“…On the other hand, PMs like SNA usually have charges. Carbonaceous PMs have a polar outside composed of a few FGs like CO, O–H, N–H, etc. ,, In this work, the captured carbonaceous PMs (after 12 h of filtration with CaCl 2 (20)@MIL-101/cotton) were analyzed with FTIR; polar FGs like CO and N–H were confirmed (Figure ), in agreement with previous works. ,, So far, the interactions between PMs and filters were explained with a few mechanisms including electrostatic interactions (ESIs). ,,− The loaded ionic (or charged) species might be an active interaction (via ESI) site with PMs, which also have charges (like SNA) or polar FGs on the surface of carbonaceous PMs. However, ISs are not very effective in PM removal, if they are poorly dispersed (for example, without support on a suitable porous material) or exist in a high content, because charged species are not separated well from each other.…”