杨梅单宁为模板制备介孔氧化铝及其对水体中氟的吸附特性研究

Preparation of mesoporous alumina using bayberry tannin as template and its adsorption behaviors to fluoride in waste water

以杨梅单宁为模板,Al(NO3)3.9H2O为铝源制备了介孔Al2O3吸附材料,研究了介孔Al2O3对水体中氟的吸附特性。X-射线衍射分析表明,所制备的Al2O3的晶形为γ-Al2O3。N2-吸附/脱附分析表明,γ-Al2O3存在明显的介孔结构。吸附实验发现,在酸性条件下介孔γ-Al2O3对氟的吸附量较高;介孔γ-Al2O3对水体中氟的吸附量随温度的升高而增大,当初始氟离子浓度为95mg·L-1、温度为303K时的平衡吸附量达到58.28mg·g-1,而温度为323K时的平衡吸附量达到68.27mg·g-1,而且吸附等温线符合Langmuir方程。介孔γ-Al2O3对氟的吸附在前2h吸附较快,8h基本达平衡,吸附动力学符合拟二级速度方程。介孔γ-Al2O3吸附氟达平衡后经5mmol·L-1的NaOH溶液解吸,能将吸附的氟全部解吸,解吸后的介孔γ-Al2O3对氟的吸附能力基本不变,表现出良好的重复使用性能。

Mesoporous γ-Al2O3 adsorbent was prepared by using bayberry tannin as template and Al（NO3）3. 9H2O as aluminum source,and the adsorption behaviors of this novel adsorbent to fluoride in aqueous solution were also investigated. XRD analysis in-dicated that the crystal structure of as prepared Al2 O3 wasγ-Al2 O3 ,and N2 adsorption/desorption analysis confirmed that the meso-porous were obviously existed inγ-Al2 O3 . Adsorption experimental results indicated that the adsorption capacity of as prepared ad-sorbent to fluoride was higher at relative low pH. The adsorption capacity was increased as the increase of temperature. When the in-itial concentration of fluoride was 95mg·L-1 ,adsorption capacity was 58. 28mg·g-1 at 303K,while it was increased to 68. 27mg·g-1 at 323K. It was also found that the adsorption isotherms can be well described by the Langmuir equation. Furthermore,the adsorption rate of as prepared adsorbent to fluoride was very quickly at first 2 h and adsorption equilibrium was attended about 8 h,and its ad-sorption kinetics can be well fitted by using pseudo-second-order rate model. In addition,mesoporousγ-Al2 O3 can be easily regen-erated after saturated adsorption,exhibiting excellent repeated application property.