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Flux increase occurring when an ultrafiltration membrane is flipped from a normal to an inverted position—experiments and theory

Zoka, Ladan and Khoo, Ying Siew and Lau, Woei Jye and Matsuura, Takeshi and Narbaitz, Roberto and Ismail, Ahmad Fauzi (2022) Flux increase occurring when an ultrafiltration membrane is flipped from a normal to an inverted position—experiments and theory. Membranes, 12 (2). pp. 1-13. ISSN 2077-0375

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Official URL: http://dx.doi.org/10.3390/membranes12020129

Abstract

The effects of flipping membranes with hydrophilic/hydrophobic asymmetry are well documented in the literature, but not much is known on the impact of flipping a membrane with dense/porous layer asymmetry. In this work, the pure water flux (PWF) of a commercial polyethersulfone (PES) membrane and a ceramic ultrafiltration (UF) membrane was measured in the normal and inverted positions. Our experimental results showed that the PWF was two orders of magnitude higher when the PES membrane was flipped to the inverted position, while the increase was only two times for the ceramic membrane. The filtration experiments were also carried out using solutions of bovine serum albumin and poly(vinylpyrrolidone). A mathematical model was further developed to explain the PWF increase in the inverted position based on the Bernoulli’s rule, considering a straight cylindrical pore of small radius connected to a pore of larger radius in series. It was found by simulation that a PWF increase was indeed possible when the solid ceramic membrane was flipped, maintaining its pore geometry. The flow from a layer with larger pore size to a layer with smaller pore size occurred in the backwashing of the fouled membrane and in forward and pressure-retarded osmosis when the membrane was used with its active layer facing the draw solution (AL-DS). Therefore, this work is of practical significance for the cases where the direction of the water flow is in the inverted position of the membrane.

Item Type:Article
Uncontrolled Keywords:Bernoulli’s principle, inverted position, theory, ultrafiltration, water flux
Subjects:Q Science > Q Science (General)
Divisions:Chemical and Energy Engineering
ID Code:103169
Deposited By: Yanti Mohd Shah
Deposited On:20 Oct 2023 02:06
Last Modified:20 Oct 2023 02:06

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