relation: https://khub.utp.edu.my/scholars/16899/ title: Controlling Air Bubble Formation Using Hydrophilic Microfiltration Diffuser for C. vulgaris Cultivation creator: Shafie, S.N.A. creator: Shen, W.Y. creator: Jaymon, J.J. creator: Nordin, N.A.H.M. creator: Mohamednour, A.E.E. creator: Bilad, M.R. creator: Kee, L.M. creator: Matsuura, T. creator: Othman, M.H.D. creator: Jaafar, J. creator: Ismail, A.F. description: In this project, a commercial polytetrafluoroethylene (PTFE) membrane was coated with a thin layer of polyether block amide (PEBAX) via vacuum filtration to improve hydrophilicity and to study the bubble formation. Two parameters, namely PEBAX concentration (of 0�1.5 wt) and air flow rate (of 0.1�50 mL/s), were varied and their effects on the bubble size formation were investigated. The results show that the PEBAX coating reduced the minimum membrane pore size from 0.46 µm without coating (hereafter called PEBAX0) to 0.25 µm for the membrane coated with 1.5wt of PEBAX (hereafter called PEBAX1.5). The presence of polar functional groups (N-H and C=O) in PEBAX greatly improved the membrane hydrophilicity from 118� for PEBAX0 to 43.66� for PEBAX1.5. At an air flow rate of 43 mL/s, the equivalent bubble diameter size decreased from 2.71 ± 0.14 cm for PEBAX0 to 1.51 ± 0.02 cm for PEBAX1.5. At the same air flow rate, the frequency of bubble formation increased six times while the effective gas�liquid contact area increased from 47.96 cm2 /s to 85.6 cm2 /s. The improved growth of C. vulgaris from 0.6 g/L to 1.3 g/L for PEBAX1.5 also shows the potential of the PEBAX surface coating porous membrane as an air sparger. © 2022 by the authors. Licensee MDPI, Basel, Switzerland. publisher: MDPI date: 2022 type: Article type: PeerReviewed identifier: Shafie, S.N.A. and Shen, W.Y. and Jaymon, J.J. and Nordin, N.A.H.M. and Mohamednour, A.E.E. and Bilad, M.R. and Kee, L.M. and Matsuura, T. and Othman, M.H.D. and Jaafar, J. and Ismail, A.F. (2022) Controlling Air Bubble Formation Using Hydrophilic Microfiltration Diffuser for C. vulgaris Cultivation. Membranes, 12 (4). ISSN 20770375 relation: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85128613143&doi=10.3390%2fmembranes12040414&partnerID=40&md5=ebb794e6b7cf8837d3e836b568f58c8f relation: 10.3390/membranes12040414 identifier: 10.3390/membranes12040414