The idea of disinfecting, depolluting and desalinatinating contaminated water using nanoscale particles is not new. Before now, however, there was no reliable way to remove the invisible-to-the-naked-eye scavengers and make the water safe for human use once the nanoscale purifiers had done their work.

A new type of nanoscavenger developed by an interdisciplinary team of engineers at Stanford University shows promise as an effective means of purifying water using nanotechnology. The particles have a synthetic core “ultraresponsive to magnetism” that provides an efficient, effective means of retrieving the active materials once the water has been purified. A paper outlining the team’s research was published online May 14 in the journal Nature Communications.

“In contaminated water, nanoscavengers float around, randomly bumping into bacteria and killing them or attaching themselves to molecular pollutants,” said Shan Wang, the study’s senior author and a professor of materials science and engineering and of electrical engineering, in a Stanford release. “When the contaminants are either stuck to the nanoscavenger or dead, the magnet is turned on and the particles vanish.”

Although the concept of magnetic nanoscale purifiers is not new — commercial technologies using a magnetic iron oxide core surrounded by an active material to purify the water exist — the Stanford technology is reportedly the first to employ “synthetic antiferromagnetic cores” that are ultraresponsive when exposed to a permanent magnet.

According to the Stanford researchers, the nanofilter’s core is not a single material but instead a multi-layer disk. Magnetic outer layers are sandwiched on either side of a titanium center. In their natural state, the magnetic layers are not magnetic at all; however, when exposed to a strong magnetic field, the layers align, and this alignment actually strengthens the magnetic effect.

Having developed a working prototype, the Stanford team is focused on tailoring the nanoscale purifiers for specific contaminants and perhaps even developing a “one-pot solution.” Should they prove successful, the technology could prove useful for cooling water reuse and recycling in water-restricted areas.