Raspberry bush - derived magnetic nanocomposites for water purification and microwave absorption.

Integrating heavy-metal remediation and electromagnetic wave (EMW) attenuation within a single, sustainable material system remains a critical challenge, primarily due to the difficulty of synergistically regulating adsorption-active porous architectures and charge-transport networks. Herein, we address this challenge by utilizing raspberry bush biomass, an abundant, renewable, and naturally microstructured precursor, to fabricate a hierarchical porous activated carbon framework decorated with magnetite nanoparticles (Fe3O4/AC). The inherent structural advantages of the raspberry-bush-derived carbon matrix provide abundant oxygen-containing surface functionalities and a tailored pore distribution, which serve the dual purpose of facilitating heavy-metal capture and modulating dielectric loss. For environmental remediation, the Fe3O4/AC nanocomposite achieved an exceptional Pb2+ removal efficiency of >99.5% with a maximum removal capacity of 249.24 mg g-1 under optimized conditions (pH 9, 30 min, and 50 mg L-1 initial concentration), demonstrating robust recyclability over four cycles. Thermochemical and kinetic modeling confirmed a spontaneous process governed by pseudo-second-order kinetics. For electromagnetic shielding, the nanocomposite exhibited a minimum reflection loss (RLmin) of -30 dB at 16 GHz within the Ku band. This outstanding electromagnetic dissipation is governed by a magneto-dielectric synergistic effect, where the carbon framework drives interfacial polarization and conduction losses, while the Fe3O4 nanoparticles optimize impedance matching. This work highlights a sustainable, biomass-derived strategy for designing high-performance, multifunctional materials that can find applications in both water purification and electromagnetic wave absorption.