Crosslinked polytriazole membranes for organophilic filtration

We report the preparation of crosslinked membranes for organophilic filtration, by reacting a new polytriazole with free OH groups, using non-toxic poly (ethylene glycol) diglycidyl ether (PEGDE). The OH-functionalized polymer was obtained by converting the oxadiazole to triazole rings with high yield (98%). The maximum degree of crosslinking is achieved after 6 h of reaction. The crosslinked polytriazole membranes are stable in a wide range of organic solvents and show high creep recovery, indicating the robustness of crosslinked membranes. The influence of different casting solutions and different crosslinking time on the membrane morphology and membrane performance was investigated. The membranes performance was studied in dimethylformamide (DMF) and (tetrahydrofuran) THF. We achieved a permeance for THF of 49 L m 122 h 121 bar 121 for membranes with molecular weight cut off (MWCO) of 7 kg mol 121 and a permeance for THF of 17.5 L m 122 h 121 bar 121 for membranes with MWCO of 3 kg mol 121 . Our data indicate that by using the new polytriazole is possible to adjust the pore dimensions of the membranes to have a MWCO, which covers ultra- and nanofiltration range

Highly porous polytriazole ion exchange membranes cast from solutions in non-toxic cosolvents

The development of highly functionalized porous materials for protein separation is important for biotech processes. We report the preparation of highly porous polytriazole with sulfonic acid functionalization. The resulting ion exchange membranes are selective for protein adsorption. The starting material was a hydroxyl-functionalized polytriazole, which is an advantageous platform for further modification. The polymer was dissolved in a mixture of 1-ethyl-3-methylimidazolium acetate ([C2mim] OAc) and dimethyl carbonate (DMC), which can be both considered green solvents. The polymer solubilization was only possible due to an interesting effect of cosolvency, which is discussed, based in phase diagrams. Membranes were prepared by solution casting, followed by immersion in a non-solvent bath. We then grafted sulfone groups on the membranes, by reacting the hydroxyl groups with 1,3-propane sultone and 1,4-butane sultone. Lysozyme adsorption was successfully evaluated. Membranes modified with 1,4-butane sultone adsorbed more protein than those with 1,3-propane sultone

A Microfiltration Polymer-Based Hollow-Fiber Cathode as a Promising Advanced Material for Simultaneous Recovery of Energy and Water

International audienceProviding adequate supply of clean fresh water and energy as the world's population increases is one of the grand challenges facing society in the current century.1 One possible solution to address both challenges is to recover clean water for reuse and energy from wastewater by integrating micro‐ or ultrafiltration membrane cathodes with microbial electrochemical system in what is referred to as an electrochemical membrane bioreactor (EMBR).2 The porous flat cathodes used in EMBR studies served the dual function as the cathode for the oxygen reduction reaction (ORR) and the membrane for the filtration of treated water. A disadvantage of using porous flat cathodes is their low surface‐area‐to‐volume ratio. Hollow fibers with small radial dimensions provide a high surface‐area‐to‐volume ratio, combining compactness, simple and modular reactor design, and high performance.3 Porous inorganic hollow fibers composed of nickel and copper have been used recently as cathodes in aqueous electrolytes for proton or carbon dioxide (CO2) reduction.4, 5 Porous polymer‐based hollow fibers are flexible, cheaper, and easier to manufacture, as well as easier to integrate into modules.6 However, most polymers are electric insulators and there are only a few examples of conducting polymers such as polypyrrole and polyaniline.7 Processibility in solution is a problem, particularly for polypyrrole.8 Combining high electrical conductivity and catalytic activity with processibility in a hollow fiber is a challenge.In this work, we propose the use of polymeric hollow fibers as electrodes, prepared from regular non‐conductive polymers and coated with a thin electron‐conductive layer of metal catalyst. However, it is challenging to apply a uniform coating of catalysts on these 3D thin porous polymeric hollow fibers using traditional deposition techniques such as electrodeposition or chemical or physical vapor deposition.9, 10 The technique that best meets the requirements for uniform coating and precise catalyst loading on 3D hollow fibers, is atomic‐layer deposition (ALD). ALD is one of the most flexible and powerful deposition techniques currently available due to its exceptional conformality and ability to tune crystallinity, atomic composition, and film thickness down to the single‐atom level.11 Because of these advantages, ALD has been applied in various applications including microelectronics, photovoltaics, solid oxide fuel cells, and solar‐to‐fuel applications, just to name a few.9-13 To date there have been no reports on the application of ALD on porous polymeric hollow fibers, especially for enabling them to act as electrodes for current collection and catalysis