Study of Ceramic Membrane from Naturally Occurring-Kaolin Clays for Microfiltration Applications

The focus of this work is to assess the quality of porous membranes prepared from naturally occurring kaolin clays and to evaluate the performance of tubular ceramic membranes treating integrated raw effluents from seafood industry. This material has been chosen due to its natural abundance, its non-toxicity, low cost and its valuable properties. The preparation and characterization of porous tubular ceramic membranes, using kaolin powder with and without corn starch as poreforming agent, were reported. SEM photographs indicated that the membrane surface was homogeneous. The effects of material compositions, additives and the relatively lower sintering temperature, ranging from 1100° to 1250°C, on porosity, average pore size, pore-size distribution and mechanical strength of membranes have been investigated. A correlation between microstructure and mechanical properties of membranes has been discussed. The performance of the novel ceramic membranes thus obtained was determined by evaluating both the water permeability and rejection. The obtained membrane was used to treat cuttlefish effluents generated from the conditioning seawater product industry which consumes a great amount of water. Cross-flow microfiltration was performed then, in order to reduce the turbidity and chemical oxygen demand (COD).

Fabrication, Characterization and Permeation Studies of Ionically Cross-linked Chitosan/Kaolin Composite Membranes

This paper presents the successful preparation of porous membranes based on chitosan with enhanced mechanical, thermal and chemical properties applicable in water treatment field. Herein, chitosan/kaolin composite membranes with a cross-linking agent and a porogen were prepared using the solvent casting method. The characterization of the as-fabricated membranes indicated that the combined effect of kaolin as reinforcing agent, polyethylene glycol as pore former and citric acid as cross-linker in a chitosan matrix showed a significant influence on the membrane properties. The results indicated that the incorporation of a hydrophilic porogenic reagent into the collodion in addition to providing a porous morphology makes it possible to obtain a more hydrophilic membrane, and thus induces an increase in the pure water permeability. The cross-linked membranes exhibited an improved water resistance, better thermal and mechanical properties as compared to neat chitosan films. The cross-linked membranes had a mean pore size of 50 nm falling in the range of ultrafiltration. Their functional properties were determined in terms of pure water filtration and molecular weight cut-off tests

Polymeric membranes for treatment of produced water on offshore plateform

Introduction Phase separation using non-solvent coagulation of a polymer solution is the most widespread industrial process to manufacture membranes. Large solvent quantity is then use that it complicates the overall process and may lead to environmental and health problems. Knowing that polymer concentration is usually in the range 15-20 % and coagulation and washing baths require to be often renewed, large amounts of aqueous solutions must be treated. For instance 10 m2 of ultrafiltration membrane need about 1 to 1.5 kg of solvent. Our objective in this proposal is to develop a novel process for membrane mass production in agreement with the principles of green chemistry. The main technical and economic output of using water instead organic solvents should consist in a simplification of the manufacturing process by lowering wastes and recycling. Environmental outputs will be a safer process, more economic on atoms, limiting the wastes and applicable to renewable naturally-occurring polymers. Please click Additional Files below to see the full abstract

Fractionation of homologous CD6 to CD60 cyclodextrin mixture by ultrafiltration and nanofiltration

This paper investigates the membrane purification and fractionation of a mixture containing the homologous series of cyclodextrins CD6 to CD60 obtained by enzymatic conversion of starch. Three commercial polyamide thin film composite NF and UF membranes (HL, GH and GK from GE-Osmonics) were used for this purpose. In a first step, a binary mixture composed of glucose and heptacyclomaltose (β-cyclodextrin, CD7) was filtered to examine the separation performance of the studied membranes. A mathematical model based on mass balance was proposed for the simulation of the discontinuous diafiltration process assuming that the membrane separation performance is based on a sieving mechanism. A three stage diafiltration cascade (in retentate configuration) was then selected to fractionate the CD6–CD60 crude mixture. The experimental composition of the obtained permeate and retentate solutions in the targeted fractions (glucose, CD6–CD8, CD9–CD21, CD22–CD60) fit well with the predicted data indicating that membrane process enables purification and fractionation of the homologous series of large ring CDs. Some discrepancies were however observed implying that other mechanisms such as coupled transport also took place. The most striking effect was the presence of glucose in the GK retentate possibly as a result of the formation of inclusion complexes with the large ring CDs

Preparation of Smart Membranes from Block Copolymers

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Adsorption of poly(vinylimidazoles) onto silica surfaces

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Étude comparative de deux méthodes de caractérisation de membranes d’ultrafiltration et de nanofiltration : la porométrie bi-liquide et le transport de solutés neutres

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Physicochemical properties monitoring of UF hollow fiber membrane during fabrication and ageing

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Reverse micelles prepared from amphiphilic polylactide- b -poly(ethylene glycol) block copolymers for controlled release of hydrophilic drugs

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Negatively Charged Porous Thin Film from ABA Triblock Copolymer Assembly

International audienceThe preparation of well-arranged nano-porous thin films from an ABA triblock copolymer of polystyrene-block-poly(sodium 4-styrenesulfonate)-block-polystyrene (PS-PNaSS-PS) is reported. This copolymer was self-assembled in a N, N-dimethylformamide (DMF)/water mixture and the resulting micellar solution was used to prepare thin films via the compact packing of the flower-like micelles using spin coating method. The films were characterized by several microscopy techniques such as TEM, AFM, and SEM. Permeation test was performed to highlight the interconnected porous nature of the polymeric network obtained. Under applied water pressure, the micellar morphology was altered and a partial fusion of the micelles was observed that resulted in a change in the water permeability. Such hydrophilic nanoporous thin films with negatively charged interface could find applications in membrane filtration