Effect of periodic backwash in the submerged membrane adsorption hybrid system

The submerged membrane adsorption hybrid system (SMAHS) is an attractive solution in treating wastewater; however it faces membrane fouling although to a less extent. In this study, different adsorbents and resins were investigated in order to find a substitute to the powdered activated carbon (PAC); The effect of new backflush was also studied in further reducing the membrane fouling. The SMAHS led to 72–86% dissolved organic carbon (DOC) removal. A detailed study on the transmembrane pressure development led to a conclusion that there is a critical flux and this value is around 16 l/h.m2 for the wastewater studied

Comparison of capillary flow porometry (CFP) and liquid extrusion porometry (LEP) techniques for the characterization of porous and face mask membranes

Producción CientíficaThis work aims to study the characterization of several membrane filters by using capillary flow porometry (CFP) and liquid extrusion porometry (LEP) to obtain their pore size distributions (PSD) and mean pore diameters (davg). Three polymeric membranes of di erent materials namely, polyethylene (PET), cellulose nitrate (CN), and FM (face mask), and one inorganic (namely, alumina Al2O3) from ultrafiltration (UF)/microfiltration (MF) and particle separation were analyzed using a pressure constant fluid/liquid extrusion porometer, developed at institute de la filtration et techniques séparatives (IFTS). Several porosimetric fluids have been used to wet and penetrate into the porous/fiber structure. The results show the accuracy of the setup on characterizing membranes in the UF/MF range by CFP, with reasonable agreement with nominal data of the filters. Additionally, LEP extension of the equipment obtained good agreement with nominal data and the CFP results, while filters presenting a microstructure of highly interconnected pores (face mask) resulted in clear di erences in terms of resulting PSD and average sizes when CFP and LEP results are compared.Ministerio de Educación Superior, Investigación e Innovación francés - (Proyecto CIR-IFTS-2020

Couplage de procédés physico-chimiques et séparation par membranes pour la rétention de matières organiques dans les eaux.

Les eaux naturelles comme les effluents secondaires produits par les stations d’épuration contiennent des matières organiques qui constituent actuellement l’une des cibles prioritaires des filières de production d’eau potable ou de réutilisation des eaux usées. Les membranes de Microfiltration et d’Ultrafiltration ne retiennent que très partiellement ces composés organiques de faible masse moléculaire qui sont par ailleurs responsables de phénomènes importants de colmatage. Un réacteur à membranes immergées analogue dans son principe aux bio réacteurs à membrane semble constituer un outil adapté pour réaliser simultanément dans le même équipement la réaction physico-chimique et la séparation membranaire. Les résultats présentés concernent les deux aspects : ils ont été obtenus sur des effluents secondaires ou des solutions de matières humiques : · Recherche d’un adsorbant ou d’une résine échangeuse d’ions susceptible de constituer une alternative au charbon actif en poudre utilisé jusqu’ici, en permettant notamment une régénération plus facile. · Essais à l’échelle pilote sur un réacteur à membranes immergées

Improving the measurement of the Modified Fouling Index by using nanofiltration membrane ( NF-MFI)

One of the main problems when using membrane for water treatment is fouling. Several parameters have been proposed for measuring the fouling potential. Up to now, the SDI (Silt Density Index) and the MFI0,45 (Modified Fouling Index) are used but they did not reflect the real potential of fouling. In fact particles smaller than 0,45 µm responsible of fouling are not taken in consideration. In this work, an improvement of the determination of fouling index is proposed by using NF membrane and strictly defined working conditions (constant transmembrane Pressure)

Comparison of Capillary Flow Porometry (CFP) and Liquid Extrusion Porometry (LEP) Techniques for the Characterization of Porous and Face Mask Membranes

This work aims to study the characterization of several membrane filters by using capillary flow porometry (CFP) and liquid extrusion porometry (LEP) to obtain their pore size distributions (PSD) and mean pore diameters (davg). Three polymeric membranes of different materials namely, polyethylene (PET), cellulose nitrate (CN), and FM (face mask), and one inorganic (namely, alumina Al2O3) from ultrafiltration (UF)/microfiltration (MF) and particle separation were analyzed using a pressure constant fluid/liquid extrusion porometer, developed at institute de la filtration et techniques séparatives (IFTS). Several porosimetric fluids have been used to wet and penetrate into the porous/fiber structure. The results show the accuracy of the setup on characterizing membranes in the UF/MF range by CFP, with reasonable agreement with nominal data of the filters. Additionally, LEP extension of the equipment obtained good agreement with nominal data and the CFP results, while filters presenting a microstructure of highly interconnected pores (face mask) resulted in clear differences in terms of resulting PSD and average sizes when CFP and LEP results are compared

Non-Destructive Characterization of Industrial Membrane Cartridges by Using Liquid–Liquid Displacement Porosimetry (LLDP)

This works aims to propose and demonstrate the accuracy of a novel method of characterization aimed for non-destructive analysis of microfiltration (MF) membrane cartridges. The method adapts conventional liquid–liquid displacement porosimetry (LLDP) for performing an in-line porosimetric analysis of the membrane cartridges, getting their pore size distributions (PSDs) and mean pore diameters (davg). Six commercial filtration cartridges featuring polyethersulfone (PES) pleated membranes were analyzed using a newly designed filtration rig, based on the liquid–liquid displacement porometer, developed at the Institut de la Filtration et des Techniques Séparatives (IFTS) and operated at constant flow. The experimental rig allows the direct and non-destructive characterization of the cartridge in its original presentation. Results have been compared with those obtained by using gas–liquid displacement porosimetry (GLDP) on small membrane coupons detached from such cartridges. The comparison allows us to conclude that the proposed method gives enough accuracy in the determination of porosimetric characteristics of the filters. This method can be used as a precise characterization technique for a non-destructive in-line study of filter performance and can be envisaged as useful to periodic quality or fouling control of the commercial cartridges

Influence of Anisotropic Phases in the Filtration of Impregnating Pitches (Relations with Filtrability Index)

A method based on filtràtion test is used for the characterization of impregnating pitches. Pitches with the same KS, but with increasing degree of thermal evolution, issued either from crude or filtered coal tar, underwent the filtration test. They were characterized by Transmission Electron Microscopy and Optical Microscopy. The results obtained show that the filtrability index decreases from pitches with only γ resins (toluene soluble), to pitches with only various α resins such as clean mesophase spheres (anthracene oil sensitive but quinoline insoluble) or edge to edge associations (anthracene-oil and quinoline insoluble). The filtrability is minimum in pitches where the edge to edge associations are quinoline soluble (i.e., β resins). Thus the main limiting factor for the filtration test is the presence of α or β edge to edge associations, the β ones being more efficient than the α ones for blocking the filter. The β edge to edge assocations result from an evolution under stresses without intervention of temperature. The α edge to edge associations result from a normal thermal evolution

Contribution à l’étude de la chimionisation dans une flamme de propane et d'oxygène soumis à une décharge microondes

Une flamme de diffusion de propane, de plasma d’oxygène et l'azote a été stabilisée dans un réacteur cylindrique à pression moyenne (30-50 torrs) afin d’en étudier l’ionisation. Un modèle théorique simplifié concernant l’ionisation et permettant de prévoir l’évolution de la densité ionique en fonction de la concentration en atomes d’oxygène arrivant à la flamme, a été utilisé. Le bon accord entre les résultats expérimentaux et le modèle théorique apporte une évidence supplémentaire au mécanisme de formation des ions proposé par Calcote mais est en défaveur d’un mécanisme d’ionisation par collisions entre des espèces neutres et des électrons« chauds »obtenus par collisions superélastiques. Les mesures de densité ionique ont été effectuées parla méthode des sondes doubles