Influence of formulation and spinning conditions on the morphology of PES and PES/ZIF-8 hollow fiber membrane

• Published in: Applied Nanoscience (Switzerland)
• Main Author: Buddin M.M.H.S.; Ahmad A.L.
• Format: Article
• Language: English
• Published: Springer Science and Business Media Deutschland GmbH 2022
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85141456094&doi=10.1007%2fs13204-022-02682-5&partnerID=40&md5=969c776e186b329874ebc7e12c3b2e06

The morphology of a membrane is crucial in determining the permeability and selectivity in separating a gas mixture. For this purpose, a dense selective layer and porous substructure are typically desired in a polymeric membrane as gas separation obeys the solution–diffusion mechanism. Formation of such structure in polyethersulfone (PES) hollow fiber membrane (HFM) made using 1-methyl-2-pyrrolidone (NMP) as solvent and ethanol as a nonsolvent additive is the interest of this work. This study consists of two major parts. The first focuses on identifying ideal dope solution formulation and spinning conditions (air gap and bore fluid flowrate) to produce HFM. The scanning electron microscope (SEM) analysis reveals that high polymer concentration and the presence of nonsolvent additive increases the thickness of the dense layer significantly. Meanwhile, a similar observation was obtained at a wider air gap and lower bore fluid flowrate. The membrane has a consistent combination of structure; dense, teardrop and sponge-like, regardless of the air gap and bore fluid flowrate. Furthermore, mixed matrix hollow fiber membrane (MMHFM) was fabricated by incorporating 10 wt.% ZIF-8 as inorganic filler in the 29 wt.% PES solution. The dope solution was spun at the air gap and bore fluid flow rate of 15 cm and 5 mL/min, respectively. MMHFM showcases similar morphology to HFM, except that the voids' size in the substructure increases and the thickness of the dense layer reduces. © 2022, King Abdulaziz City for Science and Technology.