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Communication Dans Un Congrès Année : 2021

NaCl precleaning of microfiltration membranes fouled with oil-in-water emulsion: impact on the fouling structure

Résumé

The membrane filtration is one of the most interesting processes for the fractionation of biomolecules from microalgae [1], however few works deal with membrane cleaning after treatment of such raw material. It still requires large volumes of cleaning solutions associated with energy and water consumption and environmental impact. NaCl solutions have already been used as a precleaning step to enhance the cleaning of ultrafiltration membranes fouled with whey proteins [2]. The objective of this study was to test this innovative procedure on membranes fouled with lipids representative of microalgae extracts and to evaluate its impact on the fouling structure. Polyethersulfone (PES) based 0.1 µm membranes were fouled with an emulsion, and then cleaned following several steps: water precleaning, NaCl precleaning, detergent cleaning and sodium hypochlorite polishing. Two concentrations of saline solution (5 and 7.5 mM NaCl) and 2 temperatures (37.5 °C and 50 °C) were tested and compared to control experiments. The hydraulic cleaning efficiency (HCE) was calculated to evaluate the saline solutions cleaning efficiency. 5 mM NaCl, 50 °C was the most interesting NaCl precleaning condition allowing a HCE up to 80%. Then the detergent U115 allowed removing the remaining fouling and reaching a HCE of 100%. The NaClO-NaOH polishing step was no longer required. The impact of salt on membrane fouling was then characterized comparing (i) virgin (ii) fouled and (iii) fouled and NaCl precleaned membranes, using Scanning Electron Microscopy (SEM) coupled to Energydispersive X-ray spectroscopy (EDX) measurements, Fourier Transform Infra-Red spectroscopy in Attenuated Total Reflection mode (ATR-FTIR) analysis, Atomic Force Microscopy (AFM) and electrokinetic measurements. It was demonstrated that the fouling of PES membranes occurred on the surface and in the porous media, irregularly organized in regions containing larger and lower quantities of lipids. Using NaCl allowed to decrease significantly the internal fouling, the lipds migrating from the internal porous media to the upper surface, thus facilitating the detergent cleaning step. This work will help developing cost-effective and eco-friendly cleaning procedures for the separation processes used for example in microalgae biorefining.
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Dates et versions

hal-04212122 , version 1 (21-09-2023)

Identifiants

  • HAL Id : hal-04212122 , version 1

Citer

Estelle Couallier, Camille Rouquié, Anthony Szymczyk, Murielle Rabiller-Baudry, Helene Roberge, et al.. NaCl precleaning of microfiltration membranes fouled with oil-in-water emulsion: impact on the fouling structure. Euromembrane, Nov 2021, Copenhagen, Denmark. ⟨hal-04212122⟩
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