Energy & Green Technology Updates vol.74
October 25th 2024
Check out latest research updates in the field
TL;DR
- Wastewater bacteria can break plastic for food
- Researchers innovate sustainable metal-recycling method
- Molecular-level changes translate to big efficiency gains for organic solar cells
- Study shows how water systems can help accelerate renewable energy adoption
- New continuous reaction process can help turn plant waste into sustainable aviation fuel
- And more!
Green Technology Market
Green technology is an applicable combination of advanced tools and solutions to conserve natural resources and environment, minimize or mitigate negative impacts from human activities on the environment, and ensure sustainability development. Green technology is also referred to as clean technology or environmental technology which includes technologies, such as IoT, AI, analytics, blockchain, digital twin, security, and cloud, which collect, integrate, and analyze data from various real-time data sources, such as sensors, cameras, and Global Positioning System (GPS).
Green technology, also known as sustainable technology, protects the environment by using various forms of sustainable energy. Some of the best examples of green technologies include solar panels, LED lighting, wind energy, electric vehicles, vertical farming, and composting.
The global Green Technology and Sustainability market size to grow from USD 11.2 billion in 2020 to USD 36.6 billion by 2025, at a Compound Annual Growth Rate (CAGR) of 26.6% during the forecast period. The growing consumer and industrial interest for the use of clean energy resources to conserve environment and increasing use of Radio Frequency Identification sensors across industries are driving the adoption of green technology and sustainability solutions and services in the market.
Latest Research
by Rebecca A. Wilkes, Nanqing Zhou, Austin L. Carroll, Ojaswi Aryal, Kelly P. Teitel, Rebecca S. Wilson, Lichun Zhang, Arushi Kapoor, Edgar Castaneda, Adam M. Guss, Jacob R. Waldbauer, Ludmilla Aristilde in Environmental Science & Technology
Researchers have long observed that a common family of environmental bacteria, Comamonadacae, grow on plastics littered throughout urban rivers and wastewater systems. But what, exactly, these Comamonas bacteria are doing has remained a mystery.
Now, Northwestern University-led researchers have discovered how cells of a Comamonas bacterium are breaking down plastic for food. First, they chew the plastic into small pieces, called nanoplastics. Then, they secrete a specialized enzyme that breaks down the plastic even further. Finally, the bacteria use a ring of carbon atoms from the plastic as a food source, the researchers found.
The discovery opens new possibilities for developing bacteria-based engineering solutions to help clean up difficult-to-remove plastic waste, which pollutes drinking water and harms wildlife.
"We have systematically shown, for the first time, that a wastewater bacterium can take a starting plastic material, deteriorate it, fragment it, break it down and use it as a source of carbon," said Northwestern's Ludmilla Aristilde, who led the study. "It is amazing that this bacterium can perform that entire process, and we identified a key enzyme responsible for breaking down the plastic materials. This could be optimized and exploited to help get rid of plastics in the environment."
An expert in the dynamics of organics in environmental processes, Aristilde is an associate professor of environmental engineering at Northwestern's McCormick School of Engineering. She also is a member of the Center for Synthetic Biology, International Institute for Nanotechnology and Paula M. Trienens Institute for Sustainability and Energy. The study's co-first authors are Rebecca Wilkes, a former Ph.D. student in Aristilde's lab, and Nanqing Zhou, a current postdoctoral associate in Aristilde's lab. Several former graduate and undergraduate researchers from the Aristilde Lab also contributed to the work.
The new study builds on previous research from Aristilde's team, which unraveled the mechanisms that enable Comamonas testosteri to metabolize simple carbons generated from broken down plants and plastics. In the new research, Aristilde and her team again looked to C. testosteroni, which grows on polyethylene terephthalate (PET), a type of plastic commonly used in food packaging and beverage bottles. Because it does not break down easily, PET is a major contributor to plastic pollution.
"It's important to note that PET plastics represent 12% of total global plastics usage," Aristilde said. “And it accounts for up to 50% of microplastics in wastewaters.”
To better understand how C. testosteroni interacts with and feeds on the plastic, Aristilde and her team used multiple theoretical and experimental approaches. First, they took bacterium -- isolated from wastewater -- and grew it on PET films and pellets. Then, they used advanced microscopy to observe how the surface of the plastic material changed over time. Next, they examined the water around the bacteria, searching for evidence of plastic broken down into smaller nano-sized pieces. And, finally, the researchers looked inside the bacteria to pinpoint tools the bacteria used to help degrade the PET.
"In the presence of the bacterium, the microplastics were broken down into tiny nanoparticles of plastics," Aristilde said. "We found that the wastewater bacterium has an innate ability to degrade plastic all the way down to monomers, small building blocks which join together to form polymers. These small units are a bioavailable source of carbon that bacteria can use for growth."
After confirming that C. testosteroni, indeed, can break down plastics, Aristilde next wanted to learn how. Through omics techniques that can measure all enzymes inside the cell, her team discovered one specific enzyme the bacterium expressed when exposed to PET plastics. To further explore this enzyme's role, Aristilde asked collaborators at Oak Ridge National Laboratory in Tennessee to prepare bacterial cells without the abilities to express the enzyme. Remarkably, without that enzyme, the bacteria's ability to degrade plastic was lost or significantly diminished.
Although Aristilde imagines this discovery potentially could be harnessed for environmental solutions, she also says this new knowledge can help people better understand how plastics evolve in wastewater.
"Wastewater is a huge reservoir of microplastics and nanoplastics," Aristilde said. "Most people think nanoplastics enter wastewater treatment plants as nanoplastics. But we're showing that nanoplastics can be formed during wastewater treatment through microbial activity. That's something we need to pay attention to as our society tries to understand the behavior of plastics throughout its journey from wastewater to receiving rivers and lakes."
Flash separation of metals by electrothermal chlorination
by Bing Deng, Shichen Xu, Lucas Eddy, Jaeho Shin, Yi Cheng, Carter Kittrell, Khalil JeBailey, Justin Sharp, Long Qian, Shihui Chen, James M. Tour in Nature Chemical Engineering
A research team led by Rice University's James Tour has developed a method to recycle valuable metals from electronic waste more efficiently while significantly reducing the environmental impact typically associated with metal recycling.
Metal recycling can reduce the need for mining, which decreases the environmental damage associated with extracting raw materials such as deforestation, water pollution and greenhouse gas emissions. "Our process offers significant reductions in operational costs and greenhouse gas emissions, making it a pivotal advancement in sustainable recycling," said Tour, the T.T. and W.F. Chao Professor of Chemistry and professor of materials science and nanoengineering.
The new technique enhances the recovery of critical metals and builds upon Tour's earlier work in waste disposal using flash Joule heating (FJH). This process involves passing an electric current through a material to rapidly heat it to extremely high temperatures, transforming it into different substances.
Electrothermal chlorination system.
The researchers applied FJH chlorination and carbochlorination processes to extract valuable metals, including gallium, indium and tantalum, from e-waste. Traditional recycling methods such as hydrometallurgy and pyrometallurgy are energy-intensive, produce harmful waste streams and involve large amounts of acid.
In contrast, the new method eliminates these challenges by enabling precise temperature control and rapid metal separation without using water, acids or other solvents, significantly reducing environmental harm.
"We are trying to adapt this method for recovery of other critical metals from waste streams," said Bing Deng, former Rice postdoctoral student, current assistant professor at Tsinghua University and co-first author of the study.
The scientists found that their method effectively separates tantalum from capacitors, gallium from discarded light-emitting diodes and indium from used solar conductive films. By precisely controlling the reaction conditions, the team achieved a metal purity of over 95% and a yield of over 85%.
Moreover, the method holds promise for the extraction of lithium and rare Earth elements, said Shichen Xu, a postdoctoral researcher at Rice and co-first author of the study.
"This breakthrough addresses the pressing issue of critical metal shortages and negative environmental impacts while economically incentivizing recycling industries on a global scale with a more efficient recovery process," Xu said.
by Adarsh Kumar, David C. Bell, Zhibin Yang, Joshua Heyne, Daniel M. Santosa, Huamin Wang, Peng Zuo, Chongmin Wang, Ashutosh Mittal, Darryl P. Klein, Michael J. Manto, Xiaowen Chen, Bin Yang in Fuel Processing Technology
Washington State University scientists successfully tested a new way to produce sustainable jet fuel from lignin-based agricultural waste.
The team's research demonstrated a continuous process that directly converts lignin polymers, one of the chief components of plant cells, into a form of jet fuel that could help improve performance of sustainably produced aviation fuels.
"Our achievement takes this technology one step closer to real-world use by providing data that lets us better gauge its feasibility for commercial aviation," said lead scientist Bin Yang, professor in WSU's Department of Biological Systems Engineering.
A class of structural molecules that make plants tough and woody, lignin is derived from corn stover -- the stalks, cobs and leaves left after harvest -- and other agricultural byproducts. The team developed a process called "simultaneous depolymerization and hydrodeoxygenation," which breaks down the lignin polymer and at the same time removes oxygen to create lignin-based jet fuel.
At their Richland facility, the scientists introduced dissolved lignin polymer into a continuous hydrotreating reactor to produce the fuel. Global consumption of aviation fuel reached an all-time high of nearly 100 billion gallons in 2019, and demand is expected to increase in the coming decades. Sustainable aviation fuels derived from plant-based biomass could help minimize aviation's carbon footprint, reduce contrails and meet international carbon neutrality goals.Lignin-based jet fuel could make sustainable fuels cleaner and more easily usable in jet engines.
Thanks to their density, efficiency, and seal-swelling characteristics, hydrocarbons catalyzed from lignin could effectively replace fossil fuel-derived compounds called aromatics. Associated with contrails and climate impacts, aromatics remain in use because they enhance fuel density and help swell O-rings in metal-to-metal joints. This research marked the team's first successful test of a continuous process, which is more feasible for commercial production.
The project also used a less processed, less expensive form of lignin derived from corn stover, dubbed "technical lignin," contrasting similar research using extracted lignin bio-oil. The team's findings suggest lignin is a promising source of aromatic-replacing cycloalkanes and other useful fuel compounds.
"The aviation enterprise is looking to generate 100% renewable aviation fuel," said Josh Heyne, research team member and co-director of the WSU-PNNL Bioproducts Institute.
"Lignin-based jet fuel complements existing technologies by, for example, increasing the density of fuel blends."
Offering reduced emissions, lignin-based fuel could ultimately make sustainable aviation fuels fully "drop-in" capable, meaning they can be used with all existing engines, infrastructure and aircraft like existing fossil-derived aviation fuel.
"We're working to create an effective, commercially relevant technology for a complementary blend component that can achieve the 100% drop-in goal," Heyne said.
Valuing energy flexibility from water systems
by Akshay K. Rao, Jose Bolorinos, Erin Musabandesu, Fletcher T. Chapin, Meagan S. Mauter in Nature Water
New Stanford-led research reveals how water systems, from desalination plants to wastewater treatment facilities, could help make renewable energy more affordable and dependable. The study presents a framework to measure how water systems can adjust their energy use to help balance power grid supply and demand.
"If we're going to reach net zero, we need demand-side energy solutions, and water systems represent a largely untapped resource," said study lead author Akshay Rao, an environmental engineering PhD student in the Stanford School of Engineering. "Our method helps water operators and energy managers make better decisions about how to coordinate these infrastructure systems to simultaneously meet our decarbonization and water reliability goals."
As grids rely more on renewable energy sources like wind and solar, balancing energy supply and demand becomes more challenging. Typically, energy storage technologies like batteries help with this, but batteries are expensive. An alternative is to promote demand-side flexibility from large-load consumers like water conveyance and treatment providers. Water systems -- which use up to 5% of the nation's electricity -- could offer similar benefits to batteries by adjusting their operations to align with real-time energy needs, according to Rao and his co-authors.
Energy performance metrics.
To help realize this potential, the researchers developed a framework that assesses the value of energy flexibility from water systems from the perspectives of electric power grid operators and water system operators. The framework compares these values to other grid-scale energy storage solutions, such as lithium-ion batteries that store electricity during periods of low energy demand and release it during peak demand periods. The framework also takes into account a range of factors, such as reliability risks, compliance risks, and capital upgrade costs associated with delivering energy flexibility using critical infrastructure systems.
Researchers tested their method on a seawater desalination plant, a water distribution system, and a wastewater treatment plant. They also explored the effect of different tariff structures and electricity rates from utilities in California, Texas, Florida, and New York.
They found that these systems could shift up to 30% of their energy use during peak demand times, leading to significant cost savings and easing pressure on the grid. Desalination plants showed the greatest potential for this kind of energy flexibility by tweaking how much water they recover or shutting down specific operations when electricity prices are high.
The framework could help electricity grid operators evaluate energy flexibility resources across a range of water systems, compare them with other energy flexibility and energy storage options, and modify or price energy, according to the researchers. The approach could also help water utility operators make more informed financial decisions about how they design and run their plants in an era of rapidly changing electricity grids.
The study also highlights how important energy pricing is for making the most of this flexibility. Water systems that pay different rates for energy at different times of the day could see the biggest benefits. Facilities might even be able to make extra money by reducing energy use when the grid is stressed, as part of energy-saving programs offered by utilities.
"Our study gives water and energy managers a tool to make smarter choices," said Rao. "With the right investments and policies, water systems can play a key role in making the transition to renewable energy smoother and more affordable."
by Kai Wang, Seihou JINNAI, Takumi Urakami, Hirofumi Sato, Masahiro Higashi, Sota Tsujimura, Yasuhiro Kobori, Rintaro Adachi, Akira Yamakata, Yutaka Ie in Angewandte Chemie International Edition
Organic solar cells (OSCs) -- promising alternatives to traditional inorganic solar cells -- have many features that make them key players in a greener future. One of these features is tunable chemistry, which allows scientists to precisely adjust or modify the properties of chemical systems to achieve desired outcomes. Now, researchers from Japan have tuned them to increase power conversion efficiency.
In a study researchers from Osaka University have reported a new organic semiconductor that gives better power conversion efficiency than the accepted standard.
OSCs are light and flexible and can be produced on a large scale for relatively low cost.
They are therefore highly promising for applications such as agrivoltaics where large areas of land are used to simultaneously grow crops and turn the sun's energy into electricity.
Generally, OSCs contain two organic semiconductors, one to transport charge carriers known as electrons (the acceptor) and one to transport the other carriers known as holes (the donor). A current flows in a semiconductor when excitons -- combination of an electron and a positive hole -- are split into these carriers giving electron-hole pairs.
Excitons are bound tightly together, but sunlight with enough energy can cause them to dissociate and generate a current.
"Reducing the amount of energy needed to break up an exciton -- the exciton binding energy -- makes it easier to convert the light into the desired current," explains lead author of the study Seihou Jinnai.
"We therefore focused on the factors that contribute to the binding energy, one of which is the distance between the electron and the hole. If this is increased, then the binding energy should decrease."
The researchers therefore designed a molecule with side units that had the effect of separating the parts of the molecule that accommodate the electron and the hole.
The synthesized molecule was used as an acceptor in a bulk heterojunction OSC along with a donor material, and the system showed increased power conversion efficiency compared with the accepted standard.
The molecule was also tested as the single component of an OSC and showed better conversion of light to current.
"The molecule we designed shows that the nature of side units in acceptor molecules is key to the exciton behavior and its efficiency as a result," says senior author Yutaka Ie. "This result provides an important demonstration of what can be achieved by tuning chemistry for OSCs applications."
The findings indicate the potential of rational design of organic semiconductors and are expected to lead to new devices including high-performance OSCs and wavelength-selective transparent OSCs. General improvements in performance are also expected to enhance the potential of OSCs in large-scale photovoltaic applications, naturally leading to green energy alternatives.
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