Category: Graphene Oxide

Carbonation and Graphene Oxide:

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Carbonation and Graphene Oxide:

A Solution for Reducing CO₂ Emissions

In previous articles, we discussed the cement industry’s impact on CO₂ emissions and the commitments made to reduce them by 2050. Today, we explore how carbonation—a process generally seen as a concrete pathology—could help offset some CO₂ emissions from cement production.

What is Carbonation?

In concrete, carbonation is a natural process where CO₂ from the environment reacts with moisture in the concrete, converting the alkaline calcium hydroxide in cement paste to calcium carbonate with a more neutral pH. This reaction lowers the concrete’s pH from around 12–13 to approximately 9, exposing steel reinforcements to corrosion.

What Affects Carbonation?

Carbonation rate depends on the diffusion of CO₂ and its reactivity with the cement matrix, which is in turn influenced by the matrix’s microstructure, hydration products (calcium hydroxide, calcium silicate hydrate, alkaline oxides, etc.), and pore structure (distribution, size, and saturation). Therefore, carbonation proceeds more slowly in low-permeability or dry concretes than in permeable ones with 50–60% humidity. To reduce porosity and calcium hydroxide levels, micrometric additives like fly ash, blast furnace slag, metakaolin, silica fume, and some nanomaterials are used during concrete production, alongside practices like applying surface coatings.

Carbonation as an Emission Reduction Tool

Carbonation can be viewed in two ways: first, as a concrete pathology, and second, as a CO₂-reducing opportunity. There are two types of carbonation: natural and accelerated. Natural carbonation is slow and does not capture CO₂, while accelerated (or mineral) carbonation uses high CO₂ concentrations, speeding up cement hydration and producing carbonates in which CO₂ is permanently stored in a thermodynamically stable mineral form. This process, known as recarbonation, involves the same carbonate used as a raw material in cement production. Companies like Blue Planet, Carbon Cure, Solidia Technologies, and Carbi Crete are developing strategies to sequester up to 17 kg of CO₂ per cubic meter of prefabricated concrete, as this process requires controlled conditions.

Graphene Oxide (GO) and Its Impact

Graphene oxide (GO) is a carbon nanostructure whose multifunctionality offers numerous benefits across industries. In concrete, GO enhances mechanical strength and durability, though its effects on carbonation and CO₂ capture are less well-documented.

Research conducted by the University of Arlington, Texas, in 2022 examined GO’s interaction mechanism in concrete cured under accelerated carbonation. Results indicated that GO, by improving cement hydration, refines concrete pores with calcium carbonate precipitated on hydration products and cement particles, limiting chemical reactions between hydration products and CO₂ under continuous CO₂ flow. The study concluded that GO not only enhances concrete’s mechanical properties but also helps capture and store up to 30% of atmospheric CO₂ during early curing stages.

Authored by: EF/ DHS

References

  1. Geetika Mishra, et al., Carbon sequestration in graphene oxide modified cementitious system, Journal of Building Engineering, 2022, 62, 105356;
  2. Nur Azni Farhana Mazri et al., Graphene and its tailoring as emerging 2D nanomaterials in efficient CO2 absorption: A state-of-the-art interpretative review. Alexandria Engineering Journal, 2023, 77, 479;
  3. Mohd Hanifa et al., A review on CO2 capture and sequestration in the construction industry: Emerging approaches and commercialised technologies, Journal of CO2 Utilization, 2023, 67, 102292;
  4. Yating Ye et al., Optimizing the Properties of Hybrids Based on Graphene Oxide forCarbon Dioxide Capture, Ind. Eng. Chem. Res. 2022, 61, 1332;
  5. Sanglakpam Chiranjiakumari Devi et al., Influence of graphene oxide on sulfate attack and carbonation of concrete containing recycled concrete aggregate, Construction and Building Materials, 2020, 250, 118883

Advances in Fire Protection:

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Advances in Fire Protection:

The Promise of Graphene Oxide in Intumescent Coatings

Intumescent coatings are specialized paints applied to concrete and steel structures in industrial and residential buildings to offer fire protection. They provide safety by allowing enough time for evacuation and assistance in the event of a fire.

During a fire, these coatings expand and form a carbonized foam that isolates the fire and limits its spread, while simultaneously releasing non-combustible gases that reduce the oxygen concentration around the structures, protecting them from significant damage for approximately 1 to 3 hours.

The main components of intumescent coatings are a polymeric binder, an acid source (e.g., ammonium polyphosphate – APP), an expansion additive (e.g., melamine – MEL), a carbon source (e.g., pentaerythritol – PER), and other filler elements (e.g., expandable graphite), which often influence the expansion factor and fire retardancy.

Despite their efficiency, the carbonized foam formed by the APP-MEL-PER system may have poor oxidation resistance at high temperatures, leading to lower fire-retardant efficiency and easier destruction during combustion. Therefore, other additives such as calcium carbonate, aluminum hydroxide, silica, and certain carbon materials have been explored to enhance their protection. For example, expandable graphite in epoxy coatings improves thermal degradation and fire resistance; carbon nanotubes reduce the heat release rate in polymers, and graphene oxide (GO), thanks to its reticular nanostructure, has been identified as an effective thermal barrier to prevent flame diffusion and reduce heat propagation. This occurs because GO, when evenly dispersed within the coating matrix, forms a “tortuous path” that reduces the thermal diffusion rate and matrix decomposition, thus improving fire resistance and mechanical strength.

Although no intumescent coatings with graphene oxide are currently on the market, research has shown that GO can improve the APP-MEL-PER system by promoting the decomposition reaction of APP, which accelerates the formation of phosphoric acid that reacts with PER to form carbon. While it has been observed that GO may slightly decrease the thermal stability of coatings, its presence encourages gas production and intumescent coefficients, reducing thermal conductivity.

Energeia-Graphenemex®, in collaboration with a renowned Mexican specialized coatings company, is working on a new development to launch the first intumescent coating with graphene oxide to continue placing Mexico at the forefront of new technologies.

Authored by: EF/DHS

References:

  1. Wang Zhan et al., Influence of graphene on fire protection of intumescent fire retardant

coating for steel structure, Energy Reports 6 (2020) 693;

  • Qiuchen Zhang et al., Effects and Mechanisms of Ultralow Concentrations of Different Types of Graphene Oxide Flakes on Fire Resistance of Water-Based Intumescent Coatings, Coatings 2024, 14, 162;
  • M. Sabet, et al., The Effect of Graphene Oxide on Flame Retardancy of Polypropylene and Polystyrene, Materials Performance and Characterization 9, no. 1 (2020): 284;
  • Cheng‑Fei Cao et al., Fire Intumescent, High‑Temperature Resistant, Mechanically Flexible Graphene Oxide Network for Exceptional Fire Shielding and Ultra‑Fast Fire Warning, Nano-Micro Lett. (2022) 14:92;
  • Quanyi Liu et al., Recent advances in the flame retardancy role of graphene and its derivatives in epoxy resin materials. Composites Part A: Applied Science and Manufacturing, 2021, 149, 106539

The Impact of Graphene on the Plastic Industry:

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The Impact of Graphene on the Plastic Industry:

Innovation and Sustainability

The origins of plastic trace back to 1860 in the United States when Phelan & Collander, amid an ivory shortage—a material widely used for billiard balls, piano keys, jewelry, and decorative structures—announced a call for a material capable of replacing ivory, offering substantial financial compensation for the time. John Wesley Hyatt proposed “celluloid,” a plant-based carbohydrate that, while not fully replacing ivory, became the stepping stone for the development of plastic, with immediate successors like Bakelite and PVC leading to today’s engineering plastics.

The term “plastic” comes from the Greek “plastikos,” meaning “moldable.”

Plastics are synthetic materials obtained through various polymerization processes from petroleum derivatives. Their evolution and refinement have made them essential to numerous industries and activities. However, after years of unchecked use, plastics have become both a solution for many needs and a significant environmental and health issue, as their versatility and demand have also led to increased waste. As a result, the not-so-new philosophy of sustainable circularity, or the circular economy, involves not only awareness of resource use but also economic, infrastructure, and recycling process adaptations.

Recycling involves reprocessing used materials, such as plastics, for reuse. While an excellent tool for preserving natural resources and reducing waste, two key points must be considered. First, recycling doesn’t apply in all cases because not all plastics are recyclable. Second, reprocessing involves stages where materials may lose properties compared to virgin plastics, limiting their use in many industrial applications.

Over the past 20 years, nanotechnology’s intervention in modifying polymers like polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET), among others, with carbon nanoparticles like graphene or carbon nanotubes (CNTs), has yielded interesting results regarding improved mechanical, rheological, electrical, and thermal properties. Graphene’s advantage over CNTs, in addition to other intrinsic properties, lies in its sheet-like structure, whose large surface area and greater dispersibility allow it to create more homogeneous phases, improving load transfer and thereby increasing the mechanical strength of modified plastics.

Companies such as Gerdau Graphene (Brazil), Graphenetech S.L. (Spain), Colloids (UK), and Energeia-Graphenemex (Mexico) have positioned various types of graphene-based masterbatches or concentrated plastics in the market over the past five years. Although each company has its own objectives and markets, there are environmental and economic points of convergence that motivated them to improve the plastic industry. Graphene, even in low concentrations (< 2% by weight), can enhance the quality of both virgin and recycled polymers. For example, graphene can increase flexural modulus by 30%, impact resistance by 40%, tensile strength by 17%, and resistance to rupture by 60%. It can also improve resistance to photodegradation. Depending on the specific needs of each development or application, it is possible to restore some of the mechanical properties of recycled plastics and/or extend the material’s lifespan to reduce the circulation of single-use plastics or, alternatively, achieve the same mechanical properties of polymers with reduced thickness.

Energeia – Graphenemex®, the leading Mexican company in Latin America in graphene material research and production for industrial applications, launched a wide range of graphene-based masterbatches in 2023 through its Graphenergy Masterbatch line, designed to be used as multifunctional reinforcement additives. Key advantages include:

  • Excellent dispersion within the polymer matrix
  • Can be incorporated into recycled polymers
  • Increase tensile, deformation, and impact resistance
  • Improve resistance to ultraviolet rays
  • Facilitate processing conditions (thermal stability)
  • Act as nucleating agents (modify polymer crystallization temperature).

Drafting: EF/DHS

References:

  1. Ramazan Asmatulu et al., Synthesis and Analysis of Injection-Molded Nanocomposites of Recycled High-Density Polyethylene Incorporated With Graphene Nanoflakes, POLYMER COMPOSITES—2015;
  2. Feras Korkees et al., Functionalised graphene effect on the mechanical and thermal properties of recycled PA6/PA6,6 blends. 2021 Journal of Composite Materials 55(16);
  3. Devinda Wijerathne et. al., Mechanical and graphe properties of graphene nanoplatelets-reinforced recycled polycarbonate composites. International Journal of Lightweight Materials and Manufacture 6 (2023) 117e128;
  4. Abdou Khadri Diallo et al., A multifunctional additive for sustainability, Sustainable Materials and Technologies, 33, 2022, e000487.

Innovation with Graphene

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Innovation with Graphene:

Towards a More Sustainable and Efficient Cement Industry

Part 1

Carbon dioxide (CO2) is a colorless, odorless, and non-toxic gas naturally present in the atmosphere. Under normal conditions, it should remain balanced to retain the heat necessary for human survival without becoming a greenhouse gas. However, overpopulation, industrialization, and environmental exploitation have disrupted this balance, making CO2 levels increasingly difficult to control. Consequently, these levels rise, concentrate, absorb radiation, and prevent heat from escaping, contributing to global warming.

According to statistics, cement production and the fossil fuel industry (coal, oil, and natural gas) are responsible for releasing about 90% of CO2 and probably 70% of greenhouse gases. Other industries, such as agriculture, fashion, and transportation, also contribute.

“Sustainability of our civilization depends on whether we can provide energy, food, and chemicals to the growing population without compromising the long-term health of our planet.” Doria-Serrano, 2009.

Concerning cement, the main component of concrete, reports mention that it alone accounts for between 7% and 8% of global CO2 emissions. For reference, producing one ton of clinker, the main component of cement, releases approximately ~0.86 tons of CO2, of which around 60% comes from the transformation of limestone into calcium oxide or lime at an average temperature of 1450 °C, a process also known as clinker burning. The remaining 40% is attributed to the combustion of fossil fuel (coal) necessary for the calcination of limestone and clinker formation.

“In 2021, carbon emissions from cement production reached nearly 2,900 million tons of carbon dioxide, while in 2002, 1,400 million tons were recorded.” The Global Carbon Project.

Therefore, to achieve the net-zero emissions target by 2050 required by the Paris Agreement, the cement industry has been forced to take measures to reduce its impact by using alternative fuels (biomass, tires, urban solid waste); improving energy efficiency by reducing the clinkerization temperature through fluxes and mineralizers (such as CaF2, BaO, SnO2, P2O5, Na2O, NiO, ZnO, etc.) or by renewing kilns; modifying cement chemistry with supplementary materials to reduce clinker consumption or capture CO2; and, recently, using graphene to improve the quality of cement and concrete.

“By 2050, global concrete consumption is expected to increase by 12% to 23% from 25 billion per year.”

According to the National Cement Chamber (CANACEM), most projects registered in Latin America are working on replacing fossil fuels with alternative fuels; Mexico is the only country registering higher production of blended cements to reduce clinker content.

Graphene is a nanomaterial consisting of atomic carbon sheets separated from graphite, with mechanical, electrical, thermal, and barrier properties superior to other carbon-based materials, allowing it to venture into countless applications and industries, including construction. According to estimates by Graphene Flagship, the use of graphene in construction is expected to reduce CO2 emissions by 30%.

“The production of 1 kg of graphene produces 0.17 kg of CO2, compared to 0.86 kg of CO2 for Portland cement, reinforcing the nanomaterial’s environmental advantages.”

Since the isolation of graphene in 2004 and the subsequent Nobel Prize in Physics 2010 awarded to its discoverers, an international race began to study, understand, and obtain the nanomaterial in sufficient quantities for large-scale applications at an affordable cost. In the construction sector, it was not until 2018 that research and investments manifested their first results in various parts of the world, such as:

2018: Graphenemex® launched Nanocreto®, the world’s first graphene oxide concrete additive (Mexico).

2019: Graphenenano developed Smart additives, graphene additives for concrete (Spain).

2019: GrapheneCA presented its OG concrete admix product line for the concrete industry (USA).

2021: Scientists at the University of Manchester developed the Concretene concrete additive (UK).

2022: Energeia Fusion-Graphenemex® launched the Graphenergy construction line, an improved version of Nanocreto® (Mexico).

2022: Versarien presented Cementene™, the world’s first 3D-printed construction with a graphene-reinforced mix (UK).

Basquiroto de Souza and collaborators, in their article “Graphene opens pathways to a carbon-neutral cement industry” published in 2022 in Science Bulletin, summarized the opportunities that graphene has for the sustainability of construction materials:

Reduction of Portland cement thanks to significant improvements in compressive strength and elastic modulus of concrete.

Increase the use of by-products or recycled materials in concrete to reduce greenhouse gas emissions by up to 7%, as well as a 2% reduction in energy consumption during the manufacture of graphene oxide reinforced mortar.

Reduction in construction costs due to improved strength or greater incorporation of by-products or waste materials. A cost analysis concluded that while the use of graphene oxide may slightly increase concrete costs, the economy index (compressive strength/cost per m3) of the mixes can increase by up to 40%.

Reduction in maintenance costs. By improving the quality of concrete structures, reductions in CO2 emissions are inferred through a reduction in the amount of construction materials and energy associated with maintenance.

Energy-efficient buildings: graphene’s thermal properties can also be applied to buildings to achieve energy savings by reducing the use of cooling/heating systems.

For Energeia-Graphenemex®, the leading company in Latin America in designing applications with graphene materials, it is a pride to be part of the graphene timeline for sustainable construction.

Authored by: EF/DHS

References

  1. Ige, O.E.; Olanrewaju, O.A.; Duffy, K.J.; Collins, O.C. Environmental Impact Analysis of Portland Cement (CEM1) Using the Midpoint Method. Energies 2022, 15, 2708.
  2. International Energy Agency, World Business Council for Sustainable Development. Technology roadmap – low-carbon transition in the cement industry. April 2018
  3. Felipe Basquiroto de Souza, Xupei Yao, Wenchao Gao, Wenhui Duan, Graphene opens pathways to a carbon-neutral cement industry, Science Bulletin, 2022, 67, 1, 2022, 5
  4. Papanikolaou I, Arena N, Al-Tabbaa A. Graphene nanoplatelet reinforced concrete for self-sensing structures– a lifecycle assessment perspective. Journal of Cleaner Production, 2019, 240: 118202
  5. Devi S, Khan R. Effect of graphene oxide on mechanical and durability performance of concrete. Journal of Building Engineering, 2020, 27: 101007
  6. Doria- Serrano. Química verde: un nuevo enfoque para el cuidado del medio ambiente. Educación química. 2009. UNAM.
  7. https://theplanetapp.com/que-son-las-emisiones-de-co2/
  8. https://graphene-flagship.eu/materials/news/materials-of-the-future-graphene-and-concrete/#:~:text=Graphene%2Denhanced%20concrete%20is%202.5,CO2%20emissions%20by%2030%25.
  9. https://www.versarien.com/files/5716/3050/8952/White_Paper_-_Graphene_for_the_construction_sector_-_final_version.pdf

Innovation in Non-Stick Coatings

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Innovation in Non-Stick Coatings:

Integration of Graphene Materials for Enhanced Properties and Performance

Currently, non-stick coatings refer to coatings that, to some extent, prevent the adhesion of substances, whether solid or liquid, to the surface they are applied on. The non-stick capability of these coatings is based on their very low surface tension, also known as surface energy, represented by “γ”.

For coatings to be considered non-stick, they must have a surface energy, γ, less than 26 mJ/m² and water contact angles greater than 90°. A surface where the drop forms a contact angle greater than 90° is a hydrophobic surface. This condition implies low wettability, adhesiveness, and surface energy (see Fig. 1). In contrast, if the surface is hydrophilic, a contact angle less than 90° will be observed, and the wettability, adhesiveness, and surface energy will be high.

Fig. 1 Scheme representing the contact angles of a hydrophobic and hydrophilic surface.

Industrially, there are multiple non-stick coatings based on fluoropolymers. The uses and applications of fluoropolymers in coatings cover a wide range of products. The non-stick effect and easy demolding allow their use in various industries, such as textile, chemical, automotive, and food industries, for the production of utensils, molds, tools, and equipment that need to be isolated from chemicals or food.

Most non-stick coatings have high thermal resistance; however, they do not have great abrasion resistance. The use of fluoropolymers in kitchen utensils raises concerns about the potential health risks, as harmful substances might be released during use.

In recent years, Energeia – Graphenemex®, a Mexican company leading in graphene material production, has implemented the use of these carbon-based nanomaterials. Graphene materials, such as graphene oxide and graphene, enhance properties in coatings, for example, anticorrosive, antibacterial, greater abrasion resistance, and high UV resistance.

During these property evaluations, it was observed that graphene materials can also be used as new additives for developing non-stick coatings. Incorporating graphene materials into epoxy-type coatings improved substrate adhesion; however, the finish of these coatings was smoother and shinier. When exposed to a corrosive environment, the coating showed hydrophobic behavior, keeping its surface cleaner compared to the control coating (without graphene material), which gradually lost its shine and showed wettability and contaminant deposition on the coating surface (see Fig. 2).

Fig. 2 Non-stick effects of coatings with graphene material.

Furthermore, the non-stick effect of an ecological coating with and without graphene material was evaluated. This coating is made of lime, nopal mucilage, and mineral pigments. It is well known that lime and carbonate-based materials absorb moisture easily, so the effect of graphene material in lime-based paint was studied. The results showed that the paint had an antimicrobial effect, greater UV resistance, and higher impermeability (non-stick effect).

In Fig. 3, the response of a lime-based coating with and without graphene material, when wetted by water, is shown. The coatings with graphene materials (Graphene and graphene oxide (GO)) at different concentrations showed very little deformation in the drop as its internal energy was higher than the surface energy, displaying hydrophobic behavior (water repellency). In the case of the control coating (without graphene material), it was observed to have very little non-stick capacity, absorbing water more easily due to high surface energy. The drop spread on the surface immediately when the water drop fell on the surface, showing highly hydrophilic behavior. These results showed that graphene materials modified the nature of the coating, i.e., they modified the surface energy of the coatings at the surface level.

Fig. 3 Wetting behavior of a lime-based coating, with and without graphene materials.

Currently, Energeia – Graphenemex®, a leading Mexican company in Latin America in the research and production of graphene materials for industrial application development, offers various types of graphene materials for use in developing and producing anticorrosive, antibacterial, and enhanced non-stick coatings.

References

  1. Tong, Yao &Song, Mo. (2013). Graphene based materials and their composites as coatings.
  2. Zhen, Z. & Zhu, H. Graphene: Fabrication, Characterizations, Properties and Applications. Graphene (Academic Press, 2018).
  3. Sachin Sharma Ashok Kumar, Shahid Bashir, K. Ramesh, S. Ramesh, Progress in Organic Coatings, 154, (2021)

Graphene Oxide Versatile Applications

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Graphene Oxide Versatile Applications:

From Sensing Technologies to Environmental Solutions

Graphene and its derivatives such as graphene oxide (GO) and reduced graphene oxide (rGO) are two-dimensional, sheet-like carbon nanomaterials with a wide range of opportunities for numerous applications due to their thinness, transparency, conductivity, flexibility, chemical stability, impermeability, and mechanical strength. In the case of GO and rGO, in addition to their large surface area with hydrophilic and hydrophobic regions inherent to graphene, they allow the adsorption of organic aromatic molecules, ions, and polymers through π-π stacking, hydrogen bonding, and electrostatic interactions. These properties make them suitable materials for constructing sensors or biocatalytic and photocatalytic platforms. According to various reports, the surface-to-volume ratio of graphene materials enhances the surface charge of the desired molecules, while their excellent electrical conductivity, especially at room temperature, favors electron transfer to the surface of electrodes for analysis or photocatalysis.

On the other hand, graphene sheets are not perfectly flat; they exhibit undulations formed as a result of the bonding between their carbon atoms or thermal fluctuations, which can ultimately induce magnetic fields and alter their electronic properties for designing sensors, biosensors, or electronic devices in general. Thus, through more than ten years of research and exploration of their remarkable multifunctionality, the study of graphene has transcended to the development of highly sensitive devices for monitoring, for example, the presence of harmful gases, medically relevant molecules, or proteins, and even water decontamination.

Detection Systems

Metamaterials are a type of compound with the ability to produce useful electromagnetic responses for designing sensors or non-destructive detection devices. Generally, these sensors consist of an insulating material and a conductive material, sensitive to the refractive index of the analyte’s upper layer. In the presence of graphene, it has been observed that this interaction (sensor-analyte) is enhanced by changes in resonance intensity, leading to amplitude changes that further favor detection sensitivity.

In a study conducted in 2023 by the School of Electronic and Information Engineering at Zhejiang University of Science and Technology, Hangzhou, China, a sensor was designed comprising a polyimide (PI) film as an insulating layer, an aluminum structure as a conductive layer, and a monolayer of graphene as the detection interface. Simulation results indicated that graphene could modulate the entire electric field and produce an amplitude change that significantly increases detection limits.

In another study conducted at the Laboratory of Nanostructured Materials of the Institute of Physics at UASLP, functionalized graphene oxide with gold nanoparticles was used as a SERS (Surface Enhanced Raman spectroscopy) biodetection platform, an important technique for biological detection due to its high sensitivity, low sample requirements, relatively low cost, and real-time detection. Crystal violet was used as the standard molecule and flavin adenine dinucleotide as the experimental coenzyme for its participation in numerous redox processes of metabolic reactions and biological electron transport. The results showed that graphene oxide hybrids with gold nanoparticles substantially enhance SERS signals compared to individual nanoparticles. Additionally, the results are consistent with other research on identifying significant improvements for molecule stabilization and fluorescence reduction during measurements, which is often a major drawback of such techniques, supporting its potential as a diagnostic or monitoring tool.

Toxic Gas Removal

Advances in nanoengineering allow graphene and GO sheets to be manipulated for the detection and separation of certain gases. According to the results of a study conducted by the Department of Energy Engineering at Hanyang University, Seoul, Korea, selective diffusion can be achieved by controlling the gas flow channels and pores through different stacking methods, demonstrating that GO’s functional groups provide a unique adsorption behavior towards CO2.

CO2 Conversion

The photocatalytic properties of GO can also be harnessed for converting CO2 into hydrocarbons such as methanol for solar energy capture and CO2 reduction. In 2018, at the Advanced Technology Laboratory for Materials Synthesis and Processing, Wuhan University of Technology, China, silver chromate (Ag2CrO4) nanoparticles were used as a photosensitizer and GO as a co-catalyst for the photocatalytic reduction of CO2 into methanol and methane. The study concluded that this synergy between nanoparticles could enhance conversion activity up to 2.3 times under solar irradiation due to better light absorption, increased CO2 adsorption, and improved charge separation efficiency.

Water Decontamination

Water technologies have various areas of opportunity, particularly in improving filtration or membrane systems. In this regard, it has been found that using hybrid graphene nanostructures, for example, with ruthenium or magnetite, can allow the removal of microorganisms and organic matter present in water. However, research continues to advance to perfect graphene-based methodologies for the removal and reduction of metal ions such as zinc, copper, lead, cadmium, cobalt, among others.

At Energeia-Graphenemex®, we recognize and admire the advancements that research centers have achieved in various areas of knowledge, starting from basic science to applied science results. We firmly believe that in the short or medium term, these technologies will materialize into real products that are useful to society and the environment.

Redaction: EF/ DHS   

References

  1. A. Fasolino, J.H. Los, M.I. Katsnelson, Intrinsic ripples in graphene, Nat. Mater. 6 (2007) 858;
  2. W. Bao, F. Miao, Z. Chen, H. Zhang, W. Jang, C. Dames, C.N. Lau, Controlled ripple texturing of suspended graphene and ultrathin graphite membranes, Nat. Nanotechnol. 4 (2009) 562; 3. G. Yildiz, M. Bolton-Warberg and F. Awaja. Graphene and graphene oxide for bio-sensing: General properties and the effects of graphene ripples. Acta Biomaterialia 131 (2021) 62;
  3. Lang, T.; Xiao, M.; Cen,W. Graphene-Based Metamaterial Sensor for Pesticide Trace Detection. Biosensors 2023, 13, 560;
  4. D. Hernández- Sánchez, E. G. Villabona Leal, I. Saucedo-Orozco, V. Bracamonte, E. Pérez, C. Bittencourt and M. Quintana, Phys. Chem. Chem. Phys., 2017;
  5. Kim, H.W.; Yoon, H.W.; Yoon, S.-M.; Yoo, B.M.; Ahn, B.K.; Cho, Y.H.; Shin, H.J.; Yang, H.; Paik, U.; Kwon, S. Selective gas transport through few-layered graphene and graphene oxide membranes. Science 2013, 342, 91;
  6. Kim, D.; Kim, D.W.; Lim, H.-K.; Jeon, J.; Kim, H.; Jung, H.-T.; Lee, H. Intercalation of gas molecules in graphene oxide interlayer: The role of water. J. Phys. Chem. C 2014, 118, 11142;
  7. Xu, D.; Cheng, B.; Wang, W.; Jiang, C.; Yu, J. Ag2CrO4/g-C3N4/graphene oxide ternary nanocomposite Z-scheme photocatalyst with enhanced CO2 reduction activity. Appl. Catal. B Environ. 2018, 231, 368;
  8. Jiˇríˇcková, A.; Jankovský, O.; Sofer, Z.; Sedmidubský, D. Synthesis and Applications of Graphene Oxide. Materials 2022, 15, 920;
  9. M. Quintana, E. Vazquez & M. Prato, “Organic Functionalization of Graphene in Dispersions”, Acc. Chem. Res., vol. 46, n.o 1, pp. 138-148, 2013. DOI: 10.1021/ar300138e;
  10. Roberto Urcuyo1,2,3, Diego González-Flores1,3, Karla Cordero-Solano, Rev. Colomb. Quim., vol. 50, no. 1, pp. 51-85, 2021;
  11. B. Xue, M. Qin, J. Wu et al., “Electroresponsive Supramolecular Graphene Oxide Hydrogels for Active Bacteria Adsorption and Removal”, ACS Appl. Mater. Interfaces, 8, 24, 15120;
  12. C. Wang, C. Feng, Y. Gao, X. Ma, Q. Wu & Z. Wang, “Preparation of a graphene-based magnetic nanocomposite for the removal of an organic dye from aqueous solution”, Chem. Eng. J.,173, 1, 92.

Advancing Asphalt Durability

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Advancing Asphalt Durability:

Harnessing Graphene’s Potential for Sustainable Roads

Most of the the world’s road infrastructure is composed of pavement made from a complex system of asphalt, aggregates, and binders that interact at an interface to maintain its strength and structural stability. According to the Asphalt Institute, 87 million tons of asphalt are produced worldwide annually, with around 85% used in the paving industry, which, while offering great load capacity and durability, inevitably suffers damage from constant exposure to radiation, temperature, humidity, and traffic.

The deterioration of asphalt not only impacts a basic transportation infrastructure crucial for socio-economic development but also involves environmental impacts in terms of resource depletion and high CO2 emissions caused by roadworks. These factors add to the reasons for the constant search for modification technologies that increase durability and improve mechanical properties of pavements using fibers, rubber; additives such as thermoplastic elastomers, plastic and synthetic resins, iron powder, hydrated lime, or glass waste. However, in some cases, the application of these products can present practical problems such as special preparation conditions, low storage stability, difficulty in mixing during construction, and complexity in compatibilizing these components with the asphalt system.

Fortunately, carbon nanostructures such as graphene and graphene oxide (GO) reappear on the scene as proposed solutions to these issues with interesting contributions to asphalt regarding stiffness, anti-aging, deformation, and penetration resistance; reduction in rutting, improved consistency, heat transfer capacity; skid resistance, and even a reduction in the effort required for compaction during preparation.

Additionally, among the advantages of graphene is its ability to be mixed with other asphalt modifying technologies such as low-density polyethylene (LDPE), high-density polyethylene (HDPE), polyethylene terephthalate (PET), polystyrene (PS), granulated rubber, blast furnace slag, epoxy resins, and especially with styrene-butadiene-styrene (SBS), which is one of the most accepted polymers in the asphalt industry, and with which graphene oxide (GO), thanks to its oxygen content, promotes the absorption of aromatics and saturates from SBS with a significant improvement in temperature response, adhesion, and binder stiffness.

Some identified methods that promise to simplify the incorporation of graphene into asphalt mixes are:

  1. Direct addition method: graphene is added to the previously melted asphalt binder.
  2. Indirect addition method: graphene and asphalt binder are simultaneously dissolved in a medium solution to later form a uniform solution.
  3. Auxiliary addition method: graphene is chemically modified with functional groups or added together with other modifying agents to later melt into the asphalt binder.

Although there are few companies that have explored graphene as an asphalt improving additive so far, the extensive research conducted over the past decade is helping to lay the groundwork for understanding and projecting the potential of this technology for the benefit of the paving industry. Even in February 2024, the Infrastructure journal published the results of the ECOPAVE project funded by the European Union, which consisted of a 5-year field test conducted over 1 km of heavy traffic in southern Rome, Italy. For the study, four sections of asphalt pavement with and without additions of graphene-modified polymers were installed. After the 5-year evaluation period, researchers reaffirmed the potential of asphalt modified with graphene polymer as an innovative and feasible technology for high-traffic road paving, as it demonstrated higher stiffness values at different temperatures, better fatigue behavior, and greater deformation resistance, promising an extended lifespan with a significant reduction in maintenance costs.

At Energeia-Graphenemex®, as leaders in graphene application development, we firmly believe that, although there is still work to be done, we are very close to enjoying the economic and environmental benefits that this wonderful technology can bring not only to our streets and roads but also to society.

Draft: EF/DHS

References

  1. Mechanism and Performance of Graphene Modified Asphalt: An Experimental Approach Combined with Molecular Dynamic Simulations. Case Studies in Construction Materials. 2023, 18, e01749;
  2. Properties and Characterization Techniques of Graphene Modified Asphalt Binders. Nanomaterials 2023, 13, 955;
  3. Analysis on the road performance of graphene composite rubber asphalt and its mixture. Case Studies in Construction Materials. 2022, 17, e01664;
  4. A complete study on an asphalt concrete modified with Graphene and recycled hard-plastics: A case study. Case Studies in Construction Materials. 2022, 17, e01437;
  5. Effect of Graphene Oxide on Aging Properties of polyurethane-SBS Modified Asphalt and Asphalt Mixture. Polymers 2022, 14, 3496;
  6. Mechanical Characteristics of Graphene Nanoplatelets-Modified Asphalt Mixes: A Comparison with Polymer- and Not-Modified Asphalt Mixes. Materials 2021, 14, 2434;
  7. Impact of Graphene Oxide on Zero Shear Viscosity, Fatigue Life and Low-Temperature Properties of Asphalt Binder. Materials 2021, 14, 3073;
  8. Experimental Investigation into the Structural and Functional Performance of Graphene Nano-Platelet (GNP)-Doped Asphalt. Appl. Sci. 2019, 9, 686;
  9. Modified Asphalt with Graphene-Enhanced Polymeric Compound: A Case Study. Infrastructures 2024, 9, 39.

Glass and Carbon Fiber Composites Enhancement

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Glass and Carbon Fiber Composites Enhancement:

Improving Properties with Graphene Nanoparticles

Glass and carbon fibers, thanks to their excellent properties, are widely used in industries such as aerospace, maritime, automotive, sports, construction, and even in the manufacturing of fundamental components for renewable energies such as wind power. However, despite their excellent performance, they often exhibit a phenomenon known as “interlaminar delamination” due to weak fiber/resin interfacial interaction, which can compromise the product’s lifespan and safety due to their significant role in stress transfer between both elements. As this interaction is key to the long-term success of composite structures, various improvement alternatives have been explored, such as Z-pinning, stitching, and braiding; increasing the surface area and reactivity of fibers through surface modifications such as plasma treatment, thermal modification, or chemical functionalization, which are complex, costly processes that are not always efficient and tend to reduce the laminate’s in-plane performance.

“As an additional strategy of relatively recent emergence, the incorporation of nanoparticles into fiber composite materials was proposed to favor interaction with the embedding matrix.”

Graphene, the nanomaterial known as the cornerstone of the carbon family and which since its isolation has been described as “the material of the future” or “the miracle material,” is an attractive candidate as a nanoreinforcement for countless polymeric compounds due to its unique graphitized flat structure, which leads to better mechanical, thermal, and other properties that, unlike other nanoparticles such as carbon nanotubes (CNTs), do not significantly increase resin viscosity and therefore allow higher concentrations to be incorporated, favoring the aforementioned fiber/matrix interaction.

Research on the effects of graphene for the design of hybrid materials based on fibers (glass/carbon) embedded in a commonly epoxy-based polymeric matrix has highlighted greater compound stiffness, improvements in fracture resistance, better lubrication, and even improved electrical conductivity. This is because its large surface area allows effective load transmission from the soft polymer matrix to the relatively stiffer graphene sheets, which is an essential requirement for improving mechanical performance, confirmed by increased interlaminar shear strength of the material, greater tensile and impact strength. Additionally, during the manipulation and cutting of hybrid fiber structures, the presence of graphene contributes to generating less heat during milling, leading to lower cutting temperatures and smoother surface roughness; likewise, another benefit is that graphene produces a greater hardening effect and better bending resistance of the material exposed to different temperatures ranging from 40 °C to 200 °C.

At Energeia-Graphenemex, the leading company in Latin America in the production of graphene materials and in the development of applications, we are convinced that graphene’s extraordinary capabilities as a nanoreinforcement for countless three-dimensional matrices will continue to encourage researchers and industrial colleagues to explore its benefits for the manufacture of stronger and lighter structural components for aircraft such as fuselage and wings; automotive parts and aerodynamic bodywork; wind turbines, sports equipment, construction materials, among others.

Draft: EF/DH

References:

  1. Effect of dispersion of alumina nanoparticles and graphene nanoplatelets on microstructural and mechanical characteristics of hybrid carbon/glass fibers reinforced polymer composite. Journal of material research and technology. 2021, 14, 2624;
  2. Experimental investigation on the properties of glass fiber-reinforced polymer composites containing Graphene. AIP Conf. Proc. 2022, 2405, 050009;
  3. Reinforcement effect of graphene oxide in glass fibre/epoxy composites at in-situ elevated temperature environments: An emphasis on graphene oxide content. Composites part A: Applied science and manufacturing. 2017, 95, 40;
  4. Preparation and Mechanical Properties of Graphene/Carbon Fiber-Reinforced Hierarchical Polymer Composites. J. compos sci. 2019, 3, 30;
  5. Improving fiber/matrix interfacial strength through graphene and graphene-oxide nano platelets. IOP Conf. Ser.: Mater. Sci. Eng. 2016, 139, 012004;
  6. Effect of Graphene on Machinability of Glass Fiber Reinforced Polymer (GFRP). J. Manuf. Mater. Process. 2019, 3, 78;
  7. Size effect of graphene nanoplatelets on the morphology and mechanical behavior of glass fiber/epoxy composites. J Mater Sci. 2016, 51, 3337.

Tapping into Graphene’s Potential:

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Tapping into Graphene’s Potential:

Enhancing Coatings with Nanotechnology for Weather Resistance

Coatings are designed for decorative purposes and to protect surfaces, especially against corrosion and moisture. In a coating system (multilayer), the top or finishing layer plays a crucial role as it must provide a good appearance and protect the inner layers and the substrate against environmental factors such as sunlight, humidity, corrosion, chemical resistance, soiling, etc., throughout its lifespan.

Today, Polyurethane (PU) is considered one of the coatings with the best physical-chemical characteristics for finishing coating applications and for its weather resistance. However, its weather resistance decreases with exposure to ultraviolet light over long periods.

Sunlight is one of the main causes of damage to coatings. Damage ranges from loss of physical properties, powdering (chalking), cracking, peeling, discoloration, and color change, because of chemical photodegradation, migration, evaporation, and interaction of other components with the coating.

In recent years, various nanostructured materials such as titanium, zinc oxide, cerium, and iron oxide have been implemented to improve the weather resistance of polymeric coatings. The mechanism is based on their projection effect (both absorption and dispersion) of incident rays in the UV region. These materials can stabilize coatings against exterior exposure, possess photocatalytic activity that can destroy the organic binder material present in coatings, leading to modifying the surface of these nanostructured materials to eliminate or inhibit their photocatalytic activity, requiring more processes, time, and money.

Recently, graphene has attracted much attention as a new additive and material for producing coatings to enhance anticorrosive, antimicrobial, and weather-resistant properties, due to its special electronic structure that provides unique electrical, mechanical, and chemical properties. Graphene is a nanomaterial formed by one or more layers of carbon (formed by carbon atoms bonded hexagonally with a thickness of one carbon atom). This structure enables graphene-based materials to absorb photons in the UV region. This UV absorption capacity, as well as the absence of photocatalytic activity of graphene materials, allows introducing these materials as new additives for the photo-stabilization of polymeric coatings, i.e., with greater resistance to UV radiation

Currently, Energeia – Graphenemex®, is in constant development of nanotechnological coatings with better properties. Studies have been conducted on the influence of graphene oxide on the weathering behavior of PU coatings. To evaluate the performance of graphene oxide, a PU coating with graphene oxide (PU/GO) was compared with a PU coating containing a commercial organic UV absorber (PU/control).

Color change in a coating during exposure to weathering (sunlight) is the most important and rapid parameter to visually evaluate coating degradation. To evaluate, color change, samples coated with Polyurethane with and without graphene material were introduced into an accelerated weathering chamber (based on ASTM G154). According to the standard, a QUV weathering chamber model QUV/se was used to accelerate weathering conditions. Coated samples were cyclically exposed to UVA radiation (energy 0.89 W/m2) for 8 hours, followed by moisture condensation for 4 hours at 50 °C. The color of the coatings was evaluated before exposure to compare their initial color, and subsequently evaluated at different exposure times, this evaluation was performed until reaching an exposure time of 1200 hours.

The main component of color typically considered in weathering behavior is the total color change or Delta E (ΔE). Fig. 1 shows the ΔE, as the most comprehensive criterion of color changes, which is the sum of changes in all color components.

As can be seen, most of the color variations throughout the exposure time belong to the PU/control coating. The sample containing graphene oxide (PU/GO) at 251 hours of exposure time shows a lower color change compared to PU/control. With the increase in exposure time in the weathering chamber, color variations can be observed, but the sample with graphene oxide continues to show lower color changes, indicating that the incorporation of GO in Polyurethane provides more resistance and maintains its stability for longer exposure times to weathering.

Fig 1. Total color change (ΔE) versus exposure time for Polyurethane coatings with graphene oxide (PU/GO) and without graphene oxide (PU/control) during accelerated weathering test.

From a physical point of view, graphene oxide (GO) has higher transmittance in the visible region compared to graphene, which is more favorable for its use as a UV protector in finishing coatings. On the other hand, thanks to the high surface area of graphene materials, they can also provide excellent barrier effect properties and thus develop anticorrosive coatings with greater weather resistance.

Energeia – Graphenemex®, through its Graphenergy line, offers a wide range of nanotechnological coatings with graphene. These coatings offer high anticorrosive and antimicrobial protection. In addition to providing high wear resistance, UV resistance, impermeability, and extraordinary adhesion, with the aim of improving the life of any surface or installation and reducing maintenance costs.

References

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  3. N. Rajagopalan, A.S. Khanna, Effect of Methyltrimethoxy Silane Modification on Yellowing of Epoxy Coating on UV (B) Exposure vol. 2014, (2014).
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  5. S.M. Mirabedini, M. Sabzi, J. Zohuriaan-Mehr, M. Atai, M. Behzadnasab,
  6. Weathering performance of the polyurethane nanocomposite coatings containing silane treated TiO2 nanoparticles, Appl. Surf. Sci. 257 (no. 9) (2011) 4196–4203.
  7. N.S. Allen, M. Edge, A. Ortega, C.M. Liauw, J. Stratton, R.B. McIntyre, Behaviour of nanoparticle (ultrafine) titanium dioxide pigments and stabilisers on the photooxidative stability of water based acrylic and isocyanate based acrylic coatings, Polym. Degrad. Stab. 78 (no. 3) (2002) 467–478.
  8. Effect of Silane Modified Nano ZnO on UV Degradation of Polyurethane Coatings. vol. 79, (2015), pp. 68–74.
  9. M. Rashvand, Z. Ranjbar, S. Rastegar, Nano zinc oxide as a UV-stabilizer for aromatic polyurethane coatings, Prog. Org. Coatings 71 (4) (Aug. 2011) 362–368.