In an article printed in the newspaper CarbonCoconut husk, a typical biomass residue, is mixed with magnetic particles to form a good quality microwave absorbing nanocomposite.
Study: Absorption properties of electromagnetic waves of the nanocomposite derived from the coconut shell. Image Credit: EVANATTOZA/Shutterstock.com
Importance of EM Shielding and Absorbing Materials
As wireless communication technology advances, many electronic gadgets offer useful applications in daily life. Simultaneously, this leads to the existence of very concentrated and high electromagnetic radiation. Abundant radiation in the frequency spectrum of 2 to 18 GHz, in particular, can lead to major difficulties such as channel noise, telecommunication disturbance and danger to people’s health.
To minimize these negative impacts, electromagnetic interference shielding materials and electromagnetic absorption materials should be used. Although EMI shielding technologies protect interior electronics, additional exterior effects exist.
To completely eliminate this problem, efforts have been made to produce a variety of microwave absorbing substances. Previously, researchers used electrostatic assembly to create a core-shell [email protected] alloy. The magnetic particles greatly improved the absorption performance. In reality, microwave absorber materials must perform consistently over long periods of time, which requires them to be lightweight and resistant to corrosive environments.
Efficiency of carbon materials
Carbon materials have attracted a lot of interest in the field of microwave absorption due to their exceptional qualities, including their light weight, good conductivity, and the ease with which they can be formed into unique nanostructures. Carbon fiber, reduced graphene oxide and carbon nanotubes (CNTs), for example, are considered particularly promising microwave absorption materials.
Carbon-based materials can be integrated into specific nanostructures, which improves dielectric loss capability due to increased interfacial polarization. Nevertheless, creating typical carbon-based microwave absorber materials often involves complex synthetic procedures with substantial energy consumption, such as electrochemical deposition, solvent evaporation, and phase separation.
These processes often require the use of expensive and hazardous natural resources, which are more likely to cause noticeable environmental damage. Therefore, the mode of supply and preparation of carbonaceous materials must be optimized. As a result, new carbon-based microwave absorbing materials with improved microwave absorption capabilities can be created using less expensive, more efficient, and reusable techniques.
Biomass and its benefits
Biomass is an abundant natural resource that is both clean and renewable. The notion of transforming waste biomass into high performance microwave absorbing compounds is also consistent with the notion of environmental sustainability. Generally, biomass can be used simply as a raw material in the production of a biomass-based composite or transformed into carbon and used as a biopolymer.
Biomass frequently contains unusual porosity patterns that facilitate the transfer of water and other minerals throughout plant life. These characteristics are advantageous in the preparation of biomass-derived carbon with a variety of nanostructures and large surface areas. The porous structure of the material can effectively manage the absorptivity.
Due to the abundance of surface functional groups in virgin biomass, surface modification of biomass-derived carbon is quite straightforward. Nevertheless, the use of nanotubes derived from biomass as a material absorbing microwaves poses a significant problem. The greater electrical conductance of the pure carbon material facilitates the dispersion of internal radiant waves, but it also causes an imbalance between the carbon materials and the open space.
Other microwave absorbing materials, including magnetic nanoparticles and dielectric properties, can be added to the surface of graphene sheets to alleviate this problem. The hydrothermal process has been used to create C/CoNi compounds from bamboo fibers. On the face of the stimulated bamboo fibers, round copper nickel nanoparticles formed uniformly. The permeation was significantly increased and the nanocomposite had an RLmin -75.19 dB at 11.12 GHz.
Magnetic materials can effectively improve comparable permeability. Moreover, some biomasses are underused, such as the practicality of coconut shells, which are often ignored. It is possible to try to transform them into usable materials.
A novel coconut shell (CS) nanocomposite, a typical biomass of agricultural residues that has not previously been described as a microwave-absorbing material, was fabricated as a low-cost and microwave-absorbing material. compact using a hydrothermal calcination process in this study. The preparation procedure was quite simple which makes it not only affordable but also simple to advertise on a large scale.
Coconut husk, a typical agricultural by-product, was transformed into a low-cost carbon nanocomposite as a microwave-absorbing material in this study. The nanomaterials consisted of a multi-layered carbon matrix with magnetized Fe/Fe3C nanocrystals patterned on top after a hydrothermal process and decomposition.
In microwave absorption, PMCS has clearly outperformed current comparable materials. Overall, the research has proposed a novel method for converting biomass into ultralight, limited, and high-quality carbon-based microwave-absorbing materials.
Yang, S., Sun, X., Wang, S., Ning, Y. & Yuan, Y. (2022). Electromagnetic wave absorption properties of nanocomposite derived from coconut shell. Carbon. Available at: https://doi.org/10.1016/j.carbon.2022.05.016