Electrically Responsive Coarse Filters Endowed by High-Dielectric-Constant Surface Coatings toward Efficient Removal of Ultrafine Particles and Ozone

Abstract

Ambient ultrafine particles (UFPs) cause severe health threats, and UFPs can transport in indoor environments through building envelopes. In building HVAC (heating, ventilation, and air conditioning) systems, fibrous filtration has been extensively used to resist particulate matter. However, there is an intrinsic conflict between fibrous filters’ high filtration efficiency and low air resistance. Herein, we designed a dielectric-coated fiber structure and fabricated electrically responsive coarse filters to remove UFPs by utilizing the Coulomb force between the charged particles and the polarized fibers. The electrical responsiveness endowed the filters with an excellent performance for the removal of UFPs. With the synergistic improvement of particle precharging and filter polarization, the UFPs’ removal efficiency of the coated filter increased from ∼0% to the highest of 90.50%, with ultralow ∼13.0 Pa air resistance at 1 m/s face air velocity, which ensured a considerable filtration performance even under large face air velocity. Furthermore, the combination of MnO2 and polyurethane (PU) filters performed with the ability to remove the unwanted ozone generated by particle precharging. The promising features give these filters excellent potential for use in energy-efficient electrostatic air-cleaning devices, thus achieving a healthy and sustainable environment.