Indoor air quality improvement and purification by atmospheric pressure Non-Thermal Plasma (NTP)

Abstract

Non-thermal plasma (NTP) is a promising technology for the improvement of indoor air quality (IAQ) by removing volatile organic compounds (VOCs) through advanced oxidation process (AOP). In this paper, authors developed a laboratory scale dielectric barrier discharge (DBD) reactor which generates atmospheric NTP to study the removal of low-concentration formaldehyde (HCHO), a typical indoor air VOC in the built environment associated with cancer and leukemia, under different processing conditions. Strong ionization NTP was generated between the DBD electrodes by a pulse power zero-voltage switching flyback transformer (ZVS-FBT), which caused ionization of air molecules leading to active species formation to convert HCHO into carbon dioxide (CO2) and water vapor (H2O). The impact of key electrical and physical processing parameters i.e. discharge power (P), initial concentration (Cin), flow rate (F), and relative humidity (RH) which affect the formaldehyde removal efficiency (ɳ) were studied to determine optimum conditions. Results show that, the correlation coefficient (R2) of removal efficiency dependence on the processing parameters follow the order R2 (F) = 0.99 > R2 (RH) = 0.96, > R2 (Cin) = 0.94 > R2 (P) = 0.93. The removal efficiency reached 99% under the optimum conditions of P = 0.6 W, Cin = 0.1 ppm, F = 0.2 m3/h, and RH = 65% with no secondary pollution. The study provided a theoretical and experimental basis for the application of DBD plasma for air purification in the built environment.

Interactions of limonene and carvone on titanium dioxide surfaces

“…For all systems, a 30 ps AIMD simulation at 300 K with a time step of 0.5 fs was performed, except for the carvone on the non-hydroxylated surface with 4 water molecules, where at 13 ps AIMD simulation at 300 K with a time step of 0.5 fs was performed. The temperature as maintained at 300 K using a Nose–Hoover 14 thermostat with a relaxation time of 100 fs. The PBE 63 exchange–correlation functional with the DZVP-MOLOPT-SR-GTH 64,65 basis set and the GTH pseudopotentials in the QUICKSTEP module of the CP2K 66 package were used.…”

“…11,12 Current air treatment techniques include active carbon or zeolite adsorption, biofiltration, ozonation, and advanced oxidation process (AOP) such as non-thermal plasma and photocatalytic oxidation (PCO). [13][14][15] Among these techniques, PCO is regarded as a potential cost-effective method because its superior features of operation at room temperature and atmospheric pressure to mineralize ppb level of many hazardous gaseous organics to CO 2 and H 2 O from indoor air under solar light irradiation without chemical additives required. 16 However, it is important to note that there are unexpected consequences of using these air cleaning processes.…”

In situ online detection of atmospheric particulate matter based on laser induced breakdown spectroscopy: a review

“…Indoor particulate matter detection is closely related to indoor air quality and human health. 72,73 Because outdoor air flow velocity is much larger and more unstable than that indoors, it is also less likely to be detected when the composition of the air changes. Moreover, people tend to spend more time indoors for office, study and rest purposes, and high-quality indoor air can enhance the comfort and productivity of living and working environments.…”

Particulate Matter versus Airborne Viruses—Distinctive Differences between Filtering and Inactivating Air Cleaning Technologies

“…The technologies investigated are, in principle, able to produce reaction products that pose a health risk. Therefore, it could be assumed that the manufacturers invested increased efforts in the development of the inactivating technologies, such as optimizing electronic control of the plasma units (e.g., pulsed plasma), shaded the ozone producing wavelength below 200 nm of the UVC units, or installing activated carbon filters as absorbents for ozone and VOCs [16,23,67] Both technologies are also marketed alternatively for indoor air purification from gaseous emissions [34,68]. Therefore, the VOC concentrations in the room were also reduced (except for 1_P).…”