Ionic Salts@Metal–Organic Frameworks: Remarkable Component to Improve Performance of Fabric Filters to Remove Particulate Matters from Air

Abstract

The elimination of particulate matters (PMs) from the air is very important for our sustainability. In this study, highly porous metal–organic frameworks (MOFs) like MIL-101 and UiO-67 were first modified, coated onto cotton, and applied in PM removal via filtration. Ionic salts (ISs) like CaCl2 and LiCl, after loading onto the MOFs, remarkably increased the PM removal efficiency. For example, CaCl2(20)@MIL-101/cotton shows 5.7 times the quality factor (QF, which is the most important parameter in filtration) of that of bare cotton and has the most competitive performances in PM removal (with the highest QF of 0.085 Pa–1) compared to any filter modified with porous materials or commercial filters. The noticeable performances of ISs@MOFs can be explained by the contribution of charge separation (that is effective for electrostatic interactions with PMs) of ISs and the high porosity of MOFs. Moreover, how MOFs with small pores of a few nanometers or less can remove large PMs with sizes in the micron range could be explained. Finally, loading ISs onto highly porous materials can be a promising strategy to improve the performances of filters to remove PMs from the air.

Removal of Particulate Matters by Using Zeolitic Imidazolate Framework-8s (ZIF-8s) Coated onto Cotton: Effect of the Pore Size of ZIF-8s on Removal

“…This is agreeable with the ESI mechanism in PM removal with DEA-ZIF-8/EC. So far, ESIs have been often applied to interpret the removal of hazardous materials 69 including PMs 26,29,31,62,70 with MOFs. In summary, a large pore is not essential to capture large PMs because small interaction sites (like CO, NH, and NH 3 + , NO 3 − ) on PMs will be more than enough for effective ESIs with porous materials like ZIF-8 (with charge separation, at least in part).…”

Modeling pressure drop values across ultra-thin nanofiber filters with various ranges of filtration parameters under an aerodynamic slip effect

“…Because millions of deaths annually are estimated to be caused by exposure to indoor and outdoor air pollution, the World Health Organization (WHO) considers air pollution to be the single largest environmental health risk 5 , 6 . Particulate matter (PM), a complex mixture of fine solid and liquid particles with various chemical compositions, is one of the primary air pollutants 1 , 7 . The small size and large surface area of PM 2.5 (aerodynamic size less than 2.5 µm) can penetrate deep into the human lungs and can be toxic, thus increasing morbidity and mortality 8 – 11 .…”

Hierarchically Micro‐ and Mesoporous Zeolitic Imidazolate Frameworks Through Selective Ligand Removal

“…However, as research has progressed, the lack of mesoscale cavities has shown to impede the diffusion/adsorption of macromolecules (e.g. enzymes, drugs and particulate matter), [ 7–10 ] which severely restricts the expansion of ZIFs’ application. Thus, the incorporation of mesopores (2–50 nm) in parent ZIFs is crucial in order to meet the requirements of modern applications.…”