Cleaning water with 'smart rust' and magnets

Pouring flecks of rust into water usually makes it dirtier. But researchers have developed special iron oxide nanoparticles called 'smart rust' that actually makes it cleaner. The magnetic nanoparticles attract different pollutants by changing the particles' coating and are removed from water with a magnet. Now, the team is reporting a smart rust that traps estrogen hormones, which are potentially harmful to aquatic life.