Category Archives: environment

Creating nanofibres from your old clothing (cotton waste)

Researchers at the University of British Columbia (UBC; Canada) have discovered a way to turn cotton waste into a potentially higher value product. An October 15, 2019 UBC news release makes the announcement (Note: Links have been removed),

In the materials engineering labs at UBC, surrounded by Bunsen burners, microscopes and spinning machines, professor Frank Ko and research scientist Addie Bahi have developed a simple process for converting waste cotton into much higher-value nanofibres.

These fibres are the building blocks of advanced products like surgical implants, antibacterial wound dressings and fuel cell batteries.

“More than 28 million tonnes of cotton are produced worldwide each year, but very little of that is actually recycled after its useful life,” explains Bahi, a materials engineer who previously worked on recycling waste in the United Kingdom. “We wanted to find a viable way to break down waste cotton and convert it into a value-added product. This is one of the first successful attempts to make nanofibres from fabric scraps – previous research has focused on using a ready cellulose base to make nanofibres.”

Compared to conventional fibres, nanofibres are extremely thin (a nanofibre can be 500 times smaller than the width of the human hair) and so have a high surface-to-volume ratio. This makes them ideal for use in applications ranging from sensors and filtration (think gas sensors and water filters) to protective clothing, tissue engineering and energy storage.
Ko and Bahi developed their process in collaboration with ecologyst, a B.C.-based company that manufactures sustainable outdoor apparel, and with the participation of materials engineering student Kosuke Ayama.

They chopped down waste cotton fabric supplied by ecologyst into tiny strips and soaked it in a chemical bath to remove all additives and artificial dyes from the fabric. The resulting gossamer-thin material was then fed to an electrospinning machine to produce very fine, smooth nanofibres. These can be further processed into various finished products.

“The process itself is relatively simple, but what we’re thrilled about is that we’ve proved you can extract a high-value product from something that would normally go to landfill, where it will eventually be incinerated. It’s estimated that only a fraction of cotton clothing is recycled. The more product we can re-process, the better it will be for the environment,” said lead researcher Frank Ko, a Canada Research Chair in advanced fibrous materials in UBC’s faculty of applied science.

The process Bahi and Ko developed is lab-scale, supported by a grant from the Natural Sciences and Engineering Research Council of Canada. In the future, the pair hope to refine and scale up their process and eventually share their methods with industry partners.

“We started with cotton because it’s one of the most popular fabrics for clothing,” said Bahi. “Once we’re able to develop the process further, we can look at converting other textiles into value-added materials. Achieving zero waste [emphasis mine] for the fashion and textile industries is extremely challenging – this is simply one of the many first steps towards that goal.”

The researchers have a 30 sec. video illustrating the need to recycle cotton materials,

You can find the researchers’ industrial partner, ecologyst here.

At the mention of ‘zero waste’, I was reminded of an upcoming conference, Oct. 30 -31, 2019 in Vancouver (Canada) where UBC is located. It’s called the 2019 Zero Waste Conference and, oddly,there’s no mention of Ko or Bahi or Ayama or ecologyst on the speakers’ list. Maybe I was looking at the wrong list or the organizers didn’t have enough lead time to add more speakers.

One final comment, I wish there was a little more science (i.e., more technical details) in the news release.

Graphene from gum trees

Caption: Eucalyptus bark extract has never been used to synthesise graphene sheets before. Courtesy: RMIT University

It’s been quite educational reading a June 24, 2019 news item on Nanowerk about deriving graphene from Eucalyptus bark (Note: Links have been removed),

Graphene is the thinnest and strongest material known to humans. It’s also flexible, transparent and conducts heat and electricity 10 times better than copper, making it ideal for anything from flexible nanoelectronics to better fuel cells.

The new approach by researchers from RMIT University (Australia) and the National Institute of Technology, Warangal (India), uses Eucalyptus bark extract and is cheaper and more sustainable than current synthesis methods (ACS Sustainable Chemistry & Engineering, “Novel and Highly Efficient Strategy for the Green Synthesis of Soluble Graphene by Aqueous Polyphenol Extracts of Eucalyptus Bark and Its Applications in High-Performance Supercapacitors”).

A June 24, 2019 RMIT University news release (also on EurekAlert), which originated the news item, provides a little more detail,

RMIT lead researcher, Distinguished Professor Suresh Bhargava, said the new method could reduce the cost of production from $USD100 per gram to a staggering $USD0.5 per gram.

“Eucalyptus bark extract has never been used to synthesise graphene sheets before and we are thrilled to find that it not only works, it’s in fact a superior method, both in terms of safety and overall cost,” said Bhargava.

“Our approach could bring down the cost of making graphene from around $USD100 per gram to just 50 cents, increasing it availability to industries globally and enabling the development of an array of vital new technologies.”

Graphene’s distinctive features make it a transformative material that could be used in the development of flexible electronics, more powerful computer chips and better solar panels, water filters and bio-sensors.

Professor Vishnu Shanker from the National Institute of Technology, Warangal, said the ‘green’ chemistry avoided the use of toxic reagents, potentially opening the door to the application of graphene not only for electronic devices but also biocompatible materials.

“Working collaboratively with RMIT’s Centre for Advanced Materials and Industrial Chemistry we’re harnessing the power of collective intelligence to make these discoveries,” he said.

A novel approach to graphene synthesis:

Chemical reduction is the most common method for synthesising graphene oxide as it allows for the production of graphene at a low cost in bulk quantities.

This method however relies on reducing agents that are dangerous to both people and the environment.

When tested in the application of a supercapacitor, the ‘green’ graphene produced using this method matched the quality and performance characteristics of traditionally-produced graphene without the toxic reagents.

Bhargava said the abundance of eucalyptus trees in Australia made it a cheap and accessible resource for producing graphene locally.

“Graphene is a remarkable material with great potential in many applications due to its chemical and physical properties and there’s a growing demand for economical and environmentally friendly large-scale production,” he said.

Here’s a link to and a citation for the paper,

Novel and Highly Efficient Strategy for the Green Synthesis of Soluble Graphene by Aqueous Polyphenol Extracts of Eucalyptus Bark and Its Applications in High-Performance Supercapacitors by Saikumar ManchalaV. S. R. K. Tandava, Deshetti Jampaiah, Suresh K. Bhargava, Vishnu Shanker. ACS Sustainable Chem. Eng.2019XXXXXXXXXX-XXX DOI: https://doi.org/10.1021/acssuschemeng.9b01506 Publication Date:June 13, 2019

Copyright © 2019 American Chemical Society

This paper is behind a paywall.

Low-cost carbon sequestration and eco-friendly manufacturing for chemicals with nanobio hybrid organisms

Years ago I was asked about carbon sequestration and nanotechnology and could not come up with any examples. At last I have something for the next time the question is asked. From a June 11, 2019 news item on ScienceDaily,

University of Colorado Boulder researchers have developed nanobio-hybrid organisms capable of using airborne carbon dioxide and nitrogen to produce a variety of plastics and fuels, a promising first step toward low-cost carbon sequestration and eco-friendly manufacturing for chemicals.

By using light-activated quantum dots to fire particular enzymes within microbial cells, the researchers were able to create “living factories” that eat harmful CO2 and convert it into useful products such as biodegradable plastic, gasoline, ammonia and biodiesel.

A June 11, 2019 University of Colorado at Boulder news release (also on EurekAlert) by Trent Knoss, which originated the news item, provides a deeper dive into the research,

“The innovation is a testament to the power of biochemical processes,” said Prashant Nagpal, lead author of the research and an assistant professor in CU Boulder’s Department of Chemical and Biological Engineering. “We’re looking at a technique that could improve CO2 capture to combat climate change and one day even potentially replace carbon-intensive manufacturing for plastics and fuels.”

The project began in 2013, when Nagpal and his colleagues began exploring the broad potential of nanoscopic quantum dots, which are tiny semiconductors similar to those used in television sets. Quantum dots can be injected into cells passively and are designed to attach and self-assemble to desired enzymes and then activate these enzymes on command using specific wavelengths of light.

Nagpal wanted to see if quantum dots could act as a spark plug to fire particular enzymes within microbial cells that have the means to convert airborne CO2 and nitrogen, but do not do so naturally due to a lack of photosynthesis.

By diffusing the specially-tailored dots into the cells of common microbial species found in soil, Nagpal and his colleagues bridged the gap. Now, exposure to even small amounts of indirect sunlight would activate the microbes’ CO2 appetite, without a need for any source of energy or food to carry out the energy-intensive biochemical conversions.

“Each cell is making millions of these chemicals and we showed they could exceed their natural yield by close to 200 percent,” Nagpal said.

The microbes, which lie dormant in water, release their resulting product to the surface, where it can be skimmed off and harvested for manufacturing. Different combinations of dots and light produce different products: Green wavelengths cause the bacteria to consume nitrogen and produce ammonia while redder wavelengths make the microbes feast on CO2 to produce plastic instead.

The process also shows promising signs of being able to operate at scale. The study found that even when the microbial factories were activated consistently for hours at a time, they showed few signs of exhaustion or depletion, indicating that the cells can regenerate and thus limit the need for rotation.

“We were very surprised that it worked as elegantly as it did,” Nagpal said. “We’re just getting started with the synthetic applications.”

The ideal futuristic scenario, Nagpal said, would be to have single-family homes and businesses pipe their CO2 emissions directly to a nearby holding pond, where microbes would convert them to a bioplastic. The owners would be able to sell the resulting product for a small profit while essentially offsetting their own carbon footprint.

“Even if the margins are low and it can’t compete with petrochemicals on a pure cost basis, there is still societal benefit to doing this,” Nagpal said. “If we could convert even a small fraction of local ditch ponds, it would have a sizeable impact on the carbon output of towns. It wouldn’t be asking much for people to implement. Many already make beer at home, for example, and this is no more complicated.”

The focus now, he said, will shift to optimizing the conversion process and bringing on new undergraduate students. Nagpal is looking to convert the project into an undergraduate lab experiment in the fall semester, funded by a CU Boulder Engineering Excellence Fund grant. Nagpal credits his current students with sticking with the project over the course of many years.

“It has been a long journey and their work has been invaluable,” he said. “I think these results show that it was worth it.”

Here’s a link to and a citation for the paper,

Nanorg Microbial Factories: Light-Driven Renewable Biochemical Synthesis Using Quantum Dot-Bacteria Nanobiohybrids by Yuchen Ding, John R. Bertram, Carrie Eckert, Rajesh Reddy Bommareddy, Rajan Patel, Alex Conradie, Samantha Bryan, Prashant Nagpal. J. Am. Chem. Soc.2019XXXXXXXXXX-XXX DOI: https://doi.org/10.1021/jacs.9b02549 Publication Date:June 7, 2019
Copyright © 2019 American Chemical Society

This paper is behind a paywall.

Safe nanomaterial handling on a tiny budget

A June 3, 2019 news item on Nanowerk describes an inexpensive way to safely handle carbon nanotubes (CNTs), Note: A link has been removed,

With a little practice, it doesn’t take much more than 10 minutes, a couple of bags and a big bucket to keep nanomaterials in their place.

The Rice University lab of chemist Andrew Barron works with bulk carbon nanotubes on a variety of projects. Years ago, members of the lab became concerned that nanotubes could escape into the air, and developed a cheap and clean method to keep them contained as they were transferred from large containers into jars for experimental use.

More recently Barron himself became concerned that too few labs around the world were employing best practices to handle nanomaterials. He decided to share what his Rice team had learned.

“There was a series of studies that said if you’re going to handle nanotubes, you really need to use safety protocols,” Barron said. “Then I saw a study that said many labs didn’t use any form of hood or containment system. In the U.S., it was really bad, and in Asia it was even worse. But there are a significant number of labs scaling up to use these materials at the kilogram scale without taking the proper precautions.”

The lab’s inexpensive method is detailed in an open-access paper in the Springer Nature journal SN Applied Sciences (“The safe handling of bulk low-density nanomaterials”).

Here’s a bag and a bucket,

Caption: A plastic bucket and a plastic bag contain a 5-gallon supply of carbon nanotubes in a lab at Rice University, the beginning of the process to safely transfer the nanotubes for experimental use. The Rice lab published its technique in SN Applied Sciences. Credit: Barron Research Group/Rice University

A June 3, 2019 Rice University news release (also on EurekAlert and received separately by email), which originated the news item, provides more detail,

In bulk form, carbon nanotubes are fluffy and disperse easily if disturbed. The Rice lab typically stores the tubes in 5-gallon plastic buckets, and simply opening the lid is enough to send them flying because of their low density.

Varun Shenoy Gangoli, a research scientist in Barron’s lab, and Pavan Raja, a scientist with Rice’s Nanotechnology-Enabled Water Treatment center, developed for their own use a method that involves protecting the worker and sequestering loose tubes when removing smaller amounts of the material for use in experiments.

Full details are available in the paper, but the precautions include making sure workers are properly attired with long pants, long sleeves, lab coats, full goggles and face masks, along with two pairs of gloves duct-taped to the lab coat sleeves. The improvised glove bag involves a 25-gallon trash bin with a plastic bag taped to the rim. The unopened storage container is placed inside, and then the bin is covered with another transparent trash bag, with small holes cut in the top for access.

After transferring the nanotubes, acetone wipes are used to clean the gloves and more acetone is sprayed inside the barrel so settling nanotubes would stick to the surfaces. These can be recovered and returned to the storage container.

Barron said it took lab members time to learn to use the protocol efficiently, “but now they can get their samples in 5 to 10 minutes.” He’s sure other labs can and will enhance the technique for their own circumstances. He noted a poster presented at the Ninth Guadalupe Workshop on the proper handling of carbon nanotubes earned recognition and discussion among the world’s premier researchers in the field, noting the importance of the work for agencies in general.

“When we decided to write about this, we were originally just going to put it on the web and hope somebody would read it occasionally,” Barron said. “We couldn’t imagine who would publish it, but we heard that an editor at Springer Nature was really keen to have published articles like this.

“I think this is something people will use,” he said. “There’s nothing outrageous but it helps everybody, from high schools and colleges that are starting to use nanoparticles for experiments to small companies. That was the goal: Let’s provide a process that doesn’t cost thousands of dollars to install and allows you to transfer nanomaterials safely and on a large scale. Finally, publish said work in an open-access journal to maximize the reach across the globe.”

Here’s a link to and a citation for the paper,

The safe handling of bulk low-density nanomaterials by Varun Shenoy Gangoli, Pavan M. V. Raja, Gibran Liezer Esquenazi, Andrew R. Barron. SN Applied Sciences June 2019, 1:644 DOI: https://doi.org/10.1007/s42452-019-0647-5 First Online 25 May 2019

This paper is open access.

‘Smart’ windows in Vancouver (Canada): engineering issues?

This post was going to focus on the first building in Canada to feature ‘smart’ windows. In this case, they are electrochromic windows and the company, View Dynamic Glass, was mentioned here in a September 17, 2018 posting about the windows’ use at the Dallas/Fort Worth Airport. (The posting includes a link to the View Dynamic Glass report on the windows’ use and a short video.)

However, things changed but, first, let’s start with an explanation as to what electrochromic glass ir. Chris Woodford in a December 5, 2018 article on explainthatstuff.com offers a great overview which includes an explanation, a description of how they work, and more. What follows is a brief excerpt from Woodford’s overview (Note: Links have been removed),

What is electrochromic glass?

Glass is an amazing material and our buildings would be dark, dingy, cold, and damp without it. But it has its drawbacks too. It lets in light and heat even when you don’t want it to. On a blinding summer’s day, the more heat (“solar gain”) that enters your building the more you’ll need to use your air-conditioning—a horrible waste of energy that costs you money and harms the environment. That’s why most of the windows in homes and offices are fitted with curtains or blinds. If you’re into interior design and remodeling, you might think furnishings like this are neat and attractive—but in cold, practical, scientific terms they’re a nuisance. Let’s be honest about this: curtains and blinds are a technological kludge to make up for glass’s big, built-in drawback: it’s transparent (or translucent) even when you don’t want it to be.

Since the early 20th century, people have got used to the idea of buildings that are increasingly automated. We have electric clothes washing machines, dishwashers, vacuum cleaners and much more. So why not fit our homes with electric windows that can change from clear to dark automatically? Smart windows (also referred to by the names smart glass, switchable windows, and dynamic windows) do exactly that using a scientific idea called electrochromism, in which materials change color (or switch from transparent to opaque) when you apply an electrical voltage across them. Typically smart windows start off a blueish color and gradually (over a few minutes) turn transparent when the electric current passes through them.

As for the news about its Vancouver debut, I was very excited to see this April 28, 2019 article by Kenneth Chan for dailyhive.com/vancouver,

BlueSky Properties’ 10-storey office building at 988 West Broadway [in Vancouver, Canada; emphasis mine] is home to the new Vancouver offices of Industrial Alliance Financial Group, which has leased nine stories and 93,700-sq-ft of office space.



One of the building’s unique design features is its use of View Dynamic Glass technology [emphases mine] — a glass technology that controls heat and glare, reduces overall energy consumption and costs, and improves the health and wellness of individuals working inside the building.

These smart windows optimize the amount of natural light to enhance mental and physical well-being without the need for shades or blinds. The application of the technology on this building, the first of its kind in Canada, will result in energy savings of up to 20%, [emphasis mine] with the amount of sunlight streaming through automatically tinted to block glare.

Blue Sky Properties (a Bosa Family Company), the local developer for this building, was very excited about the building and the ‘smart’ glass technology, according to its April 23, 2019 news release (here for a short version and here for the full version).

Other than being happy to see the technology being employed in Vancouver, I didn’t spend a lot of time thinking about the property. That changed on reading a May 8, 2019 article by Kenneth Chan for dailyhive.com/vancouver,

A structural engineer based in Vancouver has been stripped of his license to work in British Columbia [emphasis mine] following an investigation that determined his design for a condominium tower in Surrey fell short of the provincial building code.

According to a disciplinary notice posted by Engineers and Geoscientists British Columbia Association (EGBCA) on April 30, John Bryson, a managing partner of Bryson Markulin Zickmantel Structural Engineers (BMZSE), [emphases mine] admitted to unprofessional conduct and acted contrary to the association’s code of ethics that requires its members to “hold paramount the safety, health, and welfare of the public.”

“Mr. Bryson admitted that his structural design for the building did not comply with the 2006 BC Building Code, to which he certified it had been designed, in particular with respect to seismic and wind loads,” reads the notice. [emphases mine]

BMZSE has been involved in the design work of a number of projects across Metro Vancouver, including Station Square, Rogers Arena South Tower, Lougheed Heights, River District Parcel 17, The Jervis, Harwood, Plaza 88, Solo District, Burrard Place, Centreview Place, Trump International Hotel & Tower Vancouver, Central, Sovereign, Kings Crossing, and 988 West Broadway. [emphases mine]

You can find the ‘disciplinary notice’ (it’s an account of what Bryson failed to do and the punishment for the failure) here on the Association of Professional Engineers and Geoscientists of the Province of British Columbia (also known as Engineers and Geoscientists British Columbia) website.

Presumably, all of Bryson’s projects have been reviewed since the disciplinary action.

Mushroom compost as a biobased nanocarrier for curing plant diseases

Scientists in Europe have just cured a plant disease Esca (fungi that destroy grapevines) for the first time ever. A May 22, 2019 news item on Nanowerk announces the research success,

Plant diseases, though a normal part of nature, can have disastrous effects in agriculture. They reduce food for people and revenues in rural areas. In the worst cases they result in hunger and starvation, as many famines in history show. About 16% of all crops are lost to plant diseases each year across the world.

The Max Planck Institute for Polymer Research in Mainz has just delivered a double novelty to the scientific world: nanocarriers made of “waste”, which release drugs in a way that cured a plant disease for the first time.

Nanocarriers are very tiny degradable capsules that have been studied for medical applications in the last 30 years. These nanocapsules are considered the “magic bullet” to cure human cancer, because they discharge the drug directly to the targeted cells.

A May 20, 2019 BIOrescue project press release, which originated the news item, delves further into the research,

Treating plant diseases that have never been cured before

Thanks to the European research funds of the BIOrescue project, the researchers at the Max Plank Institute investigated the possibility to transpose the same principle to cure plant diseases. They have been testing these nanocapsules to treat ESCA, a fungi disease that affects 2 billion grapevine plants across the world for which there has not been a cure so far.
Dr Frederik Wurm, who is leading this research at Max Planck said “After two years of testing in our labs and then on Riesling vineyards in Germany, it looks like we have managed to reduce the symptoms of the disease. Further tests will confirm if this cure is a solution in the long term. If the effects are confirmed the same method can be extended potentially to any other disease in agriculture”.

“Circular” nanocarriers made of waste

The second novelty of these nanoscopic capsules is that they can be made of waste material – in this case used mushrooms compost.

“Normally nanocarriers are made of polymers based on fossil fuels. In the past, we have developed biobased nanocarriers made of lignin coming from the paper and pulp industry. But this is the very first time we try to develop them from agricultural residues, which makes them a truly “circular” product, from used plant fertiliser to plant cure. Nothing is going to be wasted!” said Wurm.

To obtain these tiny biodegradable capsules, the Max Planck researchers carried out a chemical conversion to transform the soluble lignin obtained after the pretreatment of used mushroom compost.

Afterwards the nanocarriers have been loaded with the drug that is usually sprayed on the plant with very limited effects. Thanks to the natural enzymatic degradation of the nanocarriers, the drug is released inside the plant in a controlled and progressive way. With this effective method the drug only targets the fungi, which destroy the plant from inside. Tests demonstrated that these nanocarriers are not toxic for the plants and do not reach the crop.

“Beyond the agricultural sector, the capsules have a myriad of other potential applications from food enhancement to pharmaceutical products. It’s only a matter of time until we find biobased nanocarriers available on the market for any of these uses” said Wurm.

Bio-based nanocarrier Courtesy: BIOrescue

You can find out more about the BIOrescue project here, including interesting facts such as this,

To satisfy consumer demand for mushrooms, European farmers use over three million tonnes of compost each year. Though the compost contains valuable organic components, it is only suitable for one to three mushroom harvests, and disposing of it creates significant economic and logistical problems for Europe’s farmers.

Apparently, this is is a ‘circular economy’ project. ‘Circular economy’ being one of the latest buzz terms. Let’s hope it graduates to something ‘beyond buzz’, as it were.

Desalination waste as a useful resource?

For anyone not familiar with the concept, it’s possible to remove salt from water to make it potable (i.e., drinkable). With growing concerns about water shortages worldwide, turning the ocean into something drinkable is seen as a reasonable solution. One of the problems associated with the solution is waste. As you can see in this post, it’s a big problem.

Illustration depicts the potential of the suggested process. Brine, which could be obtained from the waste stream of reverse osmosis (RO) desalination plants, or from industrial plants or salt mining operations, can be processed to yield useful chemicals such as sodium hydroxide (NaOH) or hydrochloric acid (HCl). Credit: Illustration courtesy of the researchers [downloaded from https://www.sciencedaily.com/releases/2019/02/190213124439.htm]

A February 13, 2019 news item on ScienceDaily announced research from MIT (Massachusetts Institute of Technology) into research on desalination and waste,

The rapidly growing desalination industry produces water for drinking and for agriculture in the world’s arid coastal regions. But it leaves behind as a waste product a lot of highly concentrated brine, which is usually disposed of by dumping it back into the sea, a process that requires costly pumping systems and that must be managed carefully to prevent damage to marine ecosystems. Now, engineers at MIT say they have found a better way.

In a new study, they show that through a fairly simple process the waste material can be converted into useful chemicals — including ones that can make the desalination process itself more efficient

A February 13, 2019 MIT news release (also on EurekAlert), which originated the news item, describes the work in detail,

The approach can be used to produce sodium hydroxide, among other products. Otherwise known as caustic soda, sodium hydroxide can be used to pretreat seawater going into the desalination plant. This changes the acidity of the water, which helps to prevent fouling of the membranes used to filter out the salty water — a major cause of interruptions and failures in typical reverse osmosis desalination plants.

The concept is described today in the journal Nature Catalysis and in two other papers by MIT research scientist Amit Kumar, professor of mechanical engineering John. [sic] H. Lienhard V, and several others. Lienhard is the Jameel Professor of Water and Food and the director of the Abdul Latif Jameel Water and Food Systems Lab.

“The desalination industry itself uses quite a lot of it,” Kumar says of sodium hydroxide. “They’re buying it, spending money on it. So if you can make it in situ at the plant, that could be a big advantage.” The amount needed in the plants themselves is far less than the total that could be produced from the brine, so there is also potential for it to be a saleable product.

Sodium hydroxide is not the only product that can be made from the waste brine: Another important chemical used by desalination plants and many other industrial processes is hydrochloric acid, which can also easily be made on site from the waste brine using established chemical processing methods. The chemical can be used for cleaning parts of the desalination plant, but is also widely used in chemical production and as a source of hydrogen.

Currently, the world produces more than 100 billion liters (about 27 billion gallons) a day of water from desalination, which leaves a similar volume of concentrated brine. [emphases mine] Much of that is pumped back out to sea, and current regulations require costly outfall systems to ensure adequate dilution of the salts. Converting the brine can thus be both economically and ecologically beneficial, especially as desalination continues to grow rapidly around the world. “Environmentally safe discharge of brine is manageable with current technology, but it’s much better to recover resources from the brine and reduce the amount of brine released,” Lienhard says.

The method of converting the brine into useful products uses well-known and standard chemical processes, including initial nanofiltration to remove undesirable compounds, followed by one or more electrodialysis stages to produce the desired end product. While the processes being suggested are not new, the researchers have analyzed the potential for production of useful chemicals from brine and proposed a specific combination of products and chemical processes that could be turned into commercial operations to enhance the economic viability of the desalination process, while diminishing its environmental impact.

“This very concentrated brine has to be handled carefully to protect life in the ocean, and it’s a resource waste, and it costs energy to pump it back out to sea,” so turning it into a useful commodity is a win-win, Kumar says. And sodium hydroxide is such a ubiquitous chemical that “every lab at MIT has some,” he says, so finding markets for it should not be difficult.

The researchers have discussed the concept with companies that may be interested in the next step of building a prototype plant to help work out the real-world economics of the process. “One big challenge is cost — both electricity cost and equipment cost,” at this stage, Kumar says.

The team also continues to look at the possibility of extracting other, lower-concentration materials from the brine stream, he says, including various metals and other chemicals, which could make the brine processing an even more economically viable undertaking.

“One aspect that was mentioned … and strongly resonated with me was the proposal for such technologies to support more ‘localized’ or ‘decentralized’ production of these chemicals at the point-of-use,” says Jurg Keller, a professor of water management at the University of Queensland in Australia, who was not involved in this work. “This could have some major energy and cost benefits, since the up-concentration and transport of these chemicals often adds more cost and even higher energy demand than the actual production of these at the concentrations that are typically used.”

The research team also included MIT postdoc Katherine Phillips and undergraduate Janny Cai, and Uwe Schroder at the University of Braunschweig, in Germany. The work was supported by Cadagua, a subsidiary of Ferrovial, through the MIT Energy Initiative.

Here’s a link to and a citation for the paper,

Direct electrosynthesis of sodium hydroxide and hydrochloric acid from brine streams by Amit Kumar, Katherine R. Phillips, Gregory P. Thiel, Uwe Schröder, & John H. Lienhard V. Nature Catalysis volume 2, pages106–113 (2019) DOI: https://doi.org/10.1038/s41929-018-0218-y Published 13 February 2019

This paper is behind a paywall.

Let them (Rice University scientists) show you how to restore oil-soaked soil

I did not want to cash in (so to speak) on someone else’s fun headline so I played with it. Hre is the original head, which was likely written by either David Ruth or Mike Williams at Rice University (Texas, US), “Lettuce show you how to restore oil-soaked soil.”

A February 1, 2019 news item on ScienceDaily on the science behind lettuce and oil-soaked soil,

Rice University engineers have figured out how soil contaminated by heavy oil can not only be cleaned but made fertile again.

How do they know it works? They grew lettuce.

Rice engineers Kyriacos Zygourakis and Pedro Alvarez and their colleagues have fine-tuned their method to remove petroleum contaminants from soil through the age-old process of pyrolysis. The technique gently heats soil while keeping oxygen out, which avoids the damage usually done to fertile soil when burning hydrocarbons cause temperature spikes.

Lettuce growing in once oil-contaminated soil revived by a process developed by Rice University engineers. The Rice team determined that pyrolyzing oil-soaked soil for 15 minutes at 420 degrees Celsius is sufficient to eliminate contaminants while preserving the soil’s fertility. The lettuce plants shown here, in treated and fertilized soil, showed robust growth over 14 days. Photo by Wen Song

A February 1, 2019 Rice University news release (also on EurekAlert), which originated the news item, explains more about the work,

While large-volume marine spills get most of the attention, 98 percent of oil spills occur on land, Alvarez points out, with more than 25,000 spills a year reported to the Environmental Protection Agency. That makes the need for cost-effective remediation clear, he said.

“We saw an opportunity to convert a liability, contaminated soil, into a commodity, fertile soil,” Alvarez said.

The key to retaining fertility is to preserve the soil’s essential clays, Zygourakis said. “Clays retain water, and if you raise the temperature too high, you basically destroy them,” he said. “If you exceed 500 degrees Celsius (900 degrees Fahrenheit), dehydration is irreversible.

The researchers put soil samples from Hearne, Texas, contaminated in the lab with heavy crude, into a kiln to see what temperature best eliminated the most oil, and how long it took.

Their results showed heating samples in the rotating drum at 420 C (788 F) for 15 minutes eliminated 99.9 percent of total petroleum hydrocarbons (TPH) and 94.5 percent of polycyclic aromatic hydrocarbons (PAH), leaving the treated soils with roughly the same pollutant levels found in natural, uncontaminated soil.

The paper appears in the American Chemical Society journal Environmental Science and Technology. It follows several papers by the same group that detailed the mechanism by which pyrolysis removes contaminants and turns some of the unwanted hydrocarbons into char, while leaving behind soil almost as fertile as the original. “While heating soil to clean it isn’t a new process,” Zygourakis said, “we’ve proved we can do it quickly in a continuous reactor to remove TPH, and we’ve learned how to optimize the pyrolysis conditions to maximize contaminant removal while minimizing soil damage and loss of fertility.

“We also learned we can do it with less energy than other methods, and we have detoxified the soil so that we can safely put it back,” he said.

Heating the soil to about 420 C represents the sweet spot for treatment, Zygourakis said. Heating it to 470 C (878 F) did a marginally better job in removing contaminants, but used more energy and, more importantly, decreased the soil’s fertility to the degree that it could not be reused.

“Between 200 and 300 C (392-572 F), the light volatile compounds evaporate,” he said. “When you get to 350 to 400 C (662-752 F), you start breaking first the heteroatom bonds, and then carbon-carbon and carbon-hydrogen bonds triggering a sequence of radical reactions that convert heavier hydrocarbons to stable, low-reactivity char.”

The true test of the pilot program came when the researchers grew Simpson black-seeded lettuce, a variety for which petroleum is highly toxic, on the original clean soil, some contaminated soil and several pyrolyzed soils. While plants in the treated soils were a bit slower to start, they found that after 21 days, plants grown in pyrolyzed soil with fertilizer or simply water showed the same germination rates and had the same weight as those grown in clean soil.

“We knew we had a process that effectively cleans up oil-contaminated soil and restores its fertility,” Zygourakis said. “But, had we truly detoxified the soil?”

To answer this final question, the Rice team turned to Bhagavatula Moorthy, a professor of neonatology at Baylor College of Medicine, who studies the effects of airborne contaminants on neonatal development. Moorthy and his lab found that extracts taken from oil-contaminated soils were toxic to human lung cells, while exposing the same cell lines to extracts from treated soils had no adverse effects. The study eased concerns that pyrolyzed soil could release airborne dust particles laced with highly toxic pollutants like PAHs.

”One important lesson we learned is that different treatment objectives for regulatory compliance, detoxification and soil-fertility restoration need not be mutually exclusive and can be simultaneously achieved,” Alvarez said.

Here’s a link to and a citation for the paper,

Pilot-Scale Pyrolytic Remediation of Crude-Oil-Contaminated Soil in a Continuously-Fed Reactor: Treatment Intensity Trade-Offs by Wen Song, Julia E. Vidonish, Roopa Kamath, Pingfeng Yu, Chun Chu, Bhagavatula Moorthy, Baoyu Gao, Kyriacos Zygourakis, and Pedro J. J. Alvarez. Environ. Sci. Technol., 2019, 53 (4), pp 2045–2053 DOI: 10.1021/acs.est.8b05825 Publication Date (Web): January 25, 2019

Copyright © 2019 American Chemical Society

This paper is behind a paywall.

Eco-friendly nanocomposite catalyst and ultrasound to remove pollutants from water

The best part of this story is that they’re using biochar from rice hulls to create the nanocomposite catalyst. A July 19, 2019 news item on ScienceDaily reveals a few details about the research without discussing the rice hulls,

The research team of Dr. Jae-woo Choi and Dr. Kyung-won Jung of the Korea Institute of Science and Technology’s (KIST, president: Byung-gwon Lee) Water Cycle Research Center announced that it has developed a wastewater treatment process that uses a common agricultural byproduct to effectively remove pollutants and environmental hormones, which are known to be endocrine disruptors.

A July 19, 2019 Korea National Research Council of Science & Technology news release on EurekAlert, which originated the news item, provides more detail,

The sewage and wastewater that are inevitably produced at any industrial worksite often contain large quantities of pollutants and environmental hormones (endocrine disruptors). Because environmental hormones do not break down easily, they can have a significant negative effect on not only the environment but also the human body. To prevent this, a means of removing environmental hormones is required.

The performance of the catalyst that is currently being used to process sewage and wastewater drops significantly with time. Because high efficiency is difficult to achieve given the conditions, the biggest disadvantage of the existing process is the high cost involved. Furthermore, the research done thus far has mostly focused on the development of single-substance catalysts and the enhancement of their performance. Little research has been done on the development of eco-friendly nanocomposite catalysts that are capable of removing environmental hormones from sewage and wastewater.

The KIST research team, led by Dr. Jae-woo Choi and Dr. Kyung-won Jung, utilized biochar,** which is eco-friendly and made from agricultural byproducts, to develop a wastewater treatment process that effectively removes pollutants and environmental hormones. The team used rice hulls [emphasis mine] which are discarded during rice harvesting, to create a biochar that is both eco-friendly and economical. The surface of the biochar was coated with nano-sized manganese dioxide to create a nanocomposite. The high efficiency and low cost of the biochar-nanocomposite catalyst is based on the combination of the advantages of the biochar and manganese dioxide.

**Biochar: a term that collectively refers to substances that can be created through the thermal decomposition of diverse types of biomass or wood under oxygen-limited condition

The KIST team used the hydrothermal method, which is a type of mineral synthesis that uses high heat and pressure, when synthesizing the nanocomposite in order to create a catalyst that is highly active, easily replicable, and stable. It was confirmed that giving the catalyst a three-dimensional stratified structure resulted in the high effectiveness of the advanced oxidation process (AOP), due to the large surface area created.

When used under the same conditions in which the existing catalyst can remove only 80 percent of Bisphenol A (BPA), an environmental hormone, the catalyst developed by the KIST team removed over 95 percent in less than one hour. In particular, when combined with ultrasound (20kHz), it was confirmed that all traces of BPA were completely removed in less than 20 minutes. Even after many repeated tests, the BPA removal rate remained consistently at around 93 percent.

Dr. Kyung-won Jung of KIST’s Water Cycle Research Center said, “The catalyst developed through this study makes use of a common agricultural byproduct. Therefore, we expect that additional research on alternative substances will lead to the development of catalysts derived from various types of organic waste biomass.” Dr. Jae-woo Choi, also of KIST’s Water Cycle Research Center, said, “We have high hopes that future studies aimed at achieving process optimization and increasing removal rates will allow for the development an environmental hormone removal system that is both eco-friendly and low-cost.”

Here’s a link to and a citation for the paper,

Ultrasound-assisted heterogeneous Fenton-like process for bisphenol A removal at neutral pH using hierarchically structured manganese dioxide/biochar nanocomposites as catalysts by Kyung-Won Jung, Seon Yong Lee, Young Jae Lee, Jae-Woo Choi. Ultrasonics Sonochemistry
Volume 57, October 2019, Pages 22-28 DOI: https://doi.org/10.1016/j.ultsonch.2019.04.039 Available online 29 April 2019

This paper is behind a paywall.

Better performing solar cells with newly discovered property of pristine graphene

Light-harvesting devices—I like that better than solar cells or the like but I think that the term serves as a category rather than a name/label for a specific device. Enough musing. A December 17, 2018 news item on Nanowerk describes the latest about graphene and light-harvesting devices (Note: A link has been removed,

An international research team, co-led by a physicist at the University of California, Riverside, has discovered a new mechanism for ultra-efficient charge and energy flow in graphene, opening up opportunities for developing new types of light-harvesting devices.

The researchers fabricated pristine graphene — graphene with no impurities — into different geometric shapes, connecting narrow ribbons and crosses to wide open rectangular regions. They found that when light illuminated constricted areas, such as the region where a narrow ribbon connected two wide regions, they detected a large light-induced current, or photocurrent.

The finding that pristine graphene can very efficiently convert light into electricity could lead to the development of efficient and ultrafast photodetectors — and potentially more efficient solar panels.

A December 14, 2018 University of California at Riverside (UCR) news release by Iqbal Pittalwala (also on EurekAlert but published Dec. 17, 2018), which originated the news item,gives a brief description of graphene while adding context for this research,


Graphene, a 1-atom thick sheet of carbon atoms arranged in a hexagonal lattice, has many desirable material properties, such as high current-carrying capacity and thermal conductivity. In principle, graphene can absorb light at any frequency, making it ideal material for infrared and other types of photodetection, with wide applications in bio-sensing, imaging, and night vision.

In most solar energy harvesting devices, a photocurrent arises only in the presence of a junction between two dissimilar materials, such as “p-n” junctions, the boundary between two types of semiconductor materials. The electrical current is generated in the junction region and moves through the distinct regions of the two materials.

“But in graphene, everything changes,” said Nathaniel Gabor, an associate professor of physics at UCR, who co-led the research project. “We found that photocurrents may arise in pristine graphene under a special condition in which the entire sheet of graphene is completely free of excess electronic charge. Generating the photocurrent requires no special junctions and can instead be controlled, surprisingly, by simply cutting and shaping the graphene sheet into unusual configurations, from ladder-like linear arrays of contacts, to narrowly constricted rectangles, to tapered and terraced edges.”

Pristine graphene is completely charge neutral, meaning there is no excess electronic charge in the material. When wired into a device, however, an electronic charge can be introduced by applying a voltage to a nearby metal. This voltage can induce positive charge, negative charge, or perfectly balance negative and positive charges so the graphene sheet is perfectly charge neutral.

“The light-harvesting device we fabricated is only as thick as a single atom,” Gabor said. “We could use it to engineer devices that are semi-transparent. These could be embedded in unusual environments, such as windows, or they could be combined with other more conventional light-harvesting devices to harvest excess energy that is usually not absorbed. Depending on how the edges are cut to shape, the device can give extraordinarily different signals.”

The research team reports this first observation of an entirely new physical mechanism — a photocurrent generated in charge-neutral graphene with no need for p-n junctions — in Nature Nanotechnology today [Dec. 17, 2018].

Previous work by the Gabor lab showed a photocurrent in graphene results from highly excited “hot” charge carriers. When light hits graphene, high-energy electrons relax to form a population of many relatively cooler electrons, Gabor explained, which are subsequently collected as current. Even though graphene is not a semiconductor, this light-induced hot electron population can be used to generate very large currents.

“All of this behavior is due to graphene’s unique electronic structure,” he said. “In this ‘wonder material,’ light energy is efficiently converted into electronic energy, which can subsequently be transported within the material over remarkably long distances.”

He explained that, about a decade ago, pristine graphene was predicted to exhibit very unusual electronic behavior: electrons should behave like a liquid, allowing energy to be transferred through the electronic medium rather than by moving charges around physically.
“But despite this prediction, no photocurrent measurements had been done on pristine graphene devices — until now,” he said.

The new work on pristine graphene shows electronic energy travels great distances in the absence of excess electronic charge.

The research team has found evidence that the new mechanism results in a greatly enhanced photoresponse in the infrared regime with an ultrafast operation speed.
“We plan to further study this effect in a broad range of infrared and other frequencies, and measure its response speed,” said first author Qiong Ma, a postdoctoral associate in physics at the Massachusetts Institute of Technology, or MIT.

The researchers have provided an image illustrating their work,

Caption: Shining light on graphene: Although graphene has been studied vigorously for more than a decade, new measurements on high-performance graphene devices have revealed yet another unusual property. In ultra-clean graphene sheets, energy can flow over great distances, giving rise to an unprecedented response to light. Credit: Max Grossnickle and QMO Labs, UC Riverside.

Here’s a link to and a citation for the paper,

Giant intrinsic photoresponse in pristine graphene by Qiong Ma, Chun Hung Lui, Justin C. W. Song, Yuxuan Lin, Jian Feng Kong, Yuan Cao, Thao H. Dinh, Nityan L. Nair, Wenjing Fang, Kenji Watanabe, Takashi Taniguchi, Su-Yang Xu, Jing Kong, Tomás Palacios, Nuh Gedik, Nathaniel M. Gabor, & Pablo Jarillo-Herrero. Nature Nanotechnology (2018) Published 17 December 2018 DOI: https://doi.org/10.1038/s41565-018-0323-8

This paper is behind a paywall.