膨润土负载纳米零价铁去除水中铅的研究

将纳米零价铁通过液态还原法负载于膨润土上，目的是为了比较负载对提高纳米零价铁去除重金属铅的能力的影响。从负载后扫描电镜图像中可以看出，负载后的纳米零价铁分散度更好。在相同投加量下，负载了纳米零价铁的膨润土对重金属铅的去除能力要远高于膨润土和纳米零价铁。铅的起始浓度为200mg／L，膨润土＋纳米零价铁的复合材料在0．4g／L的投加量下，去除率就达到90％以上。对材料的动力学研究结果则表明：纳米零价铁的反应速度较快，大部分的铅的去除都在1h以内完成。将吸附动力学实验结果进行一级和二级动力学反应拟合。二级拟和的线性相关系数明显高于一级。说明纳米零价铁和膨润土＋纳米零价铁复合材料与铅的反应更符合二级动力学反应假设。另外，纳米零价铁对铅的去除受到起始浓度的影响较大，而膨润土＋纳米零价铁则基本不受起始浓度的影响。

Removal of lead in water by nano zero valent iron loaded on bentonite

Nano zero valent iron was impregnated onto bentonite by an aqueous reduction method in this research. The purpose was to compare the effect of impregnation on nano zero valent iron~ ability to re- move lead. SEM images show that impregnated nano zero valent iron manifests a higher level of disper- sion. With the same dosage, bentonite impregnated with nano zero valent iron exhibits much higher re- moval of lead than bentonite and zero valent iron alone. Bentonite ＋ nano zero valent iron was able to re- moval 90% of lead at initial concentration of 200 mg/L and dosage of 0.4g/L. The results of kinetics study reveal that the reaction between lead and nano zero valent iron is quite fast. Most of the lead remov- al occurr within one hour. The result of adsorption kinetics experiment is fitted to both first - order and second - order kinetics. The linear correlation coefficient of second - order kinetics is higher than that of first -order kinetics. Based on correlation coefficients, reactions between nano zero valent iron and ben- tonite ＋ nano zero valent iron with lead are more in accordance with second - order, after data were. In addition, zero valent iron~ removal of lead is more impacted by initial lead concentration but the concen- tration has little effect on bentonite ＋ nano zero valent iron.