Abstract
The negative air ions (NAI) are used for the removal of particles or droplets from the air. In this study, three types of piezoelectric cold plasma generators (PCPG), in combination with cylindrical electrostatic ion filters, are applied for NAI production. The high voltage on the filter cylinder is induced by the electric field from the piezoelectric transformer of the PCPG. To achieve the dc bias, the cylinder of the electrostatic filter is connected to the ground over ultrafast switching diodes. The ion concentrations are measured for different airflows, PCPG powers, and electrostatic filter geometries. The NAI concentration in the order of magnitude of 107 cm−3, and a negative-to-positive ion concentration ratio of over 200 is reached. The production of ozone is evaluated and the PCPG configuration with a minimum ozone production rate is proposed. The ozone concentration below 60 ppb is reached in the airflow of 90 m3/h.
Highlights
Negative Air Ions by Use ofThe negative air ions (NAI) are immanently present in ambient air
The ion concentrations are measured for different airflows, piezoelectric cold plasma generators (PCPG) powers, and electrostatic filter geometries
To reduce the amount of ozone produced by the PCPG, the electrode configuration similar to this used for ionic wind generation in [27] is evaluated
Summary
The negative air ions (NAI) are immanently present in ambient air. The natural NAI sources include [1] radiant or cosmic rays, sunlight ultraviolet, natural electric discharges including lightning and friction-induced discharging (tribodischarging) [2], the shearing forces of water (Lenard effect) [3], and plant-based sources of ions [4]. The origin of NAIs are the negatively charged oxygen atoms O− , generated mainly by electron dissociative attachment to the oxygen molecule. Once produced, they can contribute to the creation of secondary oxygen ions such as O2− and O3−. Hagbom et al [14] used an ionizer to generatie an NAI that attaches to the airborne particles or aerosol droplets The latter, whcih are negatively charged, are electrostatically attracted to a positively charged collector plate. To reduce the amount of ozone produced by the PCPG, the electrode configuration similar to this used for ionic wind generation in [27] is evaluated. The PCPG configuration and process parameters are proposed, allowing the ozone concentration to remain below 60 ppb
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
