Innovative Antibacterial Air Filters Impregnated with Photocatalytic MgFe2O4 Nanoparticles for Improved Microbiological Air Quality

Over time, nanoparticles’ chemistry has shown exceptional ability to solve a wide range of problems in various fields, including the control of microbiological air quality in buildings. Herein, magnesium ferrite (MgFe2O4) was synthesized using coprecipitation, then characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM) and photoelectron spectroscopy (XPS). MgFe2O4 nanoparticles were then assessed for their ability to inhibit Escherichia coli ATCC 8739 growth and airborne bacterial viability in a laboratory atmosphere through a direct air filtration system. The material showed strong inhibitory activity against E. coli by eliminating practically all viable cells in the tested suspensions after 1 h contact time in the presence of light. Finally, the prepared air filtration setup revealed that passing air bacteria through non-woven fabric filters impregnated with MgFe2O4 effectively eliminates them. Thus, only 1 colony-forming unit (CFU) was obtained from 36 L of filtered air, while a control filter (without MgFe2O4) allowed the passage of 2.6 × 105 CFU to the liquid medium. The obtained results initiate potential applications of MgFe2O4 nanoparticles in controlling microbiological indoor air quality (IAQ), especially in healthcare facilities where microbial resistance to antibiotics is the most notable, individuals are the most exposed, and contamination risks are the highest.