PCN-222 Metal–Organic Framework Nanoparticles with Tunable Pore Size for Nanocomposite Reverse Osmosis Membranes

Abstract

Nanorods of PCN-222, a large-pore, zirconiumbased porphyrinic metal−organic framework (MOF), have been prepared through coordination modulationcontrolled crystal growth through competing monodentate ligands known as modulatorsfor incorporation into reverse osmosis thin-film nanocomposite (TFN) membranes. Postsynthetic modification of the MOF node through binding of myristic acid (MA) altered channel dimensions and pore size distribution. The extent of MOF modification was characterized through Brunauer−Emmett−Teller gas sorption and 1 H NMR following digestion of the particles. TFN membranes containing PCN-222 nanoparticles modified with varying levels of MA were fabricated via dispersion in the aqueous phase during interfacial polymerization, and the resulting flux and rejection performance of each membrane were evaluated. Increased water flux was observed with increasing MA content in the PCN-222 nanorods. Up to 95% increase in water flux was observed for a TFN containing 0.01 wt % loading of PCN-222 nanorods with a 10:1 MA to linker ratio, while maintaining high salt rejection. The flux change was attributed to tunable water transport through the nanorod pore structure and also through rapid water transport pathways at the nanorod−polymer interface.

Applications of Metal–Organic Frameworks‐Based Membranes in Separation

“…The following methods are noteworthy: 1) functional modification of ligands; 2) functional modification of metal sites; and 3) methods such as surface modification of particles. At the same time, the bonding ability and compatibility between them can be improved by modifying [89] Copyright 2020, American Chemical Society.…”

“…The dense layer of MA group in the pores of PCN-222 reduced the effective pore size of PCN-222, allowing the passage of water molecules and inhibiting the transport of Na þ ions, as shown in Figure 12. [89]…”

“…With the increase of MA load, the schematic diagram of water transmission through PCN-222 hole. Reproduced with permission [89]. Copyright 2020, American Chemical Society.…”

l-Cysteine modified metal–organic framework as a chiral stationary phase for enantioseparation by capillary electrochromatography

“…Aerwards, the weight loss at 150-450 C mainly corresponded to the coordinated water of L-Cys-PCN-222 and the carboxyl and phenyl groups in the TCPP ligands. 38,48,49 Decomposition of the porphyrin ring was attributed to the loss beyond 430 C, leaving behind ZrO 2 . 38 Compared with the TGA curve of PCN-222, the weight loss difference from 200 C to 430 C might be assigned to the decomposition of L-Cys existing in L-Cys-PCN-222, 50 and the weight loss ratio of L-Cys was 16%.…”

“…38,48,49 Decomposition of the porphyrin ring was attributed to the loss beyond 430 C, leaving behind ZrO 2 . 38 Compared with the TGA curve of PCN-222, the weight loss difference from 200 C to 430 C might be assigned to the decomposition of L-Cys existing in L-Cys-PCN-222, 50 and the weight loss ratio of L-Cys was 16%. Aer deducting the non-coordinating water and L-Cys, the remaining weight was 76% of PCN-222.…”