Abstract
Fluoroquinolones (FQs) are a class of antibiotics mainly used in public health and veterinary
medicine to address bacterial infections. Furthermore, they are used as feed supplements to
promote growth in animal husbandry. However, even though they are useful, their disposal
in the water bodies poses a risk to human health and the ecosystem due to the development
of antibiotic-resistant bacteria. FQs detection in complex matrices, such as wastewater, is
considered challenging due to their presence at trace levels. Thus, different sample
pretreatment methods have been explored for sample enrichment. Sample preparation is
primarily essential for eliminating sample interferences through clean-up and enrichment of
samples. Moreover, various methods were used for the removal of FQs in wastewater. To
date, adsorption has demonstrated itself to be a highly effective method for removing FQs
in various water matrices. This work focuses on the synthesis of Fe3O4@SiO2 and
Fe3O4@SiO2-cellulose-chitosan as efficient, sustainable, and cost-effective adsorbent
materials for the preconcentration and removal of FQs in various wastewater matrices. The
prepared adsorbents were used for the preconcentration and removal of selected FQs through
dispersive magnetic solid phase extraction (DMSPE) coupled with high-performance liquid
chromatography with diode array detector (HPLC-DAD).
Fe3O4@SiO2 was synthesised by incorporating magnetite (Fe3O4) with silica (SiO2).
Silica was extracted from sugarcane bagasse through hydrothermal treatment and modified
with magnetite (Fe3O4). In contrast, Fe3O4@SiO2-cellulose-chitosan was prepared by
functionalizing Fe3O4@SiO2 with cellulose-chitosan to enhance the surface chemistry. The
properties of Fe3O4@SiO2 and Fe3O4@SiO2-cellulose-chitosan were studied using various
characterisation techniques, including Fourier transform infrared (FTIR) spectroscopy,
scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), transmission
electron microscopy (TEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET)
analysis, and zeta potential. The BET results suggested that Fe3O4@SiO2 and Fe3O4@SiO2-
cellulose-chitosan had surface areas of 104 m²/g and 155 m²/g, respectively. Both
Fe3O4@SiO2 and Fe3O4@SiO2-cellulose-chitosan were confirmed to be mesoporous by BET
BJH. Thus, the functionalization of Fe3O4@SiO2 with cellulose-chitosan did not bring any
change in porosity. Furthermore, the presence of all expected elements (iron, silicon, and
oxygen) and functional groups (Fe-O-Si and N-H) was confirmed by EDS and FTIR,
respectively...