A microwave absorber for microwave pyrolysis: wave-absorbing composites prepared with the components of silicon carbide and activated carbon

In recent years, with the acceleration of urbanization and the improvement of consumption level, the annual output of global domestic waste continues to climb at an average annual growth rate of 3% to 5%, of which organic solid waste accounts for more than 60%. Microwave-assisted pyrolysis is widely regarded as a highly promising approach in thermal decomposition processes, owing to its superior energy efficiency and precise control over the resulting products. However, this technology still faces a key material bottleneck in its engineering application, the lack of composite wave-absorbing media with specific frequency response, high temperature resistance, and cost controllability, which restricts the improvement of the energy efficiency ratio and the added value of the products of the system. In this study, to address this problem, innovatively designed and prepared silicon carbide/activated carbon (SiC/AC) double loss composites were prepared. The samples were analyzed by XRD, IR, XPS, and SEM, and their dielectric properties were tested. Research data indicate the synthesized composite exhibits minimal microwave reflection at -14 dB with a 4 mm sample thickness. Under a weight proportion of 1:9 between SiC and AC components, optimal electromagnetic compatibility is attained at 2.45 GHz through balanced dielectric characteristics (real component value of 4.68 paired with loss factor of 0.82), and the Cole-Cole mapping reveals a synergistic loss mechanism of interfacial polarization and defective dipole polarization. The material characterization confirms that the SiOC interfacial structure significantly enhances the charge transport capability. The material has good thermal conductivity and structural stability at high temperatures, and the manufacturing expenditure for this process is approximately 100 times more economical than that required for producing graphene-derived substances, which provides a new solution for microwave pyrolysis equipment for organic solid waste.