By dipping plain cotton fabric into a high-tech broth of silver nanowire and carbon nanotubes, Standford scientists have created a water filter capable of killing deadly pathogens other filters leave behind.
Instead of attempting to trap the bacteria and pathogens like other filtration systems, this device forces them through an electrical field that runs through the highly conductive “nano-coated” cotton.
As the bacterial passes through the filter, it is killed instantly, rendering the polluted water harmless to human drinkers.
In lab tests, over 98 percent of Escherichia coli bacteria that were exposed to 20 volts of electricity in the filter for several seconds were killed. Multiple layers of fabric were used to make the filter 2.5 inches thick (Futurity.org).
Reserachers involved in the study claim that this could be a new high-speed, low-cost water treatment method for remote areas where people don’t have access to chemical treatments such as chlorine.
Traditional filters use fabrics or sand with very small pore spaces to trap waterborne bacteria, but this results in a very restricted flow rate, meaning it takes a long time to filter a large amount of water.
Because the nano-cotton doesn’t need to trap the bacteria, it has much larger pores which allow a flow rate that is 80,000 times faster than traditional filters.
Waterborne diseases are on the rise, especially in countries without dependable infrastructure, or the ability to deal with natural disasters that can contaminate water supplies, such as the recent flooding in Pakistan.
The nano-filtration device can deliver almost 100% bacteria removal with very low cost materials, and is an easy-to-distribute solution for villages and cities with at-risk water supplies.
Image Credit - Yi Cui/Stanford