聚乙烯亚胺
铝土矿
吸附
残留物(化学)
壳聚糖
渗滤液
化学
地穴
共价键
X射线光电子能谱
无机化学
核化学
化学工程
离子
环境化学
有机化学
工程类
物理化学
基因
生物化学
转染
作者
Feiping Zhao,Ziqi Yang,Zongsu Wei,Richard Spinney,Mika Sillanpää,Juntao Tang,Kam Chiu Tam,Ruiyang Xiao
标识
DOI:10.1016/j.cej.2020.124307
摘要
The separation and recovery of rare earth elements (REEs) from leachates of bauxite residue has attracted increasing attention. Yet, the characteristics of bauxite residue leachates (low pH, low concentration of REEs, and co-existence of other trivalent ions) results in a longstanding challenge in the recovery of REEs. Here, we reported on the development of polyethylenimine (PEI) modified chitosan materials as efficient adsorbents for REE, La(III). The introduction of PEI brought abundant protonatable amino nitrogen atoms, which endows materials with excellent buffering capacity at extremely acidic pH. The PEI-chitosan materials can easily separate La(III) from Al(III), a major co-existing ion, with a separation factor of 3.1. The single-metal adsorption behavior showed fast and efficient adsorption capacity of 2.015 mmol/g for La(III). In binary systems, La(III) was preferentially adsorbed over Al(III) due to the higher degree of association with PEI. The FT-IR, XPS and EDS mapping results revealed that in the binding mechanism the N atoms form coordination bonds with La(III) by sharing an electron pair, resulting in eight-membered chelate rings. The PEI-chitosan materials also exhibited an excellent reusability with regeneration efficiency of 90% after 4 recycles. Overall, PEI-chitosan demonstrates that it is a viable and economical material for the separation and preconcentration of REEs from leachates of bauxite residue.
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