Porous carbon/Fe composites from waste fabric for high-efficiency electromagnetic wave absorption

Nowadays, a large amount of waste fabrics has brought huge environmental and resource problems, while the traditional recycling routes are downcycling with low efficiency and complex separation processes. Herein, we demonstrate a green and facile route to up-recycle waste fabrics (cotton-polyester blending or cotton fabrics) into a high-performance microwave absorber. In this design, an assistant coating was deposited onto the fiber surface of the waste fabric through the assembly of tannic acid-Fe (2 +) (TA-Fe (2 +) ), which effectively catalyzed the polymer fiber into highly graphitized porous carbon fiber at high temperatures. Meanwhile, the Fe nanoparticles from the reduction of Fe 2 + ions were evenly embedded on the surface of porous carbon fibers. Consequently, the resultant porous carbon/Fe composites with hierarchical microstructures displayed excellent microwave absorption performances. Typically, the microwave absorber from waste polyester-cotton blended fabric could reach a minimum reflection loss ( RL ) of -50.5 dB at a thin coating thickness of 1.7 mm, and the minimum RL from waste cotton fabric absorber reached -47.1 dB at a thickness of 2.5 mm. This work provides a new idea to convert waste fabrics into high value-added microwave absorbing materials in a simple and environmentally friendly way, which will help reuse resources and protect the environment. (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.