包埋纳米铁去除地下水中硝酸盐氮及铬污染

【摘要】 采用液相还原法制备纳米零价铁颗粒（nZVI）及包埋纳米铁,并采用扫描式电子显微镜和X射线衍射对其表面形貌、颗粒大小和结构性能进行表征。考察不同包埋比、DnZVI投加量、NO₃^--N初始浓度、pH等因素对NO₃^--N去除效果的影响,结果表明,硅藻泥与nZVI的最佳包埋比为5∶1;pH是影响DnZVI去除NO₃^--N的重要因素,较低pH有利于NO₃^--N的还原。在pH为3,NO₃^--N初始浓度为40 mg/L,DnZVI投加量为5 g/L的条件下,NO₃^--N的去除率为99%。实验考察了DnZVI对Cr（Ⅵ）在不同DnZVI投加量、Cr（Ⅵ）溶液初始浓度、pH、温度影响因素下的去除效果,并对材料的重复利用性进行实验。结果表明,在温度为25℃,pH为3,投加量为2 g/L,初始浓度为10 mg/L的条件下,DnZVI对Cr（Ⅵ）的去除效果最好,去除率为95.5%。DnZVI和nZVI材料重复利用3次后,DnZVI对Cr（Ⅵ）的去除率约为nZVI的4倍,DnZVI重复利用性更好。更多还原

【Abstract】 Nanoscale zero valent iron（nZVI） and diatom mud embedded nanoscale zero valent iron（DnZVI） were prepared by liquid phase reduction method,and the surface morphology,particle size and structural properties are characterized by scanning electron microscope（SEM）and X ray diffraction（XRD）. The effects of different embedding ratios,DnZVI dosage,initial concentration of NO₃^-N,pH and other factors on NO₃^-N removal were investigated. The results showed the optimum embedding ratio of diatom mud to nanoscale zero valent iron is 5:1;pH,which is an important factor affecting the removal of NO₃^--N by DnZVI,and the lower pH is beneficial to the reduction of NO₃^--N. When the pH is 3,the initial concentration of NO₃^--N is 40 mg/L,DnZVI dosage is 5 g/L,the removal rate of NO₃^--N was 99%. The effect of DnZVI in different DnZVI dosage,Cr（Ⅵ）solution initial concentration,pH,temperature on the removal of Cr （Ⅵ）were investigated. The reusability of the material was also studied. The results show that when the temperature is 25 ℃,the pH is 3,the dosage is 2 g/L,and the initial concentration is 10 mg/L,the removal efficiency of Cr（Ⅵ）by DnZVI was the best,and the removal rate was 95.5%. After three times reuse of DnZVI and nZVI,the removal rate of Cr （Ⅵ） by DnZVI was about 4 times than that of n ZVI,and the DnZVI reusability is better.更多还原