纳米零价铁液相还原制备及其对水中Pb^(2+)的去除作用

Nano zero-valent iron preparation by using method of liquid phase reduction and its removal to Pb^(2+)

为研究液相还原法制备的纳米零价铁去除Pb^(2+)的机理,在液相还原法的基础上加入有机高分子材料,制备纳米零价铁;利用扫描电镜(SEM)和X射线衍射(XRD)对其进行表征;研究不同时间时离子初始浓度和溶液初始p H值对纳米零价铁去除Pb^(2+)的影响。结果表明:纳米零价铁对Pb^(2+)的去除在120 min内基本达到平衡,当Pb^(2+)初始浓度为50、100 mg/L、纳米零价铁添加量为1 g/L时,Pb^(2+)去除率达99%以上;p H值从2.0增大至3.0时,Pb^(2+)的去除率从41.47%增大至73.58%;p H值从3.0增大至4.0时,Pb^(2+)去除率从73.58%增大至92.62%;动力学拟合结果表明,纳米零价铁去除Pb^(2+)的过程符合准二级动力学模型;纳米零价铁去除Pb^(2+)的机制主要是氧化还原和共沉淀。

In order to clarify the removal effect and mechanism of Pb^2＋from water,the nano zero-valent iron（NZVI） was prepared by the method of liquid phase reduction. NZVI was prepared by liquid phase reduction with addition of organic polymer material. The characteristics of NZVI was investigated using scanning electron microscope（SEM） and X-ray diffraction（XRD）. The experiment was conducted to investigate the influence of initial ion concentration and solution initial p H value on removal of Pb^2＋with time changing, and clarify the removal effect and mechanisms of Pb^2＋from water using NZVI. The results show that the reaction equilibrium achieves within 120 min and the removal rate of Pb^2＋is more than 99% when the Pb^2＋initial concentration is 50 and 100mg/L and the addition of NZVI is 1 g/L. The removal ratio of Pb^2＋increased from 41.47% to 73.58% while solution initial p H value increase from 2 to 3, and from 73.58% to 92.62% initial p H value from 3 to 4. The results also indicate that the removal of Pb^2＋by NZVI is suitable for pseudo second-order model and it is mainly conducted by the redox reaction and co-precipitation.