Use of carbon nanotube filter in removing bioaerosols

In this study, the carbon nanotube (CNT) filters were created by depositing both single-walled and multi-walled CNT on polypropylene and polyamide membrane supports. The physical efficiencies of the CNT filters with different CNT loadings when removing the aerosolized Bacillus subtilis var niger, Pseudomonas fluorescens and NaCl were studied using an optical particle counter together with a button aerosol sampler. The removal efficiencies of CNT filters prepared on polypropylene membrane supports of 10 pm pore size when collecting B. subtilis var niger aerosols were shown to range from 10% to 95% in average for the CNT loadings of 0.2-1.6 mu g/cm(2). When collecting aerosolized P. fluorescens, the efficiencies were shown to range from 5% to 60% given similar CNT loadings used. The results revealed that particle types and CNT loading had greater effects on the efficiencies than the membrane types and pore sizes tested. When collecting aerosolized NaCl, the efficiencies were observed relatively lower, i.e., below 50% for loadings of 0.3-1.5 mu g/cm(2). Acid-rinsing was shown to exhibit statistically significant effect on the removal efficiency of single-walled CNT filters when collecting aerosolized NaCl. Multi-walled CNT filters were shown to perform better than single-walled CNT filters. The performances of CNT filters prepared were observed to vary greatly, which was likely due to the CNT loading efficiency, membrane support filtration variance and the CNT uniformity on the support. The information obtained here can be used to develop future indoor air pollution control measures. (C) 2010 Elsevier Ltd. All rights reserved.