Tag Archives: mercury

Gold from e-waste opens rich vein for miners and the environment plus there’s ancient golden sea silk from Korea

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I have two ‘golden’ stories, one from Australia and the other from Korea.

Extracting and recovering gold from ore and electronic waste

A Flinders University (Australia) June 26, 2025 press release (also on EurekAlert) announces research into a technique for reducing toxic waste, Note: Links have been removed,

An interdisciplinary team of experts in green chemistry, engineering and physics at Flinders University in Australia has developed a safer and more sustainable approach to extract and recover gold from ore and electronic waste.

Explained in the leading journal Nature Sustainability, the gold-extraction technique promises to reduce levels of toxic waste from mining and shows that high purity gold can be recovered from recycling valuable components in printed circuit boards in discarded computers.

The project team, led by Matthew Flinders Professor Justin Chalker, applied this integrated method for high-yield gold extraction from many sources – even recovering trace gold found in scientific waste streams.

The progress toward safer and more sustainable gold recovery was demonstrated for electronic waste, mixed-metal waste, and ore concentrates.

“The study featured many innovations including a new and recyclable leaching reagent derived from a compound used to disinfect water,” says Professor of Chemistry Justin Chalker, who leads the Chalker Lab at Flinders University’s College of Science and Engineering.

“The team also developed an entirely new way to make the polymer sorbent, or the material that binds the gold after extraction into water, using light to initiate the key reaction.”

Extensive investigation into the mechanisms, scope and limitations of the methods are reported in the new study, and the team now plans to work with mining and e-waste recycling operations to trial the method on a larger scale.

“The aim is to provide effective gold recovery methods that support the many uses of gold, while lessening the impact on the environment and human health,” says Professor Chalker.

The new process uses a low-cost and benign compound to extract the gold. This reagent (trichloroisocyanuric acid) is widely used in water sanitation and disinfection. When activated by salt water, the reagent can dissolve gold.

Next, the gold can be selectively bound to a novel sulfur-rich polymer developed by the Flinders team. The selectivity of the polymer allows gold recovery even in highly complex mixtures.

The gold can then be recovered by triggering the polymer to “un-make” itself and convert back to monomer. This allows the gold to be recovered and the polymer to be recycled and re-used.

Global demand for gold is driven by its high economic and monetary value but is also a vital element in electronics, medicine, aerospace technologies and other products and industries. However, mining the previous metal can involve the use of highly toxic substances such as cyanide and mercury for gold extraction – and other negative environmental impacts on water, air and land including CO2 emissions and deforestation.

The aim of the Flinders-led project was to provide alternative methods that are safer than mercury or cyanide in gold extraction and recovery.

The team also collaborated with experts in the US and Peru to validate the method on ore, in an effort to support small-scale mines that otherwise rely on toxic mercury to amalgamate gold.

Gold mining typically uses highly toxic cyanide to extract gold from ore, with risks to the wildlife and the broader environment if it is not contained properly. Artisanal and small-scale gold mines still use mercury to amalgamate gold. Unfortunately, the use of mercury in gold mining is one of the largest sources of mercury pollution on Earth.

Professor Chalker says interdisciplinary research collaborations with industry and environmental groups will help to address highly complex problems that support the economy and the environment.

“We are especially grateful to our engineering, mining, and philanthropic partners for supporting translation of laboratory discoveries to larger scale demonstrations of the gold recovery techniques.”

Lead authors of the major new study – Flinders University postdoctoral research associates Dr Max Mann, Dr Thomas Nicholls, Dr Harshal Patel and Dr Lynn Lisboa – extensively tested the new technique on piles of electronic waste, with the aim of finding more sustainable, circular economy solutions to make better use of ever-more-scarce resources in the world. Many components of electronic waste, such as CPU units and RAM cards, contain valuable metals such as gold and copper.

Dr Mann says: “This paper shows that interdisciplinary collaborations are needed to address the world’s big problems managing the growing stockpiles of e-waste.”

ARC DECRA Fellow Dr Nicholls, adds: “The newly developed gold sorbent is made using a sustainable approach in which UV light is used to make the sulfur-rich polymer. Then, recycling the polymer after the gold has been recovered further increases the green credentials of this method.”

Dr Patel says: “We dived into a mound of e-waste and climbed out with a block of gold! I hope this research inspires impactful solutions to pressing global challenges.”

“With the ever-growing technological and societal demand for gold, it is increasingly important to develop safe and versatile methods to purify gold from varying sources,” Dr Lisboa concludes.

…

Fast Facts:

Electronic waste (e-waste) is one of the fastest growing solid waste streams in the world.  In 2022, an estimated 62 million tonnes of e-waste was produced globally. Only 22.3% was documented as formally collected and recycled. 

E-waste is considered hazardous waste as it contains toxic materials and can produce toxic chemicals when recycled inappropriately. Many of these toxic materials are known or suspected to cause harm to human health, and several are included in the 10 chemicals of public health concern, including dioxins, lead and mercury. Inferior recycling of e-waste is a threat to public health and safety. 

Miners use mercury, which binds to gold particles in ores, to create what are known as amalgams. These are then heated to evaporate the mercury, leaving behind gold but releasing toxic vapours. Studies indicate that up to 33% of artisanal miners suffer from moderate metallic mercury vapor intoxication.

Between 10 million and 20 million miners in more than 70 countries work in artisanal and small-scale gold mining, including up to 5 million women and children. These operations, which are often unregulated and unsafe, generate 37% of global mercury pollution (838 tonnes a year) – more than any other sector.

Most informal sites lack the funding and training needed to transition towards mercury-free mining. Despite accounting for 20% of the global gold supply and generating approximately US$30 billion annually, artisanal miners typically sell gold at around 70% of its global market value. Additionally, with many gold mines located in rural and remote areas, miners seeking loans are often restricted to predatory interest rates from illegal sources, pushing demand for mercury.

High quality gold recovered from electronic waste in the Flinders University study. Credit: Flinders University

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

Sustainable gold extraction from ore and electronic waste (2025) by Maximilian Mann, Thomas P Nicholls, Harshal D Patel, Lynn S Lisboa, Jasmine MM Pople, Le Nhan Pham, Max JH Worthington, Matthew R Smith, Yanting Yin, Gunther G Andersson, Christopher T Gibson, Louisa J Esdaile, Claire E Lenehan, Michelle L Coote, Zhongfan Jia and Justin M Chalker .Nature Sustainability 8, pages 947–956 (2025) Published online: 26 June 2025 Issue Date: August 2025 DOI: 10.1038/s41893-025-01586-w

This paper is behind a paywall.

I have a May 24, 2024 posting “Deriving gold from electronic waste” featuring a different extraction strategy, this time from Switzerland.

Golden sea silk

Always a favourite of mine, a structural colour story,

Caption: Golden sea silk Credit: POSTECH (Pohang University of Science & Technology)

A Pohang University of Science & Technology (POSTECH) press release on EurekAlert describes how researchers have developed a technique for creating ‘golden sea silk’,

A luxurious fiber once reserved exclusively for emperors in ancient times has been brought back to life through the scientific ingenuity of Korean researchers. A team led by Professor Dong Soo Hwang (Division of Environmental Science and Engineering / Division of interdisciplinary bioscience & bioengineering, POSTECH) and Professor Jimin Choi (Environmental Research Institute) has successfully recreated a golden fiber, akin to that of 2,000 years ago, using the pen shell (Atrina pectinata) cultivated in Korean coastal waters. This breakthrough not only recreates the legendary sea silk but also reveals the scientific basis behind its unchanging golden color. The study was recently published in the prestigious journal Advanced Materials.

Sea silk—often referred to as the “golden fiber of the sea”—was one of the most prized materials in the ancient Roman period, used exclusively by figures of high authority such as emperors and popes. This precious fiber is made from the byssus threads secreted by Pinna nobilis, a large clam native to the Mediterranean, which uses the threads to anchor itself to rocks. Valued for its iridescent, unfading golden color, light weight, and exceptional durability, sea silk earned its reputation as the “legendary silk.” A notable example is the Holy Face of Manoppello, a relic preserved for centuries in Italy, which is believed to be made from sea silk.

However, due to recent marine pollution and ecological decline, Pinna nobilis is now an endangered species. The European Union has banned its harvesting entirely, making sea silk an artifact of the past—produced only in minuscule quantities by a handful of artisans.

The POSTECH research team turned their attention to the pen shell Atrina pectinata, a species cultivated in Korean coastal waters for food. Like Pinna nobilis, this clam secretes byssus threads to anchor itself, and the researchers found that these threads are physically and chemically similar to those of Pinna nobilis. Building on this insight, they succeeded in processing pen shell byssus to recreate sea silk.

However, their achievement goes beyond mere replication of its appearance. The team also revealed the scientific secret behind sea silk’s distinctive golden hue and its resistance to fading over time.

The golden color of sea silk is not derived from dyes, but from structural coloration—a phenomenon caused by the way light reflects off nanostructures. Specifically, the researchers identified that the iridescence arises from a spherical protein structure called “photonin,” which forms layered arrangements that interact with light to produce the characteristic shine. Similar to the color seen in soap bubbles or butterfly wings, this structure-based coloration is highly stable and does not fade easily over time.

Moreover, the study revealed that the more orderly the protein arrangement, the more vivid the structural color becomes. Unlike traditional dyeing, this color is not applied but instead generated by the alignment of proteins within the fiber, contributing to the material’s remarkable lightfastness over millennia.

Another significant aspect of this research is the upcycling of pen shell byssus, previously discarded as waste, into a high-value sustainable textile. This not only helps reduce marine waste but also demonstrates the potential of eco-friendly materials that carry cultural and historical significance.

Professor Dong Soo Hwang noted, “Structurally colored textiles are inherently resistant to fading. Our technology enables long-lasting color without the use of dyes or metals, opening new possibilities for sustainable fashion and advanced materials.”

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

Structurally Colored Sustainable Sea Silk from Atrina pectinata by Jimin Choi, Jun-Hyung Im, Young-Ki Kim, Tae Joo Shin, Patrick Flammang, Gi-Ra Yi, David J. Pine, Dong Soo Hwang. Advanced Materials Volume37, Issue30 July 29, 2025 2502820 DOI: https://doi.org/10.1002/adma.202502820 First published online: 29 April 2025

This paper is behind a paywall.

Effects of soil contamination could be blunted with nanonutrients

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An October 15, 2024 news item on phys.org highlights research into soil remediation, Note: A link has been removed,

One of the pressing problems that the world faces in the era of climate change is how to grow enough healthy food to meet the increasing global population, even as soil contamination rises. Research recently published in Nature Food by an international team of scientists led by the University of Massachusetts Amherst, Guangdong University of Technology, and Central South University of Forestry and Technology, has shown that nutrients on the nanometer scale can not only blunt some of the worst effects of heavy metal and metalloid contamination, but increase crop yields and nutrient content.

…

Caption: Nanomaterials can enter plants through above-ground tissues and root tissues. Soil rhizosphere microorganisms, soil particles, organic matter and rhizosphere deposits can also influence NM uptake in plants. Credit: 10.1038/s43016-024-01063-1 Courtesy of University of Massachusetts Amherst

An October 15, 2024 University of Massachusetts Amherst news release (also on EurekAlert), which originated the news item, describes the problem and the proposed solution, Note: Links have been removed,

“Much of the world’s arable soil is contaminated by heavy metals, like cadmium, lead and mercury, as well as metalloids, like arsenic and selenium,” says Baoshan Xing, University Distinguished Professor and director of the Stockbridge School of Agriculture at UMass Amherst. Xing, who is also the paper’s senior author, notes that such contamination puts severe stress on the ability to grow staple crops, which also affects the nutritional value of the crops that manage to survive. “We need to come up with solutions to reduce the heavy metals that wind up in our food,” says Xing, and one approach that has shown promise is the use of nutrients at nanoscale, or what he calls a “nano-enabled” agriculture.


The bulk fertilizers that you may be more familiar with are made up of large particles, which aren’t as readily absorbed by the crop. This means that farmers need to apply more, which then increases the levels of fertilizer runoff into streams, lakes and the ocean. However, crop nutrients at the nanometer scale can be specifically designed and mixed for particular crops, growing conditions and application methods, and engineered so that the target plant can most efficiently absorb the nutrients into its system, cutting down on the amount of fertilizer needed, keeping costs down and limiting runoff.

Though nanomaterials are already available on the agricultural market and have plenty of peer-reviewed science looking at their effect on the soil and crop growth, Xing and his colleagues’ research is the first comprehensive account of the effectiveness of nanomaterials as a class, with results that offer practical insights to help steer sustainable agriculture and global food safety.

“We collected data from 170 previous publications on the effectiveness of nanoparticles in reducing heavy metal and metalloid uptake,” says Chuanxin Ma, the paper’s co-lead author who completed his doctoral training at UMass Amherst’s Stockbridge School of Agriculture and is now a professor at China’s Guangdong University of Technology. “From those 170 papers, we collected 8,585 experimental observations of how plants respond to nanomaterials.”

The team then conducted a meta-analysis on this enormous trove of data, running it through a series of machine-learning models to quantify the effect of nanomaterials on crop growth and metal and metalloid uptake, before finally testing a flexible quantitative approach, known as the “IVIF-TOPSIS-EW method,” that can illuminate how to choose different types of nanomaterials according to a range of realistic agricultural scenarios.

The results show that nanomaterials are more effective than conventional fertilizers at mitigating the harmful effects of polluted soil (by 38.3%), can enhance crop yields (by 22.8%) and the nutritional value of those crops (by 30%), as well as combat plant stress (by 21.6%) due to metal and metalloid pollution. Nanomaterials also help increase soil enzymes and organic carbon, both of which help drive soil fertility.

“Of course, nanomaterials are not a silver bullet,” explains Xing. “They need to be applied in distinct ways based on the individual crop and soil.” Which is where the team’s IVIF-TOPSIS-EW method comes into play. “Our method can help policy makers choose the best course of action for their particular situation,” says Ma.

Yini Cao from Central South University of Forestry and Technology also contributed greatly to collecting and analyzing the data in this work.

This research was supported by the National Natural Science Foundation of China and the United States National Institute of Food and Agriculture (USDA).

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

Engineered nanomaterials reduce metal(loid) accumulation and enhance staple food production for sustainable agriculture by Yini Cao, Chuanxin Ma, Jason C. White, Yuchi Cao, Fan Zhang, Ran Tong, Hao Yu, Yi Hao, Wende Yan, Melanie Kah & Baoshan Xing. Nature Food volume 5, pages 951–962 (2024) DOI: https://doi.org/10.1038/s43016-024-01063-1 Published: 11 October 2024 Issue Date: November 2024

This paper is behind a paywall.

‘Hunting’ pharmaceuticals and removing them from water

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Pharmaceuticals are not the first pollutants people think of when discussing water pollution but, for those who don’t know, it’s a big issue and scientists at the University of Surrey (UK) have developed a technology they believe will help to relieve the contamination. From an April 10, 2017 University of Surrey press release (also on EurekAlert),

The research involves the detection and removal of pharmaceuticals in or from water, as contamination from pharmaceuticals can enter the aquatic environment as a result of their use for the treatment of humans and animals. This contamination can be excreted unchanged, as metabolites, as unused discharge or by drug manufacturers.

The research has found that a new type of ‘supermolecule’, calix[4], actively seeks certain pharmaceuticals and removes them from water.

Contamination of water is a serious concern for environmental scientists around the world, as substances include hormones from the contraceptive pill, and pesticides and herbicides from allotments. Contamination can also include toxic metals such as mercury, arsenic, or cadmium, which was previously used in paint, or substances that endanger vital species such as bees.

Professor Danil de Namor, University of Surrey Emeritus Professor and leader of the research, said: “Preliminary extraction data are encouraging as far as the use of this receptor for the selective removal of these drugs from water and the possibility of constructing a calix[4]-based sensing devices.

“From here, we can design receptors so that they can bind selectively with pollutants in the water so the pollutants can be effectively removed. This research will allow us to know exactly what is in the water, and from here it will be tested in industrial water supplies, so there will be cleaner water for everyone.

“The research also creates the possibility of using these materials for on-site monitoring of water, without having to transport samples to the laboratory.”

Dr Brendan Howlin, University of Surrey co-investigator, said: “This study allows us to visualise the specific receptor-drug interactions leading to the selective behaviour of the receptor. As well as the health benefits of this research, molecular simulation is a powerful technique that is applicable to a wide range of materials.

“We were very proud that the work was carried out with PhD students and a final year project student, and research activities are already taking place with the Department of Chemical and Processing Engineering (CPI) and the Advanced Technology Institute (ATI).

“We are also very pleased to see that as soon as the paper was published online by the European Journal of Pharmaceutical Sciences, we received invitations to give keynote lectures at two international conferences on pharmaceuticals in Europe later this year.”

That last paragraph is intriguing and it marks the first time I’ve seen that claim in a press release announcing the publication of a piece of research.

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

A calix[4]arene derivative and its selective interaction with drugs (clofibric acid, diclofenac and aspirin) by Angela F Danil de Namor, Maan Al Nuaim, Jose A Villanueva Salas, Sophie Bryant, Brendan Howlin. European Journal of Pharmaceutical Sciences Volume 100, 30 March 2017, Pages 1–8 https://doi.org/10.1016/j.ejps.2016.12.027

This paper is behind a paywall.

Using a sponge to remove mercury from lake water

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I’ve heard of Lake Como in Italy but Como Lake in Minnesota is a new one for me. The Minnesota lake is featured in a March 22, 2017 news item about water and sponges on phys.org,

Mercury is very toxic and can cause long-term health damage, but removing it from water is challenging. To address this growing problem, University of Minnesota College of Food, Agricultural and Natural Sciences (CFANS) Professor Abdennour Abbas and his lab team created a sponge that can absorb mercury from a polluted water source within seconds. Thanks to the application of nanotechnology, the team developed a sponge with outstanding mercury adsorption properties where mercury contaminations can be removed from tap, lake and industrial wastewater to below detectable limits in less than 5 seconds (or around 5 minutes for industrial wastewater). The sponge converts the contamination into a non-toxic complex so it can be disposed of in a landfill after use. The sponge also kills bacterial and fungal microbes.

Think of it this way: If Como Lake in St. Paul was contaminated with mercury at the EPA limit, the sponge needed to remove all of the mercury would be the size of a basketball.

A March 16, 2017 University of Minnesota news release, which originated the news item, explains why this discovery is important for water supplies in the state of Minnesota,

This is an important advancement for the state of Minnesota, as more than two thirds of the waters on Minnesota’s 2004 Impaired Waters List are impaired because of mercury contamination that ranges from 0.27 to 12.43 ng/L (the EPA limit is 2 ng/L). Mercury contamination of lake waters results in mercury accumulation in fish, leading the Minnesota Department of Health to establish fish consumption guidelines. A number of fish species store-bought or caught in Minnesota lakes are not advised for consumption more than once a week or even once a month. In Minnesota’s North Shore, 10 percent of tested newborns had mercury concentrations above the EPA reference dose for methylmercury (the form of mercury found in fish). This means that some pregnant women in the Lake Superior region, and in Minnesota, have mercury exposures that need to be reduced.  In addition, a reduced deposition of mercury is projected to have economic benefits reflected by an annual state willingness-to-pay of $212 million in Minnesota alone.

According to the US-EPA, cutting mercury emissions to the latest established effluent limit standards would result in 130,000 fewer asthma attacks, 4,700 fewer heart attacks, and 11,000 fewer premature deaths each year. That adds up to at least $37 billion to $90 billion in annual monetized benefits annually.

In addition to improving air and water quality, aquatic life and public health, the new technology would have an impact on inspiring new regulations. Technology shapes regulations, which in turn determine the value of the market. The 2015 EPA Mercury and Air Toxics Standards regulation was estimated to cost the industry around of $9.6 billion annually in 2020. The new U of M technology has a potential of bringing this cost down and make it easy for the industry to meet regulatory requirements.

Research by Abbas and his team was funded by the MnDRIVE Global Food Venture, MnDRIVE Environment, and USDA-NIFA. They currently have three patents on this technology. To learn more, visit www.abbaslab.com.

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

A Nanoselenium Sponge for Instantaneous Mercury Removal to Undetectable Levels by Snober Ahmed, John Brockgreitens, Ke Xu, and Abdennour Abbas. Advanced Functional Materials DOI: 10.1002/adfm.201606572 Version of Record online: 6 MAR 2017

© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Test your tuna for mercury and other heavy metals with nano-velcro

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Scientists Francesco Stellacci at the École Polytechnique Fédérale de Lausanne (EPFL) and Bartosz Grzybowski at Northwestern University have devised an easy and economical way to test for mercury and other heavy metals in fish. From the Sept. 9, 2012 news release on EurekAlert,

Mercury, when dumped in lakes and rivers, accumulates in fish, and often ends up on our plates. A Swiss-American team of researchers led by Francesco Stellacci at the Ecole Polytechnique Fédérale de Lausanne (EPFL) and Bartosz Grzybowski at Northwestern University has devised a simple, inexpensive system based on nanoparticles, a kind of nano-velcro, to detect and trap this toxic pollutant as well as others. The particles are covered with tiny hairs that can grab onto toxic heavy metals such as mercury and cadmium. This technology makes it possible to easily and inexpensively test for these substances in water and, more importantly, in the fish that we eat. Their new method can measure methyl mercury, the most common form of mercury pollution, at unprecedentedly small attomolar concentrations.

Here’s a description of how the technique works, from the Sept. 12, 2012 news release on the EPFL website,

The technology developed by the Swiss-American team is simple to use. A strip of glass covered with a film of “hairy”nanoparticles is dipped into the water. When an ion – a positively charged particle, such as a methyl mercury or cadmium ion – gets in between two hairs, the hairs close up, trapping the pollutant.

A voltage-measuring device reveals the result; the more ions there are trapped in the nano-velcro, the more electricity it will conduct. So to calculate the number of trapped particles, all one needs to do is measure the voltage across the nanostructure.

By varying the length of the nano-hairs, the scientists can target a particular kind of pollutant. “The procedure is empirical,” explains Stellacci. Methyl mercury, fortunately, has properties that make it extremely easy to trap without accidentally trapping other substances at the same time; thus the results are very reliable.

The interesting aspect of this approach is that the ‘reading’ glass strip could costs less than 10 dollars, while the measurement device will cost only a few hundreds of dollars. The analysis can be done in the field, so the results are immediately available. “With a conventional method, you have to send samples to the laboratory, and the analysis equipment costs several million dollars,” notes Stellacci.

They have tested the system in the field,

The researchers tested the system in Lake Michigan, near Chicago. Despite the high level of industry in the region, mercury levels were extremely low. “The goal was to compare our measurements to FDA [US Food and Drug Administration] measurements done using conventional methods,” explains Stellacci. “Our results fell within an acceptable range.”

A mosquito fish from the Everglades in Florida was also tested. This species is not very high on the food chain and thus does not accumulate high levels of mercury in its tissues. “We measured tissue that had been dissolved in acid. The goal was to see if we could detect even minuscule quantities.” says Bartosz Grzybowski, Burgess Professor of Chemistry and Director of Non-Equilibrium Energy Research Center at Northwestern University. The United States Geological Survey reported near-identical results after analyzing the same sample.

…

“I think it is quite incredible,” Grzybowski adds, “how the complex principles of quantum tunneling underlying our device translate into such an accurate and practically useful device. It is also notable that our system – through some relatively simple chemical modifications – can be readily adapted to detect other toxic species” Researchers have already demonstrated the detection of cadmium with a very high femtomolar sensitivity.

“With this technology, it will be possible to conduct tests on a much larger scale in the field, or even in fish before they are put on the market,” says lead author Eun Seon Cho. This is a necessary public health measure, given the toxic nature of methyl mercury and the extremely complex manner in which it spreads in the environment and accumulates in living tissues.

Northwestern University provided an illustration of the nano-velcro trapping an ion of heavy metal,

Nano-velcro (Courtesy Northwestern University & EPFL; downloaded from http://actu.epfl.ch/news/nano-velcro-clasps-heavy-metal-molecules-in-its-gr/)

Nanoremediation techniques from Iran and from South Carolina

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Researchers in Iran have announced a method of removing mercury from water. From the Aug. 6, 2012 news item on Nanowerk,

A research team from Martyr Chamran University of Ahvaz [Iran] succeeded in the elimination of mercury from aqueous media by using 2-mercaptobenzothiazole and by coating it on the magnetic iron oxide nanoparticles. Removal of mercury from water at lower concentrations was carried out by using the same compound successfully.

… According to the results of the experiments, the nano adsorbent is able to rapidly adsorb mercury at low concentrations. It causes the amount of mercury remaining in the environment to be less than the amount announced by WHO.

You can find the study (Fast and efficient removal of mercury from water samples using magnetic iron oxide nanoparticles modified with 2-mercaptobenzothiazole) behind a paywall in the Journal of Hazardous Materials.

Moving onto the work at Clemson University in South Carolina (US), researchers there have developed a dendrimer-fullerenol which could be used for cleaning up the environment and/or drug delivery. From the Aug. 6, 2012 news item on Nanowerk (Note: This seems to have been written by the study’s lead author, Priyanka Bhattacharya),

Our recent paper, “Dendrimer-fullerenol soft-condensed nanoassembly” [behind a paywall] published in The Journal of Physical Chemistry C, showed how the soft nanomaterial dendrimer can be used to remediate the environment from potentially toxic nanomaterials. Here, we used fullerenol – a 60 carbon molecule in the shape of a buckyball and functionalized with hydroxyl groups – as a model system. Such an assembly also has implications for drug delivery.

Here’s an image the researchers included with their published study,

Here we show that poly(amidoamine) (PAMAM) dendrimers of both generations 1 (G1) and 4 (G4) can host 1 fullerenol per 2 dendrimer primary amines as evidenced by isothermal titration calorimetry, dynamic light scattering, and spectrofluorometry. (downloaded from http://pubs.acs.org/doi/abs/10.1021/jp3036692)

Here’s a little more about the dendrimers,

Dendrimers are highly branched, polymeric macromolecules with a high degree of surface functionalities. Their branching determines their generation number (G) – the higher the generation, the greater the degree of surface functionalities. We used both G1 and G4 poly(amidoamine) (PAMAM) dendrimers and found that both these dendrimers hosted one fullerenol per primary amine on the dendrimer surfaces. However, G4 PAMAM dendrimers hosted fullerenols 40 times better than G1, simply because of their higher degree of surface functionalities. Based on our findings, we recommended proper loading capacities of fullerenols for G1 and G4 dendrimers in drug delivery and environmental remediation.

You can also find this news item in an Aug. 6, 2012 postingfeaturing images of the lead author (Priyanka Bhattacharya is a Ph.D. student at Clemson University’s College of Engineering and Science) on the ScienceCodex website,

Our group, led by my advisor Dr. Pu-Chun Ke and funded by the National Science Foundation, has delved into a crucial topic of frontier research termed “nanoparticle-protein corona”. In short, nanoparticles do not interact directly with living systems but are often coated with biological fluids in the form of a protein corona. Another direction in our group, through collaboration between Dr. Ke and Dr. David Ladner in Clemson’s Department of Environmental Engineering and Earth Sciences and funded by the U.S. Environmental Protection Agency is to employ dendritic polymers for remediating oil spills.

(It’s unusual to see a news release written in the first person.)

I’m glad to see more research about exploiting nanotechnology for environmental cleanups.

Dental fillings that improve your teeth

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If you have lousy teeth, this is exciting news. From the May 2, 2012 news item on Nanowerk (I have removed a link),

Scientists using nanotechology at the University of Maryland School of Dentistry have created the first cavity-filling composite that kills harmful bacteria and regenerates tooth structure lost to bacterial decay. [emphasis mine]

Rather than just limiting decay with conventional fillings, the new composite is a revolutionary dental weapon to control harmful bacteria, which co-exist in the natural colony of microorganisms in the mouth, says professor Huakun (Hockin) Xu, PhD, MS. [emphasis mine]

While the possibilities are promising, I find the idea of a weapon in my mouth disconcerting. (They might want to check out their metaphors a little more closely.) Moving on, there’s a little more detail about this new composite  (from the news item),

Fillings made from the School of Dentistry’s new nanocomposite, with antibacterial primer and antibacterial adhesive, should last longer than the typical five to 10 years, though the scientists have not thoroughly tested longevity. Xu says a key component of the new nanocomposite and nano-structured adhesive is calcium phosphate nanoparticles that regenerate tooth minerals. The antibacterial component has a base of quaternary ammonium and silver nanoparticles along with a high pH. The alkaline pH limits acid production by tooth bacteria.

“The bottom line is we are continuing to improve these materials and making them stronger in their antibacterial and remineralizing capacities as well as increasing their longevity,” Xu says.

The new products have been laboratory tested using biofilms from saliva of volunteers. The Xu team is planning to next test its products in animal teeth and in human volunteers in collaboration with the Federal University of Ceara in Brazil.

The folks at the enewsparkforest blog are not quite so sanguine about this dental development as per their May 3, 2012 posting on the topic (I have removed llinks),

A study conducted in 2008 and confirmed by another study in 2009 shows that washing nano-silver textiles releases substantial amounts of the nanosilver into the laundry discharge water, which will ultimately reach natural waterways and potentially poison fish and other aquatic organisms. A study found nanosilver to cause malformations and to be lethal to small fish at various stages of development since they are able to cross the egg membranes and move into the fish embryos. A 2010 study by scientists at Oregon State University and in the European Union highlights the major regulatory and educational issues that they believe should be considered before nanoparticles are used in pesticides.

As Dexter Johnson in his May 3, 2012 posting on his Nanoclast blog (on the Institute for Electrical and Electronics Engineers website) notes,

The researchers are continuing with their animal and human testing with the nanocomposite. Given that some sectors of the public are concerned about the potential risks of silver nanoparticles, they should probably take a look at the issue as part of their research.

This is not unreasonable especially in light of the concern some folks have had over mercury in dental fillings. Sufficient concern by the way to occasion this cautionary note from Health Canada (from the Mercury and Human Health webpage on their website),

Minimizing Your Risk

Elemental mercury from dental fillings does not generally pose a health risk. There is, however, a fairly small number of people who are hypersensitive to mercury. While Health Canada does not recommend that you replace existing mercury dental fillings, it does suggest that when the fillings need to be repaired, you may want to consider using a product that does not contain mercury.

Pregnant women, people allergic to mercury and those with impaired kidney function should avoid mercury fillings. Whenever possible, amalgam fillings should not be removed when you are pregnant because the removal may expose you to mercury vapour. When appropriate, the primary teeth of children should be filled with non-mercury materials.

Side note: I find it interesting that while Health Canada has not banned the use of mercury in fillings, it does advise against adding more mercury-laced fillings to your mouth and/or using them in your children’s primary teeth, if possible.

Getting back to silver nanoparticles in our mouths, I reiterate Dexter’s suggestion.