Researchers Develop Inexpensive, Simple, On-Demand Water Disinfection Process
Clean, disinfected water is essential for a good life, but millions of people around the world do not have access to it. Cardiff University researchers plan to change this with an on-site disinfection approach that is massively more effective than our current disinfection approaches. The method relies only on atmospheric hydrogen, oxygen and a gold-palladium catalyst.
The new method aims to provide clean and safe water for consumption and hygiene in areas without access to such resources or reliable disinfection methods. Overall, this could help improve the lives of billions of people struggling with water scarcity or water insecurity.
Cleaning on demand
“The considerably improved [anti-viral and anti-bacterial] The activities carried out during the reaction of hydrogen and oxygen using our catalyst, rather than using commercial hydrogen peroxide or chlorination, show the potential to revolutionize water disinfection technologies. ‘water in the world,’ says Professor Graham Hutchings, Regius Professor of Chemistry at the Cardiff Catalysis Institute author of the paper.
The gold-palladium catalyst allows the hydrogen and oxygen atoms in the air to melt into hydrogen peroxide. It is a common chemical produced in huge quantities around the world and is also widely used as a disinfectant. More than four million tonnes of the compound are produced worldwide each year.
Typically, hydrogen peroxide is produced at one site and used (for a variety of purposes, including water disinfection) at another. This means that it requires storage and transportation before use, so hydrogen peroxide is often mixed with other chemicals that stabilize it and keep it fresh until use. While these serve their intended purpose, they also reduce its effectiveness as a disinfectant (since it is now essentially diluted).
An alternative to this approach is to use chlorine as a disinfectant – add enough of it to the water and it will kill most pathogens that enter it, just like hydrogen peroxide. However, chlorine can react with chemicals naturally present in water, creating compounds that can be toxic to humans.
The new approach circumvents these problems, however, by producing the disinfectant – hydrogen peroxide – at the point where it is used. The team first tested the effectiveness of commercially available hydrogen peroxide and chlorine in disinfecting water, and then compared it to the effectiveness of their catalytic method. All were compared based on their ability to destroy Escherichia coli, a common bacterial species, under identical conditions. After this quantitative step, a qualitative step followed, where the team investigated exactly how each method killed the germs.
First, their method was found to be the most effective, being 10,000,000 times more effective at killing bacteria per unit volume than hydrogen peroxide, and over 100,000,000 times more effective than chlorine per unit volume. unit of volume. It also killed bacteria faster than either of the other two methods.
Its secret seems to be that the reaction that creates hydrogen peroxide also produces reactive oxygen species (ROS), highly reactive compounds that bind to other chemicals, breaking them down in the process. Bacteria are also made up of chemicals – therefore, they are also broken down. This process is the same that causes us to age with age.
Interestingly enough, the team found that these ROSs are what kill bacteria and other pathogens, not hydrogen peroxide itself.
The team notes that about 785 million people worldwide do not have access to water, and about 2.7 billion suffer from water scarcity for at least a month every year. Inadequate sanitation, which is also fueled by the lack of clean water, affects an additional 2.4 billion people worldwide and can lead to a host of water-borne illnesses.
This method of on-site disinfection could help all of these people finally have reliable access to clean water for drinking, bathing and any other necessities they may have. Hopefully the team’s work will quickly find its place in practice.
“We now have a proven one-step process where, besides the catalyst, inputs of contaminated water and electricity are the only requirements to achieve disinfection. Importantly, this process offers the possibility of rapidly disinfecting water over time scales in which conventional methods are ineffective, while also preventing the formation of dangerous compounds and biofilms, which can help bacteria and viruses to break down. develop.
The article “A residue-free approach to water disinfection using in situ catalytic generation of reactive oxygen species” was published in the journal Natural catalysis.