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Nanoscale dispersing of zero-valent iron on CaCO3 and their significant synergistic effect in high performance removal of lead

Author:
Zhang, Xiaodi, Shi, Dongyang, Li, Xiang, Zhang, Yajing, Wang, Jianji, Fan, Jing
Source:
Chemosphere 2019 v.224 pp. 390-397
ISSN:
0045-6535
Subject:
absorption, calcium carbonate, dispersibility, iron, lead, remediation, synergism, water pollution
Abstract:
Rapid aggregation and deactivation of nanoscale zero-valent iron (nZVI) hinder its application in environmental remediation. In this work, micro-scale CaCO3 is used as a dispersive carrier of nZVI to create a novel composite, CaCO3-supported nZVI (nZVI@CaCO3), through simplified liquid-phase reduction strategy. The morphology analysis shows that CaCO3 exhibits a fagot-like structure, and Fe0 particles are well dispersed on CaCO3 with an average diameter of around 15 nm. The removal of Pb(II) from water by nZVI@CaCO3 is studied, and it is found that the removal capacity of lead is as high as 3828 mg/g, which is much greater than that by neat CaCO3 (2209 mg/g) and bare nZVI (1308 mg/g). Owing to the loading of Fe (50%) in nZVI@CaCO3, a significant synergistic effect is observed between CaCO3 and nZVI in high performance removal of lead. Furthermore, a possible removal mechanism is proposed from a comparative investigation on the surface valence state and nZVI@CaCO3 phase before and after absorption of Pb(II). Considering the advantages of improved dispersibility, easy preparation and remarkable performance, the as-prepared nZVI@CaCO3 has the potential to become a promising remediation material for Pb(II) polluted water.
Agid:
6328995