Stanford Develops High Speed, Low-Cost Water Purifying Nanofilter

New Stanford Water Purifying Nanofilter is 80,000 Times Faster than Conventional Filter Systems

A research team from Stanford University has developed a water purifying nanofilter that is at least 80,000 times faster than conventional filter systems. The secret is a combination of very low voltage electricity, ordinary cotton, silver nanowires, and nanotubes.

Traditional water purification systems use filters to trap harmful water-borne bacteria. These filters require very small openings that slowly become coated with trapped material, which leads to a very slow water flow.

Stanford’s new water purifying nanofilter, however, doesn’t rely on physically trapping bacterial pathogens. Instead, the water purifying nanofilter system sends a 20 volt electrical current through cotton coated with silver nanowires and nanotubes. Exposure of just a few seconds of the resulting electrical field kills up to 98 percent of E.coli bacteria present in the water. This high kill rate is achieved using just one water purifying nanofilter. A 100 percent kill rate is easily achievable with using multiple filters. Since the process involves killing bacteria instead of trapping it, the filters themselves can have larger openings allowing for much faster water movement.

Along with its inherent efficiency in removing pathogens, the water purifying nanofilter is a low-cost system. It has no moving parts, uses inexpensive cotton, and runs on electricity that is easily acquired from a few 12-volt car batteries or a small solar panel. All of these features make Stanford's water purifying nanofilter especially appealing to people living in remote areas.