Pilot Study on the Production of Negative Oxygen Ions Based on Lower Voltage Ionization Method and Application in Air Purification

In the current highly industrialized living environment, air quality has become an increasing public health concern. Natural environments like forests have excellent air quality due to high concentrations of negative oxygen ions originating from low-voltage ionization, without harmful ozone. Traditional negative oxygen ion generators require high voltage for corona discharge to produce ions. However, high voltage can increase electron collisions and excitations, leading to more dissociation and recombination of oxygen molecules and consequently higher ozone production. To address the challenge of generating negative oxygen ions without accompanying ozone production, this study designed and constructed a low-voltage negative oxygen ion generator based on nanometer-tip carbon fiber electrodes. The advantage of this device lies in the high curvature radius of carbon fibers, which provides high local electric field strength. This allows for efficient production of negative oxygen ions at low operating voltages without generating ozone. Experiments demonstrated that the device can efficiently generate negative oxygen ions at a working voltage as low as 2.16 kV, 28% lower than the lowest voltage reported in similar studies. The purification device manufactured in this study had a total decay constant for PM_2.5 purification of 0.8967 min⁻^¹ within five minutes, compared to a natural decay constant of only 0.0438 min⁻^¹, resulting in a calculated Clean Air Delivery Rate (CADR) of 0.1535 m³/min. Within half an hour, concentrations of PM_2.5, PM₁, PM₁₀, formaldehyde, and TVOC were reduced by 99.09%, 99.40%, 99.37%, 94.39%, and 99.35%, respectively, demonstrating good decay constants and CADR. These findings confirm its effectiveness in improving indoor air quality, highlighting its significant application value in air purification.