Simultaneous removal of VOCs and PM2.5 by metal-organic framework coated electret filter media

Abstract

The electret filter media coated with highly porous metal-organic frameworks (MOFs) particles, named E-MOFilter, is newly developed and evaluated for its capacity for simultaneous removal of fine particulate matters (PM2.5) and volatile organic compounds (VOCs). Three different MOF particles, including MIL-125-NH2, UiO-66-NH2, and ZIF-67, were synthesized and systematically characterized. The produced MOF particles were suspended in ultrapure water and then a liquid filtration apparatus was used to deposit the MOF particles onto two electret media with different minimum efficiency reporting values (MERV 13 and 17) to form the E-MOFilters. Results showed that the MOF particles deposited in MERV 13 media more uniformly than that of MERV 17. In the PM filtration tests, results showed that the E-MOFilter gained only a few more pascals of air resistance compared with clean electret media. Besides, its PM removal efficiency was found to be close to that of clean electret media. This indicates that a uniform MOF particle deposition and negligible charge degradation from the current coating process were obtained. Further, the E-MOFilter with MIL-125-NH2 particle coating not only had a decent toluene removal efficiency (>80%) but also maintained its original PM2.5 holding capacity. This work may shed light on applying the novel E-MOFilter in the residential and commercial HVAC systems and indoor air purifiers to simultaneously and effectively remove PM2.5 and VOCs.