#hydroxyl radicals

[biology-geology-beaches-india]

The Science Research Diaries of S. Sunkavally, page 346.

[tenth-sentence]

In the same manner as hydroxyl, the nitrate radical is able to add to the double bond of olefins:

"Environmental Chemistry: A Global Perspective", 4e - Gary W. VanLoon & Stephen J. Duffy

[whats-in-a-sentence]

ROS generation occurs in several cellular compartments and as a result of the activities of specialized oxidases, such as NADPH oxidases, amine oxidases, and cell wall-bound peroxidases (Table 24.2).

"Plant Physiology and Development" int'l 6e - Taiz, L., Zeiger, E., Møller, I.M., Murphy, A.

[mindblowingscience]

How OH itself forms in the atmosphere was viewed as a complete story, but in new research published in Proceedings of the National Academy of Sciences, a research team that includes Sergey Nizkorodov, a University of California, Irvine professor of chemistry, report that a strong electric field that exists at the surface between airborne water droplets and the surrounding air can create OH by a previously unknown mechanism.

It's a finding that stands to reshape how scientists understand how the air clears itself of things like human-emitted pollutants and greenhouse gases, which OH can react with and eliminate. "You need OH to oxidize hydrocarbons, otherwise they would build up in the atmosphere indefinitely," said Nizkorodov.

"OH is a key player in the story of atmospheric chemistry. It initiates the reactions that break down airborne pollutants and helps to remove noxious chemicals such as sulfur dioxide and nitric oxide, which are poisonous gases, from the atmosphere," said Christian George, an atmospheric chemist at the University of Lyon in France and lead author of the new study. "Thus, having a full understanding of its sources and sinks is key to understanding and mitigating air pollution."

Continue Reading

[tearsinthemist]

The invention is a powder that almost instantly kills thousands of waterborne bacteria when simply mixed with water and exposed to normal sunlight for a few seconds. It consists of nano-sized flakes of aluminum oxide, molybdenum sulfide, copper, and iron oxide, which combine with sunlight to form hydrogen peroxide and hydroxyl radicals, Phys.org reported.

These newly formed chemical byproducts work quickly to kill off any bacteria and then dissipate just as quickly.

The powder has several advantages over existing methods of cleaning drinking water. It does not use any chemicals that create lasting toxic byproducts, and it does not require ultraviolet light, which takes a long time and requires electricity, according to Phys.org.

In addition, the powder is recyclable. It can be removed from the now-clean water with a magnet, and researchers were able to reuse the same powder 30 times.

[imaec-digital]

Cidaltek W10

Description:

Proper disinfection and cleaning of dental work surfaces are vital in preventing infectious pathogens’ transmission to healthcare workers and patients. The CDC defines disinfection as the destruction of pathogenic microorganisms, physically or chemically. It offers guidelines on environmental surface disinfection for dental offices. Environmental surface disinfection is the cleaning and disinfecting of non-critical environmental surfaces using low-level to intermediate-level surface disinfectants.

CidalTek-W10 is a multi-component disinfectant containing Hydrogen peroxide as an oxidizing agent with combination of stabilizing agents to form a complex solution. A long-lasting disinfectant effect is achieved with addition of silver ions to the formula. It is Non-Carcinogenic, Bio-Degradable, Eco-friendly, and most importantly easy to use highly effective in dental clinic & dental labs.

Composition: Each 100 ml contains

Salient Features:

Broad spectrum against micro-organisms

Penetrates the biofilms formed by microorganisms

Sporicidal in action

Environment friendly & Bio-degradable

Non-Carcinogenic

Generates highly reactive hydroxyl radical in synergy with Ag+

Tasteless, Colorless & Odorless disinfectant

No toxic disinfection by-products

Direction Of Use:

For Surface & Environmental Disinfection

Add 100 ml (10%) of CidelTek-W10 disinfectant to 900 ml of water and mix well, apply on surface for 30 min contact time.

For Sporicidal action on surface use 20% Conc. Solution of CidalTek-W10 for 60 min contact time.

After thoroughly wetting the surface with lint free cloth, mop, sponge.

Treated surface must remain wet for respective contact time & allow to air dry.

Use 2-3 Bucket system for surface cleaning & disinfection

For Aerial Disinfection

Add 200 ml (20 %) of CidalTek W10 in 950 ml of water for 1000 cubic feet area.

For Sporicidal action on use 20% Conc. Solution of CidalTek-W10 for 60 min contact time.

Fogging machine should be mounted 2-3 feet from the floor level.

The angle of fogger machine kept at approximately 45 degrees.

Ensure the room is thoroughly cleaned before & after fogging with CidalTek W10 solution.

Area Of Application:

In the dental operatory to decontaminate environmental surfaces.

For disinfection of housekeeping surfaces (floors, walls, and sinks) have risk of disease transmission in dental healthcare settings.

For disinfection of dental environmental surfaces by removing organic matter, salts, and visible soils in dental settings such as area in dental laboratory, bathroom, and reception room in dental.

Soil surfaces (e.g., Blood, or body fluid) disinfection at dental clinic.

For disinfection of walls, and other vertical surfaces which are visibly contaminated by blood or OPIM (Other Potentially Infectious Material) in dentistry.

For cleaning and disinfection of environmental surfaces including blood and body substance spills.

For disinfecting spills of blood and other body fluids in dental clinic.

For aerial fogging in dental surgery unit, labs etc.

Microbial Efficacy:

Bactericidal, Fungicidal, Yeasticidal, Tuberculocidal, Virucidal & Sporicidal.

[whumpster-fire]

H: a hydrogen atom all by itself. This isn't stable in high density environments like anywhere on Earth because hydrogen atoms on their own want to form bonds with anything and everything, including other hydrogen atoms, but neutral monoatomic hydrogen can be found in the interstellar medium. Splitting hydrogen molecules in half with an electric arc and then letting them recombine apparently generates temperatures hot enough to weld tungsten.

H2: Good old hydrogen gas. Forms the majority of the atmospheres of giant planets. On lighter planets, the molecule is too light and is easily removed from the exosphere by solar wind and whatever other funky high energy stuff happens up there. Also really wants to react with oxygen and turn itself into water, making it a pretty good rocket fuel and a suboptimal lifting gas for balloons and dirigibles.

O: Again, this is too reactive to exist on Earth's surface except for an extremely short time in the middle of chemical reactions. In the exosphere/thermosphere it's relatively common due to splitting of oxygen molecules.

O2: Molecular oxygen, a notoriously highly reactive gas. It is a corrosive air pollutant harmful to organic life, and in high concentrations it can literally set many substances, including metals and organic matter, on fire. We take it for granted because we are among the descendants of the life that evolved to withstand and take advantage of its properties after oxygen-producing bacteria and archaea devastated Earth's biosphere.

O3: Ozone. An even more reactive form of oxygen formed by splitting oxygen molecules with electricity or UV radiation, and another one we're dependent on due to its ability to block a lot of the sun's UV output from reaching Earth's surface.

O8: Oxygen atoms in a cuboid shape. A solid oxygen phase that can form at very high temperature and pressure.

HO: Hydroxyl radical. Very reactive due to its unpaired valence electron. Found in the interstellar medium and is a short lived intermediate in some chemical reactions in our atmosphere.

H2O: Dihydrogen Monoxide, AKA water. One of the deadliest chemicals known to science: nearly 100% of people who have touched or ingested it have died. /s

HO2: Hydroperoxyl. Yet another highly reactive oxygen radical with important roles as an intermediary in chemical reactions.

H2O2: Hydrogen peroxide. This fun substance is in the sweet spot of sketchy chemicals where it's extremely reactive with other chemicals and also readily decomposes into water and oxygen gas, but it's stable enough that you can actually store enough of it to cause an explosion. I don't think it's quite in the "Hypergolic with test engineers" category, but high enough concentrations might be hypergolic with clothing, and high-concentration hydrogen peroxide can cause severe chemical burns.

H2O(n) where n > 2: assorted unstable stuff.

[organicsupplement]

The Power of Organic Quercetin: A Natural Antioxidant for Your Daily Wellness

Organic quercetin, a powerful natural antioxidant, is gaining attention for its impressive health benefits and versatility in promoting overall wellness. This plant compound, found in various fruits, vegetables, and herbs, plays a crucial role in protecting the body from oxidative stress.

 And supporting immune function. Whether you’re looking to enhance your energy, reduce inflammation, or support your cardiovascular health, organic quercetin could be the natural supplement you’ve been searching for. Few reports have suggested that the best organic quercetin supplement has anti-aging properties. 

The origin of quercetin

The name quercetin comes from the Latin word quercetum, which means “oak forest”. Quercetin is a naturally occurring flavonoid found in many plants, including fruits, vegetables, and grains. Quercetin is recognized as safe, it has not shown any side effects in humans or animals.

What is Organic Quercetin and Why You Should Care?

Organic Quercetin is a flavonoid found in fruits and vegetables that has many potential health benefits organic quercetin destroys harmful particles in the body known as free radicals which damage cell membranes.

Top Sources of Organic Quercetin for the Diet

Dark-colored grapes, apples, berries, kale, red onions, broccoli, buckwheat, and green tea are natural and top sources of quercetin organic apart from the best organic quercetin supplement.

The Antioxidant Benefits of Quercetin for Daily Wellness

Organic Quercetin has antioxidant and anti-inflammatory effects that might help reduce swelling, kill cancer cells, control blood sugar, help prevent heart disease, and may help reduce blood pressure levels.

Supercharge Your Workouts with Quercetin: The Ultimate Exercise Aid

Studies show that intake of quercetin may improve endurance and increase strength while working, an individual consuming organic quercetin supplements are less likely to feel tired while doing heavy lifting.

The Synergy of Quercetin with Other Nutrients for Optimal Health

When consumed with other nutrients like carbohydrates and proteins, organic quercetin improves glucose utilization in peripheral tissues antiviral properties of quercetin may prevent fevers.

The Science Behind Quercetin’s Anti-Cancer Potential

The antitumor efficacy of organic quercetin derivatives varied from quercetin based on the subunit location and chain length. Insertion of Phenolic hydroxyl group such as etherification (O-alkylation) cancer cell proliferation may effectively be suppressed.

Quercetin’s Role in Supporting Healthy Gut Function

Organic Quercetin can improve gut microbiota dysbiosis (the ecosystem of microorganisms that reside within a host), by increasing the diversity of the gut microbiota and promoting beneficial bacteria like Bifidobacterium, Bacteroides, and Lactobacillus. It can also suppress pathogens like E. coli and proteobacteria.

Quercetin: A Secret Weapon for Allergy Sufferers 

Researchers have concluded that organic quercetin may help reduce symptoms of allergies, including runny nose, watery eyes, hives, and swelling of the face and lips. By preventing immune cells from releasing histamines.

Conclusion  

Organic quercetin is a powerhouse antioxidant with a wide array of health benefits, from supporting the immune system and reducing inflammation to improving heart health and combating oxidative stress. By incorporating quercetin-rich foods into your daily routine, you can naturally enhance your wellness and potentially prevent the onset of chronic conditions. Always consider consulting with a healthcare professional before adding any new supplements to your routine, especially if you have pre-existing health conditions.

[sunaleisocial]

New climate chemistry model finds “non-negligible” impacts of potential hydrogen fuel leakage

New Post has been published on https://sunalei.org/news/new-climate-chemistry-model-finds-non-negligible-impacts-of-potential-hydrogen-fuel-leakage/

New climate chemistry model finds “non-negligible” impacts of potential hydrogen fuel leakage

As the world looks for ways to stop climate change, much discussion focuses on using hydrogen instead of fossil fuels, which emit climate-warming greenhouse gases (GHGs) when they’re burned. The idea is appealing. Burning hydrogen doesn’t emit GHGs to the atmosphere, and hydrogen is well-suited for a variety of uses, notably as a replacement for natural gas in industrial processes, power generation, and home heating.

But while burning hydrogen won’t emit GHGs, any hydrogen that’s leaked from pipelines or storage or fueling facilities can indirectly cause climate change by affecting other compounds that are GHGs, including tropospheric ozone and methane, with methane impacts being the dominant effect. A much-cited 2022 modeling study analyzing hydrogen’s effects on chemical compounds in the atmosphere concluded that these climate impacts could be considerable. With funding from the MIT Energy Initiative’s Future Energy Systems Center, a team of MIT researchers took a more detailed look at the specific chemistry that poses the risks of using hydrogen as a fuel if it leaks.

The researchers developed a model that tracks many more chemical reactions that may be affected by hydrogen and includes interactions among chemicals. Their open-access results, published Oct. 28 in Frontiers in Energy Research, showed that while the impact of leaked hydrogen on the climate wouldn’t be as large as the 2022 study predicted — and that it would be about a third of the impact of any natural gas that escapes today — leaked hydrogen will impact the climate. Leak prevention should therefore be a top priority as the hydrogen infrastructure is built, state the researchers.

Hydrogen’s impact on the “detergent” that cleans our atmosphere

Global three-dimensional climate-chemistry models using a large number of chemical reactions have also been used to evaluate hydrogen’s potential climate impacts, but results vary from one model to another, motivating the MIT study to analyze the chemistry. Most studies of the climate effects of using hydrogen consider only the GHGs that are emitted during the production of the hydrogen fuel. Different approaches may make “blue hydrogen” or “green hydrogen,” a label that relates to the GHGs emitted. Regardless of the process used to make the hydrogen, the fuel itself can threaten the climate. For widespread use, hydrogen will need to be transported, distributed, and stored — in short, there will be many opportunities for leakage. 

The question is, What happens to that leaked hydrogen when it reaches the atmosphere? The 2022 study predicting large climate impacts from leaked hydrogen was based on reactions between pairs of just four chemical compounds in the atmosphere. The results showed that the hydrogen would deplete a chemical species that atmospheric chemists call the “detergent of the atmosphere,” explains Candice Chen, a PhD candidate in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “It goes around zapping greenhouse gases, pollutants, all sorts of bad things in the atmosphere. So it’s cleaning our air.” Best of all, that detergent — the hydroxyl radical, abbreviated as OH — removes methane, which is an extremely potent GHG in the atmosphere. OH thus plays an important role in slowing the rate at which global temperatures rise. But any hydrogen leaked to the atmosphere would reduce the amount of OH available to clean up methane, so the concentration of methane would increase.

However, chemical reactions among compounds in the atmosphere are notoriously complicated. While the 2022 study used a “four-equation model,” Chen and her colleagues — Susan Solomon, the Lee and Geraldine Martin Professor of Environmental Studies and Chemistry; and Kane Stone, a research scientist in EAPS — developed a model that includes 66 chemical reactions. Analyses using their 66-equation model showed that the four-equation system didn’t capture a critical feedback involving OH — a feedback that acts to protect the methane-removal process.

Here’s how that feedback works: As the hydrogen decreases the concentration of OH, the cleanup of methane slows down, so the methane concentration increases. However, that methane undergoes chemical reactions that can produce new OH radicals. “So the methane that’s being produced can make more of the OH detergent,” says Chen. “There’s a small countering effect. Indirectly, the methane helps produce the thing that’s getting rid of it.” And, says Chen, that’s a key difference between their 66-equation model and the four-equation one. “The simple model uses a constant value for the production of OH, so it misses that key OH-production feedback,” she says.

To explore the importance of including that feedback effect, the MIT researchers performed the following analysis: They assumed that a single pulse of hydrogen was injected into the atmosphere and predicted the change in methane concentration over the next 100 years, first using four-equation model and then using the 66-equation model. With the four-equation system, the additional methane concentration peaked at nearly 2 parts per billion (ppb); with the 66-equation system, it peaked at just over 1 ppb.

Because the four-equation analysis assumes only that the injected hydrogen destroys the OH, the methane concentration increases unchecked for the first 10 years or so. In contrast, the 66-equation analysis goes one step further: the methane concentration does increase, but as the system re-equilibrates, more OH forms and removes methane. By not accounting for that feedback, the four-equation analysis overestimates the peak increase in methane due to the hydrogen pulse by about 85 percent. Spread over time, the simple model doubles the amount of methane that forms in response to the hydrogen pulse.

Chen cautions that the point of their work is not to present their result as “a solid estimate” of the impact of hydrogen. Their analysis is based on a simple “box” model that represents global average conditions and assumes that all the chemical species present are well mixed. Thus, the species can vary over time — that is, they can be formed and destroyed — but any species that are present are always perfectly mixed. As a result, a box model does not account for the impact of, say, wind on the distribution of species. “The point we’re trying to make is that you can go too simple,” says Chen. “If you’re going simpler than what we’re representing, you will get further from the right answer.” She goes on to note, “The utility of a relatively simple model like ours is that all of the knobs and levers are very clear. That means you can explore the system and see what affects a value of interest.”

Leaked hydrogen versus leaked natural gas: A climate comparison

Burning natural gas produces fewer GHG emissions than does burning coal or oil; but as with hydrogen, any natural gas that’s leaked from wells, pipelines, and processing facilities can have climate impacts, negating some of the perceived benefits of using natural gas in place of other fossil fuels. After all, natural gas consists largely of methane, the highly potent GHG in the atmosphere that’s cleaned up by the OH detergent. Given its potency, even small leaks of methane can have a large climate impact.

So when thinking about replacing natural gas fuel — essentially methane — with hydrogen fuel, it’s important to consider how the climate impacts of the two fuels compare if and when they’re leaked. The usual way to compare the climate impacts of two chemicals is using a measure called the global warming potential, or GWP. The GWP combines two measures: the radiative forcing of a gas — that is, its heat-trapping ability — with its lifetime in the atmosphere. Since the lifetimes of gases differ widely, to compare the climate impacts of two gases, the convention is to relate the GWP of each one to the GWP of carbon dioxide. 

But hydrogen and methane leakage cause increases in methane, and that methane decays according to its lifetime. Chen and her colleagues therefore realized that an unconventional procedure would work: they could compare the impacts of the two leaked gases directly. What they found was that the climate impact of hydrogen is about three times less than that of methane (on a per mass basis). So switching from natural gas to hydrogen would not only eliminate combustion emissions, but also potentially reduce the climate effects, depending on how much leaks.

Key takeaways

In summary, Chen highlights some of what she views as the key findings of the study. First on her list is the following: “We show that a really simple four-equation system is not what should be used to project out the atmospheric response to more hydrogen leakages in the future.” The researchers believe that their 66-equation model is a good compromise for the number of chemical reactions to include. It generates estimates for the GWP of methane “pretty much in line with the lower end of the numbers that most other groups are getting using much more sophisticated climate chemistry models,” says Chen. And it’s sufficiently transparent to use in exploring various options for protecting the climate. Indeed, the MIT researchers plan to use their model to examine scenarios that involve replacing other fossil fuels with hydrogen to estimate the climate benefits of making the switch in coming decades.

The study also demonstrates a valuable new way to compare the greenhouse effects of two gases. As long as their effects exist on similar time scales, a direct comparison is possible — and preferable to comparing each with carbon dioxide, which is extremely long-lived in the atmosphere. In this work, the direct comparison generates a simple look at the relative climate impacts of leaked hydrogen and leaked methane — valuable information to take into account when considering switching from natural gas to hydrogen.

Finally, the researchers offer practical guidance for infrastructure development and use for both hydrogen and natural gas. Their analyses determine that hydrogen fuel itself has a “non-negligible” GWP, as does natural gas, which is mostly methane. Therefore, minimizing leakage of both fuels will be necessary to achieve net-zero carbon emissions by 2050, the goal set by both the European Commission and the U.S. Department of State. Their paper concludes, “If used nearly leak-free, hydrogen is an excellent option. Otherwise, hydrogen should only be a temporary step in the energy transition, or it must be used in tandem with carbon-removal steps [elsewhere] to counter its warming effects.”

[jcmarchi]

New climate chemistry model finds “non-negligible” impacts of potential hydrogen fuel leakage

New Post has been published on https://thedigitalinsider.com/new-climate-chemistry-model-finds-non-negligible-impacts-of-potential-hydrogen-fuel-leakage/

New climate chemistry model finds “non-negligible” impacts of potential hydrogen fuel leakage

As the world looks for ways to stop climate change, much discussion focuses on using hydrogen instead of fossil fuels, which emit climate-warming greenhouse gases (GHGs) when they’re burned. The idea is appealing. Burning hydrogen doesn’t emit GHGs to the atmosphere, and hydrogen is well-suited for a variety of uses, notably as a replacement for natural gas in industrial processes, power generation, and home heating.

But while burning hydrogen won’t emit GHGs, any hydrogen that’s leaked from pipelines or storage or fueling facilities can indirectly cause climate change by affecting other compounds that are GHGs, including tropospheric ozone and methane, with methane impacts being the dominant effect. A much-cited 2022 modeling study analyzing hydrogen’s effects on chemical compounds in the atmosphere concluded that these climate impacts could be considerable. With funding from the MIT Energy Initiative’s Future Energy Systems Center, a team of MIT researchers took a more detailed look at the specific chemistry that poses the risks of using hydrogen as a fuel if it leaks.

The researchers developed a model that tracks many more chemical reactions that may be affected by hydrogen and includes interactions among chemicals. Their open-access results, published Oct. 28 in Frontiers in Energy Research, showed that while the impact of leaked hydrogen on the climate wouldn’t be as large as the 2022 study predicted — and that it would be about a third of the impact of any natural gas that escapes today — leaked hydrogen will impact the climate. Leak prevention should therefore be a top priority as the hydrogen infrastructure is built, state the researchers.

Hydrogen’s impact on the “detergent” that cleans our atmosphere

Global three-dimensional climate-chemistry models using a large number of chemical reactions have also been used to evaluate hydrogen’s potential climate impacts, but results vary from one model to another, motivating the MIT study to analyze the chemistry. Most studies of the climate effects of using hydrogen consider only the GHGs that are emitted during the production of the hydrogen fuel. Different approaches may make “blue hydrogen” or “green hydrogen,” a label that relates to the GHGs emitted. Regardless of the process used to make the hydrogen, the fuel itself can threaten the climate. For widespread use, hydrogen will need to be transported, distributed, and stored — in short, there will be many opportunities for leakage. 

The question is, What happens to that leaked hydrogen when it reaches the atmosphere? The 2022 study predicting large climate impacts from leaked hydrogen was based on reactions between pairs of just four chemical compounds in the atmosphere. The results showed that the hydrogen would deplete a chemical species that atmospheric chemists call the “detergent of the atmosphere,” explains Candice Chen, a PhD candidate in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “It goes around zapping greenhouse gases, pollutants, all sorts of bad things in the atmosphere. So it’s cleaning our air.” Best of all, that detergent — the hydroxyl radical, abbreviated as OH — removes methane, which is an extremely potent GHG in the atmosphere. OH thus plays an important role in slowing the rate at which global temperatures rise. But any hydrogen leaked to the atmosphere would reduce the amount of OH available to clean up methane, so the concentration of methane would increase.

However, chemical reactions among compounds in the atmosphere are notoriously complicated. While the 2022 study used a “four-equation model,” Chen and her colleagues — Susan Solomon, the Lee and Geraldine Martin Professor of Environmental Studies and Chemistry; and Kane Stone, a research scientist in EAPS — developed a model that includes 66 chemical reactions. Analyses using their 66-equation model showed that the four-equation system didn’t capture a critical feedback involving OH — a feedback that acts to protect the methane-removal process.

Here’s how that feedback works: As the hydrogen decreases the concentration of OH, the cleanup of methane slows down, so the methane concentration increases. However, that methane undergoes chemical reactions that can produce new OH radicals. “So the methane that’s being produced can make more of the OH detergent,” says Chen. “There’s a small countering effect. Indirectly, the methane helps produce the thing that’s getting rid of it.” And, says Chen, that’s a key difference between their 66-equation model and the four-equation one. “The simple model uses a constant value for the production of OH, so it misses that key OH-production feedback,” she says.

To explore the importance of including that feedback effect, the MIT researchers performed the following analysis: They assumed that a single pulse of hydrogen was injected into the atmosphere and predicted the change in methane concentration over the next 100 years, first using four-equation model and then using the 66-equation model. With the four-equation system, the additional methane concentration peaked at nearly 2 parts per billion (ppb); with the 66-equation system, it peaked at just over 1 ppb.

Because the four-equation analysis assumes only that the injected hydrogen destroys the OH, the methane concentration increases unchecked for the first 10 years or so. In contrast, the 66-equation analysis goes one step further: the methane concentration does increase, but as the system re-equilibrates, more OH forms and removes methane. By not accounting for that feedback, the four-equation analysis overestimates the peak increase in methane due to the hydrogen pulse by about 85 percent. Spread over time, the simple model doubles the amount of methane that forms in response to the hydrogen pulse.

Chen cautions that the point of their work is not to present their result as “a solid estimate” of the impact of hydrogen. Their analysis is based on a simple “box” model that represents global average conditions and assumes that all the chemical species present are well mixed. Thus, the species can vary over time — that is, they can be formed and destroyed — but any species that are present are always perfectly mixed. As a result, a box model does not account for the impact of, say, wind on the distribution of species. “The point we’re trying to make is that you can go too simple,” says Chen. “If you’re going simpler than what we’re representing, you will get further from the right answer.” She goes on to note, “The utility of a relatively simple model like ours is that all of the knobs and levers are very clear. That means you can explore the system and see what affects a value of interest.”

Leaked hydrogen versus leaked natural gas: A climate comparison

Burning natural gas produces fewer GHG emissions than does burning coal or oil; but as with hydrogen, any natural gas that’s leaked from wells, pipelines, and processing facilities can have climate impacts, negating some of the perceived benefits of using natural gas in place of other fossil fuels. After all, natural gas consists largely of methane, the highly potent GHG in the atmosphere that’s cleaned up by the OH detergent. Given its potency, even small leaks of methane can have a large climate impact.

So when thinking about replacing natural gas fuel — essentially methane — with hydrogen fuel, it’s important to consider how the climate impacts of the two fuels compare if and when they’re leaked. The usual way to compare the climate impacts of two chemicals is using a measure called the global warming potential, or GWP. The GWP combines two measures: the radiative forcing of a gas — that is, its heat-trapping ability — with its lifetime in the atmosphere. Since the lifetimes of gases differ widely, to compare the climate impacts of two gases, the convention is to relate the GWP of each one to the GWP of carbon dioxide. 

But hydrogen and methane leakage cause increases in methane, and that methane decays according to its lifetime. Chen and her colleagues therefore realized that an unconventional procedure would work: they could compare the impacts of the two leaked gases directly. What they found was that the climate impact of hydrogen is about three times less than that of methane (on a per mass basis). So switching from natural gas to hydrogen would not only eliminate combustion emissions, but also potentially reduce the climate effects, depending on how much leaks.

Key takeaways

In summary, Chen highlights some of what she views as the key findings of the study. First on her list is the following: “We show that a really simple four-equation system is not what should be used to project out the atmospheric response to more hydrogen leakages in the future.” The researchers believe that their 66-equation model is a good compromise for the number of chemical reactions to include. It generates estimates for the GWP of methane “pretty much in line with the lower end of the numbers that most other groups are getting using much more sophisticated climate chemistry models,” says Chen. And it’s sufficiently transparent to use in exploring various options for protecting the climate. Indeed, the MIT researchers plan to use their model to examine scenarios that involve replacing other fossil fuels with hydrogen to estimate the climate benefits of making the switch in coming decades.

The study also demonstrates a valuable new way to compare the greenhouse effects of two gases. As long as their effects exist on similar time scales, a direct comparison is possible — and preferable to comparing each with carbon dioxide, which is extremely long-lived in the atmosphere. In this work, the direct comparison generates a simple look at the relative climate impacts of leaked hydrogen and leaked methane — valuable information to take into account when considering switching from natural gas to hydrogen.

Finally, the researchers offer practical guidance for infrastructure development and use for both hydrogen and natural gas. Their analyses determine that hydrogen fuel itself has a “non-negligible” GWP, as does natural gas, which is mostly methane. Therefore, minimizing leakage of both fuels will be necessary to achieve net-zero carbon emissions by 2050, the goal set by both the European Commission and the U.S. Department of State. Their paper concludes, “If used nearly leak-free, hydrogen is an excellent option. Otherwise, hydrogen should only be a temporary step in the energy transition, or it must be used in tandem with carbon-removal steps [elsewhere] to counter its warming effects.”

[biology-geology-beaches-india]

S. Sunkavally's Science Research Diaries, page 332.

[hyperfilteration]

The Future of Water Treatment Plant Technologies: Innovations for Clean Water

Water treatment plants are critical infrastructures designed to ensure the availability of clean and safe water for drinking, agriculture, and industrial purposes. As global challenges such as climate change, population growth, and pollution intensify, the demands on water treatment plants are increasing. The future of water treatment plant technologies lies in the integration of innovative processes, sustainable practices, and advanced monitoring systems to tackle these growing challenges effectively.

The Growing Need for Innovation in Water Treatment Plants

Rising Water Demand With global population growth, urbanization, and industrial expansion, the demand for clean water is at an all-time high. Water treatment plants must process increasing volumes of water while maintaining stringent quality standards.

Water Pollution Challenges Pollutants such as microplastics, pharmaceuticals, heavy metals, and agricultural runoff present unique challenges for traditional water treatment processes. Advanced technologies are required to address these contaminants effectively.

Sustainability Goals Modern water treatment plants must align with global sustainability goals, including reducing greenhouse gas emissions, conserving energy, and minimizing waste generation.

Emerging Technologies in Water Treatment Plants

Membrane Technologies Membrane technologies such as nanofiltration, ultrafiltration, and reverse osmosis are becoming more prevalent in water treatment plants. These systems use semi-permeable membranes to remove contaminants, including salts, heavy metals, and organic compounds, ensuring high-quality water output.

Advanced Oxidation Processes (AOPs) AOPs involve the generation of reactive species, such as hydroxyl radicals, to degrade complex organic pollutants and disinfect water. These processes are particularly effective against pharmaceuticals, pesticides, and industrial chemicals that resist conventional treatment methods.

Smart Monitoring and Automation The integration of IoT devices, AI, and machine learning allows for real-time monitoring and control of water treatment plant operations. These technologies optimize energy usage, chemical dosing, and maintenance schedules, ensuring cost-effectiveness and efficiency.

Electrocoagulation Electrocoagulation is an innovative process that uses electrical currents to remove suspended solids, heavy metals, and other contaminants. This method is highly effective for treating industrial wastewater and is gaining traction in modern water treatment plants.

Decentralized Treatment Systems Decentralized water treatment plants are designed to serve smaller communities and industrial facilities. These systems are modular, energy-efficient, and can be customized to address specific water quality issues.

Sustainability in Water Treatment Plant Technologies

Energy Efficiency Modern water treatment plants are adopting energy-efficient technologies, such as energy recovery systems, solar panels, and wind turbines, to reduce their carbon footprint.

Resource Recovery Water treatment plants are increasingly focusing on recovering valuable resources, such as nutrients and biogas, from wastewater. For instance, phosphorus can be extracted from sludge for use as fertilizer.

Water Reuse Treated wastewater can be further purified for reuse in agriculture, industrial processes, and even drinking water. Advanced treatment processes, such as reverse osmosis and UV disinfection, make water reuse a viable option.

Overcoming Challenges in Implementing New Technologies

Cost and Infrastructure Advanced technologies often require significant investment and infrastructure upgrades. Governments and private sectors must collaborate to fund and implement these innovations in water treatment plants.

Training and Expertise Operating advanced water treatment technologies requires skilled personnel. Training programs and knowledge-sharing initiatives are essential to ensure the effective use of these systems.

Regulatory Compliance Emerging technologies must meet stringent regulatory standards to ensure the safety and quality of treated water.

Conclusion

The future of water treatment plants lies in the adoption of innovative technologies that address emerging water quality challenges while prioritizing sustainability and efficiency. By investing in advanced processes, smart monitoring, and resource recovery, water treatment plants can continue to provide clean and safe water for all while reducing their environmental impact.

[tenth-sentence]

Considering the various hydrocarbon reactants, there are two principal mechanisms by which hydroxyl radicals initiate oxidation.

"Environmental Chemistry: A Global Perspective", 4e - Gary W. VanLoon & Stephen J. Duffy

[whats-in-a-sentence]

The most common forms of ROS in plant cells are superoxide (O2•-), singlet oxygen (¹O2), hydrogen peroxide (H2O2), and hydroxyl radicals (OH•) (Figure 24.3).

"Plant Physiology and Development" int'l 6e - Taiz, L., Zeiger, E., Møller, I.M., Murphy, A.

[ainews]

Embassies are critical diplomatic posts—they represent the interests of a foreign power in a given country. But for hydroxyl, a type of sulfur-containing molecule, they can be particularly painful. Hydroxyl radicals—which form when a hydroxyl molecule gains an electron and creates an unstable state of higher energy—have been shown to emit abnormally high concentrations of ultraviolet radiation when in direct sunlight. This has been linked to greater risks of skin cancer and other health complications in many instances.

Hydroxyl radical concentrations are typically kept to a minimum in natural environments, but they can increase in certain situations. One of those situations is of particular concern for embassy workers: when the embassies are near natural sunlight. Sunlight can drive the formation of higher concentrations of hydroxyl radicals in the air, leading to potentially dangerous levels of UV radiation. Studies have revealed that workers at embassies located near sunny areas may be exposed to higher levels of UV radiation than other people, potentially increasing their risk for skin cancer and other ailments.

Therefore, it’s important for embassies to assess hydroxyl radical concentrations in their environment and take the necessary precautions to protect workers from UV radiation exposure. That should include limiting direct sunlight exposure for embassy workers in addition to other protective measures such as blocking windows and using more protective clothing. By taking these steps, embassies can help ensure the health of their workers and hopefully avoid the potentially dangerous effects of hydroxyl radiation exposure.