In the twentieth and twenty-first centuries, synthetic chemicals such as pesticides, medicines and household cleaners were increasingly used worldwide, many of which land in our waterways. Even in small amounts, these substances can attack wildlife, plants and humans, and some of them have shown resistance to normal water treatment methods, causing them to accumulate uncontrollably in the environment.
In a study published in ACS Catalysis researchers at Carnegie Mellon University's Institute of Green Science (IGS) paved the way for a new field of sustainable chemistry by revealing high-performance, safe and cost-effective oxidation catalysts that were inspired by the biological processes in us that degrade even the most stubborn micropollutants.
"It may be the most important paper we have produced in 20 years," said Teresa Heinz, a professor of green chemistry at Terrence J. Collins, who heads the IGS.
Collins, who has studied the deleterious biological effects of synthetic chemicals since his time in New Zealand, has spent the past four decades developing methods to remove these chemicals from the water by oxidation, a process common to the human body.
"Oxidation chemistry is a significant percentage of our biochemistry," Collins noted. "This is how nature deals with the problem of converting organic substances, especially chemically resistant organic substances, into biochemically usable substances or into energy, in order to keep the organism running." Sometimes the resistance for the enzymes that drive the oxidation chemistry, too large 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 activate peroxidase enzymes to release molecules from food and other substances Collins' goal since 1980 has been to restore the efficiency and efficiency of these enzymes with artificial catalysts of his creation, the so-called tetraamidomacrocyclic ligands (TAMLs).
"We had to get our catalysts' iron center to do this" The same kind of chemistry as the iron center of peroxidase enzymes, "said Collins." For 15 years we have systematically figured out how the TAML catalyst composition works properly. Then we developed the first one – we tried to improve it for 20 years. "
In this new study, Collins describes the" record-setting "performance of these improved catalysts, called NewTAMLs. Tests have shown that infinitely small amounts These catalysts activate hydrogen peroxide to remove the pharmaceutical and often persistent micropollutant propranolol from the water in less than five minutes.
Because of its speed and efficiency, Collins NewTAMLs provides significant cost savings over current water treatment techniques such as ozone purification – more important than cost and electricity, however, he is certain that a catalyst that eliminates micropollutants would be meaningless if the catalyst itself had harmful effects on living organisms.
"It is trivial to find out if something is acutely toxic – it is when something in Share per trillion Secretly toxic in your body is a big problem, "said Collins. "Endocrine hormones in your body work in parts per trillion to low parts per billion in concentrations, they control how much life develops and what we become, and today's multitude of everyday chemicals that we've discovered are endocrine disruptors and read like a sci-fi horror story – but it's a reality. "
To test the safety of the catalysts, Collins helped leading endocrine disruptor scientists to identify and log appropriate assays to detect the detrimental effects of chemicals in low doses search. TAMLs and NewTAMLs were used to beta test the resulting Tiered Protocol for Endocrine Disruption. The NewTAML paper contains an endocrine disruption assay for mice that the candidate catalyst passed with flying colors.
In addition, Collins and his team rejected potential catalyst elements that could significantly improve the performance of TAMLs because of their lack of presence of TAMLs living organisms. For example, the addition of fluorine to TAMLs significantly improved their performance and stability. However, fluorine is a rare substance in living organisms and researchers feared that incorporation into catalysts used in drinking water could increase the fluoride and fluorochemical degradation products in the treated water. "No negative toxicity results were found in our tests," Collins said. "The decision to reproduce the unique and remarkable electronic properties of fluorine without using it turned out to be the main reason why we were rewarded with NewTAMLs."
The same elements that make them up, "said Collins.
This" bio-inspired "approach to chemistry is one pillar of the new field of sustainable catalysis of ultradilutive oxidation, pioneered by Collins and the Institute for Green Science ,
Green catalysts promise to clean toxins and pollutants
Genoa R. Warner et al., Bio-inspired, multidisciplinary, iterative catalyst design, develops the most powerful peroxidase mimetics and the field of sustainable ultradilute oxidation catalysis (SUDOC), ACS Catalysis (2019). DOI: 10.1021 / acscatal.9b01409
Purification of our water with groundbreaking "bioinspired" chemistry (2019, 18th of July)
retrieved on July 19, 2019
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