A KU research team has developed a hybrid material capable of adsorbing pollutants from industrial wastewater using two natural resources of great abundance in the UAE – sand and dates.
Removing pollutants from industrial wastewater safely and affordably is a fundamental concern for governments worldwide. Now, an emerging technology is being explored by researchers at Khalifa University that aims to clean wastewater using two natural resources of great abundance in the UAE – sand and dates.
The KU research team developed a graphene-sand hybrid material capable of adsorbing pollutants, which involves attaching pollutants onto small particles that are then easily removed. While synthesizing graphene-sand adsorbents can be prohibitively expensive, the KU researchers have turned to a previously unused resource – date syrup – to provide the carbon needed to produce the graphene.
“While other routes have been studied, using sugar, for example, as the carbon base for graphene-sand adsorbents, our project aims at utilizing locally available resources for tackling global challenges. As far as we know, we’re the first to use date syrup as a sustainable carbon source,” explained Dr. Fawzi Banat, Professor of Chemical Engineering, at Khalifa University.
Dr. Banat, along with Anjali Edathil, former Research Engineer in the Department of Chemical Engineering, and Shaihroz Khan, visiting Research Assistant, described the in-situ strategy used to produce the graphene-sand hybrid with date syrup in a paper published in Scientific Reports.
Their adsorbent can be used as an environmentally benign and scalable option for decontaminating wastewater, with the adsorption capacity far surpassing that of similar reported graphene-based adsorbents.
“Water is one of the world’s most valuable resources, and only one percent of the global water supply is available for consumption and domestic use,” explained Dr. Banat. “With augmented urbanization and substantial industrialization activity, enormous amounts of hazardous chemicals are discharged into receiving waters every day. Among the emerging inorganic and organic contaminants, heavy metals and dyes are frequently found in industrial effluents, which, if untreated, become a principal concern to the environment and public health. They are non-biodegradable and tend to accumulate in living organisms.”
Numerous efforts have focused on developing cost-effective and appropriate materials and technologies to regulate the amount of these persistent water pollutants to permissible levels before wastewater is discharged to water bodies. Different treatment technologies have been tested, including photodegradation, precipitation, coagulation, membrane separation, and ion exchange. While all work, they suffer from drawbacks in applicability and cost-effectiveness.
Comparatively, the process of adsorption – where a solid holds molecules of a dissolved solid, liquid or gas on its surface by adhesion – is a relatively mature and versatile method for removing pollutants. Traditionally, carbon-rich materials such as charcoal, soot and biochar are used as adsorbents due to their low costs and high surface areas.
“With the advent of nanotechnology, researchers have explored the use of carbon nanomaterials for water purification, with the hope that it may open new fruitful pathways to curb the existing water shortage,” explained Dr. Banat.
“Graphene has attracted tremendous research interest. Its unique physiochemical and mechanical properties have led to its potential as a revolutionary adsorbent for environmental pollutant management. However, a key barrier in the practicality of pristine graphene nanosheets for water purification is its high cost and post-treatment handling, including recovery after the decontamination process.”
Graphene is a novel 2D, one-atom-thick nanomaterial made of carbon atoms arranged in a honeycomb structure. In many cases, such as this one, graphene is organized into sheets a few layers thick rather than existing as a single monolayer. Regardless of organization, however, graphene’s high surface area, combined with its versatile chemistry and highly hydrophobic surface, makes it an ideal adsorbent for removing pollutants. The natural defects and ‘wrinkles’ on its surface act as high-surface-energy adsorption sites for organic pollutants. However, graphene aggregates heavily in water due to the strong forces between the graphene layers.
“To overcome these issues, we can anchor the nanosheets onto an economical and reliable inorganic substrate such as sand,” explained Dr. Banat. “Graphene-sand hybrids not only allow the full expression of the graphene adsorption sites but also ensure dispersibility and easy separation from water.”
Dr. Banat’s research proposes a single-step strategy to develop efficient and eco-friendly graphene sand hybrids using date syrup, a widely available and sustainable carbon source in the Middle East.
Different carbon sources are available in different parts of the world, with several synthetic routes already reported for the preparation of graphene-sand hybrids from sugar, palm sugar, gelatin and asphalt.
Dr. Banat’s team used pyrolysis – the process of chemically decomposing organic materials at high temperatures in the absence of oxygen – to decompose the date syrup, triggering a change of chemical composition and the synthesis of a large volume of graphene material, that subsequently attaches to desert sand without the use of any external chemical agents.
“It is believed that during pyrolysis, the naturally abundant sucrose and fructose molecules in the date syrup undergo complete exfoliation to form graphene nanosheets on the desert sand surface, thereby exposing the powerful adsorption sites concealed in the stacked graphene,” said Dr. Banat.
Dr. Banat’s graphene-sand hybrid adsorbent was tested in the laboratory and showed remarkable efficiency in simultaneously removing both dye and heavy metals from multicomponent systems. The researchers concluded that their adsorbent had great potential as an exceptional material resource of water purification.
“This will undoubtedly open new avenues for the practicability of graphene to curb the existing water shortage,” added Dr. Banat. “We hope our material will help in increasing water resources in the UAE, reducing energy consumption in wastewater treatment processes and be used to convert oily wastewaters from waste to commodity than can be used in applications such as industrial recycling and agriculture.”
The Graphene Council encourages members to join a webinar delivered by Nanotech Industry Association (NIA) Member Cerion to understand planning and implementation of nanomaterials manufacture during COVID-19 disruption.
About this Event
COVID-19 has changed the way that businesses and the world are operating and looking towards the future. Questions like: “How do I adapt to this rapidly-changing environment?” and “How do I plan for when the economy returns?” are top of mind for us all right now.
Join us along with NIA member Cerion Nanomaterials to discuss the practical steps you can take to get your business through these challenging times, no matter what phase of the outbreak curve you are experiencing.
The discussion will include an analysis of the current outbreak projections, some key triggers you should keep in mind when planning your strategy, along with how to keep employees safe that are still working (in the lab, manufacturing or business operations) -- as well as, developing a plan for when everyone returns to work.
Scientists at the University of Sussex have secured a major cash boost for their research into the real-world applications of nanomaterials. With new funding of £1 million from private company Advanced Material Development, Professor Alan Dalton and his team will pursue their research into nanomaterials, including camouflage technology to stop soldiers from being spotted by thermal imaging cameras or night vision goggles – potentially paving the way for a Harry Potter or Predator-style invisibility cloak.
The team will also develop their research into anti-counterfeiting graphene inks which can be printed onto clothes and medicine containers; incorporated into smart tyres which monitor for problems; used on banknotes; included on metal-free radio-frequency identification tags (RFID) tags for supermarkets to track products; and wearable technology including monitors for babies’ heartbeats or diabetic patients’ glucose levels.
Carbon based nanomaterials, such as graphene, are metal-free and more ecologically-friendly than many alternatives. They can also be flexible and highly conductive.
Professor Alan Dalton said:
“The funding we’ve received from AMD means that we can push forward with our research into useful applications for nanomaterials like graphene. Whether that’s to develop wearable technology to remotely track babies’ heartbeats, or to print ink onto car tyres which can monitor the tyres and warn the driver about problems, the potential applications of these materials are vast.
“One of the most exciting applications is for camouflage clothing which masks the heat or light being emitted from a material or surface. This paves the way for one day making a cloaking device like the one in the movie Predator which lowers its wearer’s thermal temperature, or like Harry Potter’s invisibility cloak.”
The £1 million is split over two years and covers four post-doctorate researchers and various students who will primarily produce nanomaterial inks. The versatile applications include:
Invisibility cloaks for the military and heat-proof windows
When the graphene ink is laid onto a textile or substrate, its reflectiveness can be manipulated. In the laboratory, Alan Dalton’s team have been able to control how ions move between graphene sheets which modifies the sheet’s optical properties. The team have shown that this works with heat as well as light, recording more than a 5 degree drop in the temperature in the lab. There are clear military applications for this, using a graphene coating to hide the infrared signature of a soldier, or a vehicle. With further development, a soldier’s thermal signature could be totally camouflaged to keep them safe from detection at night or from thermal imaging.
The same technology can work on hard surfaces too such as windows. In hot climates it will be possible to cool a room by reducing the amount of heat passing through the window into it, and visa versa in cold weather. Similarly, the amount of light coming into a room could be changed with the touch of a button.
Smart tyres which monitor for defects
The team at Sussex are developing a graphene ink which would be flexible and conductive enough to be printed onto car tyres. It would be able to inform the driver about the health of the tyres. In collaboration with AMD, they are already working with a German automotive company on this technology.
Metal-free tags for supermarkets
AMD and the Sussex team are already working with a major UK retailer on creating metal-free RFID tags for products. They have created an alternative to metal tags on clothing and food by developing antennas based on graphene inks which can be printed onto paper. This will help stores to track their items within supply chains and also to keep more accurate inventories of their stocks within stores. Retailers will be able to bin their metal-dependent tags and replace them with this much more eco-friendly answer. There’s no need now for the old fashioned supermarket tags of the past to populate landfill sites. With various supermarkets pledging to improve their green credentials, including Walmart in the US, this technology is set to disrupt this aspect of the retail sector.
Anti-counterfeiting for fashion and medicine
The Sussex laboratory has created a way to incorporate an invisible but unique ink-based signature into textiles and onto hard materials. With this, fashion houses can be sure their clothes are genuinely theirs and not rip-off copies. Hospitals and pharmaceutical companies could likewise be assured of the authenticity of medicines. Even often-stolen items such as metal power line cables could be stamped with the ink so their true origin can be tracked.
Wearable technology for health
The team have also developed a potentially lifesaving baby monitor to track newborns’ heartbeats remotely in developing countries where medical centres are sparse. They’re now looking to take the developments further including to create printable tattoos for diabetic patients which could track their glucose levels and give them early notice that they are at risk.
Dr Sue Baxter, Director of Innovation and Business Partnerships, said:
“The University is thrilled at the ground-breaking technologies that are bursting out of this university-business partnership. We have such great research capability at Sussex and teaming up with AMD has created a fantastic platform for Alan and his team to get their innovations out of the lab and into our daily lives in a transformational way.”
Professor Dalton’s team has already created a proto-type capacitive sensor for smart phone screen using silver nanowires and graphene which was both highly conductive, didn’t rely on ITO (which maybe facing critical shortage in supply and contains damaging indium) and crucially is also flexible and almost smash-proof.
Advanced Material Development was set up in 2017 to develop applications for graphene technology from Professor Dalton’s lab, and is based at the Sussex Innovation Centre. John Lee (right) is the Chief Executive Officer, Dr James Johnstone (left) is Chief Operating Officer and Alan Dalton is Chief Scientific Officer. This is the second grant the laboratory has received from AMD, following £600,000 in Autumn 2018.
In a study published in the Royal Society of Chemistry journal Nanoscale,https://pubs.rsc.org/en/content/articlelanding/2019/nr/c9nr06815e#!div Abstract Spanish and Italian researchers provided a comprehensive and relevant study on the potential of topically applied graphene for irritating the skin.
While graphene producers have heralded this study https://www.graphenea.com/blogs/graphene-news/graphene-not-irritant-to-skin-study-shows as a clear indication that graphene materials do not irritate the skin, it is only one brick in a much larger wall that is still in the very early stages of being built around understanding the potential health risks of graphene exposure, and its safe use, according to Andrew Maynard, https://isearch.asu.edu/profile/2670673 a professor at Arizona State University and an expert on the environmental and health impact of nanomaterials.
Maynard recognizes that the results are significant in that they indicate that there is greater potential for skin harm to occur from the surfactants that some graphene materials are held in, or contain residues of, than from the graphene itself.
“However, while the paper makes an important addition to what is known about the potential impacts or otherwise of skin exposures to graphene, more work is needed to clearly establish how the skin responds to different types and preparations of graphene, and safe limits of graphene skin exposure with regard to irritation,” says Maynard.
Maynard emphasizes that care needs to be taken in comparing skin vs inhalation toxicity/risk/impacts.“Both the exposure mechanisms, the biological barriers and routes, the toxic mechanisms, and the impacts of the outcomes, differ - especially where the end point is irritation rather than other end points,” says Maynard.
While the available exposure area of the skin can make it quite serious if it is exposed to enough material, localized irritation is unlikely to be directly comparable to adverse effects from inhalation, simply because the lungs are vital organs that are highly sensitive to damage. This is true even in instances when the material is able to penetrate through the skin and reach other parts of the body.
Because of the differences between the skin and the lungs, it is dangerous to draw direct comparisons between skin exposure and lung inhalation. Maynard says it more appropriate to consider each system on its own merits and vulnerabilities in terms of exposure and response.
The key formula in understanding the risk of any material is this: risk = hazard (toxicity) x exposure. If a highly toxic material is totally inaccessible, it does not pose a large risk. While a relatively more benign material that is more accessible can pose a larger risk.
While this research brings in the element of skin irritation to discussions of the risk of graphene, there remains a paucity of data, especially when it comes dermal toxicity, despite this most recent research, according to Maynard.
“Like many materials, indications of hazard and risk are highly dependent on many different factors, including the specific material type (including synthesis route and any matrix it is in), exposure route, dose, organs and systems potentially impacted etc.,” says Maynard.“This latest research is the most comprehensive of recent reviews, and indicates that it’s complicated. There is evidence that some forms of graphene are hazardous under certain conditions and scenarios, but the links between hazard are risk (and these links are still vital to assessing risk) remain elusive.”
Maynard agrees with the researchers that because skin exposure is likely to be an issue during production or the use of graphene-based products designed for skin contact, it is important to understand the potential health impacts so they can be avoided.
Maynard adds: “The workplace, even if there’s a hint of possible harm from skin exposure, exposure control is possible by using routine barriers such as gloves, making the possibility of irritation less concerning if good work practices are followed.”
With a porosity of 99.99 %, it consists practically only of air, making it one of the lightest materials in the world: Aerobornitride is the name of the material developed by an international research team led by Kiel University. The scientists assume that they have thereby created a central basis for bringing laser light into a broad application range.
Based on a boron-nitrogen compound, they developed a special three-dimensional nanostructure that scatters light very strongly and hardly absorbs it. Irradiated with a laser, the material emits uniform lighting, which, depending on the type of laser, is much more efficient and powerful than LED light. Thus, lamps for car headlights, projectors or room lighting with laser light could become smaller and brighter in the future.
The research team presents their results in Nature Communications ("Conversionless efficient and broadband laser light diffusers for high brightness illumination applications").
More light in the smallest space
In research and industry, laser light has long been considered the “next generation” of light sources that could even exceed the efficiency of LEDs (light-emitting diode).
“For very bright or a lot of light, you need a large number of LEDs and thus space. But the same amount of light could also be obtained with a single laser diode that is one-thousandth smaller,” Dr. Fabian Schütt emphasizes the potential.
The materials scientist from the working group "Functional Nanomaterials" at Kiel University is the first author of the study, which involves other researchers from Germany, England, Italy, Denmark and South Korea.
Powerful small light sources allow numerous applications. The first test applications, such as in car headlights, are already available, but laser lamps have not yet become widely accepted. On the one hand, this is due to the intense, directed light of the laser diodes. On the other hand, the light consists of only one wavelength, so it is monochromatic. This leads to an unpleasant flickering when a laser beam hits a surface and is reflected there.
Porous structure scatters the light extremely strongly
“Previous developments to laser light normally work with phosphors. However, they produce a relatively cold light, are not stable in the long term and are not very efficient,” says Professor Rainer Adelung, head of the working group.
The research team in Kiel is taking a different approach: They developed a highly scattering nanostructure of hexagonal boron nitride, also known as "white graphene", which absorbs almost no light. The structure consists of a filigree network of countless fine hollow microtubes. When a laser beam hits these, it is extremely scattered inside the network structure, creating a homogeneous light source.
"Our material acts more or less like an artificial fog that produces a uniform, pleasant light output," explains Schütt. The strong scattering also contributes to the fact that the disturbing flickering is no longer visible to the human eye.
The nanostructure not only ensures that the material withstands the intense laser light, but can also scatter different wavelengths. Red, green and blue laser light can be mixed in order to create specific color effects in addition to normal white - for example, for use in innovative room lighting. Here, extremely lightweight laser diodes could lead to completely new design concepts in the future.
"However, in order to compete with LEDs in the future, the efficiency of laser diodes must be improved as well," says Schütt. The research team is now looking for industrial partners to take the step from the laboratory to application.
Wide range of applications for aeromaterials
Meanwhile the researchers from Kiel can use their method to develop highly porous nanostructures for different materials, besides boron nitride also graphene or graphite. In this way, more and more new, lightweight materials, so-called “aeromaterials”, are created, which allow particularly innovative applications. For example, the scientists are currently doing research in collaboration with companies and other universities to develop self-cleaning air filters for aircraft.
Oxford Advanced Surfaces (OAS) a pioneer and market leader in the surface treatment of polymeric, plastic and composite materials by the application of highly reactive carbene chemistry has entered into a collaboration agreement with 2-DTech Limited, a subsidiary of Versarien plc.
The aim is to develop a new range of products that incorporate nano-materials, such as graphene, into OAS’s proprietary Onto™ chemistry platform to deliver enhanced mechanical performance and improved electrical and thermal conductivity.
OAS’s patented Onto™ chemistry platform delivers a range of versatile and reliable chemical surface treatments that are used to improve the adhesion of paints, coatings and adhesives to composite materials and engineering plastics. Current Onto™ products are used in demanding applications ranging from transportation and aerospace to wind energy.
By combining 2-DTechs graphene products into OAS’s unique OntoTM chemistry the collaboration is intended to produce a range of new products that potentially will allow both companies to address a wide range of applications and address new materials challenges encountered in both our current and potentially new markets.
Dr Jon-Paul Griffiths, Chief Technology Officer, Oxford Advanced Surfaces said: “Challenging applications for new and existing materials require innovative surface treatments; through our collaboration with 2-Dtech we have the opportunity to develop new products by incorporating nano-materials, such as graphene, to meet these challenges.”
Steve Hodge, Versarien Chief Technology Officer, commented: “We are delighted and very excited to work collaboratively with OAS; our aqueous GraphinksTM and OAS’ aqueous based adhesion promoters (OntoTM) are a natural fit and can bring about unique opportunities and markets that we haven’t yet explored.”
For more than a decade, two-dimensional nanomaterials, such as graphene, have been touted as the key to making better microchips, batteries, antennas and many other devices. But a significant challenge of using these atom-thin building materials for the technology of the future is ensuring that they can be produced in bulk quantities without losing their quality. For one of the most promising new types of 2D nanomaterials, MXenes, that’s no longer a problem. Researchers at Drexel University and the Materials Research Center in Ukraine have designed a system that can be used to make large quantities of the material while preserving its unique properties.
The team recently reported in the journal Advanced Engineering Materials that a lab-scale reactor system developed at the Materials Research Center in Kyiv, can convert a ceramic precursor material into a pile of the powdery black MXene titanium carbide, in quantities as large as 50 grams per batch.
Proving that large batches of material can be refined and produced with consistency is a critical step toward achieving viability for manufacturing. For MXene materials, which have already proven their mettle in prototype devices for storing energy, computing, communication and health care, reaching manufacturing standards is the home stretch on the way to mainstream use.
“Proving a material has certain properties is one thing, but proving that it can overcome the practical challenges of manufacturing is an entirely different hurdle — this study reports on an important step in this direction,” said Yury Gogotsi, PhD, Distinguished University and Bach professor in Drexel’s College of Engineering, who has pioneered the research and development of MXene and is a lead author of the paper. “This means that MXene can be considered for widespread use in electronics and energy storage devices.”
Researchers at Drexel have been making MXene in small quantities — typically one gram or less — since they first synthesized the material in 2011. The layered nanomaterial, which looks like a powder in its dry form, starts as a piece of ceramic called a MAX phase. When a mixture of hydrofluoric and hydrochloric acid interacts with the MAX phase it etches away certain parts of the material, creating the nanometer-thin flakes characteristic of MXenes.
In the lab, this process would take place in a 60 ml container with the ingredients added and mixed by hand. To more carefully control the process at a larger scale, the group uses a one-liter reactor chamber and a screw feeder device to precisely add MAX phase. One inlet feeds the reactants uniformly into the reactor and another allows for gas pressure relief during the reaction. A specifically designed mixing blade ensures thorough and uniform mixing. And a cooling jacket around the reactor lets the team adjust the temperature of the reaction. The entire process is computerized and controlled by a software program created by the Materials Research Center team.
The group reported successfully using the reactor to make just under 50 grams of MXene powder from 50 grams of MAX phase precursor material in about two days (including time required for washing and drying the product). And a battery of tests conducted by students at Drexel’s Materials Science and Engineering Department showed that the reactor-produced MXene retains the morphology, electrochemical and physical properties of the original lab-made substance.
This development puts MXenes in a group with just a handful of 2D materials that have proven they can be produced in industrial-size quantities. But because MXene-making is a subtractive manufacturing process — etching away bits of a raw material, like planing down lumber —
it stands apart from the additive processes used to make many other 2D nanomaterials.
“Most 2D materials are made using a bottom-up approach,” said Christopher Shuck, PhD, a post-doctoral researcher in the A.J. Drexel Nanomaterials Institute. “This is where the atoms are added individually, one by one. These materials can be grown on specific surfaces or by depositing atoms using very expensive equipment. But even with these expensive machines and catalysts used, the production batches are time-consuming, small and still prohibitively expensive for widespread use beyond small electronic devices.”
MXenes also benefit from a set of physical properties that ease their path from processed material to final product — a hurdle that has tripped up even today’s widely used advanced materials.
“It typically takes quite a while to build out the technology and processing to get nanomaterials in an industrially usable form,” Gogotsi said. “It’s not just a matter of producing them in large quantities, it often requires inventing completely new machinery and processes to get them in a form that can be inserted into the manufacturing process — of a microchip or cell phone component, for example.”
But for MXenes, integrating into the manufacturing line is a fairly easy part, according to Gogotsi.
“One huge benefit to MXenes is that they be used as a powder right after synthesis or they can be dispersed in water forming stable colloidal solutions,” he said. “Water is the least expensive and the safest solvent. And with the process that we’ve developed, we can stamp or print tens of thousands of small and thin devices, such as supercapacitors or RFID tags, from material made in one batch.”
This means it can be applied in any of the standard variety of additive manufacturing systems — extrusion, printing, dip coating, spraying — after a single step of processing.
Several companies are looking developing the applications of MXene materials, including Murata Manufacturing Co, Ltd., an electronics component company based in Kyoto, Japan, which is developing MXene technology for use in several high-tech applications.
“The most exciting part about this process is that there is fundamentally no limiting factor to an industrial scale-up,” Gogotsi said. “There are more and more companies producing MAX phases in large batches, and a number of those are made using abundant precursor materials. And MXenes are among very few 2D materials that can be produced by wet chemical synthesis at large scale using conventional reaction engineering equipment and designs.”
Graphene is well-known for its remarkable electronic, mechanical and thermal properties, but industrial production of high-quality graphene is very challenging. A research team at Delft University of Technology has now developed a mathematical model that can be used to guide the large-scale production of these ultrathin layers of carbon. The findings were published this week in The Journal of Chemical Physics.
“Our model is the first to give a detailed view of what happens at the micro and nanoscale when graphene is produced from plain graphite using energetic fluid mixing,” says Dr. Lorenzo Botto, researcher at the department of Process & Energy at TU Delft. “The model will help the design of large-scale production processes, paving the way for graphene to be incorporated in commercial applications from energy storage devices to biomedicine”.
Graphite and graphene
Graphene can be made from graphite, which is a crystalline form of pure carbon, widely used for example in pencils and lubricants. The layers that make up graphite are called graphene and consists of carbon atoms arranged in a hexagonal structure. These extremely thin carbon layers possess remarkable electrical, mechanical, optical and thermal properties.
For example, a single layer of graphene is about 100 times stronger than the strongest steel of the same thickness. It conducts heat and electricity extremely efficiently and is nearly transparent. Graphene is also intrinsically very cheap, if scalable methods to produce it in large quantities can be found. Graphene has attracted much attention of the past decade as a candidate material for applications in a variety fields such as electronics, energy generation and storage, and biomedicine. In the near future we may replace the copper wiring in our houses with graphene cables, and develop all-carbon batteries that use graphene as the main building block. However, the fabrication of high quality graphene at industrial scale and affordable price remains a challenge. A new theoretical and computational model developed at TU Delft addresses this challenge.
Production of graphene
One of the most promising techniques to produce graphene from graphite is so-called liquid-phase exfoliation. In this technique, graphite is sheared in a liquid environment until layers of graphene detach from the bulk material. The liquid causes the graphene layers to detach gently, which is important to obtain high-quality graphene.
The process has already been successful in the production of graphene on laboratory scale, and, on a trial-and-error basis, on larger scales. It has the potential to be used on industrial scales, to produce tons of material. However, in order to increase the scale of graphene production, we need to know the process parameters that make the exfoliation work efficiently without damaging the graphene sheets.
A research team at TU Delft led by Dr. Lorenzo Botto has now developed the first rigorously derived and validated mathematical model to determine those parameters. This model can be embedded in large-scale industrial process optimisation software or used by practitioners to choose processing parameters.
“The exfoliation process is difficult to model,” explains Botto. “The adhesion between graphene layers is not easy to quantify and the fluid dynamical forces exerted by the liquid on the graphite depend sensitively on surface properties and geometry.” Team members Catherine Kamal and Simon Gravelle developed and tested the model against molecular dynamics simulations, and proved that that the model can be very accurate. Key to the success of the model is the inclusion of hydronamic slip of the liquid pushing against the graphite surface, and of the fluid forces on the graphene edges.
Botto: “The model forms the basis for better control of the technique at any scale. We hope it will pave the way to the large-scale production of graphene for all kinds of useful applications.”
Dr. Botto obtained his Ph.D. in Fluid Mechanics at Johns Hopkins University (USA), and has worked in the USA, UK and Switzerland. He recently moved to TU Delft. The mission of his research is to use fluid mechanics knowledge to support the large-scale, sustainable production of materials that can solve important societal challenges, from sustainable energy production to environmental remediation. His work on graphene exfoliation is funded by a 1.5M€ Starting Grant (Grant agreement ID: 715475) from the European Research Council (ERC). Read more about the project.
Botto: “Fluid forces can be used to produce and process graphene at the scale required by market applications. However, to reach market readiness we need control over quality and processes. By uncovering underlying fluid mechanical principles, I aim for a profound impact on our ability to produce two-dimensional carbon nanomaterials on large scales.
Not only does loading antiviral agents on graphene oxide produce a synergistic antiviral effect, but it also enhances the biocompatibility and reduces the cytotoxicity of the drugs. Researchers have found that the antivirus nanomedicines designed based on GO which have been tested against a specific virus can also exert the same antiviral effect against a wider range of viruses from the Herpesviruses to the novel Coronavirus.
Due to their two-dimensional structure, sharp edges, and negatively charged surfaces, graphene oxide (GO) nanosheets are capable of interacting with microorganisms such as bacteria and viruses and destroying them by disrupting their plasma membrane or by generating reactive oxygen species to induce oxidative stress. Nevertheless, GO also interacts with living cells depending on its concentration; as the wise saying goes: “The only real difference between medicine and poison is the dose....and intent.”
On the other hand, there are a large number of substances whose antimicrobial properties have been proven over the years, among which are hypericin and curcumin; studies have shown that hypericin and its derivatives, which are extracted from Hypericum perforatum, have antiviral activity against a broad spectrum of viruses including the herpes simplex virus types 1 & 2, influenza virus, Sendai virus, chronic hepatitis C virus, etc.
Hence, now it is time to integrate what researchers have learned during all those years of research and experiment; GO’s high drug-loading capacity and low cytotoxicity make it the standout choice as a drug carrier; according to a recent study conducted by the researcher of Sichuan Agricultural University, loading an optimized dosage of hypericin on GO reduced its cytotoxicity while improving its antiviral activity both in vitro and in vivo. The resulting antiviral combination was tested against novel duck reovirus (NDRV) and reported to inhibit its replication by preventing the transcription of its target gene and suppressing the expression of its target protein in the early stage of the treatment. Moreover, in vivo tests indicated that hypericin-loaded GO could reduce pathological lesions of the ducklings infected with NDRV, thus increasing their chance of survival.
Similar antiviral and antibacterial effects have also been seen in curcumin, which is the most biologically active substance in Curcuma longa – also known as turmeric. In 2017, a group made up of American and Chinese researchers reported in their article – published in the Nanoscale journal – that loading curcumin on GO not only did improve the biocompatibility of GO but also reduced the cytotoxicity of both GO and curcumin. Their studies revealed that curcumin-loaded GO had synergistic antiviral activity against the respiratory syncytial virus, and inhibited its binding to host cells. This virus is recognized as the major viral pathogen of the lower respiratory tract in infants.
Apart from the curcumin itself, carbon quantum dots derived from curcumin have been proven effective against enterovirus 71 (EV71). In a new study carried out in Taiwan, core-shell quantum dots were synthesized from curcumin using a one‐step dry heating method, resulting in their surfaces preserving many of the moieties of polymeric curcumin, as if curcumin were loaded on the quantum dots. Figure 1 schematically illustrates the synthesis process and antiviral activity of these nanomaterials; accordingly, the mechanism behind their antiviral activity is inhibiting the EV71 virus from both attaching to the host cells, replicating, and exiting from the infected cells.
What is remarkable about all three of these studies is that loading antiviral agents on GO enhances its biocompatibility while reducing the cytotoxicity of both GO and the antiviral agents (e.g., curcumin and hypericin), in addition to the fact that the two substances combine synergistically to form a more effective therapeutic agent than each of those substances alone. Furthermore, researchers have found that the antivirus nanomedicines designed based on GO which have been tested against a specific virus can also exert the same antiviral effect against a wider range of viruses from the herpes virus to the novel Coronavirus.
Nanotech Energy is developing cutting-edge energy storage solutions for the electric and portable electronics markets. This technology is based on the wonder material graphene that is established as the thinnest, strongest and most conductive material. Our mission at Nanotech Energy is to harness the power of graphene into world-changing battery solutions. We also take advantage of the outstanding structural, mechanical and electronic properties of graphene to develop conductive inks and adhesives as well as electromagnetic interference shielding materials with unparalleled performance. Nanotech Energy seeks talented scientists and engineers to join the expanding development and production teams. Choosing where to start and grow your career has a major impact on your professional and personal life. Nanotech Energy is home for cutting-edge graphene and nanomaterials technology and our scientists develop solutions that impact our community and the world. We offer you a chance to join a high-growth company at an early stage and shape the direction of our culture.
Position Summary :
Nanotech Energy, Inc. is seeking a talentedInk Formulation Scientist to join our expanding team located in Northern California. As a leading company in the manufacture of graphene oxide, silver nanoparticles and nanowires, we plan to offer our customers a full spectrum of conductive inks for a wide range of applications.
The successful candidate will work with our chemistry team and analytical scientists to develop conductive inks for the growing markets of printed electronics and smart packaging.You will use your knowledge in conductive ink formulations to develop, validate and implement inkjet, aerosol and screen printing inks. This job requires a strong hands-on experience in a variety of printing processes and ink formulations and the ability to work independently with little supervisions, yet also be an integral team member. As our residential expert in conductive inks, you will coordinate ink development with cross-functional teams to meet our engineering and customer needs. You will also be responsible for facilitating the transition of our inks from development to manufacturing. Nanotech Energy is made up of amazing individuals but it’s only through teamwork that we achieve greatness. At Nanotech Energy, you will be given the opportunity to participate and join in the growth stage of a startup company and contribute at all levels to make an impact.
Job Type: Full-time
Job level: Senior level
Responsibilities and Duties
• Lead technical and quality needs for our conductive inks projects to address immediate and strategic problems of the company.
• Contribute to the continuous improvement of processes and capabilities in the company.
• Participate in the design and development ofa new laboratory for inkjet, aerosol and screen printing applications.
• Develop or improve existing products and processes to prepare dispersions and inks and help to implement in production.
• Synthesize and characterize new products, components, and formulations.
• Assist in collecting data and writing of patent inventions associated with the development of new products.
• Apply knowledge to provide customer support and troubleshooting in the application of commercial products.
• Assist our engineers and plant production personnel in scaling up the technology from bench to manufacturing.
• Review and write standard operating procedures for analytical development.
• Conduct experiments to test the long-term stability of our inks. Analyze results of experiments and trials and write reports.
• Assist in the supervision of less experienced chemists and technicians in the team. Provide other support as needed to help maintain an efficientdevelopment lab.
• Communicate ideas and results internally across multiple teams.
Education and Qualifications
• Bachelor degree in chemistry, materials science, chemical engineering or related field. PhD degree with relevant experience is also acceptable.
• Experience in the preparation, processing and characterization of conductive inks for printed and flexible electronics.
• Knowledge of fluid dynamics, rheology, and fluid development is required.
• Demonstrated history of solving problems with a chemical and analytical approach.
• Strong background in colloidal and surface chemistry and surface treatment through material design, synthesis, and characterization.
• Experience with the development of transparent conducting electrodes with different surface properties is highly desirable.
• Examples of instrumentation / techniques: Viscometry, goniometry (with tensiometry), DLS, zeta potential, SEM, TEM
• Knowledge of nanocolloidal system stability; nanoparticle synthesis experience is a plus
• Scale up experience with nanocolloidal systems
• Experience with at least one printing process is required.
• Experience with nanomaterial surface coatings for added functions is a plus.
• 3-5 years of industry experience (less for candidates with advanced degrees).
• Ability to respond to multiple priorities simultaneously; ability to coordinate team and projects to meet the company needs and deadlines.
• Strong project management skills.
• Skilled in troubleshooting and analytical thinking with an interest in solving complex problems.
• Ability to deal with a variety of abstract and concrete variables and to conduct studies using the scientific method
• Demonstrated understanding of analytical chemistry and materials science, especially in rheology, polymer, and thermal analysis.
• Demonstrated ability to communicate effectively in both verbal and written formats; ability to work effectively with team members and management.
• Competency level should allow the employee to author internal reports, reports to customers, or articles for ink industry publications.
• Experience in 3D printing and thermal inkjet is a plus.
Work authorization / location:
• United States (Required)