A supramolecular assembly made with sulfobutylether-β-cyclodextrin and magnetic Fe3O4 showing water remediation properties

• Self-assembly between iron oxide nanoparticles (MNPs) and sulfobutylether β-cyclodextrin (Captisol). • The MNPs@Captisol assembly was characterized by TGA, spectroscopic (FT-IR, XPS, μXRF) and imaging (TEM) techniques, mass magnetization, DLS analysis and an adapted turbidimetric method. • The assembly shows water remediation properties towards paraquat, a model positive-charged pollutant. • The sequestering mechanism was related to electrostatic complexation. In literature many examples of magnetic nanohybrids based on cyclodextrins are reported, but they often require multistep processes and preliminary synthetic efforts that affect the scale-up for the final application. In this paper, a magnetic hybrid system was produced by supramolecular self-assembly between low-cost precursors: the sulfobutylether-β-cyclodextrin (Captisol®) and magnetic iron oxide-based nanoparticles (MNPs). The interaction between the Captisol® and MNPs was elucidated by spectroscopic (Fourier Transform Infrared − FT-IR, X-ray Photoelectron Spectroscopy – XPS, micro X-ray fluorescence – μXRF) and imaging (Transmission Electron Microscopy − TEM) techniques. The resulting MNPs@Captisol assembly was also characterized by thermogravimetric analysis to establish the amount of the organic moiety. The colloidal features were evaluated by dynamic light scattering measurements and an adapted turbidimetric analysis. Finally, a promising use of MNPs@Captisol as remediation agent against paraquat (chosen as a model of cationic pollutant), has been demonstrated. The sequestering mechanism, depending on the concentration and by electrostatic interactions, was ascertained.