Limited swelling of deposit (gel) layer obtained in crossflow filtration of casein micelles dispersion

Maksym Loginov (1) , F Doudiès (1) , Nadine Leconte (1) , Fabienne Garnier-Lambrouin (1) , Geneviève Gésan-Guiziou (1)

1 STLO - Science et Technologie du Lait et de l'Oeuf

In the crossflow filtration, analysis of deposit swelling after the transmembrane pressure decrease can shed light on deposit properties and removal mechanism. Recently [1], we proposed a method for the deposit analysis, which is based on a comparison between modeled and experimentally observed deposit swelling curves. The method was applied for the analysis of membrane fouling deposits obtained during the crossflow ultrafiltration of casein micelles dispersions. Special cell was used for the simultaneous measurement of the average filtrate flux and the local deposit structure (i.e. dependency of local casein micelles concentration on the distance to the membrane, c(z)). The deposit structure was measured with the help of a small-angle X-ray scattering (SAXS) method. Fouling deposits with a thickness of about 100µm and 150 µm were obtained under transmembrane pressures of 0.5 bar and 1.1 bar, respectively, and the crossflow velocity of 3.1 cm/s. For both studied transmembrane pressures (both deposits), SAXS data were combined with the average filtrate flux data in order to calculate the local compressibility-permeability of deposit: k·dP/dc vs c, where k is the local hydraulic permeability and P is the local osmotic (or compressive solid) pressure. Despite of the difference in c(z) curves observed for two studied pressures (two studied deposits), two k·dP/dc vs. c curves merged, as it is expected for a function describing a material property. Further, the transmembrane pressure was removed and the c(z) curves were measured via SAXS during the pressure relaxation stage of experiment. The deposit swelling (i.e. decrease of the local micelles concentration) was observed for both studied deposits. Also, the swelling kinetics was modelled numerically using the conventional filtration-consolidation equation with the k·dP/dc-function obtained as described above. For both studied deposits, the model predicted significantly slower swelling, as compared to that measured in experiments. It was concluded that the deposit compression resulted in micelles interaction (attraction), which was partially reversible, since the deposit swelled and re-dispersed in course of time.

Mots clés: crossflow filtration; casein micelle; filtration; dispersion; Limited swelling; fouling deposit

Domaines: Ingénierie des aliments; Génie des procédés

Maksym Loginov, F Doudiès, Nadine Leconte, Fabienne Garnier-Lambrouin, Geneviève Gésan-Guiziou. Limited swelling of deposit (gel) layer obtained in crossflow filtration of casein micelles dispersion. Euromembrane 2021, Nov 2021, Copenhage, Denmark. , 2021. ⟨hal-03464834⟩