Combined Layer-by-Layer/Hydrothermal Synthesis of Fe3O4@MIL-100(Fe) for Ofloxacin Adsorption from Environmental Waters

Michela Sturini; Constantin Puscalau; Giulia Guerra; Federica Maraschi; Giovanna Bruni; Francesco Monteforte; Antonella Profumo; Doretta Capsoni

doi:10.3390/nano11123275

Combined Layer-by-Layer/Hydrothermal Synthesis of Fe₃O₄@MIL-100(Fe) for Ofloxacin Adsorption from Environmental Waters

Nanomaterials (Basel). 2021 Dec 2;11(12):3275. doi: 10.3390/nano11123275.

Authors

Michela Sturini¹, Constantin Puscalau^{2

3}, Giulia Guerra^{1

4}, Federica Maraschi¹, Giovanna Bruni², Francesco Monteforte², Antonella Profumo¹, Doretta Capsoni²

Affiliations

¹ Department of Chemistry, University of Pavia, 27100 Pavia, Italy.
² C.S.G.I. (Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase) & Department of Chemistry, Physical Chemistry Section, University of Pavia, 27100 Pavia, Italy.
³ The GlaxoSmithKline Neutral Laboratories for Sustainable Chemistry, University of Nottingham, Jubilee Campus, Nottingham NG7 2TU, UK.
⁴ Istituto di Tecnologie Biomediche, ITB-CNR, 20054 Segrate, Milano, Italy.

Abstract

A simple not solvent and time consuming Fe₃O₄@MIL-100(Fe), synthesized in the presence of a small amount of magnetite (Fe₃O₄) nanoparticles (27.3 wt%), is here presented and discussed. Layer-by-layer alone (20 shell), and combined layer-by-layer (5 shell)/reflux or /hydrothermal synthetic procedures were compared. The last approach (Fe₃O₄@MIL-100_H sample) is suitable (i) to obtain rounded-shaped nanoparticles (200-400 nm diameter) of magnetite core and MIL-100(Fe) shell; (ii) to reduce the solvent and time consumption (the layer-by-layer procedure is applied only 5 times); (iii) to give the highest MIL-100(Fe) amount in the composite (72.7 vs. 18.5 wt% in the layer-by-layer alone); (iv) to obtain a high surface area of 3546 m² g^-1. The MIL-100(Fe) sample was also synthesized and both materials were tested for the absorption of Ofloxacin antibiotic (OFL). Langmuir model well describes OFL adsorption on Fe₃O₄@MIL-100_H, indicating an even higher adsorption capacity (218 ± 7 mg g^-1) with respect to MIL-100 (123 ± 5 mg g^-1). Chemisorption regulates the kinetic process on both the composite materials. Fe₃O₄@MIL-100_H performance was then verified for OFL removal at µg per liter in tap and river waters, and compared with MIL-100. Its relevant and higher adsorption efficiency and the magnetic behavior make it an excellent candidate for environmental depollution.

Keywords: adsorption; combined layer-by-layer/hydrothermal synthesis; fluoroquinolone antibiotic; iron-based metal-organic frameworks; magnetic remediation; polluted waters; wastewater treatment.