High-performance amino-crosslinked phosphorylated microcrystalline cellulose/MoS hybrid aerogel for polystyrene nanoplastics removal from aqueous environments.

Currently, the development of high-performance adsorbents for the removal of nanoplastics in complex aquatic environments is challenging. In this study, a functionalized polyethyleneimine-phosphorylated microcrystalline cellulose/MoS (PEI-PMCC/MoS) hybrid aerogel was prepared and applied to remove carboxyl-modified polystyrene (PS-COOH) nanoplastics from the aqueous solution. Benefiting from the introduced functional groups and the expanded lamellar structure in MoS nanosheets as well as the highly porous 3D structure of the aerogel, PEI-PMCC/MoS demonstrated high efficiency in PS-COOH nanoplastics removal, achieving a 402.4 ± 7.5 mg/g maximum adsorption capacity at the optimal adsorption pH of 7.0 (C = 300 mg/L). The adsorption isotherm and kinetics data fitted well with the Langmuir and pseudo-second-order models, respectively, suggesting that the removal of PS-COOH nanoplastics was dominated by the monolayer chemisorption process, and the thermodynamic studies revealed the exothermic nature of the spontaneous adsorption process. Furthermore, the adsorption performance of PEI-PMCC/MoS in different complex aqueous environments, as well as its reusability, was evaluated, and the interactions between PEI-PMCC/MoS and PS-COOH nanoplastics were analyzed to elaborate the adsorption mechanism. These results confirmed the high nanoplastics removal efficiency and favorable reusability in PEI-PMCC/MoS, laying a solid foundation for developing high-performance adsorbents for nanoplastics removal.