Fabrication of MMMs
Before membrane fabrication, the PSF powders, MOF NPs, and pMOF MSs were dried in vacuum at 100 °C overnight to remove the adsorbed water. The MOF NPs and pMOF MSs were employed as fillers. As shown in Eqs. (1) and (2), the amount of the solid substances (polymers and fillers) were 10 wt% of the mixtures, while the fillers accounted for 10 wt% of the solid substances. The fillers were first dispersed in CHCl3 to prepare the initial suspension, followed by constant stirring and ultrasonic treatment for 2 h. The PSF powders were added into the above suspension and then stirred overnight. To completely remove the air bubbles, the casting ink was ultrasonically treated for 5 min and stirred for 5 min, repeating this process for 6 times and then standing for 1 h. The prepared viscous membrane ink was poured on a glass plate and casted with a scraper. After standing at room temperature for 1 h, the formed membrane was placed in an oven at 50 °C for 4 h, and then dried in vacuum at 80 °C overnight to completely evaporate the residual solvent. The pure PSF membrane was prepared by the same method as above.
\(\frac{\text{PSF}+\text{MOF}}{\text{\ PSF}+MOF+\text{CHCl}_{3}}=10\ wt\%\)(1)
\(MOF\ loading\ (wt\%)=\frac{\text{MOF}}{\text{PSF}+MOF}\times 100=10\ wt\%\)(2)