Coumarin-anchored halloysite nanotubes for highly selective detection and removal of Zn(II)
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.