Researchers Propose Method to Choose More Sustainable Nanomaterials

From the May 1, 2018 edition of Science Daily:  “Engineered nanomaterials hold great promise for medicine, electronics, water treatment, and other fields. But when the materials are designed without critical information about environmental impacts at the start of the process, their long-term effects could undermine those advances. A team of researchers hopes to change that.

In a study published in Nature Nanotechnology, Yale researchers outline a strategy to give materials designers the tools they need to make the necessary assessments efficiently and at the beginning of the design process. Engineers traditionally focus on the function and cost of their products. Without the information to consider long-term environmental impacts, though, it is difficult to predict adverse effects. That lack of information means that unintended consequences often go unnoticed until long after the product has been commercialized. This can lead to hastily replacing the material with another that proves to have equally bad, or even worse, effects. Having materials property information at the start of the design process could change that pattern. “As a researcher, if I have limited resources for research and development, I don’t want to spend it on something that’s not going to be viable due to its effects on human health,” said Julie Zimmerman, professor of chemical & environmental engineering and co-senior author of the study. “I want to know now, before I develop that product.” To that end, the researchers have developed a database that serves as a screening tool for environmentally sustainable material selection. It’s a chart that lists nanomaterials and assesses each for properties such as size, shape, and such performance characteristics as toxicity and antimicrobial activity. Mark Falinski, a PhD student and lead author of the study, said this information would allow researchers to weigh the different effects of the material before actually developing it.”

The database created by the research team also allows other researchers to enter information to improve the material selection framework. It includes engineered nanomaterials and conventional alternatives with human health and environmental metrics for all materials.

The research team includes scientists affiliated with Yale University, the University of Illinois at Chicago, City University of Hong Kong, and the University of Pittsburgh.

Image of three different illustrations of nanoscale materials: white crystals, pyramidal dark crystals joined together, and a tubular mesh-like formation of molecules
Researchers propose a new method for nanomaterial selection that incorporates environmental and functional performance, as well as cost. Credit: Steve Geringer.

Read the full story in Science Daily at https://www.sciencedaily.com/releases/2018/05/180501161754.htm.

Read the referenced article in Nature Nanotechnology at https://www.nature.com/articles/s41565-018-0120-4.  [Mark M. Falinski, Desiree L. Plata, Shauhrat S. Chopra, Thomas L. Theis, Leanne M. Gilbertson, Julie B. Zimmerman. A framework for sustainable nanomaterial selection and design based on performance, hazard, and economic considerationsNature Nanotechnology, 2018; DOI: 10.1038/s41565-018-0120-4]

To learn more about the potential environmental and health impacts of nanotechnology, see the following:

Researchers Use Ultrasound to Recover Gold from Electronic Scrap

The last few months have been ripe with reports on new research related to material recovery from electronic scrap (commonly referred to as “e-scrap” or “e-waste”), as highlighted in a previous post. I’ve learned of yet another exciting innovation in this field, thanks to a feature written by Jared Paben in the latest edition (4/19/18) of E-Scrap News.

As Paben reports, researchers from Sandia National Laboratories have developed a method to use ultrasonic waves, coupled with surfactants, to cheaply and efficiently recover gold from scrap electronics. Their experiments involved application of two different surfactants to the surface of a cell phone SIM card, which was then submerged in water. Ultrasonic waves were applied, which imploded micro-bubbles on the SIM card’s surface. Upon collapse of these micro-bubbles, micro-jets ejected gold nanoparticles from the card’s surface, and the nanoparticles were captured and stabilized by the surfactants.

According to the research group’s paper, published in the journal Small on 3/24/18), this mechanical method may not only present an effective way of reclaiming gold and other metals from electronic scrap, but could potentially be used to manufacture gold nanoparticles from native gold metal directly upon recovery from mining, which they say “may represent the greenest possible approach to nanoparticle synthesis.” (Citation: J. Watt, M. J. Austin, C. K. Simocko, D. V. Pete, J. Chavez, L. M. Ammerman, D. L. Huber, Small 2018, 1703615. https://doi.org/10.1002/smll.201703615)

You can read more about this research in a 4/3/18 article from New Scientist.

To learn about cavitation and cavitation bubbles, the phenomena which allow this mechanical process to work, see https://www.nsf.gov/news/special_reports/science_nation/cavitationbubbles.jsp and https://en.wikipedia.org/wiki/Cavitation.

For more information on gold in electronics, see How Much Gold is in Smartphones and Computers? and Uses of Gold in Industry, Medicine, Computers, Electronics, Jewelry.

To learn about the properties and applications of gold nanoparticles, see https://www.sigmaaldrich.com/technical-documents/articles/materials-science/nanomaterials/gold-nanoparticles.html.

Further Developments in E-Waste Recycling

In a previous post, we discussed how researchers at the Illinois Sustainable Technology Center (ISTC), on the campus of the University of Illinois at Urbana-Champaign have developed an energy-efficient, non-toxic, nondestructive chemical process to recover polymers from the complex plastic blends found in items like cellphone cases.

But that’s not the only exciting news this Earth Month related to innovations in reclaiming materials from electronic scrap (commonly referred to as “e-waste”). In a GreenBiz article dated 4/18/18, Heather Clancy highlights an electrochemical process developed by Canadian venture EnviroLeach Technologies, which is similar to the conventional method of leaching gold and other metals out of ores, concentrates and tailings. The difference is that “instead of using cyanide, the patent-pending formula uses five non-toxic, FDA-approved ingredients that are combined with water at ambient temperatures.’The process does not require pressure, elevated temperatures, complex process circuits, intensive gas monitoring or costly detoxification systems,’ explained EnviroLeach on its website.” Read the full story on the GreenBiz web site. You can also check out the EnviroLeach web site for further information. This development is particularly encouraging considering a recent article from Environmental Leader reporting that n a study by researchers from Tsinghua University in Beijing and Macquarie University in Australia, which suggests extracting metals from e-waste costs 13 times less than mining ore. Perhaps the new process will make the economic benefit even more striking, while minimizing environmental impacts.

Elsewhere in Canada, researchers at the University of British Columbia “have perfected a process to efficiently separate fibreglass and resin – two of the most commonly discarded parts of a cellphone – bringing them closer to their goal of a zero-waste cellphone.” As UBC News reports, “Most e-waste recycling firms focus on recovering useful metals like gold, silver, copper and palladium, which can be used to manufacture other products. But nonmetal parts like fibreglass and resins, which make up the bulk of cellphones’ printed circuit boards, are generally discarded because they’re less valuable and more difficult to process. They’re either fed to incinerators or become landfill, where they can leach hazardous chemicals into groundwater, soil and air.” But UBC mining engineering professor Maria Holuszko, along with PhD student Amit Kumar, has developed a process using gravity separation “and other simple phycial techniques to process cellphone fibreglass and resins in an environmentally neutral fashion.” The next step in pursuing this innovation is developing a large-scale commercial model of the process with their industrial partner and recycling company Ronin8. Read the full UBC article on the UBC News web site.

Read more at https://ifixit.org/recycling on why electronics recycling, though of course important, should not be considered the answer to the problem of ever-growing amounts of e-waste, due to the difficulty in reclaiming materials (eased slowly by new innovations like the ones described above) and energy use. While these developments in electronic scrap recycling are heartening, it’s important to remember to keep your electronics in service as long as possible through repair and upgrades, and when you no longer want or need a functioning device, sell or donate it so someone else can use it. Recycling should only come at the ultimate end of a device’s useful life.

ISTC Researchers Tap Problematic E-waste Surplus to Recover High-quality Polymers

Two smiling men stand in a laboratory
Illinois Sustainability Technology Center researchers B.K. Sharma, left, and Sriraam Chandrasekaran have developed the first energy-efficient and environmentally benign e-waste recycling process.
Photo by L. Brian Stauffer

Mixed-plastic electronics waste could be a valuable source of reusable polymers, a new study led by Illinois Sustainability Technology Center (ISTC) scientists suggests. The team’s findings, published in the journal ACS Sustainable Chemistry & Engineering, are the first to demonstrate a nontoxic, nondestructive and energy-efficient chemical solvent process to recover polymers from the complex plastic blends found in items like like cellphone cases.

HOBI International, Inc. and the ISTC Hazardous Waste Research Fund supported this research. The ISTC is part of the Prairie Research Institute at the University of Illinois.

Read more about this cutting edge project on the University of Illinois News Bureau web site.

See also the ACS News Service Weekly PressPac: March 14, 2018: An eco-friendly alternative to recycling e-waste.

Learn more about the researchers on their ISTC staff pages:

 

 

Green Chemistry and Biomimicry: A More Sustainable Process for Metal Extraction

A team of chemists from McGill University in Montreal, Quebec, Canada, and Western University in London, Ontario, Canada, have developed a way to process metals without toxic solvents and reagents. Their innovation could help reduce negative environmental impacts of metal extraction from raw materials and electronic scrap.

As reported by McGill, “The system, which also consumes far less energy than conventional techniques, could greatly shrink the environmental impact of producing metals from raw materials or from post-consumer electronics…In an article published recently in Science Advances, the researchers outline an approach that uses organic molecules, instead of chlorine and hydrochloric acid, to help purify germanium, a metal used widely in electronic devices. Laboratory experiments by the researchers have shown that the same technique can be used with other metals, including zinc, copper, manganese and cobalt.”

The development is an interesting example of biomimicry. Germanium is a semiconductor not found in substantial quantities in any one type of ore, so a series of processes are used to reduce mined materials with small quantities of the metal to a mixture of germanium and zinc. Isolation of germanium from the zinc in this resulting mixture involves what one of the researchers called “nasty processes.” For an alternative less dependent upon toxic materials and energy use, the researchers found inspiration in melanin, the pigment molecule present in skin, hair, and irises of humans and other animals. Besides contribution to coloration, melanin can bind to metals. The researchers synthesized a molecule that mimics some of melanin’s metal-binding qualities. Using it they were able to isolate germanium from zinc at room temperature, without solvents.

Image of a shiny, silver-grey metallic rock
Image of germanium by W. Oelen, CC BY 3.0

As the McGill article states, “The next step in developing the technology will be to show that it can be deployed economically on industrial scales, for a range of metals.”

Read the full story, published June 7, 2017 by the McGill Newsroom at https://www.mcgill.ca/newsroom/channels/news/more-sustainable-way-refine-metals-268517.

See also “A chlorine-free protocol for processing germanium,” Martin Glavinović et al., Science Advances, 5 May 2017. DOI: 10.1126/sciadv.1700149 http://advances.sciencemag.org/content/3/5/e1700149

To learn more about germanium and its applications (including fiber-optics, infrared optics, solar electric applications, and LEDs), see the Wikipedia article on germanium at https://en.wikipedia.org/wiki/Germanium.

NASA Invests in Innovative Concepts, Including Electronic-recycling Microbes

The National Aeronautics and Space Administration (NASA) recently announced that 13 proposals had been selected for funding as part of the NASA Innovative Advanced Concepts (NIAC) program, which “invests in transformative architectures through the development of pioneering technologies.” According to the press release, “NIAC Phase I awards are valued at approximately $100,000 for nine months, to support initial definition and analysis of their concepts. If these basic feasibility studies are successful, awardees can apply for Phase II awards, valued up to $500,000 for two additional years of concept development.” Read the full press release on the NASA web site.

Among the funded proposals is a concept entitled Urban bio-mining meets printable electronics: end-to-end at destination biological recycling and reprinting,” submitted by Lynn Rothschild, NASA’s Ames Research Center in Moffett Field, California. The project description states:

“Space missions rely utterly on metallic components, from the spacecraft to electronics. Yet, metals add mass, and electronics have the additional problem of a limited lifespan. Thus, current mission architectures must compensate for replacement. In space, spent electronics are discarded; on earth, there is some recycling but current processes are toxic and environmentally hazardous. Imagine instead an end-to-end recycling of spent electronics at low mass, low cost, room temperature, and in a non-toxic manner. Here, we propose a solution that will not only enhance mission success by decreasing upmass and providing a fresh supply of electronics, but in addition has immediate applications to a serious environmental issue on the Earth. Spent electronics will be used as feedstock to make fresh electronic components, a process we will accomplish with so-called ‘urban biomining’ using synthetically enhanced microbes to bind metals with elemental specificity. To create new electronics, the microbes will be used as ‘bioink’ to print a new IC chip, using plasma jet electronics printing. The plasma jet electronics printing technology will have the potential to use martian atmospheric gas to print and to tailor the electronic and chemical properties of the materials. Our preliminary results have suggested that this process also serves as a purification step to enhance the proportion of metals in the ‘bioink’. The presence of electric field and plasma can ensure printing in microgravity environment while also providing material morphology and electronic structure tunabiity and thus optimization. Here we propose to increase the TRL level of the concept by engineering microbes to dissolve the siliceous matrix in the IC, extract copper from a mixture of metals, and use the microbes as feedstock to print interconnects using mars gas simulant. To assess the ability of this concept to influence mission architecture, we will do an analysis of the infrastructure required to execute this concept on Mars, and additional opportunities it could offer mission design from the biological and printing technologies. In addition, we will do an analysis of the impact of this technology for terrestrial applications addressing in particular environmental concerns and availability of metals.”

Note that “TRL” refers to “Technology Readiness Level,” a measure of the technological maturity of a concept, indicative of the degree to which it has developed beyond the initial faults and unforeseen problems that inevitably arise when something theoretical is brought into practice. NASA TRL definitions help characterize whether a concept is ready for use in space flight during missions or has been “flight proven” as part of successful missions.

Printable Electronics
Graphic depiction of printable electronics, from concept description on NASA web site.

Though the idea is geared toward making missions to Mars more practical in terms of the weight of materials needed to pack for missions and dealing with the lack of a local repair shop in the event of a device breakdown, the concept–if successful–could have obvious positive impacts on sustainable electronic product design and responsible management of the ever-growing stream of discarded electronics here on Earth. This could end up becoming one more example of how technology developed to enable space exploration could have benefits to humans in their everyday terrestrial lives. NASA has published an annual accounting of such technologies called “Spinoff” since 1976.

For more information on the NIAC program, visit https://www.nasa.gov/directorates/spacetech/niac/index.html. For more information on technological “spinoffs”  from space exploration which improve life on Earth, see the press release for the 2016 edition of Spinoff, and the official NASA Spinoff web site.