磷酸化纳米铁去除水中Cd2+、Zn2+、Ni2+的比较
Investigation on the removal of Cd2+,Zn2+,Ni2+from water by phosphorylated nanoscale zero-valent iron
王欣瑶 1盛杰 1邹云杰 1凌岚1
作者信息
- 1. 污染控制与资源化研究国家重点实验室,同济大学环境科学与工程学院,上海污染控制与生态安全研究院,上海,200092
- 折叠
摘要
重金属污染已成为全球关注的环境问题,镉、镍和锌是工业生产中常见的重金属污染.纳米零价铁是重金属污染控制的重要环境功能材料,其改性优化工作也备受关注.本文采用液相还原法在制备过程中添加 KH2PO4 合成磷酸化纳米铁(phosphorylated nanoscale zero-valent iron,P-nZVI),考察了磷酸化对纳米铁去除Cd2+、Zn2+、Ni2+的效果的影响,评估了磷酸化对抗pH、干扰离子影响的效果,并结合XRD、SEM、S/TEM、XPS等表征手段比较了 P-nZVI去除3种重金属的作用机制.研究表明,P-nZVI对Cd2+、Zn2+的去除效率均显著优于纳米零价铁(nanoscale zero-valent iron,nZVI),分别为79.6％、90.6％.吸附过程以P-nZVI表面磷酸基团的吸附为主,均可用准二级动力学描述.Ni2+的去除包括吸附和还原作用,加剧了铁芯腐蚀,使其去除效率达到92.6％.因此,磷酸化修饰能通过累积零价铁表面负电荷以加速吸附过程;裂纹结构能降低金属离子跨越氧化铁层的阻碍,促进氧化还原,提高Fe0利用率.
Abstract
Heavy metal pollution has become an environmental issue raising global concern,and cadmium,nickel and zinc are common heavy metal pollution in industrial production.Nano zero-valent iron is an important environmental functional material for heavy metal pollution removal,and its modification as well as optimization have attracted much attention.In this study,we prepared phosphorylated nanoscale zero-valent iron(P-nZVI)by liquid-phase reduction using NaBH4,FeCl3-6H2O in the presence of KH2PO4.The performances of P-nZVI on the removal of Cd2+,Zn2+,Ni2+were examined and the effects of initial solution pH and interfering ions were also investigated.Several characterization techniques were adopted to explore the morphology,structure and interface characteristics of P-nZVI including scanning electron microscopy(SEM),scanning transmission electron microscopy(STEM)integrated with energy-dispersive X-ray spectrometry(EDS),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).The results indicated that the removal efficiency of P-nZVI was significantly improved than that of nanoscale zero-valent iron(nZVI)for both Cd2+and Zn2+with 79.6％and 90.6％,respectively.The removal process was dominated by the adsorption of phosphate groups on the surface of P-nZVI,and both could be described by quasi-secondary kinetics.Unlike Cd2+and Zn2+,removal of Ni2+involved adsorption and reduction,with increased corrosion of internal iron core,resulting in a high removal efficiency of 92.6％.In summary,the advantages of phosphorylated zero-valent iron nanoparticles are described as follows:phosphate groups can accelerate the adsorption process resulting from more negative charge on the zero-valent iron surface;the cracked structure can reduce the barrier of metal ions across the iron oxide layer,promote e-transfer and improve utilization of Fe0.
关键词
纳米铁/磷酸化修饰/重金属/吸附/氧化还原Key words
nanoscale zero-valent iron/phosphorylation/heavy metal/adsorption/redox reaction引用本文复制引用
基金项目
国家自然科学基金(22176147)
国家自然科学基金优秀青年基金(21822607)
出版年
2024
NETL
NSTL
万方数据