Rational design of FeCo/C/FA by recycling of fly ash for electromagnetic pollution.

In order to realize the sustainable development of turning waste into treasure and treating pollution with waste, the feasibility of resource utilization of fly ash (FA) to solve electromagnetic pollution was investigated. In this study, FeCo/carbon-loaded FA composites (FeCo/C/FA) were successfully synthesized via a facile one-pot method using solid waste FA as the raw material. Such ingenious design endowed FA enhanced microwave absorption (MA) capacity, and the MA mechanism derived from conductivity loss, multiple interface polarization and impedance matching. As expected, the FeCo/C/FA composites exhibited the excellent MA performance, its minimum reflection loss (RL min) reached − 32.5 dB with the coating thickness of 1.5 mm. When the coating thickness was adjusted to 2.0 mm, the maximum value of effective absorption band was measured to be 4.7 GHz. This work confirms that FA can be directly recycled to construct a low-cost microwave absorber in the treatment of electromagnetic pollution. A facile one-pot method is put forward to construct FeCo/C/FA composites with outstanding microwave absorption performances. [Display omitted] • The low-cost absorber is synthesized by the facile one-pot method. • The novel method realizes the recycling of FA and solves electromagnetic pollution. • The FeCo/C/FA composites are lightweight and possess excellent performance. • Impedance matching and interfacial polarization play a key role to performance. [ABSTRACT FROM AUTHOR]