writer：Zhiyi Su, Hailei Zhang*, Yan Gao, Li Huo, Yonggang Wu and Xinwu Ba*
keywords：halloysite
source：期刊
specific source：Chemical Engineering Journal
Issue time：2020年

Development of a facile

tool for selective detection and separation of heavy metals present in aqueous

media is a demanding challenge in the chemosensing field. In this study, a

natural product, halloysite nanotube (HNT), which shows excellent

dispersibility in water, was selected as the scaffold to demonstrate

simultaneous detection and removal of Zn ions from aqueous solution. For this

purpose, HNTs were rationally integrated with coumarin moieties. The

nanocomposite was prepared by treating amino-functionalized HNTs with

7-hydroxy-4-methyl-2-oxo-2H-chromene-8-carbaldehyde (1) to give the C=N bond in

the spacer resulting in the formation of the Zn2+-sensitive

chemosensor (CHNTs). The successful modification was confirmed by FTIR, XPS,

solid-state NMR, TG and TEM analyses. The free CHNTs showed a weak fluorescence

signal, while a remarkable “turn on” behavior can be observed upon exposure to

Zn2+ ions of the concentration as low as 1×10-6 M. In

addition, CHNTs displayed excellent selectivity toward Zn2+ ions

over other metal cations. Moreover, the selective removal of Zn2+

ions from an aqueous solution containing various metal ions was achieved by

precipitation. The as-prepared CHNTs showing high efficiency and

selectivity on the detection and separation of Zn2+ will pave the

way towards novel approaches for the remediation of heavy metal pollution.