From Industrial Waste to Multistage Applications: Ultralight Lignin‐Based Aerogel with Situ Vertically Oriented Structure for Photothermal‐Assisted Pb 2+ Adsorption in Wastewater and Reuse as Efficient Output and Stability Triboelectric Materials

In this work, the ultralight lignin-based aerogel (GSPCAA) with situ vertically oriented structure is developed through a simple and green synthesis strategy for efficient photothermally assisted adsorption of Pb²⁺, and then reused as a lignin-based triboelectric nanogenerator (TENG). Sulfonation is first performed on lignin's structure to enhance its water solubility and introduce the number of active adsorption sites. Then, GSPCAA is prepared using directed freezing and ionic crosslinking methods. The synergistic interactions between sulfonated lignin (SL) and graphene (GO) components endow GSPCAA with excellent photothermal properties, thereby generating the localized thermal environment on GSPCAA's surface to further improve the adsorption capacity of Pb²⁺. Finally, the spent adsorbent (GSPCAA-Pb²⁺) is applied as lignin-based TENG for the first time to achieve multi-stage application of lignin-based adsorbent. It displays excellent electric signal output performances. Meanwhile, a 3 × 3 self-powered array is designed to accurately identify and visualize the pressure distributions of different load objects. Besides, combined with deep learning model algorithms, an overall recognition accuracy of 98.5% is achieved in the classification and identification of 11 different objects, fully indicating its application potential in the field of smart homes.