certained as type IV, and specific surface area was a- bout 270.3 m2/g with pore diameter of about 56 nm. With pH increasing,the adsorption rate increased, while the pH was 4.0, the adsorption rate reached the highest point. As well, the adsorption reaction reached equilibrium at 210 min. The adsorption isotherm data could be better described by Langmuir model than Freundlich model. At 20℃ , 30℃ and 40℃ , the maximum adsorption amount can be expected to reach 76.34, 76.34 and 77.52 mg/g, respectively.