Abstract: The invention relates to a device for membrane filtration and for the removal of micropollutants from liquids by way of a reactive substance, the device comprising a reaction chamber and at least one port for supplying and/or discharging the reactive substance to and/or from the reaction chamber, such that the micropollutants are able to react with the reactive substance in the reaction chamber and/or may be removed from a liquid, and the reaction chamber comprising a first membrane and a second membrane, the first membrane being designed as an inlet into the reaction chamber and the second membrane being designed as an outlet from the reaction chamber, such that the liquid to be treated is able to be filtered by the first membrane and to flow into the reaction chamber, the liquid treated with the reactive substance in the reaction chamber is able to be filtered by the second membrane and to flow out of the reaction chamber, and the outflow of treated liquid is substantially free from micropollutants.