Evaluation of the Inactivating Ability of Carbon-Nanotube Coated Plasma Treatment on Bioaerosols for Indoor Air Cleaning

Abstract

This work considers the ability of carbon-nanotube (CNT)-coated plasma to inactivate bioaerosols. Escherichia coli (E. coli) and λ virus phage were chosen as the challenge bioaerosols. A test chamber was used to simulate an indoor environment and to control the air exchange rate (ACH). The results demonstrated that CNT-coated plasma had a significant antimicrobial effect on both bacterial and viral bioaerosols. The experimental results revealed that CNT-coated plasma under an operating voltage of 6.0 kV and an ACH of 0.5 h−1 had significantly higher bioaerosol inactivating ability (kCNT, 0.24 and 0.23 min−1 for E. coli and λ virus phage, respectively) compared to the results without using CNT-coated plasma (kn, 0.09 and 0.08 min−1 for E. coli and λ virus phage, respectively). Under the higher ACH condition, the system demonstrated higher bioaerosol removal efficiency due to the mechanical effect of clean air exchange. Increasing flow rate and operating voltage could raise the inactivating ability of the CNT-coated plasma system. A CNT-coated plasma air-cleaning device was tested in a real indoor medical environment and yielded bacterial bioaerosol removal efficiency in the range from 70% to 80% within 6 h of operation (7.5 Lpm and 6.0 kV), which suggests that CNT-coated plasma treatment has the potential for further application in improving indoor air quality.