Background: Although molecularly imprinted polymers (MIPs) have now been widely
utilized for the sample pre-treatment, chromatography separation and removal of pollutants, conventional
MIPs still lack satisfactory compatibility with water, thus leading to poor molecular recognition
for target analytes in aqueous solutions. The aim of the study was to prepare water-compatible
Methods: The zwitterionic MMIPs were synthesized on vinyltrimethoxysilane-coated Fe3O4
(Fe3O4-VTMS) through a surface imprinting process by using levofloxacin (LEV) as a template,
[2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide (SPE) as a functional
monomer, N, N-methylene-bis-acrylamide (MBA) as a crosslinker and potassium persulfate as an
Results: The prepared zwitterionic LEV-MMIPs were characterized by Fourier transform infrared
spectrometry, X-ray diffraction, vibrating sample magnetometry, scanning electron microscopy and
water contact angle test. The characterization results showed that zwitterionic LEV-MMIPs exhibited
good magnetic responsiveness and super-hydrophilicity (the contact angle is 0°). The optimum pH
for binding LEV was found to be 6.0 and the binding isotherm followed the Langmuir isotherm
model of monolayer adsorption. The binding process was very fast and the pseudo-second-order
model fitted well with the kinetic data. The adsorption capacity of these zwitterionic MMIPs was
54.30 mg g-1 with a selectivity factor of 1.6 compared to the magnetic non-imprinted polymers
(MNIPs). Their feasibility for removing fluoroquinolones (FQs) from the environmental sample was
demonstrated using pearl river water spiked with LEV, gatifloxacin, ciprofloxacin and lomefloxacin.
The zwitterionic LEV-MMIPs could be reused at least five times with a removal efficiency of more
than 80% for the selected FQs.
Conclusion: The prepared zwitterionic LEV-MMIP is a promising sorbent for rapid, selective and
efficient removal of fluoroquinolones from aqueous medium.