Polyether urea membranes

Polyether urea (PEU) is another type of thin-film membrane. This membrane differs from polyamide membranes in the surface charge and morphology. Polyether urea membranes have a slightly positive charge to them. Further, the surface of a PEU membrane is smooth, similar to a CA membrane, thereby minimizing the potential for fouling. Elydranautics CPA membrane is an example of a polyamide/polyurea composite membrane. 

Microporous polyether urethane-urea membranes were prepared from DMAc and methylethylketone solutions by electrostatic spinning method [77], The membranes were functionalized using isocyanate agents and further activated... 

Unlike PA membranes, polyether urea (PEU) membranes are neutral to shghdy positive. PEU (and CA) membranes, unhke aromatic PA membranes, have a smooth surface and are, therefore, less prone to fouling [23], For RO feed water such as surface and municipal water, which are treated with cationic polymeric coagulants, PEU membranes, not negatively charged PA membranes, are used to minimise fouhng. 

Other components of the design [138—142] include the choice of the crown size or even the use of open-chain metalloclefts, not necessarily polyether armed. The issue of special importance for extraction and transport applications is the selection of substituents ensuring a necessary lipo-philicity-solubility balance. For example, use of a cyclohexano moiety as shown above, instead of the more common o-phenylene bridge between nitrogens, enhances solubility in the membrane phase. The modification of the polyether chain with binaphthyl or calixarene substituents provides high membrane transport rates due to increased ionophore lipophilicity [138,142]. Some representative examples (initial fluxes, in 10 mol cm h , through o-nitrophenyloctyl ether-impregnated Accurel membrane 1 M source urea [138]) are as follows. 

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