Light-driven catalyst can break down PFAS forever chemicals

Good news!

Remember so called "forever chemicals" is mostly alarmism, hysteria, and demagoguery! Unfortunately, too many scientists engage in this nonsense too!

Alert: Plastophobia is a serious disorder. Please seek immediate medical help! (Caution: satire)

What about all the benefits of plastics in our lives? What are the possible substitutes (how healthy are the substitutes)?

"But their ongoing impact on health issues in humans and other animals is being uncovered. Some PFAS are carcinogenic. The new research ... describes how a material can use light to catalyse a reaction which breaks down a range of pollutants in water including PFAS. This kind of approach has previously shown promise in breaking down PFAS. ..."

"... The process involves the use of a class of materials known as covalent organic frameworks, or COFs, whose porous structure ⎯ and hence high surface area ⎯ make them useful in light-driven, or photocatalytic, reactions. When they interact with light, some of the electrons in COF molecules get displaced, forming holes, and this bifurcation of charges is what makes COFs good photocatalysts. ..."

From the abstract:

"Nature-inspired photocatalysis provides a sustainable solution for energy conversion and pollutant degradation. Covalent organic frameworks (COFs), with tunable properties and high porosity, have shown promise as photocatalysts, though their synthesis often requires extensive efforts. In this study, we report the in-situ growth of COFs on defective hexagonal boron nitride (hBN) surfaces to form hBN@1,3,5-triformylphloroglucinol (Tp)-4,4′-diamino-[1,1′-biphenyl]-3,3′-dicarbonitrile (DBCN) heterostructures. Bandgap analysis and ultraviolet photoelectron spectroscopy revealed the formation of type-II heterojunctions, enhancing charge separation and minimizing recombination. Density functional theory simulations confirmed efficient charge transfer at the COF-hBN interface. The hBN@Tp-DBCN heterostructures demonstrated remarkable versatility, achieving nearly complete degradation of dyes, pharmaceutical waste, and persistent compounds such as perfluorooctanoic acid [PFAS]. Practical implementation in vertical and horizontal configurations further validated their application potential. This research underscores the efficacy of hBN@COFs heterostructures in photocatalysis and offers a promising direction for metal-free heterostructures in artificial photosynthesis and water treatment."

Light-driven catalyst can break down PFAS forever chemicals | News | ConnectSci

Engineered material uses light to destroy PFAS, other contaminants (original news release)

Covalent organic framework/hexagonal boron nitride heterostructure photocatalysts for efficient degradation of emerging contaminants (no public access)

Graphical abstract

US, Mexico agree to stop sewage flow from Tijuana to Southern California

Good news! Maybe this is the beginning of something greater between President Trump and President Sheinbaum.

Nearly a third of antibiotics consumed by people end up in surface waters worldwide. Really!

I would say it has been repeatedly reported for over 50 years that antibiotics end up in rivers or lakes etc. What is the point! This seems to be a piece of junk science!

Also one of those never dying and often repeated narratives!

This study is based on computer modeling! Junk model? Garbage in, garbage out?

Lots of estimates and thresholds! How relevant are these thresholds?

What do the authors mean by "human consumption alone represents a significant risk for rivers across all continents"? So should we not consume antibiotics anymore?

It is odd that the authors did not bother to mention wastewater treatment in the abstract nor in the significance chapter. This is shoddy science!

Caveat: I did not read the study!

"Nearly a third of antibiotics consumed by people end up in rivers, per a PNAS modeling study from McGill University and One Health Trust researchers that estimates the distribution of chemical pollutants from untreated wastewater and wastewater treatment plants."

"... Much of the focus has been on the antibiotic manufacturing process, which is known to release antibiotic-laced wastewater directly into nearby waterways. That has resulted in efforts to monitor and limit pollution from antibiotic manufacturing sites.

But since antibiotics consumed by people aren't fully metabolized, wastewaters from households and hospitals are also potential sources of antibiotic contamination. And while wastewater treatment plants can remove some antibiotic residues before the treated water is released into surface waters, they can't remove all of them [???]. ...

The researchers also estimated that 750 million people—roughly 10% of the global population—are exposed [???] to the top 1% of surface waters with the highest cumulative concentrations of antibiotics. ...

The authors say the findings suggest an "urgent need" [???] for further research on the environmental fate and impact of the antibiotics that their model predicts are most prevalent in surface waters, particularly those that pose a high potential risk to aquatic ecosystems and human health. ..."

From the abstract:

"The presence of antibiotics in surface waters poses risks to aquatic ecosystems and human health due to their toxicity and influence on antimicrobial resistance. After human consumption and partial metabolism, antibiotic residues are excreted and undergo complex accumulation and decay processes along their pathway from wastewater to natural river systems.

Here, we use a global contaminant fate model to estimate that of

the annual human consumption of the 40 most used antibiotics (29,200 tonnes), 

8,500 tonnes (29%) are released into the river system and 

3,300 tonnes (11%) reach the world's oceans or inland sinks.

Even when only domestic sources are considered (i.e. not including veterinary or industrial sources),

we estimate that 6 million km of rivers worldwide are subject to total antibiotic concentrations in excess of thresholds that are protective of ecosystems and resistance promotion during low streamflow conditions, 

with the dominant contributors being amoxicillin, ceftriaxone, and cefixime. Therefore, it is of concern that human consumption alone represents a significant risk for rivers across all continents, with the largest extents found in Southeast Asia. Global antibiotic consumption has grown rapidly over the last 15 years and continues to increase, particularly in low- and middle-income countries, requiring new strategies to safeguard water quality and protect human and ecosystem health."

"Significance Statement

Antibiotic contamination in global rivers poses significant threats to aquatic ecosystems and human health. Our model predicts that 8,500 tonnes of antibiotics enter river systems annually from domestic consumption alone, causing elevated concentrations of various antibiotics in rivers across all continents. For example, estimated concentrations of antibiotics in 6 million km of rivers worldwide exceed thresholds that are protective of ecosystems and/or resistance promotion, with the most impacted regions located in Southeast Asia. As global antibiotic consumption rises, especially in low- and middle-income countries, these findings underscore the urgent need for the development and implementation of strategies to minimize antibiotic pollution and safeguard environmental and human health."

Global Health NOW: Global Vaccinations in Jeopardy; Kenya’s Push to Improve HIV Testing During Pregnancy; and Run, Run, Robots!

Antibiotic residues prevalent in rivers globally, study reveals

Antibiotics in the global river system arising from human consumption (open access)

Fig. 1 Contaminant pathways of antibiotics in the global aquatic environment. Modeled contaminant pathways and mass balances of antibiotics by path. Values in parentheses indicate total amounts of the top 40 antibiotics consumed worldwide in tonnes year−1; percentage values are relative to the total excretion amount (20,500 tonnes year−1).

Novel filter may speed wastewater cleanup

Good news!

"... A new membrane could provide help, by dramatically improving a water filtering technology already used to clean up pollution from industrial sources and farms, researchers reported last week in Nature Sustainability. If they can be scaled up and commercialized, the authors argue, the new filters could sharply reduce the cost of turning wastewater into safe drinking water. ...

One option for cleaning up this wastewater is using “nanofiltration” membranes, which feature plastic films shot through with holes roughly 1 nanometer across to filter out pollutants such as organic compounds, metals, and microbes. (Desalination plants use even more finely perforated “reverse osmosis” membranes, with holes 0.1 nanometer across, to filter out dissolved salts.)

The sale of nanofiltration membranes is already a $1 billion business annually, according to the market research firm MarketsandMarkets. But a challenge for manufacturers has been controlling the range of pore sizes, which limits the membranes’ ability to exclude some contaminants ...

Now, ...  have come up with a way to make membranes with consistent 1-nanometer pores. The researchers started with two polymer building blocks: long, polelike molecules and short, connecting segments. When placed in solution with a porous plastic film, the poles and connector segments lined up on the film. The connectors bonded to specific sites on the poles, creating a sheet with ring-shaped voids, a bit like a chain-link fence. Stacking numerous sheets, the researchers formed a solid membrane. ..."

From the abstract:

"Membrane nanofiltration is widely used in various chemical separation and water purification processes. However, obtaining high water permeance and high solute removal selectivity for achieving energetically efficient precise separation in nanofiltration membranes remains challenging due to their inherent pore heterogeneity. Here we introduce a cinnamate-mediated polymerization method to fabricate nanofiltration membranes with highly homogenized and well-tailored nanopores to address this challenge. Our experimental data and molecular dynamics simulation results show that cinnamate-mediated polymerization can manipulate monomer diffusion and intermolecular void size to create a homogenized and tailored selective layer in a highly homogenized membrane. The obtained membrane exhibited a high water permeance of 104.3 l m−2 h−1 bar−1, which is substantially higher than that of the pristine membrane synthesized without cinnamate mediation, superior molecular sieving ability, excellent salt/dye separation factor and good operational stability, outperforming state-of-the-art membranes. Overall, this work enables the design and fabrication of nanofiltration membranes that combine other mutually exclusive properties for energetically efficient water purification applications towards a sustainable water–energy nexus."

Novel filter may speed wastewater cleanup | Science | AAAS

Polymeric membranes with highly homogenized nanopores for ultrafast water purification (no public access)

Purifying water with just a few atoms

Amazing stuff! Water purification at the level of single atoms!

This research seems to describe a further and promising advancement of nanocatalysts.

Besides purification, I bet something similar can also be applied to desalination! Desalination is salvation!

"Due to their considerable efficiency, catalysts made of just a few atoms show great promise in the field of water treatment. In a new study, researchers looked into how to optimize the performance of these catalysts and make them viable for practical use. ...
a system with a catalyst using an ensemble of palladium atoms, designed to reduce the carcinogen bromate in water. They introduced the non-metal elements sulfur, nitrogen, and boron to the surrounds of atom ensembles. The overall results suggested an improvement in the system’s catalytic performance. ..."

From the significance and abstract:

"Significance

Substrate-anchored, single-atom catalysts (SACs) have emerged as a promising alternative to conventional nanocatalysts for various catalytic processes. The catalytic performance of SACs can be controlled by various synthetic strategies, including the manipulation of substrate atoms surrounding metal sites. This study examines whether the coordination environment (CE) of the palladium metal ensemble, a newly identified small-clustered structure with CE resembling that of SAC, can also be tuned by doping nonmetal elements onto the substrate. The results demonstrate that such CE manipulation could decrease the activation energy of the rate-limiting step and achieve efficient H2 dissociation for several important reductive catalytic schemes, establishing a new strategy to effectively engineer metal ensemble catalysts.

Abstract

Atomic dispersion of metal catalysts on a substrate accounts for the increased atomic efficiency of single-atom catalysts (SACs) in various catalytic schemes compared to the nanoparticle counterparts. However, lacking neighboring metal sites has been shown to deteriorate the catalytic performance of SACs in a few industrially important reactions, such as dehalogenation, CO oxidation, and hydrogenation. Metal ensemble catalysts (Mn), an extended concept to SACs, have emerged as a promising alternative to overcome such limitation. Inspired by the fact that the performance of fully isolated SACs can be enhanced by tailoring their coordination environment (CE), we here evaluate whether the CE of Mn can also be manipulated in order to enhance their catalytic activity. We synthesized a set of Pd ensembles (Pdn) on doped graphene supports (Pdn/X-graphene where X = O, S, B, and N). We found that introducing S and N onto oxidized graphene modifies the first shell of Pdn converting Pd–O to Pd–S and Pd–N, respectively. We further found that the B dopant significantly affected the electronic structure of Pdn by serving as an electron donor in the second shell. We examined the performance of Pdn/X-graphene toward selective reductive catalysis, such as bromate reduction, brominated organic hydrogenation, and aqueous-phase CO2 reduction. We observed that Pdn/N-graphene exhibited superior performance by lowering the activation energy of the rate-limiting step, i.e., H2 dissociation into atomic hydrogen. The results collectively suggest controlling the CE of SACs in an ensemble configuration is a viable strategy to optimize and enhance their catalytic performance."

Purifying water with just a few atoms | Yale School of Engineering & Applied Science

Enhancing the activity of Pd ensembles on graphene by manipulating coordination environment (no public access)

Wastewater treatment plant On A Truck Will Ease India’s Waste Water Crisis

Good news! Happy 75th Independence Day for India!

"Mobile water treatment plants that can fit on the back of a truck are being deployed across towns and villages in India. 

The technology developed by an Israeli company will help tackle the country’s desperate sewage crisis.

India generates over 72 million liters of sewage a day, but can treat barely one-third of it. Much of it ends up, untreated, in rivers and lakes, creating a huge health hazard. ...
Huliot, an Israeli manufacturer of advanced pipe systems, developed the ClearBlack STP, which fits inside a shipping container. It was launched in 20 Indian states on August 15th, Indian Independence Day. ..."

Tech On A Truck Will Ease India’s Waste Water Crisis

Engineered yeast can remove heavy metals from wastewater

Good news! Unfortunately, article is behind paywall!

Engineered yeast can remove heavy metals from wastewater | Research | Chemistry World: Easy storage and rapid growth could see yeast compete with bacterial and chemical remediation