Leveraging Intrinsic Hemicellulose in Cellulose Nanopaper for Enhanced Nanoplastic Collection.

Abstract

Lignocellulosic materials are ideal collecting materials for biotoxic nanoplastics in purified or drinking water due to their exceptional biocompatibility and programmability. Nature has designed hierarchical and heterogeneous lignocellulose microstructure, which can be harnessed for enhanced interfacial behaviors toward specific applications. Here, we demonstrate the high-efficiency capture of diversified nanoplastics from aqueous environments by nanopaper assembled from cellulose nanofibrils primarily as a result of interfacial adsorption and physical interception, behaviors that are further intensified with the presence of the intrinsic hemicellulose component. Molecular dynamics simulations interpret that hemicellulose with high molecular accessibility and polarity significantly contributes to the intermolecular interactions between cellulose nanofibrils and nanoplastics, which in turn enhances the nanoplastic-adsorption capacity of nanopaper. Furthermore, the amorphous and hydrophilic hemicellulose component facilitates the tunability of fibril-fibril interactions, leading to mesoporous nanopaper with high specific surface area, which in turn captures nanoplastics in high-flux under dynamic hydraulic pressure. In addition, the postuse hemicellulose-rich nanopapers can be facilely processed into high-performance nanocomposites integrating the advantages of lignocellulose nanofibrils and petroleum-based nanoplastics, offering a "two birds with one stone" solution to the issues of recontamination and value-added utilization. This work designs and optimizes lignocellulosic nanomaterials by leveraging the inherent functionality of structural constituents toward applicable nanoplastic-collecting technology.