Lignin-Based Nanofibrous Membranes for Microplastic Adsorption and Closed-Loop Utilization with Triboelectric Functionalization

The inefficient high-value utilization of lignin and the widespread contamination by microplastics present dual urgent challenges in the resource and environmental sectors. Furthermore, existing microplastic adsorption materials generally lack closed-loop pathways for resource recovery after the adsorption process. This study proposes a closed-loop utilization system that employs lignin-based nanofibrous membranes for microplastic adsorption, followed by thermally induced functional reconfiguration to fabricate triboelectric sensors. Composite nanofibrous membranes with varying lignin-polyacrylonitrile (PAN) ratios were prepared via electrospinning, and the regulatory mechanisms of lignin structure on microplastic adsorption performance were systematically investigated. Leveraging the thermoplasticity of lignin and its thermal compatibility with polyethylene terephthalate (PET), the adsorbed membranes were subjected to hot pressing to induce functional restructuring, thereby conferring triboelectric properties on the membranes. Organic lignin (OL)/PAN composite membranes to achieve a high adsorption capacity of 363.94 mg/g. After thermal pressing at 150 °C, the OL/PAN membrane formed a unique honeycomb structure, which significantly reduced energy loss and enhanced triboelectric sensing signals. The resulting triboelectric sensor not only maintained stability over 5000 cycles but also demonstrated high-sensitivity detection capabilities for multiscale human movements. This study provides a novel strategy for the synergistic valorization of lignin and management of microplastic pollution.