Clean our water with a revolutionary chemistry "bioinspired"

The 20th and 21st centuries have seen an explosion in the use of synthetic chemicals around the world, including pesticides, drugs and household cleaners, many of which end up in our waterways. Even in small amounts, these substances can affect wildlife, plants, and humans, and a number of them have shown resistance to the usual water treatment methods, leaving them undisturbed. Accumulate in the environment without control.

In a study published in Catalysis ACSResearchers at Carnegie Mellon University's Institute of Green Sciences (IGS) have paved the way for a new field of sustainable chemistry by unveiling powerful, safe and inexpensive oxidation catalysts inspired by biological processes in our field. bad that destroy even the most stubborn micropollutants.

"This is perhaps the most important document we have produced in 20 years," said Teresa Heinz, professor of green chemistry, Terrence J. Collins, who heads the IGS.

Collins, concerned over the harmful biological effects of synthetic chemicals since his undergraduate studies in New Zealand, has spent the last forty years developing methods to eliminate these water products by using the process. oxidation, a familiar process. to the human body.

"Oxidation chemistry accounts for a considerable percentage of the biochemistry taking place in us," noted Collins. "This is how nature approaches the problem of converting organic matter, especially chemically resistant organic matter, into material that can be used for biochemistry or energy to keep the body active. is too big for the enzymes that regulate the chemistry of oxidation, and we have persistent compounds against which nature is powerless ".

The substrate of choice for many oxidation reactions in our bodies and elsewhere in nature is hydrogen peroxide, which peroxidase enzymes activate to break down the molecules of foods and other substances that we absorb. The aim of Collins since 1980 is essentially to recreate power and efficiency. of these enzymes with the artificial catalysts of his creation called macrocyclic tetra-amido ligands (TAML).

"We had to make sure that the iron center of our catalysts did the same kind of chemistry as the iron-peroxidase enzyme center," Collins said. "We spent 15 years systematically searching how to make the TAML catalyst composition perform, and after getting first, we spent 20 years trying to improve it."

In this new study, Collins describes the "record" performance of these improved catalysts, called NewTAML. Tests have shown that infinitely reduced amounts of these catalysts activate hydrogen peroxide to remove the persistent, pharmaceutical and common micropollutant propranolol from water in less than five minutes.

Because of their speed and efficiency, Collins believes that NewTAML will realize significant savings over current water treatment technologies, such as ozone purification. However, security is even more important than cost and power. A catalyst that eliminated micropollutants would be useless if the catalyst itself ended up having harmful effects on living organisms.

"It's trivial to know if a substance is extremely toxic – it's when a surreptitiously toxic problem expressed in parts per billion in your body that you have a big problem," Collins explained. "Endocrine hormones in your body act in parts per trillion at low concentrations in parts, they control the development of life and what we become.The multitude of chemicals we have discovered every day that we have discovered are Disruptors of the endocrine system reads like a sci-fi horror story, but that's the reality ".

To test the safety of catalysts, Collins helped the world leaders in endocrine disruption science to identify appropriate tests and organize them logically to detect the adverse effects of low-dose chemicals. And TAML and NewTAML were used for the resulting hierarchical protocol beta test for endocrine disruption. The NewTAML paper includes an endocrine disruption test in mice, which the candidate catalyst has pbaded with flying colors.

In addition, Collins and his team eventually rejected potential catalysts that could significantly improve the performance of TAMLs because of their lack of presence in living organisms. The addition of fluorine in TAML, for example, has dramatically improved their performance and stability, but fluoride is a substance rarely found in living things, and researchers feared that its use in catalysts used in 39, drinking water may increase the concentration of fluoride and fluorochemical degradation products in treated water. . "There was no negative toxicity result in the tests," Collins said. "The decision to try to replicate the singular and remarkable electronic properties of fluoride without using it has proven to be one of the main reasons why we have been rewarded with NewTAML."

"The best way to stay safe for toxicity is to build your chemical technologies from the same elements you are," Collins said.

This "bioinspired" approach to chemistry is one of the pillars of the new field of sustainable catalysis of ultradiluted oxidation that Collins and the Institute for Green Science are promoting.