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Timberland Partners with Thread International to Incorporate Plastic Waste into Fabrics

February 17, 2017 | GreenBiz

Thread transforms trash that has been collected and sorted by local workers in Haiti — where mounds of plastic bottles clogging waterways are a common sight — into fabric sourced by brands such as Timberland, which is developing a line of sneakers and boots made with Thread’s "Ground to Good" fabric. The line will launch in the spring.

 

New Tech Breakthroughs Design Impacts Out of Everyday Products

February 16, 2017 | Sustainable Brands

While recycling most certainly plays an important role in the shift to the development of a more circular, sustainable economy, it largely focuses on a product or material’s end of life. But recent initiatives and technological breakthroughs are helping more companies design environmental impacts out of their products’ life cycles.

 

Chemistry Professor at Utah State Replaces “Old-school Techniques with Cutting-edge Research with an Emphasis in Green Chemistry”

February 15, 2017 | AZo Cleantech

Specifically, Professor Sun is examining the development of a biomass intermediate for the oxidation half reaction, which could offer a green, water-soluble polymer precursor to substitute such fossil fuel-derived polymers as polyethylene terephthalate or PET.  PET is used in all types of household products, fabrics, furnishing, vehicle interiors, appliances, and more.

 

Avantium and BASF Seek IPO Funds to Build Bio-based Chemical Plant

February 15, 2017 | C&EN

Avantium, a 2000 spin-off from Shell with technologies for converting plant sugars into biochemicals and polymers, says it will make an initial public offering of shares on two European stock exchanges by the end of March.  Avantium says it will invest up to $80 million of the money it raises in its Synvina joint venture with BASF. The venture plans a 50,000-metric-ton-per-year plant for 2,5-furandicarboxylic acid, a sugar-derived intermediate for recyclable polyesters such as polyethylene furanoate (PEF).

 

Breakthrough Textiles Help Fashion Industry Close the Loop

February 13, 2017 | Sustainable Brands

Many different brands are making moves towards a more circular economy through textile innovation and consumer engagement. Recently, H&M debuted its new “Bring It” garment recycling campaign, as well as a new BIONIC-based Conscious Exclusive collection, while Kering announced the next stage of its ambitious sustainability plan. Now, Lenzing, G-Star and Patagonia are launching new initiatives to bring the fashion industry closer to closing the loop.

 

 

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By Mary M. Kirchhoff, Ph.D., Acting Director, ACS GCI; Executive Vice President of Scientific Advancement, ACS

 

I had the privilege of attending the National Science Foundation’s (NSF) “Arc of Science: Research to Results” event on Capitol Hill last evening.  Featured exhibits highlighted NSF-sponsored research that “enhances the United States economy, security and global competitiveness.”  Projects covered a breadth of topics, from cybersecurity to ocean acidification to monitoring the urban environment.  The event showcased NSF’s substantial investment in science and science education, funding that has supported 223 Nobel Prize winners in chemistry, physics, medicine and economics.  We cannot imagine our lives without the Internet, touch screens or Google, all of which were built on NSF funding.

 

The “Research to Results” theme is one that is highly relevant to green chemistry:  Translating fundamental green chemistry research into greener products and processes results in benefits to human health, the environment, and the economy.  Green chemistry discoveries will have the greatest impact when implemented at an industrial scale such that energy and water usage are minimized, efficiency is maximized, and the use and generation of hazardous materials are reduced or eliminated.

 

The goal of transforming green chemistry discoveries into commercial products is reflected in this year’s Green Chemistry & Engineering Conference theme of “Making Our Way to a Sustainable Tomorrow”.  Conference symposia will address a wide range of topics, including those focused on the academic/industry interface, such as “Bridging the Gap:  The Diverse Paths from Academic Discovery to Industrial Implementation for Innovations in Green Chemistry” and “Greener Organic Chemistry Research in Academia:  Accelerating the Pace of Industrial Adoption”.  Registration for this year’s conference opened yesterday, and I encourage you to join us in Reston, Virginia from June 13-15 by registering at http://www.gcande.org/registration/.  I look forward to seeing you there!

 

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Contributed by J. H. Docherty and S. P. Thomas, EaStCHEM School of Chemistry, University of Edinburgh

 

ed-Picture1.pngChemical catalysis is an engine that powers modern society. The majority of modern chemical transformations, however, rely on the use of precious metals, such as platinum, iridium and rhodium, which are expensive and scarce resources with many high technology applications outside of the chemical sciences.

 

A sustainable future for catalysis relies on the use of first-row, low cost, low toxicity, Earth-abundant metals. Despite this, the metals that are most abundant have yet to be adopted by the global community.

 

With this predicament in mind, we questioned:

Why do synthetic chemists not instinctively use iron, manganese or cobalt?

Why do expensive metals such as platinum, palladium and rhodium dominate?

 

A prevailing answer arose: Precious metals tend to be practical and simple to use. Earth-abundant metals are comparatively difficult, and the non-specialist chemist is simply not equipped to try.

 

One particular area of interest to our group is reductive transformations (e.g. olefin hydrogenation). In this field, several state-of-the-art Earth-abundant metal catalysts have been reported in recent years for a range of synthetically valuable transformations.1-3 However, these catalysts are often highly air- and- moisture-sensitive, or require the use of a strong reducing agent – such as; lithium aluminium hydride or Grignard reagents – to access the active catalyst,. While these strategies have proven valuable, the sensitive nature of these requisite reagents presents a practical challenge.

 

The practicality of any synthetic method is key to its modern-day use. Hence, Earth-abundant metal catalysts that will stand the test of time should be those that are easy and simple to use. At the outset, our over-arching aim was to make this catalysis as functional and simple as making a cup of tea.

 

We began with model reaction conditions, based upon literature established precedents for alkene hydroboration using an isolated low-oxidation-state iron catalyst and in situ organometallic activator. With this as a testing platform, we assessed the viability of easy-to-handle reagents as novel catalyst activators, finding that alkoxide salts were extremely effective. Of the salts tested, sodium tert-butoxide (NaOtBu) proved most robust, giving the best and most consistent results. It is worthy to note that sodium tert-butoxide is a bench-stable solid, with wide commercial availability and minimal associated hazards.

 

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Using this new activator, we assessed the generality with respect to a series of catalysts bearing unique ligand frameworks, finding that this method was successful across a range of previously developed catalysts, reliant on activation using organometallic reagents. Significantly this included expansion to other metals, including: cobalt, manganese and nickel. Now, we had the ability to set-up reactions without the need for a glove box, or strict air-and-moisture-free equipment, all enabled through the use of a simple alkoxide salt.

 

Throughout our investigations, we used various sources of NaOtBu, with the conclusion that they were all equally active. This included the use of NaOtBu that had been stored on the bench for more than six years.

 

From a sustainability perspective, these reactions could be conducted in the absence of a solvent (i.e neat) at ambient temperatures, with short reaction times and excellent product selectivities. This is further exemplified by the fact that we targeted only the most atom-economic transformations, namely: hydroboration and hydrosilylation, with expansion to hydrogenation, hydrovinylation, and 2π+2π cycloaddtion – all with 100 percent atom economy.

 

It is encouraging to hear that our collaborating partner, GlaxoSmithKline, is delighted with the highly practical nature of the methodology, which has been demonstrated in their own laboratories, and that they are actively looking to introduce such transformations to their under-development routes.

 

  1. Du, X.; Huang, Z. ACS Catalysis. 2017, 7 (2), 1227-1243.
  2. Greenhalgh, M. D, Jones, A. S., Thomas, S. P. ChemCatChem. 2015, 7, 190-222.
  3. Rodriguez-Ruiz, V., Carlino, R., Bezzenine-Lafollee, S., Gil, R., Prim, D., Shultz, E., Hannedouche, J., Dalton Trans. 2015, 44, 12029-12059.

 

 

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Contributed by Mark Evans, Founder and Chief Executive Officer of Camston Wrather

 

This three-part series will explore the task of implementing a green chemical reaction discovered and researched in the laboratory to an industrial scale, taking into consideration the economic, engineering, ecological and market conditions associated with that task. The goal of this series is to highlight the importance of taking a multi-disciplinary approach when implementing applied scientific discoveries and, in particular, the challenges faced when attempting to bring the larger concept of green chemistry to market in a circular economy.

 

Camston Wrather recovers precious metals and polymer plastics from electronic waste using proprietary micron thermal separation and green chemistry. The Twitter version might read: Camston transforms end-of-life bits into tomorrow’s atoms. The structure of this series will first touch on the consumption and disposal of electronic waste (e-waste) and its environmental and human health impacts (Part 1); followed by a technical overview of current resource recovery methods, both informal and formal (Part 2); and lastly, how implementing a green solution necessarily entails a multi-disciplinary approach (Part 3).

 

The Love Affair

 

The annual Computer Electronics Show (CES), an expo that showcases what is next in tech, recently wrapped up in Las Vegas, and to say we have an insatiable love for gadgets would be a gross understatement.

 

A Pew Research Center survey covered ownership of seven types of devices and found that roughly nine-in-ten American adults (92 percent) own a mobile phone, 73 percent own a desktop or laptop computer, 51 percent own tablets, 40 percent report having a game console; four-in-ten Americans own MP3 players; about a fifth (19 percent) of Americans have e-book readers; and 14 percent of adults own a portable gaming device, such as a PlayStation.

 

According to the Sustainability Consortium’s 2016 report, U.S. consumers were expected to purchase more than 1 billion devices in 2015, producing sales reaching $285 billion, which includes a 15 percent year-over-year increase in the number of mobile and wearable devices entering the market. This equates to approximately 24 devices per household, where at least four of those devices were connected to the Internet. In addition to recent sales figures, there were approximately 3.8 billion devices estimated to be already in use or stored in households in 2015, which equals approximately 30.5 devices per household for the 125 million households estimated in the U.S. (McCue, 2014).

 

There can be no doubt that our collective love affair for gadgets is real and growing; moreover, there are emerging categories to consider as well: artificial intelligence, virtual reality, autonomous car electronics, entertainment electronics, aerial drones, robots, app-enabled toys, musical instruments and wearable technologies. These categories indicate where the market is going as societies become more highly integrated in emerging technology and the Internet of Things (IoT).

 

There are more mobile phones in existence than there are number of people living on Earth. Based on the number of active SIM cards in use, there are more than 7.2 billion mobile devices being used, while there are less than 7.2 billion people on the planet. The growth rate of mobile devices compared to the population growth rate is five times greater.

 

Steve Jobs understood the intimate relationship between the product and the end-user, and no matter how close our relationship with our smartphones has become – how faithfully we keep them with us, how we store and share our digital lives and memories on them, or how we hold them to our faces and whisper into them – we rarely wonder where they go when they die.

 

The Breakup

 

According to the UN Environmental Programme (2015) and Solving the E-Waste Program (StEP, 2016), 85 percent of the world’s electronic waste, worth nearly $40.6 billion, is illegally traded or dumped each year. Americans throw out over 350,000 cellphones and 127,000 computers every day – and yes, this includes the old computer you dropped off at the local electronics recycling drive. This e-waste is the fastest-growing part of the municipal waste stream and accounts for over 70 percent of our toxic waste.

 

According to a CalRecycle statewide report, California diverted, via its sea ports, over 2.5 billion pounds (1.26 million tons) of non-ferrous e-waste to developing countries. CalRecycle is also forthcoming and intellectually honest about how it determines California’s recycling rate. By law, California is permitted to count its diversion activities towards the state’s recycling rate totals. Thus, when adjusted to exclude its diversion numbers, the state’s recycling rate dramatically drops. This is an important distinction and perhaps the most salient point of this article:

 

What is being counted as being recycled has never been truly recycled in the first place, but diverted.

 

There are many top Original Equipment Manufacturers (OEMs) who flood their social media posts with dazzling statistics on how much e-waste their company has “diverted,” yet it remains questionable as to what this actually entails. Is it greenwashing to report diversion rates if the reality is the consistent and illegal dumping of e-waste in developing countries?

 

The very technology that has enabled a standard of living far beyond that imagined by previous generations is currently being illegally dumped or legally diverted to developing countries, and its legacy will be one of lost opportunity, waste and environmental degradation. According to leading researchers, today’s technology revolution produces over 42 million metric tons of e-waste per year and directly causes environmental contamination and the escalation of human health and safety issues.

 

To better grasp the size of this e-waste stream: 42 million metric tons is equal to 92,568,000,000 pounds, or roughly 3.5 million fully loaded semi-tractor trailers. If you lined these trucks from end-to-end, they would stretch from San Diego to Boston and back 18 times. That’s the amount of e-waste already in the system and ready for end-of-life (EOL) processing each and every year.

 

In general, e-waste flows to disadvantaged and historically marginalized areas. A study commissioned by the U.S. Environmental Protection Agency (EPA) revealed that it was 10 times cheaper to export e-waste to Asia than it was to process it in the United States. Recovered devices and materials flow to where the most value can be gained with the least cost, including locations that may not have facilities or processes to protect workers and the environment. The incentives for e-waste movement, both legally and illegally, are enormous.

 

In the U.S., industry moves, mines, extracts, shovels, burns, wastes, pumps and disposes of 4 million pounds of material in order to provide one average middle-class American family's needs for one year. For example, the mining industry needs to produce 48,000 pounds of minerals per person per year for all 320+ million Americans just so we can maintain our standard of living. That means the mining industry needs to produce 7.1 billion tons of minerals each year just to keep pace.

 

Each of us will consume and use 3.7 million pounds of minerals, metals and fuels in our lifetime. One ton of electronic waste contains, on average, 40-800 times the concentration of precious metals than one ton of mining ore. Case in point, one ton of smartphones, approximately 10,000 units (a tiny fraction of today’s 1 billion annual production) contains, on average, 10.9 ounces of gold. To produce 10.9 ounces of gold from mining activities would take processing over one million pounds of earth.

 

It is estimated that a total of 700,000 workers are employed in the informal e-waste collection and recycling industry in China. The majority of e-waste imported to China is deposited in rural “recycling villages” clustered along the southeastern coast of China near major shipping ports such as Hong Kong, Xiamen, Ningbo, and Tianjin.

 

The widespread dumping of toxic e-waste into waterways, as well as the release of chemicals into the atmosphere from the open combustion and smelting of e-waste materials, has led to significant ecological damage and the poisoning of surrounding villages. Soil samples taken from an open burning site for circuit boards revealed lead concentrations ranging from 856 mg/kg to 7038 mg/kg, far exceeding the environmental pollutant reference value of 190 mg/kg.

 

To close out this first installment, please watch the first minute of the investigative television broadcast 60 Minutes here.

 

Stay tuned next month for Part 2: A technical overview of current resource recovery methods, both informal and formal.

 

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Mark Evans is the Founder and Chief Executive Officer of Camston Wrather and a University of California at Berkeley, Alumni.

Connect with author on LinkedIn.

 

 

 

 

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Contributed by Mats Linder, Ph.D., Project Manager, Ellen MacArthur Foundation

 

When Mr. McQuire told Dustin Hoffmann’s character Ben about the great future in plastics in the 1967 classic The Graduate, he didn’t know how right he was. In the 50 years since, total plastics production has seen a 20-fold increase, and today almost everyone everywhere encounters them every day. They have become the workhorse materials of the modern economy, combining unrivaled functionality with low cost.

 

While its products provide numerous benefits, the current plastics economy has drawbacks that become more apparent by the day. Packaging, the largest application with 26 percent of the market, leads to especially significant and sometimes starkly visual environmental, economic and social consequences. Last year, the World Economic Forum, the Ellen MacArthur Foundation and McKinsey & Company published The New Plastics Economy – Rethinking the future of plastics. This report found that most plastic packaging is used only once and 95 percent of its value, estimated at $80-120 billion, is lost to the economy every year. Forty years after the launch of the first universal recycling symbol, only 14 percent of plastic packaging is collected for recycling globally, and one-third is leaked – inadvertently or not – into the environment.

 

Seen by many as the next big issue for societies to rally around after climate change, there has been a recent wave of regulatory and social action around plastic packaging. In 2016, several countries followed India and banned single-use plastic bags: France banned non-biodegradable, single-use food service ware, and California approved Proposition 67 to prohibit retail stores from providing customers with single-use plastic bags – to name just a few examples. NGOs worldwide have also ramped up their efforts. The #breakfreefromplastic movement grew to over 500 member organizations in just a couple of weeks following its launch in Sept. 2016. With the EU Commission aiming to publish a strategy on plastics by the end of 2017 as part of its Circular Economy Action Plan, regulatory action is set to continue.

 

So is the “great future in plastics” coming to an end? The answer is likely “no, but…” While we are unlikely to back away from the benefits that plastics bring, we need to fundamentally rethink the global system through which they flow. In May 2016, the Ellen MacArthur Foundation launched the New Plastics Economy initiative, a bold, three-year project intended to stimulate such a rethink and mobilize a transition towards a system based on circular economy principles. The initiative is unprecedented in its setup and in its attraction and involvement of leading philanthropic partners and front-running participant companies, cities and governments.

 

Radical innovation is an important enabler of a new plastics economy, and one of the initiative’s goals is to mobilize large-scale ‘innovation moonshots.’ A crucial finding of the recently published report Catalysing Action – in which the initiative’s targets are crystallized into recommended actions – is the need for a fundamental redesign of 30 percent (by volume) of all plastic packaging. The products in this segment would otherwise, by their very design, be destined to be land-filled, incinerated or leaked into the environment. Often, such leakage leads to the discharge of substances of concern to human health and ecosystem integrity. There is therefore an urgent need to develop new materials, new packaging design solutions, and new after-use recovery technologies. In other words, it is a good time to be an innovator in plastics.

 

Green chemistry provides an excellent framework to guide such innovation towards creating material systems consistent with a circular economy. Its principle to prevent waste is aligned with the central aim of the New Plastics Economy initiative to move towards a system in which packaging is not wasted after its single, short use. Its emphasis on moving away from hazardous substances and processes provides a rationale for designing out these components from plastics. And its aim to shift to renewable feedstocks for chemicals echoes the same need for plastics.

 

The Ellen MacArthur Foundation has been on this journey for a few years now, but it is still very brief compared to the thousands of years of collective experience within the green chemistry community. To join the journey and continue to accelerate its momentum, we encourage the community to share its expertise and innovative ideas on how to rethink the future of plastics – its origins, its relationship to the user, and its destiny once used – with us.

 

As part the ‘innovation moonshots’ program, the Ellen MacArthur Foundation will launch two innovation challenges in the first half of 2017, aiming to address the identified need for fundamental redesign and innovation. We invite researchers, engineers and innovators across all disciplines to contribute to these challenges. But we also recognize that they are only a start – many similar efforts will be required. Innovation is unavoidably a bottom-up business, requiring a vibrant and diverse platform of research from which solutions for the future can emerge. This requires more researchers and engineers to participate in the innovation journey and more funders to finance their efforts.

 

While research funding is notoriously hard to come by, and competition for academic recognition fierce, momentum for a systemic rethink of plastics is growing. So perhaps stars are beginning to align for a virtuous circle of increasing research activities and funding which, provided firm and broad commitment, could lead to radical new innovation in coming years. At any rate, given the current increasing interest and sense of urgency for a systemic rethink to plastics production, it is safe to say that there is a great future in plastics – if you are a disruptive innovator.

 

 

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Contributed by Ed Brush, Professor of Chemistry, Bridgewater State University, ebrush@bridgew.edu, @GreenChemEd

 

Momentum is growing for the green chemistry education roadmap project (C&E News) and for the impact of systems thinking in chemistry education. As members of the chemistry enterprise continue to refine our future vision for chemistry education, we have a unique opportunity to make a contribution to these efforts in an exploration of the social and environmental justice issues that connect society with chemical exposure and the role of green chemistry in correcting unintended disparities.

 

As educators, many of us employ engaged learning as a high impact practice in our classes, where we guide students to explore topics on their own and take responsibility for their own learning. As educators, we can take advantage of conferences to challenge ourselves to explore new topics and share what we have learned with our colleagues. We investigate, share, accept feedback, and make revisions. We can then bring this back to our classes and generate new resources by collaborating with like-minded colleagues.

 

The idea of exploring green chemistry in the context of social and environmental justice (#GCSEJ) is new to many of us, but also provides a great opportunity to explore, learn, create and share (Open Education). Join the conversation and contribute!

 

  1. At the ACS National Meeting in San Francisco, Jane Wissinger and I are running a special session on #GCSEJ that is part of the “Green Chemistry: Theory and Practice” symposium on Sunday, April 2, 2017.
  2. The call for papers is now open for a multidisciplinary symposium on #GCSEJ at the 21st Annual Green Chemistry & Engineering Conference in Reston, Va. in June 2017. Grace Lasker and I are looking for speakers from a variety of disciplines to collaborate in: (1) sharing knowledge and experiences across disciplines and fields; (2) discussing strengths, weaknesses, opportunities and threats (SWOT); and (3) learning about educational strategies and resources. A potential outcome of these conversations is to place green chemistry in a more meaningful, relevant and accessible context that better connects scientists, non-scientists, students, teachers, thought leaders, policy-makers, business leaders, and community organizers in transdisciplinary teams to help form solutions that correct social and environmental disparities. Should you have a question about contributing an abstract, please feel free to contact Grace Lasker at glasker@uw.edu or Ed Brush at ebrush@bridgew.edu. The submission deadline is February 13, 2017.
  3. If you cannot attend either of these conferences, you can still contribute your thoughts and opinions on green chemistry in relation to social and environmental justice at this Google Form. Your responses will help frame our discussions at upcoming conferences.
  4. Finally, a number of chemists and green chemists are on Twitter. If you are so inclined, please use the hashtag #GCSEJ.

 

 

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Contributed by Joseph T. Grant, Graduate Research Assistant, Department of Chemistry, University of Wisconsin-Madison; Ive Hermans, Ph.D., Professor of Chemistry and Chemical & Biological Engineering, University of Wisconsin-Madison

 

Chemical catalysis plays an important role in employing green chemistry principles, most notably by improving reaction efficiencies. Improvements to reaction efficiency can tangibly come in numerous forms, including reducing the amount of energy delivered to heat a reactor and reducing the energy required to separate a desired reaction product from a reaction’s product mixture.

 

Emerging “on-purpose” propylene technologies are a contemporary example of catalysis development for the implementation of energy-efficient chemical processes. The recent surge in shale-gas production altered the landscape for the production of small olefins, especially ethylene and propylene, the no.1 and no. 2 most-produced organic chemicals worldwide, respectively.[1] Substitution of oil-derived naphtha by shale gas as the feedstock to steam crackers translates as an economical method to produce ethylene, yet the overall production of propylene from steam crackers has flat-lined as a result. With the ever-increasing demand for propylene, methods to produce propylene “on-purpose” rather than as a byproduct of steam cracking must emerge: The current “on-purpose” propylene technique, non-oxidative propane dehydrogenation, has significant process inefficiencies, including 1) unfavorable thermodynamics (endothermicity), requiring high reaction temperatures and propylene yields limited by equilibrium; 2) reactor down-time to regenerate the catalyst due to carbon deposits constantly forming on the catalyst surface; and 3) use of precious metal (Pt-based) or toxic (Cr-based) catalysts.

 

The oxidative dehydrogen of propane (ODHP, Scheme 1), however, provides practical solutions to all the process inefficiencies noted above. The inclusion of oxygen in the feedstream makes the reaction exothermic, driving down required reaction temperatures, and additionally eliminates the need for catalyst regeneration. However, inclusion of oxygen also results in the formation of unwanted CO and CO2 (COx) products, lowering the selectivity of the desired propylene product. Despite decades of research dedicated to catalyst development for ODHP, selectivity to propylene remains too low to be implemented in industrial applications. This lack of product control identifies the need for the discovery of alternative materials with the ability to better control this partial oxidation.[2]

 

scheme-1.pngWhile our research team explored an interesting discovery regarding enhanced two-dimensional dispersion of vanadium oxide on SiO2 [3, 4], we simultaneously sought out an inert material with high thermal conductivity to use as a diluent material in the catalyst bed (the area inside a tube reactor where the catalyst is present). The heat generated by the catalyst during exothermic reactions (like ODHP) must be uniformly distributed throughout a catalyst bed. In such circumstances, it is essential that a reactive catalyst be mixed with an inert thermal conductor to ensure constant temperature throughout a reactor bed. After reading literature describing the thermal conductive properties and chemical resistance of hexagonal boron nitride (hBN) [5], we decided to use it as a diluent in our reactor setup for ODHP. When performing control experiments loading hBN in our reactor to examine its inertness, we were amazed to see that hBN was not only reactive for ODHP, but that it actually yielded high selectivity to propylene and low selectivity to COx, something that traditional catalysts for ODHP have consistently struggled to do.

 

Considering this unexpected yet exciting result, we followed up with many ensuing experiments to both verify these results and further explore hBN as a catalytic material.[6,7] The selectivity to propylene offered by use of this non-toxic, metal-free, and relatively inexpensive material is among the highest reported for ODHP when compared to other state-of-the-art catalysts (Figure 1). An equally exciting observation is that the main byproduct when using hBN is ethylene rather than COx – the main byproduct of all previously studied catalysts for ODHP. Use of boron nitride nanotubes (BNNT), best described as a hollow cylinder of hBN, results in almost identical product selectivities to hBN, yet is much more reactive. The increased reactivity of BNNT over hBN is at least partially due to the higher surface area exhibited by BNNT, resulting in an intrinsically higher amount of catalytic active sites.

 

fig-1.pngBy altering the concentrations of the propane and oxygen reactants and observing the response to the rate of propane consumption, we determined a rate law that suggested adsorbed oxygen sites on the hBN surface are responsible for propylene formation. Considering this insight, taken with previous literature suggesting stable oxygen sites on the armchair-termination edges of BN [8], we performed density functional theory (DFT) calculations on potential reaction intermediates that form during the ODHP reaction. Our current hypothesis is that following the initial H-atom abstraction by the O-terminated armchair site, the stabilization of the formed propyl radical (•C3H7) by an edge nitroxyl radical is the key to the observed high olefin selectivity (Figure 2). Traditional metal oxide catalysts may not as easily stabilize the highly reactive propyl radical and instead remain in the gas phase, free to react with O2 and contribute to the substantial production of unwanted COx.

fig-2.png

 

Reactivity of hBN was confirmed across three separate reactor setups and with three separate gas-chromatographs to quantify reaction products. To be sure potential metal impurities of the hBN material were not responsible, reactivity was reproduced among various hBN batches acquired by different chemical suppliers. We used inductively coupled plasma mass spectrometry (ICP-MS) to search for potential metal impurities in each hBN sample, and revealed that it must be only the boron, nitrogen and oxygen atoms responsible for reactivity.

 

Efforts are ongoing between our lab and collaborators to perform a techno-economic analysis of ODHP on a large scale using selectivities currently offered when using hBN. This analysis will be used to determine thresholds that must be met in order to realize commercial implementation. Our lab is also in the process of broadening the substrate scope beyond propane and expanding use of hBN as a partial oxidation catalyst for other small alkanes. It is our hope that this discovery of hBN as a catalyst (and the further improvements that will surely follow) will help eventually lead to industrial-scale implementation of these efficient partial oxidation technologies.

 

[1] Sattler et. al.; Chem. Rev., 114, 2014, 114, 10613-10653.

[2] Cavani et. al.; Catal. Today, 2007, 127, 113-131.

[3] Grant et. al.; ACS Catal., 2015, 5, 5787-5793.

[4] Grant et. al.; US Patent Application #2016/0228851A1, 2016.

[5] Liu et. al.; Nat. Commun. 2013, 4, 2541.

[6] Grant et. al.; Science, 2016, 354, 1570-1573.

[7] Grant et. al.; US Patent Application #15/260,649, 2016.

[8] Lopez-Bezanilla et. al.; J. Phys. Chem. C, 2012, 116, 15675-15681.

 

 

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Contributed by Cheng-Wei Lin, Ph.D. candidate; Department of Chemistry and Biochemistry, University of California, Los Angeles; Bu Wang Ph.D.; Department of Civil and Environmental Engineering, University of California, Los Angeles; Richard Kaner, Distinguished Professor; University of California, Los Angeles; and Gaurav Sant, Associate Professor, University of California, Los Angeles

 

Scientists and engineers at the University of California, Los Angeles (UCLA) are developing an innovative way of embedding carbon dioxide (CO2) into concrete. Specifically, the process secures CO2 produced by power plants, cement plants, and other point-source emitters, and embeds it into 3D-printed building materials and components. The work seeks to mitigate the CO2 impact of cement production [N.B.: upon mixing with sand, stone and water, cement forms a “composite” referred to as ‘concrete’], which currently accounts for nearly 9 percent of anthropogenic CO2 emissions. In light of the ever-increasing demand for concrete worldwide (e.g., in China and India), it is crucial, now more than ever, to address the environmental impact of this ubiquitous building material.

 

fig-1.pngTo alleviate the CO2 emissions associated with cement production – the most CO2-intensive component in concrete – we designed a closed-loop process for manufacturing building materials as shown in Figure 1 [1]. First, quarried limestone (CaCO3) is calcined to produce lime (CaO) – a process that releases the mineralized CO2 embedded within it. Second, lime is reacted with water to form portlandite (Ca(OH)2), which is then mixed into slurry with sand, mineral aggregates, water, and performance modifying agents. The slurry can be formed into modular structural elements, such as beams and columns, using advanced shape stabilization methods like 3D printing. Finally, the shaped-stabilized structural elements are reacted with the CO2 released during calcination, or from other point-source emitters (e.g., coal and natural gas power plants) to produce the building components from CO2NCRETETM. This process of re-embedding mineralized CO2 within building materials not only reduces the effective CO2 emissions creating a cementing agent with greatly reduced CO2 impact, but also acts to reduce the impacts of electricity generation using fossil-fuels.

 

Though a related year-long approach has been attempted recently in Iceland, our team at UCLA was able to accelerate the carbonation process at near-ambient conditions in terms of temperature and pressure, thereby offering new, beneficial routes for the practical and economical use of CO2. In addition, by sourcing lime from industrial alkaline waste streams, a negative life-cycle carbon footprint can be achieved. This technology seeks to re-imagine how we perceive and address the emissions of greenhouse gases (GHGs) associated with process intensive industries today.

 

Beyond the realization of a new building material, the broader “Carbon Upcycling” effort emphasizes a vital need for technology integration and value creation. While membrane technologies are used for the capture and enrichment of CO2, 3D printing has proven an efficient method to fabricate building components like beams, columns and slabs. But 3D printing has not yet impacted the construction industry despite its aggressive adoption by various industries and even for personal use. Therefore, as a lab scale proof-of-concept, our team at UCLA has 3D-printed a beam several centimeters in length, composed of our new construction material. The Lego-like 3D-printed building blocks offer greater design flexibility and ease in on-site assembly, offering newfound efficiency for construction operations. The present challenge lies in scaling 3D printing building blocks up from centimeters to meters in size, and then to tens of meters as required for practical buildings, roads and bridges.

fig-2.png

Our “Carbon Upcycling” team – comprised of an interdisciplinary group of UCLA researchers led by Gaurav Sant, Associate Professor; Henry Samueli, Fellow in Civil and Environmental Engineering; Richard Kaner, Distinguished Professor in Chemistry & Biochemistry and Materials Science & Engineering; Laurent Pilon, Professor in Mechanical & Aerospace Engineering and Bioengineering; J. R. DeShazo, Professor of Public Policy at the Luskin School of Public Affairs; and Mathieu Bauchy, Assistant Professor of Civil & Environmental Engineering – has recently advanced to the semi-finals of the NRG COSIA Carbon XPRIZE competition. This competition challenges and stimulates people to respond to the global issue of CO2 emission. As such, our team is in the midst of transitioning its technology from the laboratory-scale to the pilot-scale by demonstrating the ability to scale up: (1) CO2 separation and enrichment, (2) the carbonation of large volumes of portlandite, and (3) the size of the 3D printed CO2NCRETETM building blocks – all while minimizing the overall consumption of water and electricity.

 

Our team has made substantial progress so far, and seeks to make transformative contributions to how CO2 management is approached by the construction sector. Indeed, this style of breakthrough advancement can only be realized when a highly motivated team from different disciplines comes together to solve important problems of global and societal relevance. We look forward to bringing sustainable building materials like CO2NCRETETM to fruition, an outcome enabled and promoted by green chemistry at large.

 


[1] K. Vance, G. Falzone, I. Pignatelli, M. Bauchy, M. Balonis, G.Sant, “Direct Carbonation of Ca(OH)2 Using Liquid and Supercritical CO2: Implications for Carbon-Neutral Cementation,” Industrial & Engineering Chemistry Research. 2015, 54(36), 8908-8918.

 

 

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News Roundup Jan14-27.jpgTarget Tightens Grip Over Chemicals in Bid to Make Goods Safer

January 25, 2017 | Bloomberg

Target Corp. introduced a sweeping new policy governing chemicals in products, a move that will push hundreds of suppliers to list ingredients in everything from fragrances to floor cleaner.

 

Carbios Develops Technological Solution to Recycle Opaque Plastics

January 25, 2017 | Packaging Business Review

According to the company, the process showed depolymerization of PET based commercial products, including bottles, packaging and films, into their original monomers such as terephthalic acid (TPG) and mono ethylene glycol (MEG).

 

Peer-driven Occupational Change and the Emergence of Green Chemistry

January 19, 2017 | Administrative Science Quarterly

Using extensive interviews, archival data, and observations, researchers found that advocates of green chemistry simultaneously advanced different frames, or ways of presenting green chemistry that resonated with a diversity of roles in the chemistry community. Further discussion on the resulting tensions between frames clarifies how a diverse message can both help and hinder behavior change.

 

Chemical Regulation: EPA Cranks Out Toxics Rules During Obama’s Last Days in Office

January 17, 2017 | C&EN

The office has been feverishly working to ensure that it meets several upcoming deadlines under the revised Toxic Substances Control Act. It has also been pushing out several proposed rules under TSCA that would ban or restrict certain uses of some high-risk solvents.

 

Researchers Derive Valuable Chiral Amino-Alcohol Structures from CO2

January 16, 2017 | Phys.org

Researchers at the Institute of Chemical Research of Catalonia (ICIQ) in Tarragona have developed new methodologies to convert small molecules like CO2 and other waste gases into useful chemicals. In previous work, they developed various catalytic routes to functional cyclic carbonates using carbon dioxide and easily accessible chemicals. Kleij and coworkers made these transformations possible with cheap and sustainable iron and aluminum catalysts.

 

 

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News Roundup Jan28-Feb3.jpg

Green Chemistry Professor Among Victims of Quebec City Mosque Shooting

January 31, 2017 | Chemical and Engineering News

Khaled Belkacemi, 60, was a professor of soil and agri-food engineering at Laval University. He earned his bachelor of science in chemical engineering from Polytechnic School of Algiers in Algeria in 1983 and graduated with a PhD from Sherbrooke University in 1990. He will be greatly missed by the chemistry community.

 

Synthesis of Graphene from Renewable Soybean Oil Could Cut the Cost of Production Ten-Fold

January 30, 2017 | ABC News

An everyday cooking oil has been used to make graphene in a lab — a development scientists said could significantly reduce the cost and complexity of making the super-substance on a commercial scale.

 

Target to invest $5 million in Green Chemistry Innovation by 2022

January 30, 2017 | Fibre 2 Fashion

In addition to improved transparency and responsible sourcing from their suppliers, Target plans to invest in research towards the reduction of harmful toxins in their products through green chemistry.

 

IN CASE YOU MISSED IT:

 

Engineering Green Biocatalysts for Chemical Reactions Not Known in Biology

California Institute of Technology | The Nexus Blog

Many catalysts that facilitate enantioselective bond formation are made from rare and non-renewable materials, such as palladium or rhodium; replacing these catalysts with renewable alternatives would allow for the more environmentally-friendly production of key chemicals.  Researchers at CIT believe that enzymes can meet this acute need for new, low-cost, sustainable catalysts, and in doing so, further advance and expand green chemistry.

 

CO2 Capture and Conversion into Concrete for Sustainable Construction

University of California, Los Angeles | The Nexus Blog

Scientists and engineers at the University of California, Los Angeles (UCLA) are developing an innovative way of embedding carbon dioxide (CO2) into concrete. Specifically, the process secures CO2 produced by power plants, cement plants, and other point-source emitters, and embeds it into 3D-printed building materials and components.

 

The Great Future in Plastics

The Ellen MacArthur Foundation | The Nexus Blog

In the past 50 years, total plastics production has seen a 20-fold increase, and today almost everyone everywhere encounters them every day. They have become the workhorse materials of the modern economy, combining unrivaled functionality with low cost.

 

 

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News Roundup Feb4-10 v2.jpgWhat's New in Cosmetic Green Chemistry?

February 9, 2017 | Cosmetics Design

Cosmetics Design interviews Dr. Barbara Olioso, founder of The Green Chemistry Consultancy, to get her take on the latest in green cosmetics chemistry.

 

Sodium Benzoate as an Alternative to Biocides

February 8, 2017 | C&EN

As retailers and product formulators band together to find new cosmetic preservatives, Emerald Kalama Chemical is investing in 50-year-old sodium benzoate, calling it a safe, readily available alternative for a number of biocides under fire.

 

NSERC Steacie Memorial Fellowship goes to McGill Chemistry Professor

February 7, 2017 | McGill University

Tomislav Friščić was awarded a two-year, $250,000 fellowship to support research into greener chemistry. His research group plans to “focus fully on developing 'Chemistry 2.0' – a cleaner, solvent-free system of chemical synthesis that could replace traditional solvent-based approaches in research and industry.”

 

Alternative to Formaldehyde 5-HMF Could Create Bio Based Industrial Adhesive

February 6, 2017 | Specialty Chemicals Magazine

Avalon Industries is launching a research project to replace formaldehyde with bio-based, non-toxic 5-HMF (5-hydroxymethylfurfural). The project focuses on resins for the furniture industry, although the research is relevant to several sectors that might employ 5-HMF as a substitute for formaldehyde, e.g. as an active ingredient in the pharmaceutical and agrochemical sectors, or in the manufacture of textiles, bottles or food packaging.

 

 

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Contributed by Amanda Morris and Lauren Winstel, Research Assistants, ACS Green Chemistry Institute®

 

Fig1-helium.pngAs the second most abundant element in the universe, it seems strange to think of helium as endangered. The gas has a wide variety of uses, from cryogenics (think super-cooling MRI magnets) to SCUBA diving equipment [1] (See Figure 1). The problem: Unlike most other elements, helium is so light, it escapes the Earth’s atmosphere with ease, and thus the supply is being constantly depleted.

 

On Earth, helium is a result of the naturally occurring radioactive decay of uranium and thorium [2],[3]. Some of that helium is trapped along with natural gas in the Earth’s mantle. Helium, at concentrations as high as seven percent, may be separated from natural gas via fractional distillation during routine processing.  However, these concentrations are often much lower, with current technology only allowing helium extraction to occur in natural gas wells containing 0.3 percent or greater concentrations of helium[4].

 

The United States currently controls the world’s largest helium supply, the National Helium Reserve, in Amarillo, Texas. The Helium Act of 1925 created this reserve to ensure provisions for airships and the U.S. Navy. This strategic supply then became integral to the Space Race and the Cold War in the 1950s and 1960s.

Today, the natural geologic gas storage in Amarillo – the Bush Dome Reservoir – holds 670 million cubic meters of helium. As a frame of reference, that is enough helium to fill the Goodyear blimp almost 8,000 times[5]! The U.S. Geological Survey (USGS) estimates the total helium resources within the United States to be 20.6 billion cubic meters1. Globally, that number increases to 51.9 billion cubic meters.

 

With that much estimated helium in reserve, why should anyone worry?  Let’s take a closer look. One potential way of looking at this abundance is to consider resource availability and production viability over the long term. In 2014, the U.S. extracted 76 million cubic meters of helium from natural gas and withdrew 24 million cubic meters from storage[6] – or in terms of percentages, approximately 0.49 percent of total known U.S. resources in a single year. Of these 100 million cubic meters of helium, 43 million were consumed domestically, and the remaining 67 million cubic meters were exported. In 2015, the U.S. imported 7.4 million cubic meters in addition to its domestic production. Altogether, this usage percentage rate may seem low, but considering that the U.S. is the world’s largest supplier of helium, a deterioration rate of approximately one percent every two years might be a bit alarming. Consider that very little helium is recycled due to the cost of the machines needed to capture the gas. Most helium simply dissipates into the atmosphere after use, so there is no getting back the 0.49 percent that is lost each year. When extending this analysis to global statistics: 165 million cubic meters of helium were extracted or recovered in 2014, depleting global reserves by 0.32 percent.

 

fig2-helium.pngThis is arguably alarming in itself, but perhaps more so if one considers that helium demand is expected to increase. During 2014, helium consumption in the U.S. increased by 7.7 percent and is expected to continue to increase at a rate of about two percent per year3. Due to the lack of data on foreign markets, it is difficult to forecast global helium demands. However, the National Research Council estimates that global demand will increase approximately three percent annually through 2020 (See Figure 2).

 

With helium reserves being depleted annually, questions over future supplies arise, and unfortunately, there are no easy solutions. Helium is a finite resource; once gone, it will take millions of years to replenish. Our current technology does not allow us to artificially produce helium, nor can we extract helium from the atmosphere[7]. There are, however, options to reduce our reliance on helium production.

 

One possible option is to raise the price of helium, which will cause the element to become too expensive to waste. In 2015, the price of helium for government users was $3.06 per cubic meter ($85 per thousand cubic feet). The price increased by 69 cents for non-government users. Helium is inexpensive due in part to the Helium Privatization Act (HPA) of 1996 and the Helium Stewardship Act (HSA) of 2013. The HPA was passed to recoup the original cost of obtaining the reserve ($1.3 billion). This act required helium stores to be sold off at a fixed rate by 2015, regardless of market value. The HSA was passed in 2013 to increase the market price of helium and reduce helium waste. Unfortunately, the price of helium has not risen at the expected rate[8].

 

Nobel Laureate Robert Richardson[9] states the price of helium should be raised by 20- and 50 -fold to make recycling worthwhile[10]. While the helium used in magnetic resonance imaging (MRI) is occasionally recycled, most large volume applications do not recycle helium.

 

The greatest concern in regard to the future inability to extract helium is how heavily mankind relies on the element. Helium’s primary use is cooling the superconducting magnets located in MRIs and nuclear magnetic resonance (NMR) scanners. Additionally, researchers across the physical sciences and engineering disciplines rely heavily on liquid helium to perform experiments and maintain instruments. There is currently no substitute, neither elemental, chemical nor synthetic, for this purpose. This is due to helium’s extremely low boiling point, 4.2 K, just four degrees short of absolute zero. If helium is not available for use in NMR and MRI machines, scientists will have to invent new ways of imaging to support modern medicine.

 

With between 25 to 50 years of helium remaining, it is clear we need to rethink its consumption. As chemists and scientists, we are at a critical point and uniquely poised to alleviate this problem based on how we use and reuse helium, and all the chemical processes we synthesize related to this element. It is our duty and responsibility to ask how we can improve – for ourselves and for our children – because if we do not, who will?

 


[1] https://minerals.usgs.gov/minerals/pubs/commodity/helium/mcs-2016-heliu.pdf

[2] Nature 179, 213 (26 January 1957); doi:10.1038/179213a0

[3] http://journals.aps.org/pr/abstract/10.1103/PhysRev.74.1590

[4] https://www.aps.org/policy/reports/popa-reports/upload/HeliumReport.pdf

[5] http://www.goodyearblimp.com/behind-the-scenes/current-blimps.html

[6] https://minerals.usgs.gov/minerals/pubs/commodity/helium/myb1-2014-heliu.pdf

[7] https://phys.org/news/2010-08-world-helium-nobel-prize-winner.html

[8] http://www.sciencemag.org/news/2015/07/new-us-rules-helium-sales-said-stifle-com petition

[9] https://www.nobelprize.org/nobel_prizes/physics/laureates/1996/press.html

[10] http://www.zmescience.com/science/chemistry/wasting-helium-recycle-052543/

 

 

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Contributed by Xijie Dai, M.Sc., Ph.D. candidate; Haining Wang; and Chao-Jun Li, Ph.D.; McGill University

 

scheme1-mcgill.pngSecondary and tertiary alcohols, especially chiral ones, are important chemical building blocks found in various biologically active complex molecules, natural products and fine chemicals. The traditionally most well-established approaches toward such alcohols rely mainly on the use of highly nucleophilic and basic organometallic reagents (i.e., organolithium and organomagnesium reagents) (Scheme 1, a). Such an approach requires excessive amounts of metal (magnesium, lithium, zinc, etc.) and pre-synthesized organohalides to produce alcohols. The stoichiometry of organometallic reagents raises concerns as it implies inefficiency and stoichiometric waste. Organohalides, on the other hand, are mostly manufactured from small petrochemicals despite their commercial availability and broad utilization in the synthetic community. Furthermore, the often high reactivity of the organometallic reagents renders them incompatible with water and many functional groups (alcohol, halides, esters, acids, amines, amides, nitrile, nitro, etc.), necessitating “protection” and “deprotection.”

 

Recently, researchers from McGill University in Canada have made a breakthrough that serves as an alternative to the classical, organometallic reagent-based, nucleophilic carbonyl addition reactions (e.g., the Grignard reaction) for alcohol synthesis. This novel reaction – that appeared in Nature Chemistry – highlights an efficient alkylation process based on two different carbonyl compounds that form new carbon-carbon bonds: Naturally prevailing (or readily available) carbonyl compounds were used as surrogates for alkyl carbanions to react with other carbonyl compounds in this reaction to produce a wide range of alcohols with great efficiency. This transformation is mediated by hydrazine and is catalyzed by a ruthenium catalyst under mild conditions (45 degrees Celsius), producing water and N2 as its stoichiometric waste (Scheme 1, b).

 

The most innovative aspect of this reaction lies in the formal umpolung reactivity of carbonyl functionalities, meaning that the polarity of the carbon in the carbonyl functionality is inverted from electrophilic (natural chemical reactivity) to nucleophilic. This was done by the formation of hydrazones from carbonyl compounds. Using a phosphine-bound, ruthenium-based catalyst; a base; and a reaction additive, hydrazones (preformed or generated in situ from aldehyde and hydrazine) can react with a broad spectrum of carbonyl compounds to produce secondary or tertiary alcohols in moderate to excellent yields. By simply switching the racemic phosphine ligand to the chiral ones, this reaction could yield enantioenriched tertiary alcohols. The weak base potassium phosphate and the additive cesium fluoride are also key ingredients to maximize efficiency.

 

One striking feature of this carbonyl-derived carbanion is its excellent chemoselectivity when present alongside other functional groups in the same molecule. This is distinct from classical organometallic reagents, which often find themselves incompatible with basic labile functionalities. In fact, it is extremely important for carbanion equivalents to have good chemoselectivity so that structurally complex alcohols can be obtained via carbonyl addition reactions. There are two reasons for this: (1) a shortened synthetic route could be designed for more efficient CC bond formations by stitching together larger pieces of carbonyl-containing molecules; (2) complex molecules bearing previously indistinguishable functional groups (e.g., esters, nitriles, alcohols, etc.) could be selectively alkylated on carbonyl functionalities at a later stage.

 

As it stands, certain aspects of this reaction – such as the safety and toxicity issues with hydrazine as well as the rarity and relatively high cost concerns associated with precious metal catalyst ruthenium – preclude it from being ideal in green chemistry and render the opportunity for further improvement. Nevertheless, it does open an avenue for converting naturally occurring carbonyl functionalities to carbanion equivalents, which is a stepping-stone toward more sustainable carbon-carbon bond-forming processes. Indeed, we believe that some of the aforementioned concerns can be addressed via further modification of the metal catalyst (by, for instance, using earth-abundant metals and via catalyst immobilizations) or the reducing reagent. Unlike copious metal waste generated in other organometallic addition reactions, this reaction’s production of only innocuous by-products (e.g. N2 and H2O), its relatively mild reaction conditions, and its tolerance toward a wide range of functional groups (as well as air and water), makes it attractive to researchers across academia and industry.

 

 

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Contributed by Mark Evans, Founder and Chief Executive Officer of Camston Wrather

 

The prior installment of this series (Part 1) touched on the consumption and disposal volumes of electronic waste (e-waste) and its impacts. This article will cover a technical overview of current resource recovery methods, both formal and informal.

 

pic-1-cw.pngMetal Fractions (MF) and Non-Metal Fractions (NMF)

 

Most electronic devices contain printed circuit boards (PCBs) that are generally composed of a non-conducting substrate laminate, printed conducting tracks, and smaller electronic components mounted on the PCB. The substrate is primarily composed of glass fiber reinforced with epoxy resin, or paper reinforced with phenolic resin. Both substrates are covered with a brominated flame retardant, which protects the PCBs when the components are assembled to the boards in the manufacturing theater. Taken as a whole, there are basically two types of recyclable materials in PCBs: The first is the metal fraction (MF), such as Cu, Fe, Sn, Ni, and Zn; and the second is the non-metal fraction (NMF), such as polymers, glass and ceramic materials. However, it is the presence of the precious metals Au, Ag, Pt, and Pd that makes PCB recycling attractive and economical.

 

Formal Recycling

 

In general, the formal recycling of PCBs follows three stages: comminution (dismantling, milling, grinding, and/or magnetic separation), followed by either thermal (heat) processing (pyrometallurgical) or non-thermal processing (hydrometallurgical). The ideal goal of the first stage is to liberate the MFs from the NMFs, which is critical to further downstream treatment.

 

Comminution

pic-2-cw.pngThe two main types of PCBs are made of glass fiber reinforced with epoxy resin, commercially referred to as (FR-4), and cellulose paper reinforced phenolic resin (FR-2). Both types of PCBs can contain the following thermoplastic resins: Polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), and polystyrene (PS).

 

Whether mining metals from ore or PCBs, the beneficiation process is similar. Raw materials are identified, secured, transported, classified, and milled, resulting in a concentrated feedstock. Milling requirements vary for different types of complex or refractory ores, and the same is true of PCBs. However, whereas ores are readily reduced in size through traditional milling technology, the same is not true for PCBs.

 

pic-3-cw.pngAll polymer thermoplastics have a different “glass temperature,” i.e., the point at which the polymer becomes brittle, amorphous or crystalline. In the current recycling of PCBs, separating the metal fractions (MFs) from the various types of polymers (NMFs) becomes problematic because the mechanical engineering and milling threshold of the equipment cannot completely account for the glass temperatures associated with the various polymer substrates. (Fig. A) In short, the target metals are not fully liberated from the polymer substrate and are discarded with the NMFs, resulting in a 10 to30 percent loss in metal revenue.

 

Moreover, an additional five to 20 percent of target metal loss can occur through magnetic separation. Magnetic separation is a means to liberate the ferrous metal fractions from the non-ferrous metals after grinding and is universally practiced in PCB recycling. However, very little research exists addressing the unique phenomenon of gold particles being magnetized during separation. Figure B depicts the phenomenon of gold being magnetically attracted to a neodymium magnet. Although gold is not magnetic, Au-Cu-Fe plating and/or Au-Ni alloys are often used in electronics, which would account for some of the ferromagnetic attraction. Still, pure gold and other non-magnetic metals can be electrostatically charged during the grinding and milling stages producing MF loss. Comminution, as a stand-alone mechanical-physical recycling technology, is not an effective or reliable process for the production of single stream recycled metals.

 

Pyrometallurgical Processing

 

Pyrometallurgical processing is the traditional approach for metal recovery from PCBs. Pyrometallurgical techniques include incineration, sintering,plasma arc smelting, blast furnace or copper smelting, and high temperature gas roasting. Currently, more than 70 percent of PCBs that are formally recycled are treated in smelters rather than through mechanical-physical processing. This is an important distinction and the most salient point of this installment:

 

Of the 15 percent of e-waste that is recycled (6.3 million metric tons), approximately 70 percent (4.41 million metric tons) of it is processed using incineration or pyrometallurgical processing, leaving approximately 1.89 million metric tons to be recycled through hydrometallurgical or other technologies.

 

Note: The remaining balance of 85 percent of PCB waste never enters any stage of formal recycling at all.

 

The downside of the pyrometallurgical approach is the large amount of waste water that needs to be treated, the lack of recycling of any of the plastic polymers, an efficient Fe and Al oxide recovery process, hazardous emissions of dioxins as a result of burning plastic polymers, and the large amount of capital investment and energy required during processing.

 

Hydrometallurgical Processing

 

Traditional hydrometallurgy processes involve using acids and other lixiviants – such as sulfate, chloride, iodide, ammonia, and thiourea – in order to leach metals from PCBs. Aggressive acids like nitric acid and nitric acid in combination with hydrochloric acid (aqua regia) are often used in the digestion of base and precious metals from PCBs. Hydrometallurgical processes can offer high metal recoveries suitable for small-scale applications, however, there has been no multi-location rollout based solely on any one hydrometallurgical method.

 

Cyanide leaching of precious metals has been used for more than a century due to the selectivity and stability of the dicyanoaurate complex. It should be pointed out that although the affinity of cyanide for gold is preferential, cyanide will also form complexes with other MFs in PCBs, including Cu, Fe and Zn. The formation of strongly bound complexes such as those with iron and copper will tie up cyanide that would otherwise be available to dissolve gold and require higher cyanide concentrations and costs.

 

A routine search on YouTube will yield countless videos of backyard hobbyists attempting to extract gold from e- waste using nitric acid and other chemical compounds. Dissolving metals or reacting organics in nitric acid can release toxic gases. Attempting to dissolve e-waste in a closed container to mitigate those toxic gases will form toxic nitrosyl chloride, nitrogen dioxide, and deadly chlorine gases. These gases will pressurize in the container and ultimately lead to an unfavorable outcome.

 

The fundamental reasons limiting the commercial multi-location roll-out of nitric acid or cyanide processing plants for PCB recycling is: 1) they are difficult to safely scale or even to permit; 2) the disposal and neutralization of NOx gases, waste water, and byproducts is not economically feasible; and 3) both processes have major toxicity concerns that can cause environmental and worker safety concerns.

 

Informal Recycling

pic-4-cw.png

 

As previously reported, it is estimated that a total of 700,000 workers are employed in the informal e-waste collection and recycling industry in developing countries. The backyard operations in Asia and Africa – especially in China, India and Ghana – are problematic because of the adoption of primitive recycling techniques that lead to hazardous elements being released into the environment. Lack of access to appropriate technologies and methodologies, and an infrastructure capable of handling the increasing volumes of PCB scrap, directly leads to the release of dioxins and furans formed during the open-air burning of waste PCBs.

 

In the last few years, a number of articles have been published on the adverse health effects (such as abnormalities in thyroid function, decreased lung function, premature birth, reduced birth weights and lengths, genotoxicity, and adverse neonatal outcomes) caused by exposure to informal PCB recycling. The proper disposal and recycling of PCB waste is currently a concern, not only because of the large volumes generated, but also because of the heavy metals and toxic substances that PCB waste contains. If not properly treated and disposed of, toxic heavy metals like Pb, Cd, Hg, As, and Cr can be released into the environment. Lui, et al., reported that PCB recycling workers had 20-fold higher chromosomal aberrations than those not exposed to informal recycling.

 

Looking forward, the next installment will address the need for a more systematic, eco-friendly and multi-disciplinary approach to processing PCB waste streams in which the MFs as well as the NMFs can be recycled while imparting minimum impact on workers and the environment.

 

pic-5-cw.png

 

Mark Evans is the Founder and Chief Executive Officer of Camston Wrather and a University of California at Berkeley, Alumni.

Connect with author on LinkedIn.

 

 

 

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It is my pleasure to return to the ACS Green Chemistry Institute® as a result of the organizational realignment announced last month by ACS Executive Director and Chief Executive Officer Tom Connelly. The ACS GCI is part of the newly formed Scientific Advancement Division, which also includes the Office of Research Grants, ACS technical divisions, and technical programming at ACS National Meetings. This new structure will enable the Society to address its mission “to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and its people” by better coordinating and focusing its activities related to advancing the chemical sciences.

 

While much has changed since I served as Assistant Director of the Institute from 2001-2004, several key initiatives remain strong. The Presidential Green Chemistry Challenge Awards continue to recognize outstanding green chemistry technologies through the partnership between the U.S. Environmental Protection Agency and the ACS Green Chemistry Institute®. The Institute awards the Ciba Travel Awards in Green Chemistry, Joseph Breen Memorial Fellowship and the Kenneth G. Hancock Memorial Award to students for their outstanding contributions to green chemistry. The annual Green Chemistry & Engineering Conference, now in its 21st year, saw record attendance last year in Portland, Oregon. The call for papers for this year’s conference is open through Monday, February 13, and I encourage you to submit a paper aligned with the symposia themes.

 

A critical ACS GCI initiative in recent years has been the creation of Roundtables, which are designed to accelerate industrial adoption of green chemistry. Current Roundtables address five key areas of the chemistry enterprise: Pharmaceuticals, formulators, chemical manufacturers, hydraulic fracturing, and biochemical technology. The Roundtables have been very effective in identifying research needs within their respective sectors and developing tools and strategies to address these needs.

 

I am delighted that ongoing support from the ACS Petroleum Research Fund will enable the ACS Summer School on Green Chemistry and Sustainable Energy to be held once again at the Colorado School of Mines, from June 20-27, 2017. The Summer School is the highlight of my professional year thanks to the commitment to and passion for green chemistry and sustainability demonstrated by the graduate students and postdoctoral scholars who participate in this program. The future of chemistry is in good hands!

 

Another education initiative of the ACS Green Chemistry Institute® is the Green Chemistry Education Roadmap. Two workshops held in 2016 produced draft green chemistry core competencies, which have recently been revised in response to stakeholder input. These competencies will serve as the foundation for the roadmap, and we will be seeking additional input from the community in the coming months.

 

I have much to learn in my new role at ACS and I would encourage you to share your ideas regarding all aspects of the ACS Green Chemistry Institute® with me at m_kirchhoff@acs.org. Thank you and I look forward to hearing from you.

 

All the best,

 

Mary-Signature.png

 

 

“The Nexus Blog” is a sister publication of “The Nexus” newsletter. To sign up for the newsletter, please email gci@acs.org, or if you have an ACS ID, login to your email preferences and select “The Nexus” to subscribe.

 

To read other posts, go to Green Chemistry: The Nexus Blog home.

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