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Preparation and Properties of Ion-Imprinted Hollow Particles for the Selective Adsorption of Silver Ions
journal contribution
posted on 2015-02-03, 00:00 authored by Hongbin Hou, Demei Yu, Guohe HuFour
kinds of silver ion-imprinted particles (Ag-IIPs) with different morphologies
were prepared by the surface ion-imprinting technology (SIIT) and
were used for the selective removal and concentration of silver ions
from wastewater. The favorable adsorptivity and selectivity of Ag-IIPs
for Ag+ were confirmed by a series of adsorption experiments
at a suitable pH value. The adsorption mechanism was elucidated by
analyzing the adsorption isotherms, adsorption thermodynamics, and
adsorption kinetics systematically. The Ag+ adsorption
onto the Ag-IIPs was well-described by the Langmuir isotherm model,
and it was likely to be a monolayer chemical adsorption. This conclusion
was also confirmed by the thermodynamic parameters. Moreover, the
adsorption kinetics indicated that the adsorption rate would be controlled
jointly by the intraparticle diffusion and the inner surface adsorption
process, and the latter process was generally associated with the
formation and breaking of chemical bonds. Finally, the effects of
different morphologies of the Ag-IIPs for Ag+ adsorption
were also investigated. In aqueous solution, the adsorptivity of the
Ag+ ion-imprinting single-hole hollow particles (Ag-IISHPs)
for Ag+ was highest (80.5 mg g–1) because
of a specific morphology that features a single hole in the shell.
In an oil–water mixture, Ag+ in the water phase
could be adsorbed efficiently by the Ag+ ion-imprinting
Janus hollow particles (Ag-IIJHPs), with emulsifiability originating
from the Janus structure.