Triboelectric charging of melt-blown nonwoven filters with high filtration efficiency

As a novel technology to convert low-frequency energy into electric power, the triboelectric nanogenerator is a hot research topic recently. However, the nature of charge carriers and their transfer mechanisms still remain poorly understood, especially for the cases of liquid–solid triboelectric nanogenerator. In this paper, charges produced by a triboelectric charging process were designed to provide melt-blown nonwoven fabrics with high filtration efficiency by making full use of the electrostatic attraction filtration mechanism. Influences of water conductivity and drying temperature on the filtration efficiency of melt-blown nonwoven fabrics were investigated. And the corresponding properties such as the surface charge potential and charge stability were analyzed by using the electrostatic voltmeter, bio atomic force microscope and thermally stimulated discharge technique. In addition, metal and inorganic elements in the masterbatch and water before and after triboelectric charging were measured in order to uncover the charge transfer mechanism. Melt-blown nonwoven fabrics with filtration efficiency as high as 96.8% was obtained through the triboelectric charging treatment by using water with the conductivity as low as 1.1 μS/cm for the first time. Negative and positive surface charge density appeared randomly on both sides of melt-blown nonwoven fabrics after the triboelectric charging treatment from the bio atomic force microscope measurement while only one kind of surface charge density can be achieved in the research of TENG, that is, negative or positive. It seems there are both electron and ion transfers during the triboelectric charging process and electron transfer seems to have more important contribution for the generation of charges.