Particulate matters removal by using cotton coated with isomeric metal-organic frameworks (MOFs): Effect of voidage of MOFs on removal

High quality of air is indispensable for our comfortable life and sustainability; however, air contamination with various substances, especially with particulate matters (PMs), is worsening in recent days. In this study, we applied three isomeric metal-organic frameworks (MOFs) such as MAF-5, MAF-6 and MAF-32 (MAF means metal-azolate framework, a sub-class of MOF), after coated on cotton, in removing PMs from air. Isomeric MOFs were applied to identify an important parameter of MOFs in PM capture/removal since those MOFs have different characteristics (even have the very same composition). It was found that removal efficiency and quality factor (QF) of MAFs/cotton linearly increased with increasing the voidage (v/v) of the investigated MAFs, suggesting the importance of voidage of MOFs in PM capture. Moreover, we could explain how MAFs with small pore (compared with the size of PMs) is effective in interaction (for capture) between PM and MAFs. Finally, the MAF-6, the best MAF among the studied MAFs, was much more efficient in PM removal than conventional or widely applied MOFs like ZIF-8 (for example, QF for PM2.5 of cotton, MAF-6/cotton and ZIF-8/cotton are 0.016, 0.060 and 0.030 Pa-1, respectively). (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Automated summary

The study applied three isomeric metal-organic frameworks coated on cotton to remove particulate matters from air, finding that voidage of MOFs plays an important role in PM capture. MOFs with small pores were more effective in interaction with PMs, and MAF-6 showed higher efficiency in PM removal compared to conventional MOFs like ZIF-8.