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 Cd, the equilibrium adsorption capacity for imazalil increased from 8.04 mg/g to 9.61 mg/g, while the adsorption capacity for Cd 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 (ΔE()) for various adsorption mechanisms indicated that electrostatic interactions were the dominant driving force for adsorption, followed by π-π 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.