Key Takeaways & Executive Findings
- •• A novel Fe3O4/resin nanocomposite (FEOR) achieved an outstanding reflection loss of −71.09 dB at a thickness of only 1 mm. • The FEOR sample exhibited near-ideal impedance matching (close to 1), leading to high absorption performance. • The use of biomaterials (oleaster seeds and apricot tree gum) provides a sustainable approach to developing high-efficiency microwave absorbers. • The presence of defects and porous structures enhances microwave attenuation through dipole polarization and charge carrier trapping.
Abstract
There has recently been a fundamental need to develop high efficiency microwave absorbers to reduce electromagnetic pollution. It is often very difficult to obtain superior absorption with only one material, so we have explored composites using fillers of activated carbon derived from biological material (oleaster seeds) and resin (apricot tree gum) with Fe3O4 in a paraffin wax matrix to improve the dielectric properties and achieve a high specific surface area. A 1 mm thick layer of a Fe3O4 + resin (FEOR), with the magnetic nanoparticles anchored to the gum, resulted in a reflection loss of −71.09 dB. We compared this with the results for composites using a filler of Fe3O4 + activated carbon, and one with a three-component filler of Fe3O4 + activated carbon + resin which had a very porous structure that had a direct effect on the surface polarization. However, the FEOR sample had near-ideal impedance matching, close to 1, which resulted in high absorption performance. In addition, the presence of defects improves microwave attenuation by dipole polarization and charge carrier trapping. This work suggests the use of new types of biomaterials to increase microwave absorption.
1. Introduction
Recent advancements in electronic devices across multiple fields, including communication, military, aerospace, Internet of Things (IoT), and artificial intelligence (AI), have greatly improved our daily lives. However, the abundant presence of electromagnetic radiation from these devices has given rise to a new kind of environmental pollution, posing significant challenges to our ecosystem and human well-being[1]. Therefore, there is a need to develop materials with electromagnetic wave absorbing capacity that can mitigate electromagnetic radiation pollution, and intense research is focused on this field[2–4]. Low-weight materials and green synthesis methods are particularly important both from a functional as well as sustainability point of view[5].
To address the weight issue, mesoporous and microporous structures are preferable, which effectively increase the specific surface area and reduce the weight of the material for equal performance[6,7]. Additionally, they also provide the possibility to incorporate secondary phases into the porous structure that could enhance the functionality through impedance matching of the two phases[8]. For example, in Wu et al.’s work, a biomass hierarchical porous carbon (BHPC) with micropores, mesopores and macropores obtained from rice husk was prepared using potassium KOH activation and one-step carbonization. The BHPC sample exhibited a minimum reflection loss (RLmin) of −47.463 dB at 9.79 GHz, and the effective absorption bandwidth was 81% of the X-band. The synergistic effects of macropores, mesopores and micropores contributed to the adsorption performance of BHPC. The macropores in BHPC form a conductive network to promote the conductivity loss of the material. It showed good absorption performance for electromagnetic waves due to good impedance matching, high dielectric loss capacity, large specific surface area and reasonable pore diameter distribution[9]. Zhao et al. used the inherent microstruc...
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Mahsa Mahmoodi, Bagher Aslibeiki, Reza Peymanfar, Hamid Naghshara, Rajesh Kumar Rajagopal, Yue Zhao, Davide Peddis, Tapati Sarkar (2025). Electromagnetic wave absorption performance of Fe3O4/activated carbon-natural resin nanocomposite. SinoTechIntel Verified Research. https://doi.org/10.1016/S1872-5805(NCM2024-39-06-08)
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Frequently Asked Questions
What is the maximum reflection loss achieved by the Fe3O4/resin nanocomposite?
The Fe3O4/resin nanocomposite (FEOR) achieved a maximum reflection loss of −71.09 dB at a thickness of 1 mm.
What biomaterials were used to synthesize the activated carbon and resin?
Activated carbon was derived from oleaster seeds, and resin was obtained from apricot tree gum.
Why does the FEOR sample show superior microwave absorption?
The FEOR sample exhibits near-ideal impedance matching (close to 1), which minimizes reflection and maximizes absorption, along with enhanced dielectric and magnetic losses.
How does the porous structure affect microwave absorption?
The porous structure increases the specific surface area, promotes surface polarization, and provides more active sites for dipole polarization and charge carrier trapping, thereby enhancing microwave attenuation.
What is the significance of using biomaterials in this study?
Using biomaterials like oleaster seeds and apricot tree gum offers a sustainable and eco-friendly approach to developing high-performance microwave absorbers, addressing both functional and environmental concerns.
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