Graphene Aerogels

A Revolution in Decontamination and Industrial Efficiency

Aerogels are synthetic, translucent materials with a gel-like appearance in which the liquid content is replaced with air or gas, creating a porous network of interconnected nanostructures. They are typically made from silica, alumina, chromium oxide, titanium, tin, or carbon, each offering specialized properties for different industries. For instance, in construction, they provide thermal and acoustic insulation; in food, they control moisture; in medicine, they release drugs and repair bone defects; in agriculture, they optimize water usage; and in environmental purification, they adsorb contaminants in water and air.

“Despite their advantages, aerogels face challenges such as fragility and high costs, prompting ongoing research to improve them.”

Graphene, a planar nanostructure consisting of one to ten layers of tightly bonded carbon atoms, boasts extraordinary mechanical, thermal, and electrical properties transferable to other materials. However, to ensure this transfer, graphene often undergoes additional functionalization with oxygen groups or chemical/physical dopants like DNA molecules, metallic ions, nanoparticles, or polymers. These modifications inhibit the π-π stacking of graphene layers, improving their interaction and stability—key challenges given graphene’s tendency to aggregate.

“A critical factor for graphene’s performance is the proper dispersion and distribution of its layers throughout the host material matrix.”

The intersection of aerogels and graphene lies in the fact that aerogels provide a three-dimensional macroscopic structure where graphene can remain stable without aggregating. Additionally, graphene enhances aerogel properties, such as lightweight construction, electrical conductivity, thermal insulation, compressibility, and elasticity. It also allows functionalization with other materials like cobalt hydroxide, cobalt oxide, manganese dioxide, molybdenum oxide, molybdenum disulfide, nitrogen, sulfur, or boron to improve electrochemical detection performance, supercapacitor efficiency, electrocatalytic functions, or contaminant adsorption.

Graphene Aerogels for Decontamination:

Graphene’s adsorbent capabilities are well-documented, particularly in its oxidized form, graphene oxide (GO), which offers a large surface area and numerous interaction sites for capturing pollutants. However, challenges such as the difficulty of removing adsorbed substances and recycling GO sheets limit practical applications. Recent advancements suggest that three-dimensional graphene aerogels effectively prevent GO aggregation during adsorption and enhance regeneration capabilities. These new structures, with their extremely low density, high porosity, and large surface area, facilitate contaminant diffusion and adsorption within the 3D network while enabling recyclability.

A 2024 study published in the renowned journal Nature detailed two methods for producing graphene aerogels. This research evaluated the photocatalytic capacity of both materials, finding superior performance compared to non-graphene counterparts. The study also analyzed various toxic organic solvents, pigments, and oils, such as formaldehyde, dichloromethane, acetone, ethanol, methanol, pump oil, castor oil, and silicone oil, achieving higher decontamination rates. Additionally, graphene aerogels have been shown to remove up to 99% of heavy metals from water, outperforming conventional adsorbents like activated carbon and other treatment methods like ion exchange, coagulation, and filtration. These advantages stem from their larger surface area, higher adsorption capacity, longer lifespan, and regenerative properties.

In air decontamination, most systems use high-efficiency particulate air (HEPA) filters with activated carbon. However, their limited adsorption capacity necessitates frequent maintenance and filter replacements. Addressing this issue, a study by Tianjin University in China explored the photocatalytic capability of titanium dioxide combined with the adsorption capacity of graphene aerogels. The research concluded that the synergy between these materials offers significant advantages over conventional filtration systems.

This demonstrates how two distinct technologies can merge to create synergies and address various challenges. For Energeia-Graphenemex, a leading Latin American company in graphene material production and application development, it is inspiring to see how graphene technology is gradually making a positive impact across different industrial sectors.

Authored by: EF/DHS

References:

1. Gaelle Nassar, et. al., A review on the current research on graphene-based aerogels and their applications. Carbon Trends 4 (2021) 100065;
2. Ting Yao et. al., Preparation of β-cyclodextrin-reduced graphene oxide aerogel and its application for adsorption of herbicides. Journal of Cleaner Production, 468, (2024) 143109;
3. Karabo G. Sekwele et. al., Cellulose, graphene and graphene‑cellulose composite aerogels and their application in water treatment: a review. Discover Materials (2024) 4:23;
4. Ashish K. Kasar et al., Graphene aerogel and its composites: synthesis, properties and applications. Journal of Porous Materials (2022) 29:1011