A circular "capture-and-upcycle" strategy for micro/nano-plastic remediation: From aquatic pollutants to fire-safe...

The widespread contamination of micro/nano-plastics (MNPs) has become a major environmental concern, highlighting the need for efficient treatment technologies and sustainable disposal methods. Herein, a hydrophobized magnetic lignocellulosic fiber (HLF) adsorbent derived from wood waste was engineered to realize a circular "capture-and-upcycle" strategy. HLF with excellent adsorption capacity can be prepared by modifying lignocellulosic fibers from wood waste through in situ synthesis of nanoscale Fe₃O₄ particles and silanization. It has achieved equilibrium adsorption capacities of 2544.7 mg g^-1 for micro-sized PS and 2571.1 mg g^-1 for PMMA. The adsorption mechanism is a synergistic physicochemical interaction dominated by van der Waals forces and hydrophobic effects. Notably, the challenge of adsorbent disposal is addressed by directly transforming the MNPs-saturated HLF into robust functional composites via hot-pressing. The resulting HLF/MNPs composites exhibit ideal mechanical properties with a flexural strength of 151.1 MPa and a tensile strength of 37.6 MPa, far surpassing commercial wood-plastic composites. Furthermore, it exhibits self-extinguishing behavior and improves fire safety due to the action of magnetic particles, and their peak smoke release rate was reduced by 79.3% compared to non-magnetic LF/MNPs composites. This work establishes a scalable, circular approach for remediating aquatic plastic pollution while simultaneously valorizing waste into high-performance engineering materials.