Mechanochemically synthesized ZIF‐8 nanoparticles blended into 6FDA‐TrMPD membranes for C₃H₆/C₃H₈ separation

Abstract

The mixed matrix membranes (MMMs) consisting zeolitic‐imidazolate framework‐8 (ZIF‐8) nanoparticles in a polymer have been of considerable interest in separation applications. The fillers used are mostly synthesized using the solvothermal method. In this study, the ZIF‐8 nanoparticles were synthesized using a solvent‐less and salt‐free mechanochemical method and were added to 6FDA‐TrMPD polyimide to prepare MMMs. The single gas permeation of C3H6 and C3H8 through the MMMs was investigated. The C3H6 permeability and C3H6/C3H8 ideal selectivity of a 20 wt% mechano‐synthesized ZIF‐8/6FDA‐TrMPD MMM were 70% and 32% higher than those of the neat polymer membrane at 0.1 MPa and 308 K, respectively. The C3H6/C3H8 separation performance of the mechano‐synthesized ZIF‐8 MMM was similar to that of the conventional solvothermal‐synthesized ZIF‐8 MMM. This separation performance was in good agreement with the Maxwell model. Temperature and pressure dependence analyses confirmed that the mechano‐synthesized ZIF‐8 nanoparticles acted as molecular sieves in the MMMs for the C3H6 and C3H8 permeation.

Covalent‐Linking‐Enabled Superior Compatibility of ZIF‐8 Hybrid Membrane for Efficient Propylene Separation

“…[ 47 ] It is worth mentioning that good ZIF‐PIM compatibility and porous PIM‐1 endow ZIF‐8 86 ‐CN 14 @tPIM‐1 with top‐class selectivity among reported ZIF‐8 MMMs and most advanced permeability over the others (Figure 5c). [ 18–31 ] Another comparison with ZIF‐8 polycrystalline membranes shows that ZIF‐8 86 ‐CN 14 @tPIM‐1 has superior C 3 H 6 permeability and moderate competence in C 3 H 6 /C 3 H 8 selectivity (Table S5, Supporting Information). The selectivity–permeability points lie well above the latest upper bound, [ 48 ] and C 3 H 6 /C 3 H 8 selectivity (23.4) and C 3 H 8 permeance (≈22 GPU) are of the industrial interest for C 3 H 6 /C 3 H 8 separation from purge gas or olefin cracker according to selectivity and permeance requirements of 6–10/15–20 and 20–40 GPU.…”

“…Minor decline in permeability and selectivity for C 3 H 6 from 1.5 bars to 3.0 bars are attributable to dual adsorption and competitive diffusion mechanisms respectively. [ 19 ] The membrane performance was examined against time in Figure 6d. High values in terms of permeability and selectivity are retained even after 7 days, signifying that the membrane is robust.…”

“…[ 12 ] Thus, ZIF‐8 has been explored as the filler to fabricate MMMs for this purpose. [ 13–31 ] In ZIF‐8 MMMs, the C 3 H 6 /C 3 H 8 selectivity is kinetically controlled by the ZIF‐8 fillers themselves. Thus, the interface engineering between ZIF‐8 and polymer is of paramount importance for tailoring the membrane selectivity because few phase‐boundary defects can severely suppress the selectivity for C 3 H 6 over C 3 H 8 .…”

“…The literature showed that the ZIF–polymer compatibility in ZIF‐8 MMMs was improved by matrix modification (i.e., synthesis of new polymer, post functionalization or binder addition). [ 15–27 ] Although the selectivity was increased, the permeability was largely sacrificed; however, high permeability is very demanding in membrane propylene separation. [ 32 ] ZIF‐8 functionalization is another method to modify the ZIF–polymer interfaces in MMMs; however, few studies have been reported on this phenomenon, [ 28–31 ] probably due to metal saturated coordination and ligand chemical inertness in the ZIF‐8 structure.…”

F3‐functionalized nanoscale metal–organic frameworks for tumor‐targeting combined chemotherapy and chemodynamic therapy

“…Metal‐organic frameworks (MOFs) are emerging multifunctional materials consisting of metal ions/clusters bridged with organic linkers (via coordination bonds) 2–4 . They have been utilized in various fields, including material storage, 5 separation, 6 catalysis, 7 bioimaging, 8 drug delivery, 9 among many others. MOFs provide a number of benefits over conventional nanomaterials, including high surface areas, tunable pore size, improved degradation resistance, less time‐consuming and simpler surface modification capability.…”