According to an example aspect of the present invention, there is provided a device for separating materials in the form of particles and/or drops from a gas flow, especially particles and/or drops the diameter of which varies from one nanometer to a few dozen nanometers, the device comprising an inlet for incoming air to be purified, a collection chamber, an outlet for the purified air, a voltage source with actuators, an fastening column to which ion yield tips have been coupled, the device is configured to direct high tension to the ion yield tips providing ion beams from the ion yield tips to the collection surface, the collection surface conducting electricity is electrically insulated from the outer wall of the collection chamber by an electrical insulation, and the device is configured to direct voltage of opposite sign to the ion yield tips than the voltage directed to the collection surface, wherein ion yield tips are arranged directly on a surface of the fastening column having a length, wherein the ion yield tips protrude from the surface of the fastening column into a cavity of the collection chamber.