Study on Decomposition of Indoor Air Contaminants by Pulsed Atmospheric Microplasma

Kazuo Shimizu,Tomoya Kuwabara,Marius Blajan

doi:10.3390/s121114525

Abstract

Decomposition of formaldehyde (HCHO) by a microplasma reactor in order to improve Indoor Air Quality (IAQ) was achieved. HCHO was removed from air using one pass through reactor treatment (5 L/min). From an initial concentration of HCHO of 0.7 ppm about 96% was removed in one pass treatment using a discharge power of 0.3 W provided by a high voltage amplifier and a Marx Generator with MOSFET switches as pulsed power supplies. Moreover microplasma driven by the Marx Generator did not generate NOx as detected by a chemiluminescence NOx analyzer. In the case of large volume treatment the removal ratio of HCHO (initial concentration: 0.5 ppm) after 60 minutes was 51% at 1.2 kV when using HV amplifier considering also a 41% natural decay ratio of HCHO. The removal ratio was 54% at 1.2 kV when a Marx Generator energized the electrodes with a 44% natural decay ratio after 60 minutes of treatment.

Highlights

Volatile Organic Compounds (VOCs) are a problem in indoor spaces as their presence worsens the indoor air quality (IAQ)
Sensors 2012, 12 concentration in indoor air is regulated at 0.08 ppm by the Japanese Ministry of Health, Labor and Active solutions can be applied for improving the indoor air quality
This paper presents the results of HCHO treatment by a microplasma at gas flow rates of 5 L/min

Summary

Introduction

Volatile Organic Compounds (VOCs) are a problem in indoor spaces as their presence worsens the indoor air quality (IAQ). Formaldehyde (HCHO) is one of these VOCs. Its. Microplasmas, which are a dielectric barrier discharge non-thermal plasma, are generated at about 1 kV between electrodes faced together with a discharge gap on the order of micrometers. The capability of a microplasma to remove low concentrations of HCHO in room air (below 1 ppm) for improving IAQ was investigated. The HCHO removal ratio was 97% at the discharge power of 0.3 W and 5 L/min gas flow rate. This paper presents the results of HCHO treatment by a microplasma at gas flow rates of 5 L/min. Experiments were carried out with microplasma electrodes energized by an AC and a pulse power supply in order to determine the optimal power supply for microplasma HCHO treatment

Experimental Section

Results and Discussion

Conclusions