The magnetic nanoparticle separation problem

Summary Magnetic nanoparticles for adsorption and subsequent magnetic removal of hazardous substances from water, as published in Science in 2006, bears enormous potential for water purification for which there is a growing need all over the world. Many publications followed this idea, but doubts remain whether nanoparticles are really separable and whether the process is really that simple. A closer look reveals uncertainties and the need for more research.