Solvent-Free Mechanochemical Synthesis of Cyclodextrin Nanosponges via Mechanical Milling for Removal of Dinotefuran from Water

Cyclodextrin-based nanosponges (NSs) have gained attention as sustainable adsorbents for emerging pollutants. However, conventional cyclodextrin cross-linking typically involves toxic solvents and prolonged reaction times, which complicate synthesis and purification. In this work, NSs were synthesized using a solvent-free mechanochemical process via mechanical milling with diphenyl carbonate as a cross-linker. The structural and physicochemical properties of the obtained NSs were characterized using morphological (FE-SEM, TEM, EDS), spectroscopic (FT-IR, Raman, NMR), thermal (TGA, DSC), and crystallographic (XRD) techniques, confirming successful cross-linking. The adsorption performance of the NSs was evaluated using dinotefuran, a model neonicotinoid pollutant. Kinetic and equilibrium studies revealed rapid adsorption within 60 min, with a removal efficiency (RE%) of 98%. The equilibrium data were best fitted by employing the Freundlich and Temkin isotherms, indicating a heterogeneous multilayer adsorption process dominated by supramolecular interactions. Notably, when tested in real river water samples from the Maipo River (Chile), the NSs maintained a high RE% of 75% and demonstrated stable performance over multiple adsorption-desorption cycles, confirming their reusability under environmentally relevant conditions. This sustainable and scalable synthesis approach, coupled with strong performance in both laboratory and natural water matrices, highlights the potential of these NSs as viable materials for water treatment applications.