PATENTS

12Membrane Technology August 2012

PATENTSPolymer films based on polyazoles

Applicant: Wacker Chemie Ag, GermanyThis invention relates to polymer films that are based on polyazoles and are 0–20% by weight soluble in N,N-dimethylacetamide at 130°C and 1000 hPa with respect to the polyazole content. This patent also describes processes for producing these materials and the way in which they are used, for example, as polymer electrolyte membranes for electrode assemblies in fuel cells, and as semi-permeable membranes for separating liquids and gases.Patent number: WO/2011/154269Inventors: E. Hanelt, M. Bortenschlager, T. Halbach, S. Haufe and M. LeutePublication date: 15 December 2011

Device for producing fresh water

Applicant: Kobelco Eco-Solutions Co Ltd, JapanDetails are provided of a device that produces fresh water efficiently. By using wastewater it is able to obtain fresh water for different uses. The device is based on a sea-water reverse osmosis (SWRO) membrane. It mixes waste-water (as a source of diluting water) with some of the sea water that is to be treated by the membrane. A first SWRO membrane device filters this mixed water, while a second SWRO membrane device filters the remainder of the sea water to be treated without it being diluted.Patent number: WO/2011/155282Inventors: K. Takata, H. Sato, Y. Ito, M. Shimada, T. Tachimi and M. NoshitaPublication date: 15 December 2011

Membrane-based filtrationApplicant: 3M Innovative Properties Co, USAOne aspect of this invention covers a method of filtering a liquid sample. Generally, the method includes passing the sample – which includes at least one biological organism – through a filter membrane at a passive water volume flux of at least 10 l/m2.h.psi. The filter membrane has a bubble point pore-size of no more than 1.0 μm. One or more biological organisms are retained (and detected) by the membrane. In certain embodiments, the biological organism may be detected in situ on the filter membrane, while in others it may be removed from the filter membrane before being detected. Thus, in

some embodiments the method includes eluting retained biological organisms from the filter mem-brane. In others the method can further include quantifying at least one of the biological organ-isms. The accompanying figure illustrates one par-ticular embodiment. Shown in the diagram is an absorbent member (16) that may be disposed on the surface of a ‘‘pocket’’ (18), which is part of the device (10). This pocket may function as a recep-tacle for the liquid sample. The absorbent mem-ber can optionally include a non-woven backing element (20) to create a seal (26), thereby fasten-ing it (the absorbent member) to a portion of the container (12). This seal may be formed using an adhesive or by heat-bonding. The filter membrane (14) may be disposed on the open-pocket surface (that is, facing the interior volume of the pocket of the absorbent member).Patent number: WO/2011/156258Inventors: P.A. Mach, R. Rajagopal, W. Xia, J. Zhou and C. GuoPublication date: 15 December 2011

Forward osmosis purification unit

Applicant: Odis Filtering Ltd, IsraelA forward osmosis (FO) purification unit is described. It comprises an inlet chamber, into which an unpurified feed solution is introduced; an outlet chamber; and a dual-membrane section. The latter is composed of a first semi-permeable membrane, which is in contact with the inlet chamber; a second semi-permeable membrane which is in contact with the outlet chamber; and a plurality of expandable cells interposed between the first and second membranes. A draw solu-tion, with an osmotic pressure that is significantly greater than that of the feed solution is used by the system. A sufficient amount of solvent can permeate through the first membrane to increase the hydraulic pressure of the draw solution within the cells, while solutes of the feed solution are rejected. The hydraulic pressure of the draw solu-tion is high enough to force the permeate to be discharged from the second membrane to the out-let chamber while the draw agent is rejected.Patent number: WO/2011/154946 Inventor: O. MenashePublication date: 15 December 2011

Composite with ion-exchange properties

Applicant: Shandong Huaxia Shenzhou New Material Co Ltd, ChinaA composite that has ion-exchange proper-ties, and a method of preparing this material is described by this patent. The composite is formed by compounding ion-exchange resin with a polymer, porous membrane contain-ing fluorine. The nitrile groups in the resin react with the nitrile groups grafted onto the polymer porous membrane to form a triazine ring cross-linked structure. The composite pos-sesses excellent mechanical properties and is gas impermeable. It also has a high ion-exchange capacity and electroconductivity.Patent number: WO/2011/156933Inventors: Y. Zhang, J. Tang, P. Liu, H. Zhang and J. WangPublication date: 22 December 2011

PTFE membrane

Applicant: Nitto Denko Corp, JapanThis patent covers a polytetrafluoroethylene (PTFE) porous membrane. In a tensile test, in which an arbitrary in-plane direction of the membrane is taken as the first direction and the in-plane, perpendicular to this direction, is taken as the second direction, the strength of the PTFE porous membrane, in these direc-tions, is 20 N/mm2 or more, and the elonga-tion, at break, in both directions is 200% or less. The ratio of the elongation in the second direction to that in the first direction is 0.5–2.0. The elongation and elongation anisotropy of the membrane, as observed during the appli-cation of an external force, are small.Patent number: WO/2011/158428Inventor: S. ShimataniPublication date: 22 December 2011

Zeolite membranes for separating a mixture containing water, alcohol or organicsApplicant: Battelle Memorial Institute, USAZeolite membrane sheets form the subject of this patent. They have been developed for sepa-rating a mixture containing water, alcohol or organic materials. Thin, but robust, these sheets contain a zeolite membrane layer that is formed directly on a thin porous metal support. The zeolite membrane layers have a thickness of less than 3 μm and are formed on a support that has a thickness of less than or equal to approxi-mately 200 μm. The metal support sheet has an average pore size of less than 3 μm and a porosity between 25% and 75%. The scanning

A schematic side view of one embodiment of the filtration device detailed by patent WO/2011/156258.

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August 2012 Membrane Technology13

electron microscope micrograph, shown in the accompanying figure, illustrates an embodi-ment of the zeolite membrane sheet in which the membrane layer was prepared by a seeding process, using a template-free synthesis solu-tion. Referring to the cross-sectional view of the sheet, the pores of the metal support (101) are fully covered by a double coating of NaA seed crystals (0.3- μm crystal sizes). Distinctive seed crystals are visible on the seeded substrate. A dense and continuous zeolite membrane (102) is formed after hydrothermal growth. The cross-sectional view of fractured membrane sheet shows certain penetration (103) of the seed crystal into the support pore, which is important to achieve strong adhesion.Patent number: WO/2011/159389Inventors: W. Liu and J. ZhangPublication date: 22 December 2011

Gas separation membrane

Applicant: Helmholtz-Zentrum Geesthacht Zentrum für Material- und Küstenforschung GmbH, GermanyThis invention relates to a method for produc-ing a membrane – in particular a gas-separation membrane – that has a selective separating layer. The method involves the following steps: a polymer solution is produced from at least one ammonium salt and at least one polymer that is compatible with this salt; this solution is cast in order to obtain a film; and the selective separat-ing layer is produced from the film in a further step – preferably by drying. This patent also covers the use of at least one ammonium salt and potential applications of this membrane.Patent number: WO/2011/157358Inventors: D. Fritsch and P. MertenPublication date: 22 December 2011

Cleaning assembly for use in fluid filtration systems

Applicant: Dow Global Technologies Llc, USAA cleaning assembly and particulate-tolerant fluid bearing that are particularly well suited to a centrifugal separation and filtration device

are detailed by this patent. In one aspect of this invention at least one bearing is arranged to carry a circulating cleaning assembly. This is able to rotate around a filtration membrane while the device is operating. The bearing is arranged to maintain the circulating cleaning assembly in coaxial alignment with the mem-brane and in a stable longitudinal position rela-tive to the membrane (as the circulating assem-bly rotates). In another embodiment, a variety of particulate-tolerant bearings are described.Patent number: WO/2011/160087Inventors: D.J. Levitt, G.D. Caffell, J.H. Mallard and S.E. O’reillyPublication date: 22 December 2011

Method for making an asymmetric polybenzoxazole membrane

Applicant: UOP Llc, USAThis invention covers a process for making an asymmetric, polybenzoxazole hollow-fibre membrane. It involves spinning a dope solu-tion, using the dry–wet phase inversion tech-nique, to form the porous, integrally skinned asymmetric o-hydroxy substituted polyimide or an o-hydroxy substituted polyamide hollow-fibre membrane. Thermal rearrangement, at a temperature of 250–500°C, is used to convert the polyimide or polyamide membrane into a polybenzoxazole membrane. These membranes contain microporous inorganic molecular sieve materials that can have a particle size ranging from 20 nm to 10 μm.Patent number: WO/2011/163293Inventors: C. Liu, R. Minkov, S.A. Faheem and J.G. MoscosoPublication date: 29 December 2011

Gas diffusion electrode

Applicant: VITO Nv, BelgiumA process for producing a gas diffusion elec-trode is described. It involves casting a porous, electrically conductive web, with a suspension of particles of an electrically conductive mate-rial in a solution of a first binder, to provide a first layer that forms an electrochemically active layer. A suspension of particles of a hydropho-bic material in a solution of a second binder is cast on the first layer to provide a second layer. The first and second layers are then subject to phase inversion (thereby realising porosity in both of the layers). Subjecting the second layer to phase inversion realises a water repellent layer. This patent also describes the use of the gas diffusion electrode in an membrane elec-trode assembly and a method of producing this assembly, which consists of a membrane sand-wiched between two electrodes – at least one of which is a gas diffusion electrode.

Patent number: WO/2012/001061Inventors: Y. Alvarez Gallego, P. Vermeiren, A.-V. Claes and W. AdriansensPublication date: 5 January 2012

Hydrogen separator

Applicant: Société Bic, FranceThis invention concerns a hydrophobic mem-brane assembly that is used within a gas-gen-erating apparatus. Hydrogen is separated from the reaction solution by passing it through a hydrophobic membrane assembly. The latter has a hydrophobic lattice-like member disposed within a composite – further enhancing the ability of the composite to separate out hydro-gen gas, and prolonging its service life.Patent number: WO/2012/003111Inventors: A.J. Curello, M. Curello and C.R. StepanPublication date: 5 January 2012

Pressure vessel containing parallel multi-membrane modules

Applicant: Siemens Aktiengesellschaft, GermanyA pressurised filtration vessel – particularly in cylindrical form – is described. It includes: a fil-ter element that consists of a plurality of filtra-tion membrane modules, particularly ultrafiltra-

A scanning electron microscope micrograph of an embodiment of the zeolite membrane sheet detailed by patent WO/2011/159389.

A schematic representation of the multi-layer gas diffusion electrode detailed by patent WO/2012/001061, showing the stainless steel mesh (current collector) (1); an active layer (2); and water-repellent layer (3).

PATENTS

14Membrane Technology August 2012

tion membrane modules; a unit (connected to an inlet) for distributing the input fluid to the filter element; and a component (connected to the outlet) for collecting the output fluid from the filter element. The filter element is located between the distributor and the collector.Patent number: WO/2012/004304Inventors: K.H.B. Drivarbekk, S. Hunter, M. Mehlen, A. Ophaug and A.L. StorliPublication date: 12 January 2012

Nano-pore device with graphene-supported artificial lipid membrane

Applicant: President and Fellows of Harvard College, USAThis patent relates to the field of artificial lipid bi-layer membranes. It describes the use of graphene – a planar sheet of bonded carbon atoms, one atom thick – to form artificial lipid membranes. It also covers the use of these mem-branes to detect the properties of polymers (for example, the sequence of a nucleic acid) and identify trans-membrane protein-interacting compounds. In general, the invention features a device, including an artificial membrane on gra-phene with apertures, each with a dimension of less than 10 μm. The plurality of apertures can be arranged in an array. The artificial membrane includes two lipid mono-layers that contact one face of the graphene. The two lipid mono-layers form a lipid bi-layer within an aperture in the graphene. In one embodiment, a graphene-sup-ported bi-layer is created by exposing both faces of the graphene to solutions containing unila-mellar liposomes whose diameter is greater than

that of an aperture in the graphene. Because intact liposomes (whose outer surfaces are hydro-philic) are unlikely to bind to the hydrophobic graphene surface, some liposomes fuse with each other across the apertures in the graphene (see the top diagram in the accompanying figure). This fusion results in molecular rearrangements and structural disruptions, creating a mono-layer of lipid on each face of the graphene and a bi-layer within an aperture (bottom diagram).Patent number: WO/2012/005857Inventors: S. Garaj and D. BrantonPublication date: 12 January 2012

Desalination system

Applicant: Megavessals Inc, USAA multi-ported vessel for a desalination system is detailed by this patent. It includes an outer pres-sure vessel, containing a number of flow distribu-tion tubes, each of which comprises a plurality of reverse osmosis (RO) membrane elements that are aligned serially within each tube. The outer pressure vessel includes bypass flow paths whereby feed water flows around each of the tubes within the vessel. Slots are disposed in the flow distribu-tion tubes at the upstream end of each RO mem-brane element such that feed water reaches all RO membrane elements of the tubes in parallel. The serial alignment of the membranes also enables serial water-processing. A product water tube col-lects the purified water from the RO elements and conveys it to a product water port. Brine water is guided to an output port where it is discarded or processed further. The parallel processing of feed water by all membrane elements increases produc-tivity and reduces costs.Patent number: WO/2012/006362Inventor: H.A. SaidPublication date: 12 January 2012

Selectively permeable membrane that uses molecular recognition macromoleculesApplicant: Sensing Network Inc, JapanThis patent provides details of a permeable membrane that uses selective molecular recog-nition macromolecules. A thin molecular recog-nition resin membrane permits the permeation of a specified, single type of component from a mixed aqueous solution of various antibiot-ics, saccharides, amino acids, organic toxic substances and other organic compounds. It is capable of fractional extraction or fractional removal, fractional isolation or detection, or quantitative analysis. According to the patent, a ‘‘template molecule’’ of a specified compound molecule, which is the object of the fractiona-tion or isolation, is ‘‘molecularly imprinted’’ – formed on a porous support membrane pro-

vided with a plurality of micro-pores that have an internal diameter through which the speci-fied compound molecule can permeate.Patent number: WO/2012/004862Inventors: T. Oomori, A. Kazusaka and T. HamadaPublication date: 12 January 2012

Grafted polyarylsulfone

Applicant: X-Flow Bv, The NetherlandsThis invention makes use of grafted polyaryl-sulfone (PAS). In particular it relates to PAS that has an aryl group grafted with a covalently attached substituent. The invention also relates to a process for grafting a PAS with an aromatic compound in the presence of an enzyme, and to a membrane that consists of grafted PAS. The patent also discusses the use of grafted PAS or the membrane in a separation process.Patent number: WO/2012/008837Inventors: M.C.R. Franssen, R.M. Boom, N.N.I. Mohamed, C.G.P.H. Schroën and J.T. ZuilhofPublication date: 19 January 2012

Synthesis method for a NaA zeolite molecular sieve membrane on a macro-pore carrierApplicant: Dalian University of Technology, ChinaA synthesis method for a NaA zeolite molecular sieve membrane on macro-pore carrier has been developed. It involves applying a continuous and uniform crystal seed-layer to the surface of the macro-pore carrier by using a thermo-dipping and brush-coating process. The growth and separation performance of the synthesised membrane can be regulated by using crystal seeds with different grain sizes. A synthesis liquid is prepared according to the molar ratio of Na2O:SiO2:Al2O3:H2O = 1–20:2–5:1:100–1000. Dynamic hydrothermal crystallisation is performed in a rotary oven to synthesise the NaA zeolite molecular sieve membrane. According to the inventors, the membrane that is produced has excellent separation performance, and it is reusable and suitable for large-scale applications.Patent number: WO/2012/010069Inventors: J. Wang, J. Yang, C. Sheng, Z. Zhou, Z. Chen, J. Lu, D. Yin and Y. ZhangPublication date: 26 January 2012

Method for producing small-diameter metallic membrane bundles

Applicant: Steri-Flow Filtration Systems (Aust) Pty Ltd, Australia

Patent WO/2012/005857 provides details of a nano-pore device with a graphene-supported artificial lipid membrane. These schematic diagrams show the use of membrane fusion to form a graphene-supported bi-layer.

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August 2012 Membrane Technology15

This invention relates to a method for produc-ing small-diameter, porous metallic membrane bundles and, in particular, bundles that are suitable for welding to a face-plate of a filter module. The invention further relates to a membrane bundle – produced using the meth-od described – for use in a filter module.Patent number: WO/2012/009762 Inventor: G. ErskinePublication date: 26 January 2012

Analysis of cultured cells

Applicant: University of Utah Research Foundation, USAAn electrophysiological ‘‘recording system’’ for the analysis of cultured cells has been developed. It includes a recording device and a housing to support this device. The device itself uses a porous membrane with a top and bottom surface. A plurality of pores extend between these surfaces. The membrane defines a first cell-culture region, disposed on the top surface and an opposed, second cell-culture region, placed on the bottom surface. The electrophysiological device has a plural-ity of electrodes positioned on the porous membrane between a first insulation layer and a similar second layer. These electrodes extend to the first cell-culture region of the porous membrane. The recording ends of the electrodes measure electrical properties of cells cultured within the first and second cell-culture regions, while the contact ends of the electrodes are connected to data-acquisition equipment.Patent number: WO/2012/009606Inventors: A.P. Moreno, G.S. Goldberg, A. Mondal, I. Harvey and B. BakerPublication date: 19 January 2012

Potted metallic membrane module

Applicant: Steri-flow Filtration Systems (Aust) Pty Ltd, AustraliaThis invention relates to a porous, metallic membrane bundle for use in a filter module, and to a method of manufacturing it. In particular, the patent shows how small-diameter tubular membranes are fitted into the filter module – providing an effective alternative to welding large-diameter membranes to module face-plates.

Patent number: WO/2012/009761Inventor: G. ErskinePublication date: 26 January 2012

Electrocatalytic membrane systemApplicant: S.C. Centrul de Cercetare Pentru Materiale Macromoleculare i Membrane Sa, Romania

An electrocatalytic membrane system – which operates at normal levels of pressure and tem-perature – has been developed for preparing fuel gas from water. The system comprises a high-frequency power source; a power-supply system; a programmable control unit; an electrocatalytic membrane module; and a module for process-ing the fuel gas. The electrocatalytic membrane module includes metallic electrodes arranged in a concentric pattern. The space between the concentric electrodes contains granular carbon and metal particles, with a fixed membrane located the lower end of the space and a mobile membrane positioned at the upper end of the space. The module has sensors for measuring process parameters, and conduits and valves for supplying and removing liquids. It also includes a system for cooling the electrodes.Patent number: WO/2012/011829Inventors: M. Radu, F. Radu, V. Radu, D. Radu, F. Cioroianu and M. CioroianuPublication date: 26 January 2012

Solvent-resistant polyamide NF membranes

Applicant: Imperial Innovations Ltd, UKThis invention relates to a composite mem-brane for the nanofiltration (NF) of a feed stream solution that is composed of a solvent and dissolved solutes. It shows preferential rejection of the solutes. The membrane consists of a thin, polymeric film, formed by interfacial polymerisation on a support membrane. The support membrane is further impregnated with a conditioning agent and is stable in polar aprotic solvents. The composite membrane is optionally treated in a quenching medium, where the interfacial polymerisation reaction can be quenched and, in certain embodiments, the membrane chemistry can be modified. Finally, the composite membrane is treated with an activating solvent prior to NF.

Patent number: WO/2012/010889Inventors: A.G. Livingston, Y.S. Bhole and M.F. Jimenez SolomonPublication date: 26 January 2012

Device for collecting a blood sampleApplicant: Becton, Dickinson and Co, USAA vent plug is disclosed which includes a body that has a distal end, a proximal end, and a lumen extending through the distal and proximal ends. A membrane is disposed across the lumen – the membrane is hydrophobic and air permeable. A distal lumen opening is shaped and sized to retain blood within the lumen until the internal pressure of the lumen increases in response to a finger pressing against a proximal lumen opening.Patent number: WO/2012/012400 Inventors: B.D. Peterson, B.G. Davis and A.J. MckinnonPublication date: 26 January 2012

Photo-catalytic purification device

Applicant: National Center for Scientific Research Demokritos, GreeceA photo-catalytic reactor, for the treatment of contaminated fluids, such as water, is described. The reactor comprises a first flow-channel, for receiving fluid from an inlet; a second flow-channel, for delivering fluid to an outlet; and a selectively-permeable filtration membrane in an intermediate position with respect to the first- and second-flow channels. This membrane has a first surface that receives fluid from the first flow-channel and an opposite, second surface defining, at least in part, the second fluid flow-channel. There is also at least one photo-catalyst support, disposed in the first flow-channel. The first and second surfaces of the filtration membrane and the photo-catalyst support are composed of an immobilised photo-catalytic material capable of catalysing the photo-catalytic break down of con-taminants in the fluid. The fluid undergoes three photo-catalytic treatment stages and a filtration stage during its passage through the reactor.Patent number: WO/2012/010645Inventors: P. Falaras, G. Romanos and P. AloupogiannisPublication date: 26 January 2012