Microporous Cobalt Ferrite with Bio‐Carbon Loosely Decorated to Construct Multi‐Functional Composite for Dye Adsorption, Anti‐Bacteria and Electromagnetic Protection

Abstract Currently, facing electromagnetic protection requirement under complex aqueous environments, the bacterial reproduction and organic dye corrosion may affect the composition and micro‐structures of absorbers to weaken their electromagnetic properties. To address such problems, herein, a series of CoFe 2 O 4 @BCNPs (cobalt ferrite @ bio‐carbon nanoparticles) composites are synthesized via co‐hydrothermal and calcining process. The coupling of magnetic cobalt ferrite and dielectric bio‐carbon derived from Apium can endow the composite multiple absorption mechanisms and matched impedance for effective microwave absorption, attaining a bandwidth of 8.12 GHz at 2.36 mm and an intensity of −49.85 dB at 3.0 mm. Due to the ROS (reactive oxygen species) stimulation ability and heavy metal ions of cobalt ferrite, the composite realizes an excellent antibacterial efficiency of 99% against Gram negative bacteria of Escherichia coli . Moreover, the loose porous layer of surface stacked bio‐carbon can promote the adsorption of methylene blue for subsequent eliminating, a high removal rate of 90.37% for organic dye can be also achieved. This paper offers a new insight for rational design of composite's component and micro‐structure to construct multi‐functional microwave absorber for satisfying the electromagnetic protection demand in complicated environments.