Submicron particles removal performance based on acoustoelectric agglomeration in a two-stage electrostatic precipitator

To address the low removal efficiency of conventional electrostatic precipitators (ESPs) for submicron particles in the built environment, this study proposed a high-frequency acoustoelectric agglomeration-enhanced two-stage ESP for low-concentration atmospheric particles. Theoretical models were developed to analyze the particle dynamics in the coupled acoustic-electric fields, while several experiments were conducted to investigate the effects of acoustic frequency (14.4∼15.2 kHz), sound pressure level (125∼138 dB), air velocity (0.5∼2 m/s), and wave type (traveling/standing waves) on the submicron particles agglomeration and corresponding filtration performance. The results showed that 14.8 kHz/132 dB delivered optimal acoustic performance to achieve significant agglomeration efficiency without excessive energy consumption, while the particle charging increased the agglomeration efficiency to 87.4 %. Particle agglomeration under the standing waves was marginally superior to that under traveling waves. The acoustoelectric synergistic effect boosted ESP filtration efficiency for submicron particles from 87.3 % to 96.6 %, elevating the filtration grade from F7 to F9 (EN779 standard). This technology significantly improved the fine-particle removal by promoting submicron particle collisions, offering an energy-efficient solution for indoor air purification systems.