Electrostatic Precipitator with a Superhydrophobic Coating for Efficient Filtration of Submicron Particles

Electrostatic precipitators (ESPs) have been extensively exploited owing to their cost-effectiveness and low-maintenance options in buildings. However, existing ESPs have low filtration efficiency for submicron particles and inefficient cleaning after dust loading. Here, an ESP with a superhydrophobic coating was proposed, and the effects of the electrode gap, charging voltage, air velocity and electric field strength of the ESP on submicron particles were considered. The results revealed that the contact angle and sliding angle of the water on the coating surface were 158.0° ± 1.1° and 2.1° ± 0.5°, respectively, due to the combination of low-surface-energy groups and highly rough structures. The filtration efficiency of the submicron particles increased with increasing charging voltage and electric field strength but decreased with increasing air velocity and electrode gap. When the air velocity was 2.5 m/s, the filtration efficiency of the ESP for 0.3–0.5 μm particles reached 96.5%. The filtration efficiency remained relatively high for 28 days, with an average of 95.6%. The filtration efficiency of the ESP for 0.3–0.5 μm particles can be restored to 99.8% of the initial efficiency, while the restoration of existing ESP is 67.5%. The ESP can maintain the filtration efficiency of 0.3–0.5 μm particles at approximately 95.0% after six cycles. The proposed ESP has great air filtering potential in ventilation systems for clean and sustainable building environments.