In many cases, hard won raw materials are not really gone after their initial use, but could be recovered for reuse if the right methods can be found – recycling at its most basic. For example, the phosphorous in fertilizers, drinks and detergents collects in water as a pollutant at the end of the process chain. The German Phosphorous Platform has therefore set the goal of recovering this valuable but harmful element from water. Researchers from the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB are showcasing one successful method at the IndustrialGreenTec flagship fair for environmental technologies as part of HANNOVER MESSE 2014.
The basic idea of phosphorous recycling relies on the specific characteristics of so-called superparamagnetic particles. Such particles become magnetic themselves in proximity to a magnetic field, but when the magnet is removed they also lose their magnetic characteristics and float freely in the water. Researchers have treated these particles to enable them to capture and bind phosphate ions from the water. They can then be pulled from the water along with these phosphates using a magnet, freeing the water of phosphorous. The same process should make it possible to remove other raw materials and pollutants, such as poisonous heavy metals, from polluted waters.