Herein,
the hydrophobic carboxyl-functionalized ionic liquid (IL-COOH)
was encapsulated into the prepared Fe3O4@Zr-MOFs,
and the novel water-stable IL-COOH/Fe3O4@Zr-MOF
nanocomposites were first synthesized. The polydopamine-functionalized
Fe3O4 was introduced to construct the core–shell
structure via layer-by-layer modification, and the controlled growth
of Zr-MOFs was achieved, which realized the adjustment of charged
properties of nanocomposites and simplified the adsorption or extraction
process. The IL-COOH/Fe3O4@Zr-MOFs were fully
studied by IR, HNMR, XRD, N2 adsorption–desorption
isotherms, TEM, EDS mapping, VSM, and so on. Then, they were employed
for the selective adsorption and detection of fluoroquinolone antibiotics
(FQs). The adsorption isotherms and kinetics demonstrated that the
adsorption process followed a pseudo-second-order kinetic model and
the Langmuir isotherm model. Among them, IL-COOH/Fe3O4@UiO-67-bpydc showed the best adsorption performance, and
the maximum adsorption capacity of ofloxacin was 438.5 mg g–1. Coupled magnetic solid-phase extraction with HPLC-DAD, a convenient,
sensitive, and efficient method for extraction and detection of FQs
in environmental water, was developed based on IL-COOH/Fe3O4@UiO-67-bpydc. The recoveries of environmental water
were ranging from 90.0 to 110.0%, and the detection limits were lower
than 0.02 μg L–1. The novel functionalized
composites served as solid-phase adsorbents and liquid-phase extractants.
This study also provided a promising strategy for designing and preparing
multi-functionalized nanocomposites for the removal or detection of
pollutants in environmental samples.