‘Glass fiber-reinforced plastic (GFRP), a strong and durable composite material, is widely used in everything from aircraft parts to windmill blades. Yet the very qualities that make it robust enough to be used in so many different applications make it difficult to dispose of ⎯ consequently, most GFRP waste is buried in a landfill once it reaches its end of life. According to a study published in Nature Sustainability, Rice University researchers and collaborators have developed a new, energy-efficient upcycling method to transform glass fiber-reinforced plastic (GFRP) into silicon carbide, widely used in semiconductors, sandpaper and other products…This new process grinds up GFRP into a mixture of plastic and carbon and involves adding more carbon, when necessary, to make the mixture conductive. The researchers then apply high voltage to it using two electrodes, bringing its temperature up to 1,600-2,900 degrees Celsius (2,912-5,252 Fahrenheit). “That high temperature facilitates the transformation of the plastic and carbon to silicon carbide,” Tour explained. “We can make two different kinds of silicon carbide, which can be used for different applications. In fact, one of these types of silicon carbide shows superior capacity and rate performance as battery anode material.”‘
On August 3, 2022 the University of Leicester reported:
“An electronic waste-recycling process that’s kinder to the planet – and uses pioneering technology developed at the University of Leicester – has attracted a £1.2m grant and national awards recognition Recycling e-waste, such as discarded mobile phones, laptops and anything with an electronic circuit board, can cause significant environmental problems. This is because the critical metals in circuit boards are difficult to recycle, with the process requiring large and expensive, polluting, smelting facilities. New alternative chemistry based techniques are on the horizon, but the vast majority of these require the use of highly dangerous acids and oxidisers that are consumed in the process and need replacing on a regular basis, meaning more transport of hazardous materials on the roads and a high CO2 footprint which comes from the necessary neutralisation of these chemicals after their use. But, there’s a potentially zero-carbon, clean chemical solution, based on the environmentally-benign Deep Eutectic Solvents (DES) – a class of chemistry developed by Leicester scientists in the early 2000s. The DES recycling process sees the solvents dissolve the target metals into a solution without the need for toxic chemicals or high temperatures. The solution is also not consumed within the process and can itself be recycled and used again...UK-based company Descycle, is using the DES chemistry to develop a commercially viable recycling plant that will be hosted by Descycle’s joint venture partners Gap Group…Descycle is also working with waste company GAP, to build a waste electrical and electronic equipment recycling facility in the north-east of England, which uses DES chemistry. Descycle’s Chief Technology Officer is Dr Rob Harris, who is also a researcher at the University and is working on making the technology commercially viable. The work he and Descycle are carrying out has attracted the attention of judges at the highly competitive Royal Society of Chemistry (RSC) Emerging Technologies Competition, which received applications from all over the globe, and were shortlisted for the Environment award. Hot on the heels of the shortlisting, comes the news that Dr Harris and Descycle have also secured a Future Leaders Fellowship from the UKRI’s flagship scheme to continue development of the e-waste and other metals recycling and recovery processes using the technology.”
On August 1, 2022, Oak Ridge National Laboratory (ORNL) reported that one of its research teams, in collaboration with Momentum Technologies, “piloted an industrial-scale process for recycling valuable materials in the millions of tons of e-waste generated annually in the United States…Researchers previously demonstrated a method for recycling scrap permanent magnets in consumer electronics using membrane solvent extraction. Now the technology has met a critical step toward deployment. The system has been scaled up to achieve high-purity separations.”
The following is the abstract from an article published by the team in Advanced Engineering Materials:
“This study reports the process scale-up and long-term performance of an energy-efficient and cost-effective membrane solvent extraction (MSX) process for separation and recovery of high purity rare earth oxides (REOs) from scrap permanent magnets (SPMs). The rare earth elements (REEs), including dysprosium, neodymium, and praseodymium, are recovered from SPMs using a neutral extractant, tetraoctyl diglycolamide (TODGA) embedded in a microporous polypropylene hollow fiber membrane module. The MSX process performance is demonstrated with bench scale module with membrane surface area of 1.4 m2 to industrial scale modules with membrane surface area of up to 20 m2 to enable the processing of up to 1 ton month−1 of SPMs. The purity and the yield of the recovered REOs are >99.5 wt% and >95%, respectively. The average extraction rate of REOs is >10 g m−2 hr−1. A skid of MSX system is assembled with a membrane area of 40 m2. The MSX skid successfully recovers REOs with a capacity of 300 kg REOs/month. Finally, it is determined that the organic phase containing the extractant maintains its performance up to 250 h. The results suggest that the MSX process is an economically viable and environmentally friendly process for separation and recovery of REOs from electronic wastes.”
ORNL scientist and lead author on the article, Syed Islam, is quoted in the ORNL announcement as saying “We’re working with partners toward commercialization and exploring applications to recycle REEs used in growing technology areas, such as wind power and electric vehicles.”
“The idea is to simplify how solar energy is harvested and stored,” says Michael De Volder, a mechanical engineer at the University of Cambridge who led the work. If the team can improve the efficiency and lifetime of the hybrid device, its cost will likely be lower than combining solar cells and batteries. “For the price of a battery, you get both functionalities,” he says.
This low cost could make it suitable for off-grid uses and for regions of the world that lack access to affordable energy.
The workhorse of the new light-rechargeable battery is a cathode made of vanadium pentoxide nanofibers. The material stores lithium ions and also harvests light to generate paired electrons and positive charges, or holes. The researchers mixed the nanofibers with poly(3-hexylthiophene-2,5-diyl) (P3HT) that blocks the movement of holes, and graphene oxide that aids electron transport.”
A glass window on the cathode side of a coin cell allows light to reach the nanofibers. This new device is more efficient than previously developed light-rechargeable batteries and can be recharged for over 200 cycles. Though the efficiency of this battery is still too low for practical use, researchers hope to explore alternatives to vanadium pentoxide to improve efficiency.
As reported on Phys.org, researchers from the National University of Singapore have created a 3D printed prototype of a shoe insole that evaporates sweat faster than normal and uses the harvested moisture to generate energy:
“In our new invention, we created a novel film that is extremely effective in evaporating sweat from our skin and then absorbing the moisture from sweat. We also take this one step further—by converting the moisture from sweat into energy that could be used to power small wearable devices,” explained research team leader Assistant Professor Tan Swee Ching, who is from the NUS Department of Material Science and Engineering.
The main components of the novel thin film are two hygroscopic chemicals—cobalt chloride and ethanolamine. Besides being extremely moisture-absorbent, this film can rapidly release water when exposed to sunlight, and it can be ‘regenerated’ and reused for more than 100 times.
To make full use of the absorbed sweat, the NUS team has also designed a wearable energy harvesting device comprising eight electrochemical cells (ECs), using the novel film as the electrolyte. Each EC can generate about 0.57 volts of electricity upon absorbing moisture. The overall energy harvested by the device is sufficient to power a light-emitting diode. This proof-of-concept demonstration illustrates the potential of battery-less wearables powered using human sweat.”
This prototype is certainly interesting and has obvious potential for improving human comfort, confidence, and possibly health. It remains to be seen whether commercialization of the technology will be feasible and whether researchers develop effective ways to recycle the product at the end of its useful life. Conventional electronics are already a waste generation challenge, and wearable technology is notoriously difficult to recycle and a potential contaminant in recycling streams. Further, the incorporation of cobalt chloride in this product could prove problematic and detrimental to sustainable design, as continues to be the case for most electronics. Cobalt mining operations have been supported by child labor, so truly sustainable designs will strive to use reclaimed cobalt from the recycling of existing products for the preparation of cobalt compounds for the manufacture of new devices. It could be the case that innovations such as this one might reduce reliance on batteries, and thus reduce overall demand for cobalt, but any cobalt in a product supply chain must be scrutinized. We can only hope that the same innovativeness that leads to prototypes such as this insole can inspire researchers to continuously improve the overall sustainability of product design and end-of-life management.
Learn more:
Xueping Zhang et al, Super-hygroscopic film for wearables with dual functions of expediting sweat evaporation and energy harvesting, Nano Energy (2020). DOI: 10.1016/j.nanoen.2020.104873
Cavusoglu, AH., Chen, X., Gentine, P. et al. Potential for natural evaporation as a reliable renewable energy resource. Nat Commun8, 617 (2017). https://doi.org/10.1038/s41467-017-00581-w
Food waste and electronic waste are two aspects of the waste stream that present a multitude of challenges for human society. Now a team of scientists led by the Nanyang Technological University (NTU), Singapore has developed a way to use food waste–specifically orange peels–to recover precious metals from spent lithium-ion batteries for reuse in the creation of new batteries.
‘An estimated 1.3 billion tonnes of food waste and 50 million tonnes of e-waste are generated globally each year.
Spent batteries are conventionally treated with extreme heat (over 500°C) to smelt valuable metals, which emits hazardous toxic gases. Alternative approaches that use strong acid solutions or weaker acid solutions with hydrogen peroxide to extract the metals are being explored, but they still produce secondary pollutants that pose health and safety risks, or rely on hydrogen peroxide which is hazardous and unstable.
Professor Madhavi Srinivasan, co-director of the NTU Singapore-CEA Alliance for Research in Circular Economy (NTU SCARCE) lab, said: “Current industrial recycling processes of e-waste are energy-intensive and emit harmful pollutants and liquid waste, pointing to an urgent need for eco-friendly methods as the amount of e-waste grows. Our team has demonstrated that it is possible to do so with biodegradable substances.”‘
Current industrial processes for recycling batteries involve shredding the batteries and crushing them into a powdery substance. That powdery substance is either smelted at temperatures above 500 degrees Celsius to separate metals or subjected to a chemical leaching technique using a mixture of acids and hydrogen peroxide plus heat. The newly developed process substitutes orange peels instead of the acids and hydrogen peroxide typically used. The researchers oven-dried orange peels, ground them to powder, and mixed them with citric acid, a weak acid found in citrus fruits.
‘Asst Prof Tay explained: “The key lies in the cellulose found in orange peel, which is converted into sugars under heat during the extraction process. These sugars enhance the recovery of metals from battery waste. Naturally-occurring antioxidants found in orange peel, such as flavonoids and phenolic acids, could have contributed to this enhancement as well.”
Importantly, solid residues generated from this process were found to be non-toxic, suggesting that this method is environmentally sound, he added.’
The researchers were further able to use metals recovered via this process to assemble new lithium-ion batteries which displayed a charge-capacity similar to commercially available batteries. The team is hoping to further optimize the batteries they can produce in this fashion and extend their “waste-to-resource” approach to other cellulose-rich fruit and vegetable waste and other lithium-ion battery types.
Learn more:
“Repurposing of Fruit Peel Waste as a Green Reductant for Recycling of Spent Lithium-Ion Batteries” by Zhuoran Wu, Tanto Soh, Jun Jie Chan, Shize Meng, Daniel Meyer, Madhavi Srinivasan and Chor Yong Tay, 9 July 2020, Environmental Science & Technology. DOI: 10.1021/acs.est.0c02873
In a paper published this summer in ACS Omega, Rumana Hossain and Veena Sahajwalla describe an innovative process for transforming electronic waste, or e-waste, into a protective coating for metal.
‘A typical recycling process converts large quantities of items made of a single material into more of the same. However, this approach isn’t feasible for old electronic devices, or “e-waste,” because they contain small amounts of many different materials that cannot be readily separated. Now, in ACS Omega, researchers report a selective, small-scale microrecycling strategy, which they use to convert old printed circuit boards and monitor components into a new type of strong metal coating…
Based on the properties of copper and silica compounds, Veena Sahajwalla and Rumana Hossain suspected that, after extracting them from e-waste, they could combine them to create a durable new hybrid material ideal for protecting metal surfaces.
To do so, the researchers first heated glass and plastic powder from old computer monitors to 2,732 F, generating silicon carbide nanowires. They then combined the nanowires with ground-up circuit boards, put the mix on a steel substrate then heated it up again. This time the thermal transformation temperature selected was 1,832 F, melting the copper to form a silicon-carbide enriched hybrid layer atop the steel. Microscope images revealed that, when struck with a nanoscale indenter, the hybrid layer remained firmly affixed to the steel, without cracking or chipping. It also increased the steel’s hardness by 125%. The team refers to this targeted, selective microrecycling process as “material microsurgery,” and say that it has the potential to transform e-waste into advanced new surface coatings without the use of expensive raw materials.’
Learn more:
Rumana Hossain, Veena Sahajwalla. Material Microsurgery: Selective Synthesis of Materials via High-Temperature Chemistry for Microrecycling of Electronic Waste. ACS Omega, 2020; 5 (28): 17062 DOI: 10.1021/acsomega.0c00485
In the March 29, 2019 edition of Resource Recycling, Jared Paben reported that researchers at the Vellore Institute of Technology in India found they could use granules of high-impact polystyrene from scrap electronics as a replacement for sand in self-compacting concrete. They also studied using fly ash from a power plant as a replacement for cement. They found HIPS and fly ash could be used at levels of up to 30 percent without significantly reducing strength, according to their paper, which was published in February in the journal Buildings. Self-compacting lightweight concrete is generally used on long-span bridges, the paper noted.
“Around 7% of the world’s gold is inside e-scrap, of which less than one-third is currently salvaged, according to project leader Professor Jason Love. One tonne of gold ore contains around up to 5 grams of pure gold. However, a tonne of discarded mobile phones easily holds 300 grams of the valuable metal, Love says. The chemical reagent pioneered by in Edinburgh effectively recovers ‘a very high purity of gold’ from various types of discarded electronics. First, the researchers place the printed circuit boards in a mild acid to dissolve metallic parts. An oily liquid containing the new reagent is then added, which allows gold to be extracted selectively from the complex mixture of metals found inside electronics. Professor Love explains that, normally, one molecule of reagent binds directly to a metal molecule. The innovative compound uses a different type of chemistry and can bind to clusters of gold molecules instead of just one. ‘This means you can use a lot less of it to recover the same amount of gold,’ he says.”
The researchers hope to find ways to recover other metals, including valuable (e.g. palladium, platinum, and neodymium), common (e.g. copper and tin), and toxic (e.g. lead and cadmium) metals. Similarly, they are interested in exploring chemical means to more effectively recover plastics from electronic scrap.
Additive manufacturing, more commonly referred to as 3D printing, is an increasingly widespread technology in schools, libraries, and other public makerspaces, often seen as a part of STEAM education. Manufacturers and innovators see the technology as means to create products or necessary items cheaply and relatively quickly, and in many cases with less waste of material than in other manufacturing processes–see for example, the MIT Technology Review article on GE’s use of additive manufacturing to produce fuel nozzles for aircraft engines. In developing nations, 3D printing can offer a means to more easily provide items that add to quality of life at a lower cost than typical. For example, the Victoria Hand project 3D prints prosthetics to assist amputees.
With so much positive potential, what could possibly be the downsides of 3D printing? While negative impacts might not be immediately obvious, sustainability advocates must always consider all potential impacts of a technology, product, or action, both positive and negative. The following resources are a good start for considering the often overlooked potential negative impacts of 3D printing.
The Health Effects of 3D Printing. This October 2016 article from American Libraries Magazine discusses exposure to ultrafine particles (UFPs), volatile organic compounds (VOCs), and the risks of bacterial growth in small fissures found within 3D printed objects. The authors provide some very basic tips for reducing risks to patrons and library staff members.
3-D printing: A Boon or Bane? Though a bit dated, this article by Robert Olson, a senior fellow at the Institute for Alternative Futures in Alexandria, VA, in the November/December 2013 issue of the Environmental Forum (the policy journal of the Environmental Law Institute) does a good job of outlining some of the issues that need to be considered when assessing the impacts or appropriateness of this technology. “How efficient are these technologies in the use of materials and energy? What materials are used and what are the worker exposure and environmental impacts? Does the design of printed objects reduce end-of-life options? Does more localized production reduce the carbon footprint? And will simplicity and ubiquity cause us to overprint things, just as we do with paper?“
The dark side of 3D printing: 10 things to watch. This 2014 article by Lyndsey Gilpin for Tech Republic concisely outlines ten potential negative impacts, such as the reliance on plastics, including some that may not have occurred to you, such as IP and licensing issues, bioethics, and national security. Note the mention of 3D printed guns, which have been in the news a fair amount during 2018.
3-D printer emissions raise concerns and prompt controls. This March 26, 2018 article by Janet Pelley in Chemical & Engineering News focuses on potential negative health impacts of inhaling VOCs and plastic particles. “Although the government has set workplace standards for a few of the VOCs released by 3-D printers, these are for healthy working-age adults in industrial settings such as tire or plastic manufacturing plants: None of the compounds is regulated in homes or libraries where 3-D printers might be used by sensitive populations such as children. Furthermore, researchers don’t know the identity of most of the compounds emitted by printers. “Scientists know that particles and VOCs are bad for health, but they don’t have enough information to create a regulatory standard for 3-D printers,” says Marina E. Vance, an environmental engineer at the University of Colorado, Boulder. What’s more, data from early studies of 3-D printer emissions are difficult to use in developing standards because of variability in the test conditions, says Rodney J. Weber, an aerosol chemist at Georgia Institute of Technology. Two years ago, UL, an independent safety certification company, established an advisory board and began funding research projects to answer basic questions about the amounts and types of compounds in 3-D printer emissions, what levels are safe, and how to minimize exposures, says Marilyn S. Black, a vice president at UL. The company is working to create a consistent testing and evaluation method so that researchers will be able to compare data across different labs. ‘By this fall we will put out an ANSI [American National Standards Institute] standard for measuring particles and VOCs for everyone to use,” she says. See the UL Additive Manufacturing pages“, specifically the “library” section for their currently available safety publications.
3D Printing and the Environment: The Implications of Additive Manufacturing. This special issue of Yale’s Journal of Industrial Ecology from November 2017 is the least “layperson friendly” resource provided in this post, but includes a variety of research articles providing important insights into its environmental, energy, and health impacts.
