The most common way to disinfect water is usually by boiling it, but this can take a lot of time and energy that may not be readily available in developing regions. Scientists are addressing the problem with devices such as solar stills, graphene filters and chlorine vending machines, but often these can be inefficient or still require energy.
For the new study, the researchers developed a method that should be relatively easy and doesn’t require energy to work. It is a hydrogel tablet that can simply be dropped into a container of water, where it kills more than 99.999% of bacteria within an hour or so. The hydrogel can then be removed, leaving no residue or chemicals behind.
The tablets work by generating hydrogen peroxide, which works with activated carbon particles to kill bacteria by disrupting their metabolism. The team says no harmful by-products are created in the process. These hydrogel purifiers could also find use in improving other techniques, such as solar distillation. These systems work by concentrating the sun’s heat to evaporate water and collect it in another container, leaving contaminants behind. This equipment can be clogged with microbes, but the team says the new hydrogel could prevent it.
Although only small-scale tests have been conducted so far, the new hydrogels should also be fairly easy to scale, the researchers say. The materials and processes are cheap and simple, and things can be molded into all sorts of shapes and sizes to fit specific use cases.
“Our multifunctional hydrogel can make a big difference in mitigating global water scarcity because it is easy to use, highly efficient and potentially scalable to mass production,” says Guihua Yu, corresponding author of the study. The team says the next steps are to find ways to refine the hydrogels to kill a wider variety of bacteria and viruses. Marketing is already in the pipeline.