Harvesting microalgae using vibrating, negatively charged, patterned polysulfone membranes

Abstract

Key issues for membrane technology in harvesting microalgae are to reach high fluxes and to alleviate fouling by microalgal cells and extracellular organic matter. To achieve this goal, negatively charged patterned membranes were prepared from polysulfone/sulfonated polysulfone (PSf/sPSf) blends using a spray-modified phase inversion method, and the effect of sPSf on the membrane morphology and filtration performance was investigated. The patterned membrane with highest sPSf concentration exhibited the highest clean water permeance (2420±260 L/m 2 h bar), lowest membrane intrinsic resistance (6.1 m -1 ) and highest critical flux (55 L/m 2 h) for harvesting microalgae. Membrane vibration could mitigate membrane fouling both for the patterned and flat membranes. The vibration system can easily achieve turbulent flow at frequencies higher than 7 Hz. The synergy between membrane vibration, surface pattern and charge thus resulted in a clearly membrane performance.

Harvesting microalgal biomass using negatively charged polysulfone patterned membranes: Influence of pattern shapes and mechanism of fouling mitigation

“…The patterned membranes were more water-permeable compared with the flat membranes (Fig. 5a), in line with previous studies (Marbelia et al, 2020;Zhao et al, 2020b;Zhao et al, 2021). The flat membranes prepared by adding 4.5w% sPSF showed a higher CWP.…”

“…1a). PSf (13.5w%), sPSf (4.5w%) and deionized water (1w%) were dissolved in N-methyl-2-pyrrolidone (99w%, Acros organics, Belgium) at 60 °C with 25w% polyethylene glycol (PEG, Mw~1000 Da, Fluka, Belgium) as pore-forming agent (Zhao et al, 2020b;Zhao et al, 2021). After degassing overnight, the solution was cast on a smooth glass plate with a wet thickness of 200 μm (measured from the valley point of the corrugation to the bottom of the polymer film, below referred to as base-layer) at a casting speed of 2.3 cm/s.…”

“…A negatively charged polyacrylonitrile membrane was used to harvest eight types of microalgae, also showing higher water permeances and less fouling (Marbelia et al, 2016b). Sulfonated polysulfone (sPSf) has been incorporated into membranes to successfully create negative charges and a higher hydrophilicity (Song et al, 2016;Zhao et al, 2020a;Zhao et al, 2021).…”

“…Patterned membranes have been used for waste water treatment and microalgae harvesting, showing higher membrane fluxes than corresponding flat membranes (Lee et al, 2013;Zhao et al, 2020b;Zhao et al, 2021). The traditional ways for modifying the membrane surface are template-based molding, direct printing (e.g.…”

Runge–Kutta Numerical Method Followed by Richardson’s Extrapolation for Efficient Ion Rejection Reassessment of a Novel Defect-Free Synthesized Nanofiltration Membrane

“…Furthermore, the more or less attractive or repulsive effect of the NF-PANZr membrane on ion rejection was highlighted in the analysis of the results produced by the Runge–Kutta model. The charge of the membrane plays a very important role in the transport of ions through the membrane active layer, and several recent studies confirm this propensity of the membrane to attract and allow itself to be more easily crossed by ions of a charge contrary to its charge [ 8 , 31 , 32 , 33 , 34 ].…”