Removal of benzophenone aerosols by a rice straw-based activated carbon filter combined with a negative air ionizer

The widely used ultraviolet (UV) protective ingredient benzophenone and its derivatives (BPs) are endocrine-disrupting chemicals and are directly or indirectly released into the environment, posing a threat to human health and environmental ecology. Therefore, this research aims to develop an environmentally friendly purification technology to eliminate BPs from air. Recycled rice straw was used to prepare activated carbon (AC), which was applied to filter BPs in the air. The surface morphology, elemental composition, specific surface area, functional groups, and thermal stability of AC were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), nitrogen adsorption/desorption isotherm analysis, Fourier transform infrared (FT-IR) spectrometry and thermogravimetric analysis (TGA). A negative air ionizer (NAI) was used to enhance the filtration efficiency of the AC filter. The experimental results show that the AC filter can effectively remove BP particles from the air, with a removal efficiency of up to 80% (filter quality factor 10 mm-H2O-1). The NAI further increased the removal efficiency of the filter system to over 99% (the filter quality increased to 60mm-H2O-1), showing the superiority of this approach. The most important filtration mechanism in this system is the external electric field generated by the NAI.