Simple method for binding pollutants in water

Researchers in Germany, at the Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB), have developed new types of membrane adsorbers that are capable of separating unwanted particles from water whilst at the same time removing dissolved substances such as bisphenol A or toxic lead. In January 2015 the European Food Safety Authority (EFSA) lowered the threshold value for bisphenol A in packaging. The hormonally active bulk chemical is, amongst other things, a basic material for polycarbonate from which, for example, CDs, plastic tableware or spectacles glasses are manufactured. Because of its chemical structure, bisphenol A is not completely degraded in the biological stages of treatment plants and is discharged into rivers and lakes by purification facilities. Activated carbon or adsorber materials are already used to remove chemicals, antibiotics or heavy metals from wastewater or process water. However, a disadvantage of these highly porous materials is the long contact time that the pollutants require in order to diffuse into the pores. To ensure that as many of these harmful substances are captured as possible - even during a short period - treatment plants use large quantities of adsorbers in correspondingly large treatment basins. However, activated carbon can be only regenerated with a high energy input, resulting, for the most part, in the need to dispose of large quantities of material contaminated with pollutants. Although filtration, using nanofiltration or reverse osmosis membranes can remove the contaminating substances, is not yet cost-effective for the removal of dissolved molecules from high-volume flows such as process or wastewater.