In Situ Evaluation of Filter Media Modified by Biocidal Nanomaterials to Control Bioaerosols in Internal Environments

Abstract

Controlling the bioaerosol present in indoor environments has been evidenced to be extremely necessary. An alternative is to develop filter media for air conditioners that have biocidal properties. This study aimed to verify the biocidal effect of a high-efficiency particulate air (HEPA) filter medium modified with the deposition of nanoparticles on its surface. For this purpose, Ag, TiO 2 , and Ag/TiO 2 nanoparticles were used and the antimicrobial activities of these nanomaterials against Escherichia coli , Staphylococcus aureus , and Candida albicans microorganisms were evaluated, as well as the biocidal efficacy of the modified HEPA filter with these nanomaterials in a real environment. The percentages of elimination obtained for the Ag, TiO 2 , and Ag/TiO 2 nanomaterials, respectively, were 53%, 63%, and 68% ( E. coli ); 67%, 67%, and 69% ( S. aureus ); and 68%, 73%, and 75% ( C. albicans ). The HEPA filter media had their surfaces modified by aspersion and deposition of Ag, TiO 2 , and Ag/TiO 2 nanomaterials. We could conclude that the nanoparticles adhered to the filter medium do not affect its permeability. The modified filters were arranged in an internal environment (bathroom) for the collection of the bioaerosols, and after the collection, the filter cake was plated and arranged to grow in a liquid medium. The results showed that the filters have 100% of biocidal action in passing air, and 55.6%, 72.2%, and 81% of inhibition to microbial growth in their surface for modification with Ag, TiO 2 , and Ag/TiO 2 , respectively, compared to unmodified filters.

Evaluation of Antimicrobial Effect of Zinc Pyrithione against Airborne Fungi and Bacteria Growth Collected onto New and Loaded HVAC Fibrous Filters

“…To address this issue, innovative air filters with photocatalytic properties [13] or containing antimicrobial treatments are designed to be implemented in HVAC systems, or in portable room air cleaners or automobiles. The antimicrobial agents are various, e.g., nanoparticles of copper or silver, or carbon nanotubes [14]. Many natural antimicrobial products have been discovered; e.g., Sophora flavescens nanoparticles revealed an inactivation efficiency against S. epidermidis between 35 and 72% according to the level of humidity [15].…”