【摘要】 零价纳米铁由于其高反应活性及应用中的灵活性,在地下水原位治理中备受关注.但在应用中,常需要加入分散剂以提高纳米铁悬浮液的稳定性.因此,本文以低浓度的聚苯乙烯磺酸钠(PSS)作为分散剂,制备了能长时间稳定的复合零价纳米铁(nZVI/PSS)悬浮液,并探讨PSS对nZVI表面结构和去除As(Ⅲ)过程中的影响.结果表明,nZVI和nZVI/PSS颗粒平均粒径均为50～60nm;X射线光电子能谱(XPS)结果表明,相比于nZVI,nZVI/PSS表面上C、OH-和O2-的百分含量增高,而吸附的H2O减少;X-射线衍射(XRD)结果显示,nZVI/PSS在44.8°出现α-Fe0的X射线衍射峰,结晶度比nZVI显著提高.批实验结果表明,As(Ⅲ)的去除率随nZVI(nZVI/PSS)投加量的增大而提高,随溶液初始pH的增大而降低,且nZVI/PSS对As(Ⅲ)的去除率略低于nZVI.动力学拟合结果显示,nZVI和nZVI/PSS对As(Ⅲ)的去除符合准一级反应动力学方程.更多还原

【Abstract】 Due to its high reactivity and flexibility, nanoscale zero-valent iron (nZVI) has drawn extensive attention in in-situ groundwater treatment in the past ten years. In this paper, poly(styrenesulfonate) (PSS) was chosen as dispersant to prepare stable nZVI/PSS slurry and the impacts of PSS on nZVI surface and during As(Ⅲ) removal process were investigated. TEM, XPS, and XRD studies indicated that after modified with low dose of PSS, nZVI/PSS kept the shape and size of nZVI. However, the percentage of C, OH-, and O2- increased, while the adsorbed H2O decreased compared to that of nZVI. In addition, Fe(0) existed as α-Fe0 at nZVI/PSS surface instead of amorphous Fe(0) at nZVI surface. Batch experiments showed that the removal rate of As(Ⅲ) by both nZVI/PSS and nZVI increased with increasing dosage of nZVI or nZVI/PSS) and decreased with increasing pH. The reactions fit in pseudo-first-order kinetics. Overall, the reactivity of nZVI/PSS with As(Ⅲ) is excellent although a little bit lower than that of nZVI.更多还原