Tag Archives: water remediation

3D nanotech blankets for clean drinking water?

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A March 24, 2025 news item on ScienceDaily announces a new technique for removing pollutants from water (aka, water remediation),

Researchers have developed a new material that, by harnessing the power of sunlight, can clear water of dangerous pollutants.

Created through a combination of soft chemistry gels and electrospinning — a technique where electrical force is applied to liquid to craft small fibers — the team constructed thin fiber-like strips of titanium dioxide (TiO₂), a compound often utilized in solar cells, gas sensors and various self-cleaning technologies.

…

A March 24, 2025 Ohio State University (OSU) news release (also on EurekAlert), which originated the news item, delves further into the topic, Note: Links have been removed,

Despite being a great alternative energy source, solar fuel systems that utilize TiO₂ nanoparticles are often power-limited because they can only undergo photocatalysis, or create chemical reactions, by absorbing non-visible UV light. This can cause significant challenges to implementation, including low efficiency and the need for complex filtration systems. 

Yet when researchers added copper to the material to improve this process, their new structures, called nanomats, were able to absorb enough light energy to break down harmful pollutants in air and water, said Pelagia-Irene Gouma, lead author of the study and a professor of materials science and engineering at The Ohio State University. 

“There hasn’t been an easy way to create something like a blanket that you can lay on water and start creating energy,” she said. “But we are the only ones who have made these structures and the only ones to demonstrate that they actually work.”

The study was recently published in the journal Advanced Science. 

When titanium dioxide absorbs light, electrons are formed that oxidize water and attack pollutants, slowly destroying them until they become benign. When copper is added, that process is supercharged, making it even more effective. 

To determine this, researchers worked to characterize the nanomat’s updated properties to understand how it behaved and what made it different from other self-cleaning nanoparticles, said Gouma. Surprisingly, researchers found that compared to traditional solar cells, these nanomats can be more successful at power generation when placed under natural sunlight, she said.

“These nanomats can be used as a power generator, or as water remediation tools,” she said. “In both ways, you have a catalyst with the highest efficiency reported to date.”

These lightweight, easy-to-remove fiber mats can float and operate atop any body of water and are even reusable through multiple cleaning cycles. Because nanomats are so effective, researchers envision that they could be used to rid water of industrial pollutants in developing countries, turning otherwise contaminated rivers and lakes into sources of clean drinking water. 

Additionally, because this technology doesn’t generate any toxic byproducts like some solar cell systems, nanomats are extremely environmentally friendly. “It’s a safe material, it won’t hurt anything, and it’s as clean as it can be,” said Gouma. 

Still, although this team’s technology is incredibly efficient, how long it will take to scale up commercially depends on how quickly industries take notice of the product. “We have the tools to make them in large quantities and translate them to various industries,” said Gouma. “The only limitation is that it needs someone to take advantage of these abundant resources.”

Overall, the study’s findings suggest that nanomats could be a promising tool in many future photocatalytic applications, including long-term sustainability efforts like environmental remediation as well as solar-driven hydrogen production. 

In the meantime, the team plans to examine ways to optimize the material further. 

“This material is completely novel in terms of a new form of nanotechnology,” said Gouma. “It’s really impressive and something that we are very excited about.”

Other Ohio State co-authors include Fateh Mikaeilia and Mohammad Mahafuzur Rahaman. This study was supported by the National Science Foundation. 

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

3D Self-Supported Visible Light Photochemical Nanocatalysts by Fateh Mikaeili, Mohammad Mahafuzur Rahaman, Pelagia-Irene (Perena) Gouma. Advanced Science Online Version of Record before inclusion in an issue 2502981 DOI: https://doi.org/10.1002/advs.202502981 First published: 24 March 2025

This paper is open access.

Sponge coated with nanoparticles removes lead from water

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It doesn’t look like much but who cares when it does the job and is being made available commercially,

Caption: Commercially available cellulose sponge coated in manganese-doped goethite nanoparticles. Credit: Caroline Harms/Northwestern University

A May 11, 2023 news item on Nanowerk announces the research,

Northwestern University engineers have developed a new sponge that can remove metals — including toxic heavy metals like lead and critical metals like cobalt — from contaminated water, leaving safe, drinkable water behind.

In proof-of-concept experiments, the researchers tested their new sponge on a highly contaminated sample of tap water, containing more than 1 part per million of lead. With one use, the sponge filtered lead to below detectable levels.

After using the sponge, researchers also were able to successfully recover metals and reuse the sponge for multiple cycles. The new sponge shows promise for future use as an inexpensive, easy-to-use tool in home water filters or large-scale environmental remediation efforts.

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A May 10, 2023 Northwestern University news release on EurekAlert (also received via email) provides more detail, Note: Links have been removed,

The study was published late yesterday (May 10 [2023]) in the journal ACS ES&T Water. The paper outlines the new research and sets design rules for optimizing similar platforms for removing — and recovering — other heavy-metal toxins, including cadmium, arsenic, cobalt and chromium.

“The presence of heavy metals in the water supply is an enormous public health challenge for the entire globe,” said Northwestern’s Vinayak Dravid, senior author of the study. “It is a gigaton problem that requires solutions that can be deployed easily, effectively and inexpensively. That’s where our sponge comes in. It can remove the pollution and then be used again and again.”

Dravid is the Abraham Harris Professor of Materials Science and Engineering at Northwestern’s McCormick School of Engineering and director of global initiatives at the International Institute for Nanotechnology.

Sopping up spills

The project builds on Dravid’s previous work to develop highly porous sponges for various aspects of environmental remediation. In May 2020, his team unveiled a new sponge designed to clean up oil spills. [Note: My June 25, 2020 posting highlights the work and includes an embedded video demonstration of the technology.] The nanoparticle-coated sponge, which is now being commercialized by Northwestern spinoff MFNS Tech, offers a more efficient, economic, ecofriendly and reusable alternative to current approaches to oil spills.

But Dravid knew it wasn’t enough.

“When there is an oil spill, you can remove the oil,” he said. “But there also are toxic heavy metals — like mercury, cadmium, sulfur and lead — in those spills. So, even when you remove the oil, some of the other toxins might remain.

Rinse and repeat

To tackle this aspect of the issue, Dravid’s team, again, turned to sponges coated with an ultrathin layer of nanoparticles. After testing many different types of nanoparticles, the team found that a manganese-doped goethite coating worked best. Not only are manganese-doped goethite nanoparticles inexpensive to make, easily available and nontoxic to human, they also have the properties necessary to selectively remediate heavy metals.

“You want a material with a high surface area, so there’s more room for the lead ions to stick to it,” said Benjamin Shindel, a Ph.D. student in Dravid’s lab and the paper’s first author. “These nanoparticles have high-surface areas and abundant reactive surface sites for adsorption and are stable, so they can be reused many times.”

The team synthesized slurries of manganese-doped goethite nanoparticles, as well as several other compositions of nanoparticles, and coated commercially available cellulose sponges with these slurries. Then, they rinsed the coated sponges with water in order to wash away any loose particles. The final coatings measured just tens of nanometers in thickness.

When submerged into contaminated water, the nanoparticle-coated sponge effectively sequested lead ions. The U.S. Food and Drug Administration requires that bottled drinking water is below 5 parts per billion of lead. In filtration trials, the sponge lowered the amount of lead to approximately 2 parts per billion, making it safe to drink.

“We’re really happy with that,” Shindel said. “Of course, this performance can vary based on several factors. For instance, if you have a large sponge in a tiny volume of water, it will perform better than a tiny sponge in a huge lake.”

Recovery bypasses mining

From there, the team rinsed the sponge with mildly acidified water, which Shindel likened to “having the same acidity of lemonade.” The acidic solution caused the sponge to release the lead ions and be ready for another use. Although the sponge’s performance declined after the first use, it still recovered more than 90% of the ions during subsequent use cycles.

This ability to gather and then recover heavy metals is particularly valuable for removing rare, critical metals, such as cobalt, from water sources. A common ingredient in lithium-ion batteries, cobalt is energetically expensive to mine and accompanied by a laundry list of environmental and human costs.

If researchers could develop a sponge that selectively removes rare metals, including cobalt, from water, then those metals could be recycled into products like batteries.

“For renewable energy technologies, like batteries and fuel cells, there is a need for metal recovery,” Dravid said. “Otherwise, there is not enough cobalt in the world for the growing number of batteries. We must find ways to recover metals from very dilute solutions. Otherwise, it becomes poisonous and toxic, just sitting there in the water. We might as well make something valuable with it.”

Standardized scale

As a part of the study, Dravid and his team set new design rules to help others develop tools to target particular metals, including cobalt. Specifically, they pinpointed which low-cost and nontoxic nanoparticles also have high-surface areas and affinities for sticking to metal ions. They studied the performance of coatings of manganese, iron, aluminum and zinc oxides on lead adsorption. Then, they established relationships between the structures of these nanoparticles and their adsorptive properties.

Called Nanomaterial Sponge Coatings for Heavy Metals (or “Nano-SCHeMe”), the environmental remediation platform can help other researchers differentiate which nanomaterials are best suited for particular applications.

“I’ve read a lot of literature that compares different coatings and adsorbents,” said Caroline Harms, an undergraduate student in Dravid’s lab and paper co-author. “There really is a lack of standardization in the field. By analyzing different types of nanoparticles, we developed a comparative scale that actually works for all of them. It could have a lot of implications in moving the field forward.”

Dravid and his team imagine that their sponge could be used in commercial water filters, for environmental clean-up or as an added step in water reclamation and treatment facilities.

“This work may be pertinent to water quality issues both locally and globally,” Shindel said. “We want to see this out in the world, where it can make a real impact.”

The study, “Nano-SCHeME: Nanomaterial Sponge Coatings for Heavy Metals, an environmental remediation platform,” was supported by the National Science Foundation and U.S. Department of Energy.

Editor’s note: Dravid and Northwestern have financial interests (equities, royalties) in MFNS Tech.

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

Nano-SCHeme: Nanomaterial Sponge Coatings for Heavy Metals, an Environmental Remediation Platform by Benjamin Shindel, Stephanie M. Ribet, Caroline Harms, Vikas Nandwana, and Vinayak P. Dravid. ACS EST Water 2023, XXXX, XXX, XXX-XXX DOI: https://doi.org/10.1021/acsestwater.2c00646 Publication Date:May 10, 2023 © 2023 American Chemical Society

This paper is behind a paywall.

You can find the MFNS Tech website here.

Biohybrid cyborgs

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Cyborgs are usually thought of as people who’ve been enhanced with some sort of technology, In contemporary real life that technology might be a pacemaker or hip replacement but in science fiction it’s technology such as artificial retinas (for example) that expands the range of visible light for an enhanced human.

Rarely does the topic of a microscopic life form come up in discussion about cyborgs and yet, that’s exactly what an April 3, 2019 Nanowerk spotlight article by Michael Berger describes in relationship to its use in water remediation efforts (Note: links have been removed),

Researchers often use living systems as inspiration for the design and engineering of micro- and nanoscale propulsion systems, actuators, sensors, and robots. …

…

“Although microrobots have recently proved successful for remediating decontaminated water at the laboratory scale, the major challenge in the field is to scale up these applications to actual environmental settings,” Professor Joseph Wang, Chair of Nanoengineering and Director, Center of Wearable Sensors at the University California San Diego, tells Nanowerk. “In order to do this, we need to overcome the toxicity of their chemical fuels, the short time span of biocompatible magnesium-based micromotors and the small domain operation of externally actuated microrobots.”

In their recent work on self-propelled biohybrid microrobots, Wang and his team were inspired by recent developments of biohybrid cyborgs that integrate self-propelling bacteria with functionalized synthetic nanostructures to transport materials.

“These tiny cyborgs are incredibly efficient for transport materials, but the limitation that we observed is that they do not provide large-scale fluid mixing,” notes Wang. ” We wanted to combine the best properties of both worlds. So, we searched for the best candidate to create a more robust biohybrid for mixing and we decided on using rotifers (Brachionus) as the engine of the cyborg.”

These marine microorganisms, which measure between 100 and 300 micrometers, are amazing creatures as they already possess sensing ability, energetic autonomy, and provide large-scale fluid mixing capability. They are also are very resilient and can survive in very harsh environments and even are one of the few organisms that have survived via asexual reproduction.

“Taking inspiration from the science fiction concept of a cybernetic organism, or cyborg – where an organism has enhanced abilities due to the integration of some artificial component – we developed a self-propelled biohybrid microrobot, that we named rotibot, employing rotifers as their engine,” says Fernando Soto, first author of a paper on this work (Advanced Functional Materials, “Rotibot: Use of Rotifers as Self-Propelling Biohybrid Microcleaners”).

This is the first demonstration of a biohybrid cyborg used for the removal and degradation of pollutants from solution. The technical breakthrough that allowed the team to achieve this task is based on a novel fabrication mechanism based on the selective accumulation of functionalized microbeads in the microorganism’s mouth: The rotifer serves not only as a transport vessel for active material or cargo but also acting as a powerful biological pump, as it creates fluid flows directed towards its mouth

Nanowerk has made this video demonstrating a rotifer available along with a description,

“The rotibot is a rotifer (a marine microorganism) that has plastic microbeads attached to the mouth, which are functionalized with pollutant-degrading enzymes. This video illustrates a free swimming rotibot mixing tracer particles in solution. “

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

Rotibot: Use of Rotifers as Self‐Propelling Biohybrid Microcleaners by Fernando Soto, Miguel Angel Lopez‐Ramirez, Itthipon Jeerapan, Berta Esteban‐Fernandez de Avila, Rupesh, Kumar Mishra, Xiaolong Lu, Ingrid Chai, Chuanrui Chen, Daniel Kupor. Advanced Functional Materials DOI: https://doi.org/10.1002/adfm.201900658 First published: 28 March 2019

This paper is behind a paywall.

Berger’s April 3, 2019 Nanowerk spotlight article includes some useful images if you are interested in figuring out how these rotibots function.

Altered virus spins gold into beads

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They’re not calling this synthetic biology but I’ m pretty sure that altering a virus gene so the virus can spin gold (Rumpelstiltskin anyone?) qualifies. From an August 24, 2018 news item on ScienceDaily,

The race is on to find manufacturing techniques capable of arranging molecular and nanoscale objects with precision.

Engineers at the University of California, Riverside, have altered a virus to arrange gold atoms into spheroids measuring a few nanometers in diameter. The finding could make production of some electronic components cheaper, easier, and faster.

An August 23, 2018 University of California at Riverside (UCR) news release (also on EurekAlett) by Holly Ober, which originated the news item, adds detail,

“Nature has been assembling complex, highly organized nanostructures for millennia with precision and specificity far superior to the most advanced technological approaches,” said Elaine Haberer, a professor of electrical and computer engineering in UCR’s Marlan and Rosemary Bourns College of Engineering and senior author of the paper describing the breakthrough. “By understanding and harnessing these capabilities, this extraordinary nanoscale precision can be used to tailor and build highly advanced materials with previously unattainable performance.”

Viruses exist in a multitude of shapes and contain a wide range of receptors that bind to molecules. Genetically modifying the receptors to bind to ions of metals used in electronics causes these ions to “stick” to the virus, creating an object of the same size and shape. This procedure has been used to produce nanostructures used in battery electrodes, supercapacitors, sensors, biomedical tools, photocatalytic materials, and photovoltaics.

The virus’ natural shape has limited the range of possible metal shapes. Most viruses can change volume under different scenarios, but resist the dramatic alterations to their basic architecture that would permit other forms.

The M13 bacteriophage, however, is more flexible. Bacteriophages are a type of virus that infects bacteria, in this case, gram-negative bacteria, such as Escherichia coli, which is ubiquitous in the digestive tracts of humans and animals. M13 bacteriophages genetically modified to bind with gold are usually used to form long, golden nanowires.

Studies of the infection process of the M13 bacteriophage have shown the virus can be converted to a spheroid upon interaction with water and chloroform. Yet, until now, the M13 spheroid has been completely unexplored as a nanomaterial template.

Haberer’s group added a gold ion solution to M13 spheroids, creating gold nanobeads that are spiky and hollow.

“The novelty of our work lies in the optimization and demonstration of a viral template, which overcomes the geometric constraints associated with most other viruses,” Haberer said. “We used a simple conversion process to make the M13 virus synthesize inorganic spherical nanoshells tens of nanometers in diameter, as well as nanowires nearly 1 micron in length.”

The researchers are using the gold nanobeads to remove pollutants from wastewater through enhanced photocatalytic behavior.

The work enhances the utility of the M13 bacteriophage as a scaffold for nanomaterial synthesis. The researchers believe the M13 bacteriophage template transformation scheme described in the paper can be extended to related bacteriophages.

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

M13 bacteriophage spheroids as scaffolds for directed synthesis of spiky gold nanostructures by Tam-Triet Ngo-Duc, Joshua M. Plank, Gongde Chen, Reed E. S. Harrison, Dimitrios Morikis, Haizhou Liu, and Elaine D. Haberer. Nanoscale, 2018,10, 13055-13063 DOI: 10.1039/C8NR03229G First published on 25 Jun 2018

This paper is behind a paywall.

For another example of genetic engineering and synthetic biology, see my July 18, 2018 posting: Genetic engineering: an eggplant in Bangladesh and a synthetic biology grant at Concordia University (Canada).

For anyone unfamiliar with the Rumpelstiltskin fairytale about spinning straw into gold, see its Wikipedida entry.

Nanopores and a new technique for desalination

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There’s been more than one piece here about water desalination and purification and/or remediation efforts and at least one of them claims to have successfully overcome issues such as reverse osmosis energy needs which are hampering adoption of various technologies. Now, researchers at the University of Illinois at Champaign Urbana have developed another new technique for desalinating water while reverse osmosis issues according to a Nov. 11, 2015 news item on Nanowerk (Note: A link has been removed) ,

University of Illinois engineers have found an energy-efficient material for removing salt from seawater that could provide a rebuttal to poet Samuel Taylor Coleridge’s lament, “Water, water, every where, nor any drop to drink.”

The material, a nanometer-thick sheet of molybdenum disulfide (MoS2) riddled with tiny holes called nanopores, is specially designed to let high volumes of water through but keep salt and other contaminates out, a process called desalination. In a study published in the journal Nature Communications (“Water desalination with a single-layer MoS2 nanopore”), the Illinois team modeled various thin-film membranes and found that MoS2 showed the greatest efficiency, filtering through up to 70 percent more water than graphene membranes. [emphasis mine]

I’ll get to the professor’s comments about graphene membranes in a minute. Meanwhile, a Nov. 11, 2015 University of Illinois news release (also on EurekAlert), which originated the news item, provides more information about the research,

“Even though we have a lot of water on this planet, there is very little that is drinkable,” said study leader Narayana Aluru, a U. of I. professor of mechanical science and engineering. “If we could find a low-cost, efficient way to purify sea water, we would be making good strides in solving the water crisis.

“Finding materials for efficient desalination has been a big issue, and I think this work lays the foundation for next-generation materials. These materials are efficient in terms of energy usage and fouling, which are issues that have plagued desalination technology for a long time,” said Aluru, who also is affiliated with the Beckman Institute for Advanced Science and Technology at the U. of I.

Most available desalination technologies rely on a process called reverse osmosis to push seawater through a thin plastic membrane to make fresh water. The membrane has holes in it small enough to not let salt or dirt through, but large enough to let water through. They are very good at filtering out salt, but yield only a trickle of fresh water. Although thin to the eye, these membranes are still relatively thick for filtering on the molecular level, so a lot of pressure has to be applied to push the water through.

“Reverse osmosis is a very expensive process,” Aluru said. “It’s very energy intensive. A lot of power is required to do this process, and it’s not very efficient. In addition, the membranes fail because of clogging. So we’d like to make it cheaper and make the membranes more efficient so they don’t fail as often. We also don’t want to have to use a lot of pressure to get a high flow rate of water.”

One way to dramatically increase the water flow is to make the membrane thinner, since the required force is proportional to the membrane thickness. Researchers have been looking at nanometer-thin membranes such as graphene. However, graphene presents its own challenges in the way it interacts with water.

Aluru’s group has previously studied MoS2 nanopores as a platform for DNA sequencing and decided to explore its properties for water desalination. Using the Blue Waters supercomputer at the National Center for Supercomputing Applications at the U. of I., they found that a single-layer sheet of MoS2 outperformed its competitors thanks to a combination of thinness, pore geometry and chemical properties.

A MoS2 molecule has one molybdenum atom sandwiched between two sulfur atoms. A sheet of MoS2, then, has sulfur coating either side with the molybdenum in the center. The researchers found that creating a pore in the sheet that left an exposed ring of molybdenum around the center of the pore created a nozzle-like shape that drew water through the pore.

“MoS2 has inherent advantages in that the molybdenum in the center attracts water, then the sulfur on the other side pushes it away, so we have much higher rate of water going through the pore,” said graduate student Mohammad Heiranian, the first author of the study. “It’s inherent in the chemistry of MoS2 and the geometry of the pore, so we don’t have to functionalize the pore, which is a very complex process with graphene.”

In addition to the chemical properties, the single-layer sheets of MoS2 have the advantages of thinness, requiring much less energy, which in turn dramatically reduces operating costs. MoS2 also is a robust material, so even such a thin sheet is able to withstand the necessary pressures and water volumes.

The Illinois researchers are establishing collaborations to experimentally test MoS2 for water desalination and to test its rate of fouling, or clogging of the pores, a major problem for plastic membranes. MoS2 is a relatively new material, but the researchers believe that manufacturing techniques will improve as its high performance becomes more sought-after for various applications.

“Nanotechnology could play a great role in reducing the cost of desalination plants and making them energy efficient,” said Amir Barati Farimani, who worked on the study as a graduate student at Illinois and is now a postdoctoral fellow at Stanford University. “I’m in California now, and there’s a lot of talk about the drought and how to tackle it. I’m very hopeful that this work can help the designers of desalination plants. This type of thin membrane can increase return on investment because they are much more energy efficient.”

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

Water desalination with a single-layer MoS2 nanopore by Mohammad Heiranian, Amir Barati Farimani, & Narayana R. Aluru. Nature Communications 6, Article number: 8616 doi:10.1038/ncomms9616 Published 14 October 2015

Graphene membranes

In a July 13, 2015 essay on Nanotechnology Now, Tim Harper provides an overview of the research into using graphene for water desalination and purification/remediation about which he is quite hopeful. There is no mention of an issue with interactions between water and graphene. It should be noted that Tim Harper is the Chief Executive Officer of G20, a company which produces a graphene-based solution (graphene oxide sheets), which can desalinate water and can purify/remediate it. Tim is a scientist and while you might have some hesitation given his fiscal interests, his essay is worthwhile reading as he supplies context and explanations of the science.

Cleaning up carbon dioxide pollution in the oceans and elsewhere

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I have a mini roundup of items (3) concerning nanotechnology and environmental applications with a special focus on carbon materials.

Carbon-capturing motors

First up, there’s a Sept. 23, 2015 news item on ScienceDaily which describes work with tiny carbon-capturing motors,

Machines that are much smaller than the width of a human hair could one day help clean up carbon dioxide pollution in the oceans. Nanoengineers at the University of California, San Diego have designed enzyme-functionalized micromotors that rapidly zoom around in water, remove carbon dioxide and convert it into a usable solid form.

The proof of concept study represents a promising route to mitigate the buildup of carbon dioxide, a major greenhouse gas in the environment, said researchers. …

A Sept 22, 2015 University of California at San Diego (UCSD) news release by Liezel Labios, which originated the news release, provides more details about the scientists’ hopes and the technology,

“We’re excited about the possibility of using these micromotors to combat ocean acidification and global warming,” said Virendra V. Singh, a postdoctoral scientist in Wang’s [nanoengineering professor and chair Joseph Wang] research group and a co-first author of this study.

In their experiments, nanoengineers demonstrated that the micromotors rapidly decarbonated water solutions that were saturated with carbon dioxide. Within five minutes, the micromotors removed 90 percent of the carbon dioxide from a solution of deionized water. The micromotors were just as effective in a sea water solution and removed 88 percent of the carbon dioxide in the same timeframe.

“In the future, we could potentially use these micromotors as part of a water treatment system, like a water decarbonation plant,” said Kevin Kaufmann, an undergraduate researcher in Wang’s lab and a co-author of the study.

The micromotors are essentially six-micrometer-long tubes that help rapidly convert carbon dioxide into calcium carbonate, a solid mineral found in eggshells, the shells of various marine organisms, calcium supplements and cement. The micromotors have an outer polymer surface that holds the enzyme carbonic anhydrase, which speeds up the reaction between carbon dioxide and water to form bicarbonate. Calcium chloride, which is added to the water solutions, helps convert bicarbonate to calcium carbonate.

The fast and continuous motion of the micromotors in solution makes the micromotors extremely efficient at removing carbon dioxide from water, said researchers. The team explained that the micromotors’ autonomous movement induces efficient solution mixing, leading to faster carbon dioxide conversion. To fuel the micromotors in water, researchers added hydrogen peroxide, which reacts with the inner platinum surface of the micromotors to generate a stream of oxygen gas bubbles that propel the micromotors around. When released in water solutions containing as little as two to four percent hydrogen peroxide, the micromotors reached speeds of more than 100 micrometers per second.

However, the use of hydrogen peroxide as the micromotor fuel is a drawback because it is an extra additive and requires the use of expensive platinum materials to build the micromotors. As a next step, researchers are planning to make carbon-capturing micromotors that can be propelled by water.

“If the micromotors can use the environment as fuel, they will be more scalable, environmentally friendly and less expensive,” said Kaufmann.

The researchers have provided an image which illustrates the carbon-capturing motors in action,

Nanoengineers have invented tiny tube-shaped micromotors that zoom around in water and efficiently remove carbon dioxide. The surfaces of the micromotors are functionalized with the enzyme carbonic anhydrase, which enables the motors to help rapidly convert carbon dioxide to calcium carbonate. Image credit: Laboratory for Nanobioelectronics, UC San Diego Jacobs School of Engineering.

Nanoengineers have invented tiny tube-shaped micromotors that zoom around in water and efficiently remove carbon dioxide. The surfaces of the micromotors are functionalized with the enzyme carbonic anhydrase, which enables the motors to help rapidly convert carbon dioxide to calcium carbonate. Image credit: Laboratory for Nanobioelectronics, UC San Diego Jacobs School of Engineering.

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

Micromotor-Based Biomimetic Carbon Dioxide Sequestration: Towards Mobile Microscrubbers by Murat Uygun, Virendra V. Singh, Kevin Kaufmann, Deniz A. Uygun, Severina D. S. de Oliveira, and oseph Wang. Angewandte Chemie DOI: 10.1002/ange.201505155 Article first published online: 4 SEP 2015

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This article is behind a paywall.

Carbon nanotubes for carbon dioxide capture (carbon capture)

In a Sept. 22, 2015 posting by Dexter Johnson on his Nanoclast blog (located on the IEEE [Institute for Electrical and Electronics Engineers] website) describes research where carbon nanotubes are being used for carbon capture,

Now researchers at Technische Universität Darmstadt in Germany and the Indian Institute of Technology Kanpur have found that they can tailor the gas adsorption properties of vertically aligned carbon nanotubes (VACNTs) by altering their thickness, height, and the distance between them.

“These parameters are fundamental for ‘tuning’ the hierarchical pore structure of the VACNTs,” explained Mahshid Rahimi and Deepu Babu, doctoral students at the Technische Universität Darmstadt who were the paper’s lead authors, in a press release. “This hierarchy effect is a crucial factor for getting high-adsorption capacities as well as mass transport into the nanostructure. Surprisingly, from theory and by experiment, we found that the distance between nanotubes plays a much larger role in gas adsorption than the tube diameter does.”

Dexter provides a good and brief summary of the research.

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

Double-walled carbon nanotube array for CO2 and SO2 adsorption by Mahshid Rahimi, Deepu J. Babu, Jayant K. Singh, Yong-Biao Yang, Jörg J. Schneider, and Florian Müller-Plathe. J. Chem. Phys. 143, 124701 (2015); http://dx.doi.org/10.1063/1.4929609

This paper is open access.

The market for nanotechnology-enabled environmental applications

Coincident with stumbling across these two possible capture solutions, I found this Sept. 23, 2015 BCC Research news release,

A groundswell of global support for developing nanotechnology as a pollution remediation technique will continue for the foreseeable future. BCC Research reveals in its new report that this key driver, along with increasing worldwide concerns over removing pollutants and developing alternative energy sources, will drive growth in the nanotechnology environmental applications market.

The global nanotechnology market in environmental applications is expected to reach $25.7 billion by 2015 and $41.8 billion by 2020, conforming to a five-year (2015-2020) compound annual growth rate (CAGR) of 10.2%. Air remediation as a segment will reach $10.2 billion and $16.7 billion in 2015 and 2020, respectively, reflecting a five-year CAGR of 10.3%. Water remediation as a segment will grow at a five-year CAGR of 12.4% to reach $10.6 billion in 2020.

…

As nanoparticles push the limits and capabilities of technology, new and better techniques for pollution control are emerging. Presently, nanotechnology’s greatest potential lies in air pollution remediation.

“Nano filters could be applied to automobile tailpipes and factory smokestacks to separate out contaminants and prevent them from entering the atmosphere. In addition, nano sensors have been developed to sense toxic gas leaks at extremely low concentrations,” says BCC research analyst Aneesh Kumar. “Overall, there is a multitude of promising environmental applications for nanotechnology, with the main focus area on energy and water technologies.”

You can find links to the report, TOC (table of contents), and report overview on the BCC Research Nanotechnology in Environmental Applications: The Global Market report webpage.

Abakan makes good on Alberta (Canada) promise (coating for better pipeline transport of oil)

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It took three years but it seems that US company Abakan Inc.’s announcement of a joint research development centre at the Northern Alberta Institute of Technology (NAIT), (mentioned here in a May 7, 2012 post [US company, Abakan, wants to get in on the Canadian oils sands market]), has borne fruit. A June 8, 2015 news item on Azonano describes the latest developments,

Abakan Inc., an emerging leader in the advanced coatings and metal formulations markets, today announced that it has begun operations at its joint-development facility in Edmonton, Alberta.

Abakan’s subsidiary, MesoCoat Inc., along with the lead project partner, Northern Alberta Institute of Technology (NAIT) will embark on an 18-month collaborative effort to establish a prototype demonstration facility for developing, testing and commercializing wear-resistant clad pipe and components. Western Economic Diversification Canada is also supporting this initiative through a $1.5 million investment toward NAIT. Improvements in wear resistance are expected to make a significant impact in reducing maintenance and downtime costs while increasing productivity in oil sands and other mining applications.

A June 4, 2015 Abakan news release, which originated the news item, provides more detail about the proposed facility, the difficulties encountered during the setup, and some interesting information about pipes,

Abakan shipped its CermaClad high-speed large-area cladding system for installation at the Northern Alberta Institute of Technology’s (NAIT) campus in Edmonton, Alberta in early 2015. Despite delays associated with the installation of some interrelated equipment and machinery, the CermaClad system and other ancillary equipment are now installed at the Edmonton facility. The Edmonton facility is intended to serve as a pilot-scale wear-resistant clad pipe manufacturing facility for the development and qualification of wear-resistant clad pipes, and as a stepping stone for setting-up a full-scale wear-resistant clad pipe manufacturing facility in Alberta. The new facility will also serve as a platform for Abakan’s introduction to the Alberta oil sands market, which, with proven reserves estimated at more than 169 billion barrels, is one of the largest oil resources in the world and a major source of oil for Canada, the United States and Asia. Since Alberta oil sands production is expected to increase significantly over the next decade, producers want to extend the life of the carbon steel pipes used for the hydro-transportation of tailings with harder, tougher coatings that protect pipes from the abrasiveness of tar-like bituminous oil sands.

“Our aim is to fast-track market entry of our wear-resistant clad pipe products for the transportation of oil sands and mining slurries. We have received commitments from oil sands producers in Canada and mining companies in Mexico and Brazil to field-test CermaClad wear-resistant clad pipe products as soon as our system is ready for testing. Apart from our work with conventional less expensive chrome carbide and the more expensive tungsten carbide wear-resistant cladding on pipes, Abakan also expects to introduce new iron-based structurally amorphous metal (SAM) alloy cladding that in testing has exhibited better performance than tungsten carbide cladding, but at a fraction of the cost.” Robert Miller stated further that “although more expensive than the more widely used chrome carbide cladding, our new alloy cladding is expected to be a significantly better value proposition when you consider an estimated life of three times that of chrome carbide cladding and those cost efficiencies that correspond to less downtime revenue losses, and lower maintenance and replacement costs.”

The costs associated with downtime and maintenance in the Alberta oil sands industry estimated at more than $10 billion a year are expected to grow as production expands, according to the Materials and Reliability in Oil Sands (MARIOS) consortium in Alberta. The development of Alberta’s oil sands has been held up by the lack of materials for transport lines and components that are resistant to the highly abrasive slurry. Due to high abrasion, the pipelines have to be rotated every three to four months and replaced every 12 to 15 months. [emphasis mine] The costs involved just in rotating and replacing the pipes is approximately $2 billion annually. The same is true of large components, for example the steel teeth on the giant electric shovels used to recover oil sands, must be replaced approximately every two days.

Abakan’s combination of high productivity coating processes and groundbreaking materials are expected to facilitate significant efficiencies associated with the extraction of these oil resources. Our proprietary materials combined with CermaClad large-area based fusion cladding technology, have demonstrated in laboratory tests a three to eight times improvement in wear and corrosion resistance when compared with traditional weld overlays at costs comparable to rubber and metal matrix composite alternatives. Abakan intends to complete development and initiate field-testing by end of year 2016 and begin the construction of a full-scale wear-resistant clad pipe manufacturing facility in Alberta in early-2017.

Given that there is extensive talk about expanding oil pipelines from Alberta to British Columbia (where I live), the information about the wear and tear is fascinating and disturbing. Emotions are high with regard to the proposed increase in oil flow to the coast as can be seen in a May 27, 2015 article by Mike Howell for the Vancouver Courier about a city hall report on the matter,

A major oil spill in Vancouver waters could potentially expose up to one million people to unsafe levels of a toxic vapour released from diluted bitumen, city council heard Wednesday in a damning city staff report on Kinder Morgan’s proposal to build a pipeline from Alberta to Burnaby [British Columbia].

In presenting the report, deputy city manager Sadhu Johnston outlined scenarios where exposure to the chemical benzene could lead to adverse health effects for residents and visitors, ranging from dizziness to nausea to possible death.

“For folks that are on the seawall, they could be actually struck with this wave of toxic gases that could render them unable to evacuate,” said Johnston, noting 25,000 residents live within 300 metres of the city’s waterfront. “These are serious health impacts. So this is not just about oil hitting shorelines, this is about our residents being exposed to very serious health effects.

…

  • Kinder Morgan’s own estimate is that pipeline leaks under 75 litres per hour may not be detected.

While I find the presentation’s hysteria a little off-putting, it did alert me to one or two new issues, benzene gas and when spillage from the pipes raises an alarm. For anyone curious about benzene gas and other chemical aspects of an oil spill, there’s a US National Oceanic and Atmospheric Administration (NOAA) webpage titled, Chemistry of an Oil Spill.

Getting back to the pipes, that figure of 75 litres per hour puts a new perspective on the proposed Abakan solution and it suggests that whether or not more and bigger pipes are in our future, we should do a better of job of protecting our environment now. That means better cladding for the pipes and better dispersants and remediation for water, earth, air when there’s a spill.

A GEnIuS approach to oil spill remediation at 18th European Forum on Eco-innovation

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In light of recent local events (an oil spill in Vancouver’s [Canada] English Bay, a popular local beach [more details in my April 16, 2015 post]), it seems appropriate to mention an* environmentally friendly solution to mopping up oil spills (oil spill remediation). A May 21, 2015 news item on Azonano features a presentation on the topic at hand (Note: A link has been removed),

Directa Plus at 18th European Forum on Eco-innovation to present GEnIuS, the innovative project that leads to the creation of a graphene-based product able to remove hydrocarbons from polluted water and soil.

The Forum untitled “Boosting competitiveness and innovation” is being held by the European Commission on 20th and 21st of May in Barcelona. The main purpose of this event is presenting the last developments in the eco-innovation field: an important moment where emerging and cutting-edge innovators will get in contact with new promising solutions under political, financial and technological point of view.

…

Directa Plus research has driven to the creation of an ecologic, innovative and highly effective oil-adsorbent, characterized by unique performances in oil adsorbency, and at the same time absence of toxicity and flammability, and the possibility to recover oil.

The creation of this graphene-based oil-adsorbent product, commercialized as Grafysorber, has been promoted by GEnIuS project and already approved by the Italian Ministry of Enviroment to be used in occasion of oil spills clean-up activities.

…

Giulio Cesareo, Directa Plus President and CEO, commented:

“Grafysorber embodies the nano-carbon paradox -in fact, with a nano-carbon material we are able to cut down part of damages caused by hydrocarbons, derived from carbon itself.

“Moreover, our product, once exhausted after depuration of water, finishes positively its life cycle inside the asphalt and bitumen, introducing new properties as thermal conductivity and mechanical reinforcement. I believe that every company is obliged to work following a sustainable approach to guarantee a balanced use of resources and their reuse, where possible.”

I have mentioned a Romanian project employing Directa Plus’s solution, Grafysorber in a December 30, 2014 post. At the time, the product name was called Graphene Plus and Grafysorber was a constituent of the product.

You can find more information about Graphene Eco Innovative Sorbent (GENIUS) here and about Directa Plus here. The company is located in Italy.

One final bit about oil spills and remediation, the Deepwater Horizon/Gulf/BP oil spill has spawned, amongst many others, a paper from the University of Georgia (US) noting that we don’t know that much about the dispersants used to clean up, from a May 14, 2015 University of Georgia news release on EurekAlert,

New commentary in Nature Reviews Microbiology by Samantha Joye of the University of Georgia and her colleagues argues for further in-depth assessments of the impacts of dispersants on microorganisms to guide their use in response to future oil spills.

Chemical dispersants are widely used in emergency responses to oil spills in marine environments as a means of stimulating microbial degradation of oil. After the Deepwater Horizon spill in 2010, dispersants were applied to the sea surface and deep waters of the Gulf of Mexico, the latter of which was unprecedented. Dispersants were used as a first line of defense even though little is known about how they affect microbial communities or the biodegradation activities they are intended to spur.

…

The researchers document historical context for the use of dispersants, their approval by the Environmental Protection Agency and the uncertainty about whether they stimulate or in fact inhibit the microbial degradation of oil in marine ecosystems.

…

One challenge of testing the toxicity from the use of dispersants on the broader ecosystem is the complex microbial communities of the different habitats represented in a large marine environment, such as the Gulf of Mexico. Development of model microbial communities and type species that reflect the composition of surface water, deep water, deep-sea sediments, beach sediments and marsh sediments is needed to evaluate the toxicity effects of dispersants.

“The bottom line is that we do not truly understand the full range of impacts that dispersants have on microbial communities, and we must have this knowledge in hand before the next marine oil spill occurs to support the decision-making process by the response community,” Joye said.

I hope the Canadians who are overseeing our waterways are taking note.

*’a’ changed to ‘an’ for grammatical correctness on Dec. 18, 2015.

Water purification, Italy, Romania, and graphene

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I’m hauling some of the material out of my backlog for publication as I clear the decks for 2015 including this Dec. 17, 2014 news item on Nanowerk about water remediation,

Graphene Plus materials have an amazing capacity for adsorbing organic pollutants such as hydrocarbons from water, soils and air. Directa Plus has already certified the removal capacity of Graphene Plus for floating oils in water and has obtained the approval of the Italian Environmental Ministry for the use these products in oil spills clean-up activities. Graphene Plus is also object of GEnIuS (Graphene Eco Innovative Sorbent), a Directa Plus’ project co-founded by European Union within the Eco-Innovation initiative. The project aims to launch into real markets an innovative solution for water treatment based on graphene.

A Dec. 17, 2014 Directa Plus press release, which originated the news item, describes how a Romanian company has tested the effectiveness of Graphene Plus for water remediation,

Directa Plus has found in SetCar – a Romanian company with fourteen years of activity in decontamination and disposal of hazardous waste – an ideal partner for testing environmental applications of Graphene Plus materials, especially in environmental remediation.

Since summer 2014, SetCar has tested on laboratory scale Graphene Plus materials as adsorbents for different type of organic pollutants. The most impressive laboratory results have been obtained with Grafysorber™ and have encouraged pilot test in hydrocarbons removal from contaminated waters.

The first treatment project started on 14th October, 2014, inside a Romanian former refinery site, containing a basin with about 16 500 m3 of water contaminated with petroleum hydrocarbons. The initial hydrocarbons concentration in water was about 56 ppm (3 drops of oil inside 1 litre of water), which means more than 1 tonne of pollutants that must be removed. The hydrocarbons maximum concentration necessary for the discharge of treated water into superficial aquatic ecosystems is 5 ppm.

“5 g/m3 of Grafysorber™ were able to bring the hydrocarbons concentration down to 1 ppm or lower and in only 10 minutes of contacts with the contaminated water! – says Eng. Covaci Melchisedec, Technical Manager of SetCar SA – We worked with a flow rate of 16 m3/h (daily flow rate of 360 -390 m3) in 2 consecutive batches of 4 m3. The total quantity of Grafysorber™ used in this project, which is now concluded, was 80 kg. In next projects, we have planned to implement the productivity of our treatment plant for low concentration hydrocarbons removal till 50 m3/h.”

Giulio Cesareo, President and CEO of Directa Plus shows his satisfaction for this collaboration and says “Our company needs partners such as SetCar SA. Setcar SA has a solid experience in decontamination field but, at the same time, a consolidate team of more than 50 engineers. Thanks to SetCar pilot test we obtained the real evidence that Grafysorber™ is an effective solution for decontamination of water containing hydrocarbons at low concentration”.

The Commercial Director of SetCar SA, Sandu Balan adds “We want to explore Graphene Plus potentiality in removing different type of pollutants from real contaminated water, soils and air and use it in other international projects of decontamination”.

Directa Plus, founded in 2005 and with headquarters in the ComoNext Science and Technology Park in Lomazzo (CO), is a technology company pursuing the development and marketing innovative manufacturing processes for the production of a new generation of nanomaterials targeting existing global markets. On June 23rd, 2014, Directa Plus opened its “Graphene Factory”, a new industrial centre distinguished for being the largest production plant in Europe of pristine graphene nanoplatelets, based on a patented and granted technology and designed according to a modular, replicable and exportable logic. The first module has 30-tonnes per year production capacity. To date, Directa Plus holds 26 granted patents and 19 patents pending. …

Setcar S.A. Established in 1994 as a joint stock company with entirely Rumanian private capital, the company is been developing since 2000 the range of services aimed to solve the environment issues, having as permanent concern the supply of a complete range of services, from chemical analyses for waste identification or, by creating new technologies, up to hazardous waste disposal or bringing the contaminated site to initial condition. …

You can find out more about Directa Plus here and about SetCar here (you will need your Romanian language skills as I cannot find an English language version of the site).

Gold nanoparticles as catalysts for clear water and hydrogen production

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The research was published online May 2014 and in a July 2014 print version,  which seems a long time ago now but there’s a renewed interest in attracting attention for this work. A Dec. 17, 2014 news item on phys.org describes this proposed water purification technology from Singapore’s A*STAR (Agency for Science Technology and Research), Note: Links have been removed,

A new catalyst could have dramatic environmental benefits if it can live up to its potential, suggests research from Singapore. A*STAR researchers have produced a catalyst with gold-nanoparticle antennas that can improve water quality in daylight and also generate hydrogen as a green energy source.

This water purification technology was developed by He-Kuan Luo, Andy Hor and colleagues from the A*STAR Institute of Materials Research and Engineering (IMRE). “Any innovative and benign technology that can remove or destroy organic pollutants from water under ambient conditions is highly welcome,” explains Hor, who is executive director of the IMRE and also affiliated with the National University of Singapore.

A Dec. 17, 2014 A*STAR research highlight, which originated the news item, describes the photocatalytic process the research team developed and tested,

Photocatalytic materials harness sunlight to create electrical charges, which provide the energy needed to drive chemical reactions in molecules attached to the catalyst’s surface. In addition to decomposing harmful molecules in water, photocatalysts are used to split water into its components of oxygen and hydrogen; hydrogen can then be employed as a green energy source.

Hor and his team set out to improve an existing catalyst. Oxygen-based compounds such as strontium titanate (SrTiO3) look promising, as they are robust and stable materials and are suitable for use in water. One of the team’s innovations was to enhance its catalytic activity by adding small quantities of the metal lanthanum, which provides additional usable electrical charges.

Catalysts also need to capture a sufficient amount of sunlight to catalyze chemical reactions. So to enable the photocatalyst to harvest more light, the scientists attached gold nanoparticles to the lanthanum-doped SrTiO3 microspheres (see image). These gold nanoparticles are enriched with electrons and hence act as antennas, concentrating light to accelerate the catalytic reaction.

The porous structure of the microspheres results in a large surface area, as it provides more binding space for organic molecules to dock to. A single gram of the material has a surface area of about 100 square meters. “The large surface area plays a critical role in achieving a good photocatalytic activity,” comments Luo.

To demonstrate the efficiency of these catalysts, the researchers studied how they decomposed the dye rhodamine B in water. Within four hours of exposure to visible light 92 per cent of the dye was gone, which is much faster than conventional catalysts that lack gold nanoparticles.

These microparticles can also be used for water splitting, says Luo. The team showed that the microparticles with gold nanoparticles performed better in water-splitting experiments than those without, further highlighting the versatility and effectiveness of these microspheres.

The researchers have provided an illustration of the process,

Improved photocatalyst microparticles containing gold nanoparticles can be used to purify water. © 2014 A*STAR Institute of Materials Research and Engineering

Improved photocatalyst microparticles containing gold nanoparticles can be used to purify water.
© 2014 A*STAR Institute of Materials Research and Engineering

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

Novel Au/La-SrTiO3 microspheres: Superimposed Effect of Gold Nanoparticles and Lanthanum Doping in Photocatalysis by Guannan Wang, Pei Wang, Dr. He-Kuan Luo, and Prof. T. S. Andy Hor. Chemistry – An Asian Journal Volume 9, Issue 7, pages 1854–1859, July 2014. Article first published online: 9 MAY 2014 DOI: 10.1002/asia.201402007

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This article is behind a paywall.