Water purification systems need to be robust, sustainable, and efficient. Although nanoparticles are a promising tool to decontaminate water, their recovery post treatment is still challenging.

To overcome this limitation, Mingliang Zhang, Stanford University, CA, USA, and colleagues created magnetically responsive nanoscavengers. These nanoparticles consist of two silver layers which wrap a polycrystalline core made of Ag, Ti, and Fe. As silver has antibacterial properties, the external layers enables the nanoparticles to quickly disinfect water from contaminating bacteria.

On the other side, as the polycrystalline core renderes the nanoparticles magnetically responsive, they could be quickly collected at the end of the purification process upon the application of an external magnetic field. Unlike conventional disinfectants, moreover, the recovered nanoscavengers could be recycled to purify novel batches of contaminated water.

• Magnetically ultraresponsive nanoscavengers for next-generation water purification systems,
  M. Zhang, X. Xie, M. Tang, C. S. Criddle, Y. Cui, S. X. Wang,
  Nat. Commun. 2013, 4:1866.
  DOI: 10.1038/ncomms2892