A new insight on the core-shell structure of zerovalent iron nanoparticles and its application for Pb(II) sequestration

JOURNAL OF HAZARDOUS MATERIALS

卷:263

Article

Zhang, Yalei^1,2  Su, Yiming¹  Zhou, Xuefei¹  Dai, Chaomeng^1,3  Keller, Arturo A.⁴ 

[1] Tongji Univ, State Key Lab Pollut Control & Resources Reuse, Shanghai 200092, Peoples R China

[2] Tongji Univ, Key Lab Yangtze Water Environm, Minist Educ, Shanghai 200092, Peoples R China

[3] Tongji Univ, Coll Civil Engn, Shanghai 200092, Peoples R China

[4] Univ Calif Santa Barbara, Bren Sch Environm Sci & Management, Santa Barbara, CA 93106 USA

关键词: Nanoscale zerovalent iron (nZVI);    Lead sequestration;    Core-shell structure;    Fe(OH)(3) shell;   

DOI  :  10.1016/j.jhazmat.2013.10.031

来源: Elsevier

【 摘 要 】

Nanoscale zerovalent iron (nZVI) has shown a high efficacy for removing heavy metals from liquid solution. However, its removal capacity has not been fully explored due to its common shell composition (FeOOH). In this study, a much higher removal capacity of Pb(II) is observed (1667 mg Pb(II)/g Fe), which is over 100% higher than the highest removal capacity of nZVI reported before. High-resolution X-ray photoelectron spectroscopy (HR-XPS) reveals that through restricting the dehydration process of Fe(OH)(3), nZVI can acquire a unique shell, which is composed of 45.5% Fe(OH)(3) and 54.5% FeOOH. The presence of Fe(OH)(3) suppresses the reduction of Pb(II), but greatly promotes the co-precipitation and adsorption of Pb(II). Combining the ratio of Fe-released to Pb-immobilized and the result of HR-XPS, a reaction between Fe core, Fe(OH)(3), and Pb(II) is proposed. The Fe released from the Fe core leads to the core depletion, observed by transmission electron microscopy (TEM) under high Pb(II) loading. While temperature has little influence on the removal capacity, pH affects the removal capacity greatly. pH < 4.5 favors Fe dissolution, while pH > 4.5 promotes Pb(II) adsorption. Given the high Pb removal capacity via the Fe(OH)(3) shell, nZVI can be used to remedy Pb(II) contamination. (C) 2013 Elsevier B.V. All rights reserved.

【 授权许可】

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