三维层级花状活性氧化铝纳米材料的制备及其除砷性能研究

3D Hierarchical Flower Like Alumina Nanomaterials:Preparation and Arsenic Removal Performance

以硝酸铝和尿素为原料,通过简单的水热和高温煅烧法自组装形成三维层级花状活性氧化铝。这种结构既保留了氧化铝丰富的纳米级别活性位点,同时具有微米级的三维尺寸,在柱吸附除砷实验中起到骨架支撑作用,而其较大的比表面积可以确保水中的砷酸根离子与吸附位点充分接触,从而有效吸附水中砷酸根离子,相较商用活性氧化铝具有更好的除砷性能,且不会对水体产生二次污染。对制备的活性氧化铝材料的除砷动力学进行了分析,明确了吸附动力学准一级和准二级模型的应用条件和范围。通过对该材料吸附砷酸根前后Zeta电位的变化的研究和离子强度实验进一步验证发现,γ-Al2O3对As(V)的吸附机理遵循内球配位模型,而对As(III)的吸附机理遵循外球配位模型。

A 3D flower-like active alumina material was synthesized through a simple hydrothermal method following by calcination at 500 ℃. This structure retains abundant nanoscale active sites and micro-scale 3D size. In the column adsorption test, when the arsenic-contaminated water flows through the material, this 3D hierarchical structure not only serves as a skeleton support, but also provides adsorption site with larger specific surface area so that the arsenate ion can be fully adsorbed. The synthesized alumina in this study performs better arsenic removal than the commercial one without secondary pollution in the water body. The arsenic removal kinetic tests clarify the application conditions of the pseudo first- and second-order adsorption kinetic models. Zeta potential and ionic strength reveal that the mechanism of adsorption of As (V) on γ-Al2O3 follows the inner spherical model, while the adsorption of As (Ⅲ) follows the outer spherical model.