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Category: chemistry – Page 288

A ‘greener’ way to clean wastewater treatment filters

Membrane filters don’t require much energy to purify water, making them popular for wastewater treatment. To keep these materials in tip-top condition, they’re commonly cleaned with large amounts of strong chemicals, but some of these agents destroy the membranes in the process. Now, researchers reporting in ACS Applied Materials & Interfaces have developed reusable nanoparticle catalysts that incorporate glucose to help efficiently break down contaminants inside these filters without damaging them.

Typically, dirty wastewater filters are unclogged with strong acids, bases or oxidants. Chlorine-containing oxidants such as bleach can break down the most stubborn organic debris. But they also damage polyamide membranes, which are in most commercial nanofiltration systems, and they produce toxic byproducts. A milder alternative to bleach is hydrogen peroxide, but it decomposes contaminants slowly.

Previously, scientists have combined hydrogen peroxide with iron oxide to form that improve hydrogen peroxide’s efficiency in a process known as the Fenton reaction. Yet in order for the Fenton reaction to clean filters, extra hydrogen peroxide and acid are needed, increasing financial and environmental costs. One way to avoid these additional chemicals is to use the enzyme glucose oxidase, which simultaneously forms and gluconic acid from glucose and oxygen. So, Jianquan Luo and colleagues wanted to combine glucose oxidase and into a system that catalyzes the Fenton-based breakdown of contaminants, creating an efficient and delicate cleaning system for .

Scientists 3D print microscopic Star Trek spaceship that moves on its own

Circa 2020 o.o!

A team of physicists at a university in the Netherlands have 3D-printed a microscopic version of the USS Voyager, an Intrepid-class starship from Star Trek.

The miniature Voyager, which measures 15 micrometers (0.015 millimeters) long, is part of a project researchers at Leiden University conducted to understand how shape affects the motion and interactions of microswimmers.

Microswimmers are small particles that can move through liquid on their own by interacting with their environment through chemical reactions. The platinum coating on the microswimmers reacts to a hydrogen peroxide solution they are placed in, and that propels them through the liquid.

Selecting the right structural materials for fusion reactors

Do two promising structural materials corrode at very high temperatures when in contact with “liquid metal fuel breeders” in fusion reactors? Researchers of Tokyo Institute of Technology (Tokyo Tech), National Institutes for Quantum Science and Technology (QST), and Yokohama National University (YNU) now have the answer. This high-temperature compatibility of reactor structural materials with the liquid breeder—a lining around the reactor core that absorbs and traps the high energy neutrons produced in the plasma inside the reactor—is key to the success of a fusion reactor design.

Fusion reactors could be a powerful means of generating clean electricity, and currently, several potential designs are being explored. In a fusion , the fusion of two nuclei releases massive amounts of energy. This energy is trapped as heat in a “breeding blanket” (BB), typically a liquid lithium alloy, surrounding the . This heat is then used to run a turbine and generate electricity. The BB also has an essential function of fusion fuel breeding, creating a closed fuel cycle for the endless operation of the reactors without fuel depletion.

The operation of a BB at extremely high temperatures over 1,173 K serves the attractive function of producing hydrogen from water, which is a promising technology for realizing a carbon-neutral society. This is possible because the BB heats up to over 1,173 K by absorbing the energy from the reaction. At such temperatures, there is the risk of structural materials in contact with the BB becoming corroded, compromising the safety and stability of the reactors. It is thus necessary to find structural materials that are chemically compatible with the BB material at these temperatures.

Reprogrammed bacterium turns carbon dioxide into chemicals on industrial scale

Process achieved at industrial scale in 120 litre reactor.

Factory

The 120 litre LanzaTech pilot plant that can convert carbon dioxide into acetone and isopropanol.

Industrial scale carbon-negative production of two commodity chemicals has been achieved for the first time using a genetically modified bacterium that can turn waste carbon dioxide into acetone and isopropanol. The work, which offers a blueprint for making other chemicals, holds promise for a more sustainable, renewable and environmentally-friendly chemical industry as the world strives to shift from fossil fuels to a circular carbon economy.

Catalyst turns carbon dioxide into gasoline 1,000 times more efficiently

Engineers working to reverse the proliferation of greenhouse gases know that in addition to reducing carbon dioxide emissions we will also need to remove carbon dioxide from power plant fumes or from the skies. But, what do we do with all that captured carbon? Matteo Cargnello, a chemical engineer at Stanford University, is working to turn it into other useful chemicals, such as propane, butane or other hydrocarbon fuels that are made up of long chains of carbon and hydrogen.

“We can create gasoline, basically,” said Cargnello, who is an assistant professor of chemical engineering. “To capture as much as possible, you want the longest chain hydrocarbons. Chains with eight to 12 would be the ideal.”

A new catalyst, invented by Cargnello and colleagues, moves toward this goal by increasing the production of long-chain hydrocarbons in chemical reactions. It produced 1,000 times more butane—the longest hydrocarbon it could produce under its maximum pressure—than the standard catalyst given the same amounts of carbon , hydrogen, catalyst, pressure, heat and time. The new catalyst is composed of the element ruthenium—a rare transition metal belonging to the platinum group—coated in a thin layer of plastic. Like any catalyst, this invention speeds up chemical reactions without getting used up in the process. Ruthenium also has the advantage of being less expensive than other high-quality catalysts, like palladium and platinum.

Clues to better batteries emerge from tracking lithium

Pure lithium metal is a promising replacement for the graphite-based anodes currently used in electric vehicle batteries. It could tremendously reduce battery weights and dramatically extend the driving range of electric vehicles relative to existing technologies. But before lithium metal batteries can be used in cars, scientists must first figure out how to extend their lifetimes.

A new study led by Peter Khalifah—a chemist at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and Stony Brook University—tracked lithium deposition and removal from a while it was cycling to find clues as to how failure occurs. The work is published in a special issue of the Journal of the Electrochemical Society honoring the contributions of Nobel Prize-winning battery researcher John Goodenough, who like Khalifah is a member of the Battery 500 Consortium research team.

“In a good battery, the rate of lithium plating (deposition) and stripping (removal) will be the same at all positions on the surface of electrodes,” Khalifah said. “Our results show that it’s harder to remove lithium at certain places, which means there are problems there. By identifying the cause of the problems, we can figure out how to get rid of them and make better batteries with higher capacities and longer lifetimes.”

Study reveals chemical link between wildfire smoke and ozone depletion

The Australian wildfires in 2019 and 2020 were historic for how far and fast they spread, and for how long and powerfully they burned. All told, the devastating “Black Summer” fires blazed across more than 43 million acres of land, and extinguished or displaced nearly 3 billion animals. The fires also injected over 1 million tons of smoke particles into the atmosphere, reaching up to 35 kilometers above Earth’s surface — a mass and reach comparable to that of an erupting volcano.

Now, atmospheric chemists at MIT have found that the smoke from those fires set off chemical reactions in the stratosphere that contributed to the destruction of ozone, which shields the Earth from incoming ultraviolet radiation. The team’s study, appearing this week in the Proceedings of the National Academy of Sciences, is the first to establish a chemical link between wildfire smoke and ozone depletion.

In March 2020, shortly after the fires subsided, the team observed a sharp drop in nitrogen dioxide in the stratosphere, which is the first step in a chemical cascade that is known to end in ozone depletion. The researchers found that this drop in nitrogen dioxide directly correlates with the amount of smoke that the fires released into the stratosphere. They estimate that this smoke-induced chemistry depleted the column of ozone by 1 percent.

What might explain Huntington’s Disease?

Could 2 B vitamins help those suffering with Huntington’s Disease?

T he Huntington’s disease (HD) community has recently experienced setbacks, but a new research report may reignite hope, from an unexpected source: the vitamin thiamine (B1), with help from biotin (B7). The investigators, from several institutions in Spain and UCLA, write in Science Translational Medicine, “Together, these results demonstrate a thiamine deficiency in HD brain and suggest that individuals with HD might benefit from thiamine and/or biotin supplementation therapy.”

Health care providers may suggest certain supplements for HD patients, based perhaps on a deficiency (vitamins C, B12, E) in the blood, or for general health. But the new findings are different. The researchers didn’t set out to detect a vitamin deficiency, but instead probed the messaging within cells in the HD brain, which led them to a biochemical juncture that revealed the thiamine/biotin connection.

Reading the mind of a worm

Circa 2021

It sounds like a party trick: scientists can now look at the brain activity of a tiny worm and tell you which chemical the animal smelled a few seconds before. But the findings of a new study, led by Salk Associate Professor Sreekanth Chalasani, are more than just a novelty; they help the scientists better understand how the brain functions and integrates information.

Discovered: An easier way to create ‘flexible diamonds’

As hard as diamond and as flexible as plastic, highly sought-after diamond nanothreads would be poised to revolutionize our world—if they weren’t so difficult to make.

Recently, a team of scientists led by Carnegie’s Samuel Dunning and Timothy Strobel developed an original technique that predicts and guides the ordered creation of strong, yet flexible, , surmounting several existing challenges. The innovation will make it easier for scientists to synthesize the nanothreads—an important step toward applying the material to practical problems in the future. The work was recently published in the Journal of the American Chemical Society.

Diamond nanothreads are ultra-thin, one-dimensional carbon chains, tens of thousands of times thinner than a human hair. They are often created by compressing smaller carbon-based rings together to form the same type of bond that makes the hardest mineral on our planet.