TEMPO-oxidized cellulose nanofiber incorporating hydrophobic TA-HBPSi nanoparticles aerogels for efficient adsorption of fungicides in water

Fungicide contamination is a critical environmental issue, and the effective removal of fungicide residues from aquatic environments has attracted significant attention from researchers. In this study, the synthesized hyperbranched polysiloxane (TA-HBPSi) was grafted onto TEMPO-oxidized cellulose nanofibers (TOCNF) to fabricate a novel aerogel material (TA-HBPSi@TOCNF) with the aim of enhancing the sorption efficiency of fungicide. The equilibrium maximum adsorption capacity of TA-HBPSi@TOCNF for imazalil (8.04 mg/g) was significantly higher compared to other fungicides, including prochloraz (6.43 mg/g), thiophanate-methyl (4.12 mg/g), carbendazim (0.16 mg/g), and thiabendazole (0.04 mg/g). In the presence of Cd2+, the equilibrium adsorption capacity for imazalil increased from 8.04 mg/g to 9.61 mg/g, while the adsorption capacity for Cd2+ increased from 0.26 mg/g to 0.88 mg/g. Quantum chemical calculations were performed at the density functional theory (DFT) level. The energy gaps between the highest occupied molecular orbital and lowest unoccupied molecular orbital (Delta E(HOMO-LUMO)) for various adsorption mechanisms indicated that electrostatic interactions were the dominant driving force for adsorption, followed by it-it electron donor-acceptor (EDA) interactions and hydrophobic interactions. The developed aerogel demonstrated effective multi-component separation capabilities without inducing secondary environmental pollution, highlighting its potential as a promising candidate for practical water purification applications.