For the filtration of water a variety of different types of membranes ranging from micro- to nanofiltration are already commercially available. Goals of our research are to improve the properties of membranes by a modification of the surface or by embedding additional functions, like adsorption sites into the membranes. In the first case the (bio-) fouling behavior could be controlled and this allows for an e.g. improved back flushing behavior of the membranes. The second case leads to so-called membrane adsorbers where filtration and adsorption are directly integrated into one system. In contrast to pure adsorbers the adsorption capacity of membrane adsorbers are independent from flow velocities and therefore allows for a high troughput. Meanwhile we have systems with different functionalities at hand for the selective adsorption of micropollutants, heavy metals or the recovery of valuable metals.