Professor Fernando Uribe-Romo and his team of students created a way to use LED light and a porous synthetic metal-organic frameworks (MOF) material to break down carbon dioxide into fuel. (credit: Bernard Wilchusky/UCF)
A University of Central Florida (UCF) chemistry professor has invented a revolutionary way to remove carbon dioxide (CO2) from air by triggering artificial photosynthesis in a synthetic material — breaking down carbon dioxide while also producing fuel for energy.
UCF Assistant Professor Fernando Uribe-Romo and his students used a synthetic material called a metal–organic framework (MOF), which converts carbon dioxide into harmless organic materials — similar to how plants convert CO2 and sunlight into food.
Scientists have been pursuing this goal for years, but the challenge is finding an economical way for visible light to trigger the chemical transformation. Ultraviolet rays have enough energy to enable the reaction in common materials, but UVs make up only about 4% of the light Earth receives from the Sun. For the lower-energy visible range, there are only a few materials that work, such as platinum, rhenium and iridium, but these are scarce and expensive.
New material converts CO2 to fuel
The solution was to combine cost-effective titanium with a highly porous metal–organic framework (MOF) material for light harvesting. (MOFs are used in the MIT-UC Berkeley system for condensing water out of air, also using only sunlight, as described recently on KurzweilAI.) The light-harvesting molecules, called N-alkyl-2-aminoterephthalates, can be designed to absorb specific colors of light when incorporated in the MOF — in this case, the color blue.
CO2 removal process. Blue light combined with a metal–organic framework (MOF) material causes CO2 to convert to formate, a fuel. (credit: adapted from illustration by Matthew W. Logan et al./ Journal of Materials Chemistry A)
In an experiment, the research team assembled a blue LED photoreactor — a glowing blue cylinder that looks like a tanning bed, using strips of LED lights inside the chamber of the cylinder to mimic the sun’s blue wavelength — and fed in CO2. The CO2 was found to convert into two modified forms of carbon — formate and formamides (two kinds of solar fuel) — and in the process, cleaning the air.
Uribe-Romo plans to continue to fine-tune the approach to create greater amounts of modified CO2 so it is more efficient and to see if other wavelengths of visible light may also trigger the reaction, with adjustments to the MOF material. If the process works efficiently, it could be a significant way to help treat greenhouse gases, while also creating a clean way to produce energy, says Uribe-Romo.
Rooftop shingles to clean air and power homes
“The idea would be to set up stations that capture large amounts of CO2, like next to a power plant. The gas would be sucked into the station, go through the process and recycle the greenhouse gases while producing energy that would be put back into the power plant.”
He also speculates that someday, homeowners could purchase rooftop shingles made of the MOF material, which would clean the air in their neighborhood while producing energy that could be used to power their homes.
The research findings are published in the Journal of Materials Chemistry A. Researchers at Florida State University also helped interpret the results of the experiments.
Abstract of Systematic Variation of the Optical Bandgap in Titanium Based Isoreticular Metal-Organic Frameworks for Photocatalytic Reduction of CO2 under Blue Light
A series of metal-organic frameworks isoreticular to MIL-125-NH2 were prepared, where the 2-amino-terephthalate organic links feature N-alkyl groups of increasing chain length (from methyl to heptyl) and varying connectivity (primary and secondary). The prepared materials display reduced optical bandgaps correlated to the inductive donor ability of the alkyl substituent as well as high photocatalytic activity towards the reduction of carbon dioxide under blue illumination operating over 120 h. Secondary N-alkyl substitution (isopropyl, cyclopentyl and cyclohexyl) exhibit larger apparent quantum yields than the primary N-alkyl analogs directly related to their longer lived excited-state lifetime. In particular, MIL-125-NHCyp (Cyp = cyclopentyl) exhibits a small bandgap (Eg = 2.30 eV), a long-lived excited-state (τ = 68.8 ns) and the larger apparent quantum yield (Φapp = 1.80%) compared to the parent MIL-125-NH2 (Eg = 2.56 eV, Φapp = 0.31%, τ = 12.8 ns), making it a promising candidate for the next generation of photocatalysts for solar fuel production based on earth-abundant elements.
The radishes on the right were grown with the help of a bionic leaf that produces fertilizer with bacteria, sunlight, water, and air. (credit: Nocera lab, Harvard University)
Harvard University chemists have invented a new kind of “bionic” leaf that uses bacteria, sunlight, water, and air to make fertilizer right in the soil where crops are grown. It could make possible a future low-cost commercial fertilizer for poorer countries in the emerging world.
The invention deals with the renewed challenge of feeding the world as the population continues to balloon.* “When you have a large centralized process and a massive infrastructure, you can easily make and deliver fertilizer,” Daniel Nocera, Ph.D., says. “But if I said that now you’ve got to do it in a village in India onsite with dirty water — forget it. Poorer countries in the emerging world don’t always have the resources to do this. We should be thinking of a distributed system because that’s where it’s really needed.”
The research was presented at the national meeting of the American Chemical Society (ACS) today (April 3, 2017). The new bionic leaf builds on a previous Nocera-team invention: the “artificial leaf” — a device that mimics photosynthesis: When exposed to sunlight, it mimics a natural leaf by splitting water into hydrogen and oxygen. These two gases would be stored in a fuel cell, which can use those two materials to produce electricity from inexpensive materials.
That was followed by “bionic leaf 2.0,” a water-splitting system that carbon dioxide out of the air and uses solar energy plus hydrogen-eating Ralstonia eutropha bacteria to produce liquid fuel with 10 percent efficiency, compared to the 1 percent seen in the fastest-growing plants. It provided biomass and liquid fuel yields that greatly exceeded those from natural photosynthesis.
Fertilizer created from sunlight + water + carbon dioxide and nitrogen from the air
For the new “bionic leaf,” Nocera’s team has designed a system in which bacteria use hydrogen from the water split by the artificial leaf plus carbon dioxide from the atmosphere to make a bioplastic that the bacteria store inside themselves as fuel. “I can then put the bug [bacteria] in the soil because it has already used the sunlight to make the bioplastic,” Nocera says. “Then the bug pulls nitrogen from the air and uses the bioplastic, which is basically stored hydrogen, to drive the fixation cycle to make ammonia for fertilizing crops.”
The researchers have used their approach to grow five crop cycles of radishes. The vegetables receiving the bionic-leaf-derived fertilizer weigh 150 percent more than the control crops. The next step, Nocera says, is to boost throughput so that one day, farmers in India or sub-Saharan Africa can produce their own fertilizer with this method.
Nocera said a paper describing the new system will be submitted for publication in about six weeks.
* The first “green revolution” in the 1960s saw the increased use of fertilizer on new varieties of rice and wheat, which helped double agricultural production. Although the transformation resulted in some serious environmental damage, it potentially saved millions of lives, particularly in Asia, according to the United Nations (U.N.) Food and Agriculture Organization. But the world’s population continues to grow and is expected to swell by more than 2 billion people by 2050, with much of this growth occurring in some of the poorest countries, according to the U.N. Providing food for everyone will require a multi-pronged approach, but experts generally agree that one of the tactics will have to involve boosting crop yields to avoid clearing even more land for farming.
American Chemical Society | A ‘bionic leaf’ could help feed the world
A research team headed by Worcester Polytechnic Institute (WPI) scientists* has solved a major tissue engineering problem holding back the regeneration of damaged human tissues and organs: how to grow small, delicate blood vessels, which are beyond the capabilities of 3D printing.**
The researchers used plant leaves as scaffolds (structures) in an attempt to create the branching network of blood vessels — down to the capillary scale — required to deliver the oxygen, nutrients, and essential molecules required for proper tissue growth.
In a series of unconventional experiments, the team cultured beating human heart cells on spinach leaves that were stripped of plant cells.*** The researchers first decellularized spinach leaves (removed cells, leaving only the veins) by perfusing (flowing) a detergent solution through the leaves’ veins. What remained was a framework made up primarily of biocompatible cellulose, which is already used in a wide variety of regenerative medicine applications, such as cartilage tissue engineering, bone tissue engineering, and wound healing.
A spinach leaf (left) was decellularized in 7 days, leaving only the scaffold (right), which served as an intact vascular network. As a test, red dye was pumped through its veins, simulating blood, oxygen, and nutrients. Cardiomyocytes (cardiac muscle cells) derived from human pluripotent stem cells were then seeded onto the surface of the leaf scaffold, forming cell clusters that demonstrated cardiac contractile function and calcium-handling capabilities for 21 days. (credit: Worcester Polytechnic Institute)
After testing the spinach vascular (leaf vessel structure) system mechanically by flowing fluids and microbeads similar in size to human blood cells through it, the researchers seeded the vasculature with human umbilical vein endothelial cells (HUVECs) to grow endothelial cells (which line blood vessels).
The decellurize-recellurize process (credit: Joshua R. Gershlak et al./Biomaterials)
The future of ”crossing kingdoms”
These proof-of-concept studies may open the door to using multiple spinach leaves to grow layers of healthy heart muscle, and a potential tissue engineered graft based upon the plant scaffolds could use multiple leaves, where some act as arterial support and some act as venous return of blood and fluids from human tissue, say the researchers.
“Our goal is always to develop new therapies that can treat myocardial infarction, or heart attacks,” said Glenn Gaudette, PhD, professor of biomedical engineering at WPI and corresponding author of an open-access paper in the journal Biomaterials, published online in advance of the May 2017 issue.
“Unfortunately, we are not doing a very good job of treating them today. We need to improve that. We have a lot more work to do, but so far this is very promising.”
Currently, it’s not clear how the plant vasculature would be integrated into the native human vasculature and whether there would be an immune response, the authors advise.
The researchers are also now optimizing the decellularization process and seeing how well various human cell types grow while they are attached to (and potentially nourished by) various plant-based scaffolds that could be adapted for specialized tissue regeneration studies. “The cylindrical hollow structure of the stem of Impatiens capensis might better suit an arterial graft,” the authors note. “Conversely, the vascular columns of wood might be useful in bone engineering due to their relative strength and geometries.”
Other types of plants could also provide the framework for a wide range of other tissue engineering technologies, the authors suggest.****
The authors conclude that “development of decellularized plants for scaffolding opens up the potential for a new branch of science that investigates the mimicry between kingdoms, e.g., between plant and animal. Although further investigation is needed to understand future applications of this new technology, we believe it has the potential to develop into a ‘green’ solution pertinent to a myriad of regenerative medicine applications.”
* The research team also includes human stem cell and plant biology researchers at the University of Wisconsin-Madison, and Arkansas State University-Jonesboro.
** The research is driven by the pressing need for organs and tissues available for transplantation, which far exceeds their availability. More than 100,000 patients are on the donor waiting list at any given time and an average of 22 people die each day while waiting for a donor organ or tissue to become available, according to a 2016 paper in the American Journal of Transplantation
*** In addition to spinach leaves, the team successfully removed cells from parsley, Artemesia annua (sweet wormwood), and peanut hairy roots.
**** “Tissue engineered scaffolds are typically produced either from animal-derived or synthetic biomaterials, both of which have a large cost and large environmental impact. Animal-derived biomaterials used extensively as scaffold materials for tissue engineering include native [extracellular matrix] proteins such as collagen I or fibronectin and whole animal tissues and organs. Annually, 115 million animals are estimated to be used in research. Due to this large number, a lot of energy is necessary for the upkeep and feeding of such animals as well as to dispose of the large amount of waste that is generated. Along with this environmental impact, animal research also has a plethora of ethical considerations, which could be alleviated by forgoing animal models in favor of more biologically relevant in vitro human tissue models,”the authors advise.
Accelerating the domestication of wild plants. During the domestication of ancestral crops, plants carrying spontaneous mutations in domestication genes were selected for. The same genes can be targeted in wild plants by genome editing, resulting in a rapidly domesticated plant. (credit: Cell)
Here’s a radical new idea for creating new GMO (genetically modified organism) plants that may appeal to staunch organic-food consumers/farmers and even #NonGMOProjectVerified advocates: don’t insert a foreign gene in today’s domestic plants — delete already existing genes in semi-domesticated or even wild plants to make those plants more domestic, and reducing pesticide use in the process.
“All of the plants we eat today are mutants, but the crops we have now were selected for over thousands of years, and their mutations … such as reduced bitterness and those that facilitate easy harvest … arose by chance,” says Michael Palmgren, a botanist who heads an interdisciplinary think tank* called “Plants for a Changing World” at the University of Copenhagen. “With gene editing, we can create ‘biologically inspired organisms’ in that we don’t want to improve nature, we want to benefit from what nature has already created.”
Palmgen is senior author of an open-access review published March 2 in the journal Trends in Plant Science.
How to turn nitrogen in the atmosphere into fertilizer, reducing environmental damage
This strategy could also address problems from pesticide use and the damaging impact of large-scale agriculture on the environment. For example, runoff from excess nitrogen in fertilizers is a common pollutant; however, wild legumes, through symbiosis with bacteria, can turn nitrogen available in the atmosphere into their own fertilizer, he suggests.
Future logo? (credit: KurzweilAI)
Out of the more than 300,000 plant species in existence, fewer than 200 are commercially important, and only three species — rice, wheat, and maize — account for most of the plant matter that humans consume, partly because in the history of agriculture, mutations arose that made these crops the easiest to harvest, the reseachers note.
But with CRISPR technology, we don’t have to wait for nature to help us domesticate plants, argue the researchers. Instead, gene editing could make, for example, wild legumes, quinoa, or amaranth, which are already sustainable and nutritious, more farmable.
The approach has already been successful in accelerating domestication of undervalued crops using less precise gene-editing methods. For example, researchers used chemical mutagenesis to induce random mutations in weeping rice grass, an Australian wild relative of domestic rice, to make it more likely to hold onto its seeds after ripening. And in wild field cress, a type of weedy grass, scientists silenced genes with RNA interference involved with fatty acid synthesis, resulting in improved seed oil quality.
Palmgren’s group published a related open-access paper two years ago on using gene editing to make domesticated plants more “wild” and thus hardier for organic farmers.
While we’re at it, what about pharming (creating pharmaceuticals from plants) — using genetically modified wild plants?
* Supported by the University of Copenhagen Excellence Programme for Interdisciplinary Research.
Abstract of Accelerating the Domestication of New Crops: Feasibility and Approaches
The domestication of new crops would promote agricultural diversity and could provide a solution to many of the problems associated with intensive agriculture. We suggest here that genome editing can be used as a new tool by breeders to accelerate the domestication of semi-domesticated or even wild plants, building a more varied foundation for the sustainable provision of food and fodder in the future. We examine the feasibility of such plants from biological, social, ethical, economic, and legal perspectives.
This simulated cross-section shows how the lipid-like peptoids interact to form a membrane. Each peptoid has two sections: a fatty-like region that interacts via benzene rings (shown in pink) with its neighbors to form a sheet, and a water-loving region that juts above or below the flat sheet. Each region can be designed to have specific functions. (credit: Chun-Long Chen/PNNL)
The “peptoid” material can assemble itself into a sheet that’s thinner, but more stable, than a soap bubble, the researchers report this week in Nature Communications. The assembled sheet can withstand being submerged in a variety of liquids and can even repair itself after damage.
“We believe these materials have potential in water filters, sensors, drug delivery, and especially fuel cells or other energy applications,” said chemist Chun-Long Chen.
Biological cell membranes, which are made from thin sheets of fatty molecules called lipids, are at least ten times thinner than an iridescent soap bubble and yet allow cells to collectively form organisms as diverse at bacteria, trees and people.
Cell membranes are also very selective about what they let pass through, using tiny embedded proteins as gatekeepers. Membranes repair dings to their structure automatically and change thickness to pass signals from the outside environment to the cell’s interior, where most of the action is.
Scientists would like to take advantage of these gatekeeping and other membrane properties to make filters. A cell-membrane-like material would have advantages over other thin materials such as graphene. For example, mimicking a cell membrane’s efficient gatekeeping could result in water purifying membranes that don’t require a lot of pressure or energy to push the water through.
Synthetic molecules called peptoids have caught the interest of researchers because they are cheap, versatile and customizable. They are like natural proteins, including those that embed themselves in cell membranes, and can be designed to have very specific forms and functions. So Chen and colleagues decided to see if they could design peptoids to make them more lipid-like (that is, more like fats).
Lipid molecules are long and mostly straight: They have a fatty end that prefers to hang out with other fats, and a water-like end that prefers the comfort of water. Because of this chemistry, lipid molecules arrange themselves with the fatty ends pointed toward each other, sandwiched between the water-loving ends pointed out. Scientists call this a lipid bilayer, essentially a sheet that envelops the contents of a cell. Proteins or carbohydrate molecules embed themselves in the membranous sheet.
Inspired by this, Chen and colleagues designed peptoids in which each base peptoid was a long molecule with one end water-loving and the other end fat-loving. They chose chemical features that they hoped would encourage the individual molecules to pack together. They examined the resulting structures using a variety of analysis methods, including some at the Advanced Light Source and the Molecular Foundry, two DOE Office of Science User Facilities at Lawrence Berkeley National Laboratory.
Peptoid nanomembrane (credit: Haibao Jin et al./Nature Communications)
The team found that after putting the lipid-like peptoids into a liquid solution, the molecules spontaneously crystallized and formed “nanomembranes” — straight-edged sheets as thin as cell membranes — floating in the beaker. These nanomembranes maintained their structure in water or alcohol, at different temperatures, in solutions with high or low pH, or high concentrations of salts, a feat that few cell membranes could accomplish.
To better understand the nanomembranes, the team simulated how single peptoid molecules interacted with each other using molecular dynamics software. The simulated peptoids formed a membrane reminiscent of a lipid bilayer: The fat-loving ends lined up in the middle, and their water-loving ends pointed outward either above or below.
They also confirmed the ability of the synthetic membranes to hold proteins that have specific functions, such as ones that let water, and only water, through, and to repair themselves.
The results showed the researchers that they are on the right path to making synthetic cell membrane-like materials. The next step, Chen said, is to build biomimetic membranes by incorporating natural membrane proteins or other synthetic water channels such as carbon nanotubes into these sheet matrices. The team is also looking into ways to make the peptoid membranes conductive for energy uses.
This work was supported by the Department of Energy Office of Science and PNNL.
Abstract of Highly stable and self-repairing membrane-mimetic 2D nanomaterials assembled from lipid-like peptoids
An ability to develop sequence-defined synthetic polymers that both mimic lipid amphiphilicity for self-assembly of highly stable membrane-mimetic 2D nanomaterials and exhibit protein-like functionality would revolutionize the development of biomimetic membranes. Here we report the assembly of lipid-like peptoids into highly stable, crystalline, free-standing and self-repairing membrane-mimetic 2D nanomaterials through a facile crystallization process. Both experimental and molecular dynamics simulation results show that peptoids assemble into membranes through an anisotropic formation process. We further demonstrated the use of peptoid membranes as a robust platform to incorporate and pattern functional objects through large side-chain diversity and/or co-crystallization approaches. Similar to lipid membranes, peptoid membranes exhibit changes in thickness upon exposure to external stimuli; they can coat surfaces in single layers and self-repair. We anticipate that this new class of membrane-mimetic 2D nanomaterials will provide a robust matrix for development of biomimetic membranes tailored to specific applications.
Oak Ridge National Laboratory | 2016 Billion-Ton Report
The U.S. has the potential to sustainably produce at least 1 billion dry tons of nonfood biomass resources annually by 2040, according to the 2016 Billion-Ton Report, jointly released by the U.S. Department of Energy and Oak Ridge National Laboratory. That amount would substantially decrease greenhouse gas emissions in the utility and transportation sectors and (as the domestic bioeconomy grows) reduce U.S. dependence on imported oil, the scientists project.
These renewable resources include agricultural, forestry and algal biomass, as well as waste. They encompass the current and future potential of biomass, from currently available logging and crop residues to future available algae and dedicated energy crops — all useable for the production of biofuel, biopower and bioproducts.
Current feedstock, sector consumption, and final product distribution, in million dry tons per year. Biomass resources are shown on the left and their allocations are shown on the right. The size of the flow is representative of the amount of biomass allocated to that end use. For this figure, contributions from landfill gas are represented as tons of biomass equivalent by applying a conversion factor of 0.2665 lb/scf (credit: U.S. DOE)
The report findings show that under a base-case scenario, the United States could increase its use of dry biomass resources from a current 400 million tons to 1.57 billion tons under a high-yield scenario.
The analysis was led by ORNL with contributions from 65 experts from federal agencies, national laboratories, universities (the University of Tennessee, North Carolina State University, South Dakota State University and Oregon State University), and private companies (Energetics, Inc. and Allegheny Science and Technology).
Proposed future feedstock supply system for transforming raw biomass into stable, tradeable commodities suitable for long-distance transport and handling in existing infrastructure (credit: Idaho National Laboratory)
New to the 2016 report are assessments of potential biomass supplies from algae, from new energy crops (miscanthus, energy cane, eucalyptus), and from municipal solid waste. For the first time, the report also considers how the cost of pre-processing and transporting biomass to the biorefinery may impact feedstock availability.
Interactive tools available through the Bioenergy Knowledge Discovery Framework allow users to visualize biomass availability scenarios and tailor the data by factors such as geographic area, biomass source and price. Researchers and decision makers can use these features to better inform national bioenergy policies and research, development and deployment strategies. Each diagram and map in the report is available in an interactive interface on the Bioenergy Knowledge Discovery Framework.
Volume 2 of the report, set for release later this year, will consist of a collection of analyses on the potential environmental sustainability effects of a subset of agricultural and forestry biomass production scenarios presented in volume 1. Volume 2 will also discuss algae sustainability, land use, and land management changes, and strategies to enhance environmental sustainability.
In a new open-access report in the NIH journal Environmental Health Perspectives, 47 scientists, health practitioners, and children’s health advocates have made a consensus statement in “Project TENDR: Targeting Environmental Neuro-Developmental Risks“ — endorsed by nine medical organizations — and issued a call to action for renewed attention to the growing evidence that many common and widely available chemicals endanger neurodevelopment in fetuses and children of all ages.
The list includes chemicals used extensively in consumer products and that have become widespread in the environment. Of most concern are lead and mercury; organophosphate pesticides used in agriculture and home gardens; phthalates, which are used in pharmaceuticals, plastics and personal care products; flame retardants known as polybrominated diphenyl ethers; and air pollutants produced by the combustion of wood and fossil fuels, said University of Illinois Comparative Biosciences professor Susan Schantz, one of dozens of individual signatories to the consensus statement.
The list provides “prime examples of toxic chemicals that can contribute to learning, behavioral, or intellectual impairment, as well as specific neurodevelopmental disorders such as ADHD or autism spectrum disorder,” according to the report.
Polychlorinated biphenyls, once used as coolants and lubricants in transformers and other electrical equipment, also are of concern. PCBs were banned in the U.S. in 1977, but can persist in the environment for decades, she said.
“These chemicals are pervasive, not only in air and water, but in everyday consumer products that we use on our bodies and in our homes,” Schantz said. “Reducing exposures to toxic chemicals can be done, and is urgently needed to protect today’s and tomorrow’s children.”
“The human brain develops over a very long period of time, starting in gestation and continuing during childhood and even into early adulthood,” Schantz said. “But the biggest amount of growth occurs during prenatal development. The neurons are forming and migrating and maturing and differentiating. And if you disrupt this process, you’re likely to have permanent effects.”
Some of the chemicals of concern, such as phthalates and PBDEs, are known to interfere with normal hormone activity. For example, most pregnant women in the U.S. will test positive for exposure to phthalates and PBDEs, both of which disrupt thyroid hormone function.
“Thyroid hormone is involved in almost every aspect of brain development, from formation of the neurons to cell division, to the proper migration of cells and myelination of the axons after the cells are differentiated,” said Schantz. “It regulates many of the genes involved in nervous system development.”
Schantz and her colleagues at Illinois are studying infants and their mothers to determine whether prenatal exposure to phthalates and other endocrine disruptors leads to changes in the brain or behavior. This research, along with parallel studies in older children and animals, is a primary focus of the Children’s Environmental Health Research Center at Illinois, which Schantz directs.
Phthalates also interfere with steroid hormone activity. Studies link exposure to certain phthalates with attention deficits, lower IQ and conduct disorders in children. “Phthalates are everywhere; they’re in all kinds of different products. We’re exposed to them every day,” Schantz said.
The report criticizes current regulatory lapses that allow chemicals to be introduced into people’s lives with little or no review of their effects on fetal and child health. “For most chemicals, we have no idea what they’re doing to children’s neurodevelopment,” Schantz said. “They just haven’t been studied.
“And if it looks like something is a risk, we feel policymakers should be willing to make a decision that this or that chemical could be a bad actor and we need to stop its production or limit its use,” she said. “We shouldn’t have to wait 10 or 15 years — allowing countless children to be exposed to it in the meantime — until we’re positive it’s a bad actor.”
Project TENDR has a website with information about each of the chemicals of concern. The National Institute of Environmental Health Sciences at the National Institutes of Health and the U.S. Environmental Protection Agency fund the Children’s Environmental Health Research Center at the University of Illinois.
Project TENDR is an alliance of 48 of the nation’s top scientists, health professionals and health advocates. It was launched by Maureen Swanson of the Learning Disabilities Association of America and Irva Hertz-Picciotto of UC Davis, who brought together participants across many disciplines and sectors, including epidemiology, toxicology, exposure science, pediatrics, obstetrics and gynecology, nursing, public health, and federal and state chemical policy. Medical and scientific societies that have signed on in support include American Congress of Obstetricians and Gynecologists, American Nurses Association, Endocrine Society, National Association of Pediatric Nurse Practitioners, National Medical Association, National Hispanic Medical Association, Alliance of Nurses for Healthy Environments, Physicians for Social Responsibility and the National Council of Asian Pacific Island Physicians. TENDR’s long-term mission is to lower the incidence of neurodevelopmental disorders by reducing exposure levels to chemicals and pollutants that can contribute to these conditions, especially during fetal development and early childhood.
Steve Drake, Beckman Institute for Advanced Science and Technology | U. of I. biosciences professor Susan Schantz directs the Children’s Environmental Health Research Center at the University of Illinois, which is studying whether, and how, exposure to phthalates disrupts child brain development. Phthalates are used in some cosmetics, food packaging and products with fragrances.
Food Safety | From DDT to Glyphosate: Rachel Carson, We Need You Again
Abstract of Project TENDR: Targeting Environmental Neuro-Developmental Risks. The TENDR Consensus Statement
SUMMARY: Children in America today are at an unacceptably high risk of developing neurodevelopmental disorders that affect the brain and nervous system including autism, attention deficit hyperactivity disorder, intellectual disabilities, and other learning and behavioral disabilities. These are complex disorders with multiple causes—genetic, social, and environmental. The contribution of toxic chemicals to these disorders can be prevented. APPROACH: Leading scientific and medical experts, along with children’s health advocates, came together in 2015 under the auspices of Project TENDR: Targeting Environmental Neuro-Developmental Risks to issue a call to action to reduce widespread exposures to chemicals that interfere with fetal and children’s brain development. Based on the available scientific evidence, the TENDR authors have identified prime examples of toxic chemicals and pollutants that increase children’s risks for neurodevelopmental disorders. These include chemicals that are used extensively in consumer products and that have become widespread in the environment. Some are chemicals to which children and pregnant women are regularly exposed, and they are detected in the bodies of virtually all Americans in national surveys conducted by the U.S. Centers for Disease Control and Prevention. The vast majority of chemicals in industrial and consumer products undergo almost no testing for developmental neurotoxicity or other health effects. CONCLUSION: Based on these findings, we assert that the current system in the United States for evaluating scientific evidence and making health-based decisions about environmental chemicals is fundamentally broken. To help reduce the unacceptably high prevalence of neurodevelopmental disorders in our children, we must eliminate or significantly reduce exposures to chemicals that contribute to these conditions. We must adopt a new framework for assessing chemicals that have the potential to disrupt brain development and prevent the use of those that may pose a risk. This consensus statement lays the foundation for developing recommendations to monitor, assess, and reduce exposures to neurotoxic chemicals. These measures are urgently needed if we are to protect healthy brain development so that current and future generations can reach their fullest potential.
Bionic leaf 2.0: An artificial photosynthesis system (credit: Jessica Polka)
Harvard scientists have created a system a system that uses solar energy plus hydrogen-eating bacteria to produce liquid fuels with 10 percent efficiency, compared to the 1 percent seen in the fastest-growing plants.
The system, co-created by Daniel Nocera, the Patterson Rockwood Professor of Energy at Harvard University, and Pamela Silver, the Elliott T. and Onie H. Adams Professor of Biochemistry and Systems Biology at Harvard Medical School, uses solar energy to split water molecules into hydrogen and oxygen molecules.
A paper on the research was published June 3 in Science.
“This is a true artificial photosynthesis system,” Nocera said. “Before, people were using artificial photosynthesis for water-splitting, but this is a true A-to-Z system, and we’ve gone well over the efficiency of photosynthesis in nature.”
“What we’ve invented is an artificial leaf. You just drop it in water and sunlight hits it, and out one side comes hydrogen and out the other side comes oxygen.” — Daniel Nocera
“The beauty of biology is it’s the world’s greatest chemist: Biology can do chemistry we can’t do easily,” said Silver, who is also a founding core member of the Wyss Institute at Harvard University. “In principle, we have a platform that can make any downstream carbon-based molecule. So this has the potential to be incredibly versatile.”
Dubbed “bionic leaf 2.0,” the new system builds on previous work by Nocera, Silver and others, which faced a number of challenges. Mainly, the catalyst they used to produce hydrogen (a nickel-molybdenum-zinc alloy) also created reactive oxygen species — molecules that attacked and destroyed the bacteria’s DNA. To avoid that problem, researchers were forced to run the system at abnormally high voltages, resulting in reduced efficiency.
Ready for commercial applications, with a new model
“For this paper, we designed a new cobalt-phosphorus alloy catalyst, which we showed does not make reactive oxygen species,” Nocera said. “That allowed us to lower the voltage, and that led to a dramatic increase in efficiency.”
Nocera and colleagues were also able to expand the portfolio of the system to include isobutanol (a solvent) and isopentanol (used in geothermal power production to drive turbines), along with PHB, a bioplastic precursor.
“Instead of having a gas station, the Sun is hitting your house, you have the artificial leaf, you could be generating your own fuel.” — Daniel Nocera (credit: Rose Lincoln/Harvard Staff Photographer)
The new catalyst’s chemical design also allows it to “self-heal,” meaning it won’t leach material into solution — it’s biologically compatible.
Nocera said the system is already effective enough to consider possible commercial applications but within a different model for technology translation. “It’s an important discovery… [that] can do better than photosynthesis,” Nocera said. “But I also want to bring this technology to the developing world.”
Working in conjunction with the First 100 Watts Project at Harvard, which helped fund the research, Nocera hopes to continue developing the technology and its applications in nations such as India with the help of that country’s scientists.
“If you think about it, photosynthesis is amazing,” he said. “It takes sunlight, water and air—and then look at a tree. That’s exactly what we did, but we do it significantly better, because we turn all that energy into a fuel.”
The work, a direct result of the First 100 Watts Project established at Harvard University, was was supported by Office of Naval Research Multidisciplinary University, Research Initiative Award, Air Force Office of Scientific Research Grant, and the Wyss Institute for Biologically Inspired Engineering. The Harvard University Climate Change Solutions Fund is supporting ongoing research into the “bionic leaf” platform.
Harvard University | Bionic Leaf Turns Sunlight Into Liquid Fuel
Abstract of Water splitting–biosynthetic system with CO2 reduction efficiencies exceeding photosynthesis
Artificial photosynthetic systems can store solar energy and chemically reduce CO2. We developed a hybrid water splitting–biosynthetic system based on a biocompatible Earth-abundant inorganic catalyst system to split water into molecular hydrogen and oxygen (H2 and O2) at low driving voltages. When grown in contact with these catalysts, Ralstonia eutropha consumed the produced H2 to synthesize biomass and fuels or chemical products from low CO2 concentration in the presence of O2. This scalable system has a CO2 reduction energy efficiency of ~50% when producing bacterial biomass and liquid fusel alcohols, scrubbing 180 grams of CO2 per kilowatt-hour of electricity. Coupling this hybrid device to existing photovoltaic systems would yield a CO2 reduction energy efficiency of ~10%, exceeding that of natural photosynthetic systems.
A sample of a new building material created to replace concrete (credit: UCLA Luskin)
A UCLA research team has developed a plan for capturing carbon from power-plant smokestacks (the largest source of harmful global greenhouse gas in the world) and use it to create a new building material — CO2NCRETE — that would be fabricated using 3D printers while replacing production of cement (which creates about 5 percent of the planet’s greenhouse gas emissions).
“I decided to get involved in this project because it could be a game-changer for climate policy,” said J.R. DeShazo, professor of public policy at the UCLA Luskin School of Public Affairs and director of the UCLA Luskin Center for Innovation. “This technology tackles global climate change, which is one of the biggest challenges that society faces now and will face over the next century.”
UCLA Luskin School of Public Affairs | Carbon upcycling: Turning carbon dioxide into CO2NCRETE
DeShazo has provided the public policy and economic guidance for this research. The scientific contributions have been led by Gaurav Sant, associate professor and Henry Samueli Fellow in Civil and Environmental Engineering; Richard Kaner, distinguished professor in chemistry and biochemistry, and materials science and engineering; Laurent Pilon, professor in mechanical and aerospace engineering and bioengineering; and Matthieu Bauchy, assistant professor in civil and environmental engineering.
Beyond just capturing CO2
This isn’t the first attempt to capture carbon emissions from power plants. It’s been done before, but the challenge has been what to do with the carbon dioxide once it’s captured.
The researchers are excited about the possibility of reducing greenhouse gas in the U.S., especially in regions where coal-fired power plants are abundant. “But even more so is the promise to reduce the emissions in China and India,” DeShazo said. “China is currently the largest greenhouse gas producer in the world, and India will soon be number two, surpassing us.”
Thus far, the new construction material has been produced only at a lab scale, using 3-D printers to shape it into tiny cones. “We have proof of concept that we can do this,” DeShazo said. “But we need to begin the process of increasing the volume of material and then think about how to pilot it commercially.
“This technology could change the economic incentives associated with these power plants in their operations and turn the smokestack flue gas into a resource countries can use, to build up their cities, extend their road systems,” DeShazo said. “It takes what was a problem and turns it into a benefit in products and services that are going to be very much needed and valued in places like India and China.”
Abstract of Direct Carbonation of Ca(OH)2 Using Liquid and Supercritical CO2: Implications for Carbon-Neutral Cementation
By invoking analogies to lime mortars of times past, this study examines the carbonation of portlandite (Ca(OH)2) by carbon dioxide (CO2) in the liquid and supercritical states as a potential route toward CO2-neutral cementation. Portlandite carbonation is noted to be rapid; e.g., >80% carbonation of Ca(OH)2 is achieved in 2 h upon contact with liquid CO2 at ambient temperatures, and it is only slightly sensitive to the effects of temperature, pressure, and the state of CO2 over the range of 6 MPa ≤ p ≤ 10 MPa and 8 °C ≤ T ≤ 42 °C. Additional studies suggest that the carbonation of anhydrous ordinary portland cement is slower and far less reliable than that of portlandite. Although cementation is not directly assessed, detailed scanning electron microscopy (SEM) examinations of carbonated microstructures indicate that the carbonation products formed encircle and embed sand grains similar to that observed in lime mortars. The outcomes suggest innovative directions for “carbon-neutral cementation.”
The Solar Thermal Electrochemical Process (STEP) converts atmospheric carbon dioxide into carbon nanotubes that can be used in advanced batteries. (credit: Julie Turner, Vanderbilt University)
The electric vehicle of the future will be carbon negative (reducing the amount of atmospheric carbon dioxide) not just carbon neutral (not adding CO2 to the atmosphere), say researchers at Vanderbilt University and George Washington University (GWU).
The trick: replace graphite electrodes in lithium-ion batteries (used in electric vehicles) with carbon nanotubes and carbon nanofibers recovered from carbon dioxide in the atmosphere. The new technology could also be used in sodium-ion batteries, currently under development for large-scale applications, such as the electric grid.
STEP uses solar energy to provide both the electrical and thermal energy needed to break down carbon dioxide into carbon and oxygen and to produce carbon nanotubes, which are stable, flexible, conductive and stronger than steel.
In lithium-ion batteries, the nanotubes replace the carbon anode used in commercial batteries. The team demonstrated that the carbon nanotubes gave a small boost to the performance, which was amplified when the battery was charged quickly.
In sodium-ion batteries, the researchers found that small defects in the carbon, which can be tuned using STEP, can unlock stable storage performance more than 3.5 times above that of sodium-ion batteries with graphite electrodes.
Both carbon-nanotube batteries were exposed to about 2.5 months of continuous charging and discharging and showed no sign of fatigue.
Depending on the specifications, making one of the two electrodes out of carbon nanotubes means that up to 40 percent of a battery could be made out of recycled CO2, according to Vanderbilt Assistant Professor of Mechanical Engineering Cary Pint, not including packaging (which could also be replaced in the future).
This approach also reduces end-user battery cost, unlike most efforts to reuse CO2 aimed at low-valued fuels, like methanol, which “cannot justify the cost required to produce them,” Pint said.
“Other applications for the carbon nanotubes include carbon composites for strong, lightweight construction materials, sports equipment and car, truck and airplane bodies,” said GWU Professor of Chemistry Stuart Licht.
The researchers estimate that with a battery cost of $325 per kWh (the average cost of lithium-ion batteries reported by the Department of Energy in 2013), a kilogram of carbon dioxide has a value of about $18 as a battery material — six times more than when it is first converted to methanol — a number that increases when moving from large batteries used in electric vehicles to the smaller batteries used in electronics.
And unlike methanol, combining batteries with solar cells provides renewable power with zero greenhouse emissions.
Comparison of conventional natural-gas plant (A), which has CO2 as an exhaust, with carbon nanofiber/carbon nanotube-based natural-gas plant (B) (steam turbine cooling/electricity-generating process (pink), common to both, omitted) (credit: Stuart Licht et al./ACS Central Science)
Licht also proposed that the STEP process could be coupled to a natural gas-powered electrical generator. The generator would provide electricity, heat, and a concentrated source of carbon dioxide that would boost the performance of the STEP process.
At the same time, the oxygen released in the process could be piped back to the generator, where it would boost the generator’s combustion efficiency to compensate for the amount of electricity that the STEP process consumes. The end result could be a fossil fuel electrical power plant with net-zero CO2 emissions.
The research was partially supported by National Science Foundation and NSF Graduate Research Fellowship grants.
Abstract of Carbon Nanotubes Produced from Ambient Carbon Dioxide for Environmentally Sustainable Lithium-Ion and Sodium-Ion Battery Anodes
The cost and practicality of greenhouse gas removal processes, which are critical for environmental sustainability, pivot on high-value secondary applications derived from carbon capture and conversion techniques. Using the solar thermal electrochemical process (STEP), ambient CO2 captured in molten lithiated carbonates leads to the production of carbon nanofibers (CNFs) and carbon nanotubes (CNTs) at high yield through electrolysis using inexpensive steel electrodes. These low-cost CO2-derived CNTs and CNFs are demonstrated as high performance energy storage materials in both lithium-ion and sodium-ion batteries. Owing to synthetic control of sp3 content in the synthesized nanostructures, optimized storage capacities are measured over 370 mAh g–1 (lithium) and 130 mAh g–1 (sodium) with no capacity fade under durability tests up to 200 and 600 cycles, respectively. This work demonstrates that ambient CO2, considered as an environmental pollutant, can be attributed economic value in grid-scale and portable energy storage systems with STEP scale-up practicality in the context of combined cycle natural gas electric power generation.