PATENTS

12Membrane Technology June 2013

PatentsZeolite-membrane separation and recovery system for carbon dioxide

Applicant: Hitachi Zosen Corp, JapanThis patent provides details of a membrane-based separation and recovery system for carbon dioxide (CO2). According to the inven-tors, it exhibits excellent CO2 permeability and CO2 separation selectivity when recover-ing the gas, which is generated in hydrogen production processes, or the like. The system described is equipped with a dewatering mod-ule, located upstream from a membrane sepa-ration module. The latter uses a hydrophilic zeolite membrane material that is formed on a porous substrate which exhibits selective per-meability with respect to CO2. The membrane is subjected to dewatering treatment by being heat-treated at a temperature of 100–800°C.Patent number: WO/2012/153763 Inventors: K. Sawamura, M. Aizawa and T. ShimizuPublication date: 15 November 2012

Porous composite membrane including microporous and nano-fibre layersApplicant: Entegris Inc, USAA filtration member that comprises a nano-fibre layer and two nano-porous membrane layers is disclosed. It can be used to remove particles and gels from photo-resist and other fluids through a combination of sieving and non-sieving particle retention mechanisms.Patent number: WO/2012/154790 Inventors: R.A. Ramirez and W.-M. ChoiPublication date: 15 November 2012

Nano-structured membranes

Applicant: Commissariat à l’Energie Atomique et aux Energies Alternatives; Ecole Polytechnique; and Centre National de la Recherche Scientifique – FranceThis invention relates to a method for produc-ing a nano-structured membrane. The process described by this patent involves irradiating a polymer substrate with heavy ions, such that latent ion tracks are formed through the entire thickness of the material; and partially etching these latent tracks so as to obtain a nano-struc-tured membrane containing nano-pores, which are less deep than the thickness of the polymer substrate, and unetched residual latent tracks.

Patent number: WO/2012/153050Inventors: M.-C. Clochard, T. Wade, H. Bessbousse and E. GallinoPublication date: 15 November 2012

Oil purification

Applicant: Bioneer Corp, KoreaA method for purifying oil has been developed. It effectively removes nano-particles from the oil. According to this patent, the oil is purified at a high temperature using a carbon nano-structure-metal, or a metal-oxide, nano-porous membrane composed of a carbon nano-struc-ture-metal composite.Patent number: WO/2012/157955Inventors: H.O. Park, J.H. Kim and J.P. KimPublication date: 22 November 2012

Fluorine-containing copolymer and ion-exchange membrane

Applicant: Asahi Glass Co Ltd, JapanThe subject of this patent is a fluorine-contain-ing copolymer. It can be used to create an ion-exchange membrane for electrolysis According to the inventors, it is not adversely affected by impurities in an aqueous alkali chloride solu-tion to which electrolysis is being applied.Patent number: WO/2012/157714 Inventors: Y. Hattori, S. Fukunaga, K. Umemura, S. Aida, A. Tsuji and T. TomitaPublication date: 22 November 2012

Process for producing hydrogen and carbon dioxide

Applicant: L’Air Liquide, Societe Anonyme pour L’Etude et L’Exploitation des Procedes Georges Claude, FranceThis patent describes a process for producing hydrogen and capturing carbon dioxide (CO2) from a feed stream containing hydrocarbons. It uses a methane reformer unit; a water gas shift reactor; hydrogen purification unit; and a first hydrogen selective membrane separa-tion unit to form a first hydrogen-rich perme-ate stream. According to this patent, another separation unit is used to produce a CO2-rich liquid stream, whilst a second hydrogen selec-tive membrane separation unit forms a second hydrogen-rich permeate stream. A CO2 selec-tive membrane separation unit forms a perme-ate stream enriched in CO2.Patent number: WO/2012/158673 Inventors: P. Terrien and P. MartyPublication date: 22 November 2012

Improved membrane with polydopamine coatings

Applicant: Advanced Hydro Inc, USAIn one embodiment of this disclosure the inventors show how to improve the rejection properties of a membrane for monovalent and divalent salts, and biochemical oxygen demand (BOD) and chemical oxygen demand (COD), whilst also improving resistance to cleaning chemicals and maintaining a high permeability for water – using a thin polymeric coating. The coating is prepared from polydopamine or hyd-roquinone, or catechol, or mixtures of these. Is deposited using a base process developed by Freeman et al. (US patent 8 017 050 issued 13 September 2011 and Freeman et al. in non-provisional patent application 12/939764). In another embodiment details are given of the unique coating process steps and conditions used to achieve the desired functionality. The inventors say that because of the presence of the thin polymeric coating, sacrificial protec-tion is provided to base materials, such as polyamide reverse osmosis and nanofiltration membranes – protecting them from accidental chlorine exposure. The interaction of free chlo-rine and the polydopamine layer is explained using contact-angle measurements. The inven-tors also suggest a way in which the coating materials can be safely disposed of once their useful service life has been exhausted. Another embodiment covers cleaning procedures for the membranes, using hot water, and a regeneration process, that do not require chemical additives.Patent number: WO/2012/158717Inventors: D. Agnihotri, X. Huang and H. LiPublication date: 22 November 2012

Mixed matrix pervaporation membrane

Applicant: Dalian Institute of Chemical Physics, Chinese Academy of Sciences, China; and BP Plc, UKA mixed matrix pervaporation membrane is described, which includes a matrix-phase, composed of a polymeric material, and a zeolitic imidazolate framework dispersed in this matrix phase. The thickness of the membrane described is greater than 0.5 μm. The mem-brane may, for example, be used in a process for separating an organic compound from an aque-ous liquid mixture. A typical process includes contacting the liquid mixture on one side of the mixed matrix pervaporation membrane to cause an organic compound to permeate through the membrane, and removing from the other side of the membrane a permeate com-

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June 2013 Membrane Technology13

position comprising a portion of the organic compound which has permeated through the membrane. The membrane described has rela-tively good selectivity in applications involving the separation of an organic compound from a liquid mixture.Patent number: WO/2012/159224Inventors: W. Yang, X. Liu and Y. LiPublication date: 29 November 2012

Liquid filtration media

Applicant: E.I. du Pont de Nemours and Co, USAThis invention relates to a liquid filtration medi-um that consists of at least one nonwoven sheet. A water flow-rate of at least 10 ml/min/cm2/KPa is achievable and the sheet has a tortuosity filter factor of at least 3.0. This medium can be used in a filtration system with an optional pre-filter layer or a microfiltration membrane.Patent number: WO/2012/158647Inventors: H.S. Lim And R.A. Marin, P.H. Young, G. Chen, T.F. Compton and S. FriskPublication date: 22 November 2012

Pore-spanning biomimetic membranes embedded with aquaporin

Applicant: National University of Singapore, SingaporeThis patent provides details of a biomimetic membrane and its supporting substrate. The structure has a porous substrate, a metal coating on the surface of this substrate, an intermediary layer on the surface of the metal coating, and a thin film, into which is incorporated a trans-membrane protein. The thin film is layered on top of the intermediary layer and spans one or more pores of the substrate. The trans-membrane protein can be an aquaporin, such as AqpZ. The porous substrate can be alumina, polycarbonate, or other polymeric membranes prepared using phase inversion, for example cellulose acetate or sulfonated polyethersulfone or polyacrylonitrile. The metal coating on the porous substrate can be gold, silver, platinum, palladium, or a combination these. The intermediary layer can be polyethylene glycol, can have methacrylate groups, or can be functionalised with a photo-reactive cross-linker, such as the acrylic acid derivatives methylacrylic acid, ethyl acrylate, methyl methacrylate, or combinations these. The thin film can be 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), or a block copolymer such as PMOXA-PDMS-PMOXA. This block copolymer can be PMOXA-PDMS-

PMOXA. It may be less than 20 nm thick and have a hydrophilic block with a molecular weight of 500–2500 and a hydrophobic block with a molecular weight of 2500–10 000. The hydrophilic-to-hydrophobic weight ratio may range from 1:4 to 2:3. The block copolymer can be PMOXA-PDMS-PMOXA – 500-2500-500; 1000-4000-1000; 1300-5000-1300; or 1600-5600-1600 or higher.Patent number: WO/2012/161662 Inventors: H. Wang, T.-S. Chung, Y.-H. Tong, M. Hong, Z. Chen, K. Jeyaseelan and A. ArmugamPublication date: 29 November 2012

Detecting live circulating or disseminated cells in bodily fluids

Applicant: Siemens Aktiengesellschaft, GermanyThis invention is relevant to the field of in vitro diagnostics. It relates to a method and an array for detecting live circulating or disseminated cells in bodily fluids (for example blood and urine) or tissue samples (for example, bone

marrow) mixed with a liquid. A series of steps is described. First, the liquid sample is filtered through a porous membrane that is suitable for retaining the cells to be detected. This is done in such a way that these cells come to rest on at least a part of the surface of the membrane and the sample liquid passes through the mem-brane. A first process liquid, containing a first agent, is applied in order to mark the cells to be detected. This process liquid, on the mem-brane, is incubated for a predetermined period, during which the cells are marked. In the final step the marked cells are detected on the sur-face of the membrane.Patent number: WO/2012/159820 Inventors: K. Friedrich, J. Bangert, W. Gumbrecht, K. Hiltawsky, P. Paulicka and M. StanzelPublication date: 29 November 2012

Method for preparing a RO membrane

Applicant: LG Chem Ltd, KoreaThis invention relates to a method for prepar-ing a reverse osmosis (RO) membrane. The method described involves the steps of: form-ing a first coating layer, the thickness of which is 20–30 μm, by applying an aqueous amine solution to one side of a microporous support body; removing the excess aqueous amine solu-tion from the support body; and forming a second coating layer, the thickness of which is 10–30 μm, by applying an aliphatic hydrocar-bon-based organic solution, composed of acyl halide, on the first coating layer.Patent number: WO/2012/161483Inventors: J.-E. Yoo, C.-K. Shin, S.-P. Jeong, P. Lee and Y.-J. LeePublication date: 29 November 2012

Filtration system

Applicant: Nederlandse Organisatie voor Toegepast-Natuurwetenschappelijk Onderzoek TNO, The NetherlandsThis invention relates to a system for filtering a fluid containing solid particles. The filtration system comprises a deformable wall (3) defin-ing a chamber (2) interior to the wall, and a tubular-shaped membrane (4) arranged in this chamber. Furthermore, the system is arranged for periodically deforming the chamber wall inwardly and outwardly, respectively, for fil-tering a fluid that is present in the chamber, exterior to the membrane. The accompanying figure shows a schematic cross-sectional view of the filtration system detailed by this patent. It comprises a number of chambers (2a–d) defined interior to deformable walls (3a–d). It

A schematic representation of a biomimetic membrane on a porous substrate, detailed by patent WO/2012/161662. In the top figure the biomimetic membrane is formed on a carboxylated polyethylene glycol cushion, chemisorbed on a gold layer that is deposited on porous alumina. In the bottom figure the biomimetic membrane is formed on a methacrylate cushion, chemisorbed on a gold layer that is deposited on polycarbonate.

PATENTS

14Membrane Technology June 2013

includes respective tubular-shaped membranes (4a–d) arranged in corresponding chambers, and housings (5a–d) in which these chambers are accommodated. The filtration system also includes a number of intermediate chamber members (6a–d) and corresponding intermediate tubular-shaped membranes (7a–d) for arranging the chambers (2) and the membranes (4) in series. In the embodiment shown, these chambers and membranes form a closed circuit, respectively. It is noted that membranes and intermediate mem-branes can be integrated into unitary elements. As an example, a first tubular-shaped mem-brane (4a) and an adjacent second tubular-shaped membrane (4b) can be implemented as a single membrane, including the intermediate tubular-shaped membrane (7a), between the first and the second membrane. Patent number: WO/2012/165963 Inventor: M. MinekusPublication date: 6 December 2013

Central core element for a separator assembly

Applicant: General Electric Co, USAThis invention aims to create a central core ele-ment for a reverse osmosis (RO) separator assem-bly that is used for the purification of fluids. The central core element comprises an outer exhaust conduit, defining an inner volume and a gap starting at its first end and extending towards its second end, and an inner porous exhaust conduit, comprising a first section disposed within the inner volume defined by outer exhaust conduit and a second section configured to abut and seal the first end of the outer exhaust conduit. The latter is configured to accommodate a first portion of a membrane stack assembly within the inner volume and a second portion of the

membrane stack assembly disposed as a multi-layer membrane assembly on an outer surface of the outer exhaust conduit. The gap is config-ured to accommodate a transition section of the membrane stack assembly – linking the first and second portions of the assembly. The first inner porous exhaust conduit section is configured to be disposed within the first portion of the membrane stack assembly.Patent number: WO/2012/166834 Inventors: C. Wang, T.A. Anderson, S. Lu and H. LiPublication date: 6 December 2013

Method of treating anaemia in haemodialysis patients

Applicant: Gambro Lundia Ab, SwedenThis patent describes a method of treating anae-mia, especially in an erythropoietin-resistant hae-modialysis patient. It involves using haemodialysis with a high cut-off dialysis membrane. This mem-brane is characterised in that it has a molecular weight cut-off in water – based on dextran sieving coefficients – of between 90 kD and 200 kD, and a molecular weight retention onset in water – based on dextran sieving coefficients – of between 10 kD and 20 kD, and a �MW of between 90 kD and 170 kD. Patent number: WO/2012/164019 Inventors: W. Beck and J. BoschPublication date: 6 December 2013

Membrane ‘‘functionalised’’ by nano-particles

Applicant: Cornell University; and Yale University – USAA membrane with a surface that has been ‘‘func-tionalised’’ by nano-particles forms the subject

of this patent. The nano-particles closest to the membrane’s surface are covalently bonded to the surface. This membrane can be used in forward osmosis, reverse osmosis and ultrafiltration systems.Patent number: WO/2012/166701Inventors: E.P. Giannelis, Y. Wang, M. Elimelech, A. Tiraferri and M.S. MauterPublication date: 6 December 2013

Films and membranes made of poly(aryl ketones)

Applicant: Arkema Inc, USAThis invention relates to films and mem-branes made from poly(aryl ketones), such as poly(etherketoneketone) (PEKK), and methods of making them by using a solvent cast process. The manufacturing process includes dissolving at least one polymer, composed of a poly(aryl ketone) – such as PEKK – in at least one solvent to form a dope. This dope is then deposited on a substrate, under appropriate conditions, to form a coated surface. Finally, the coated substrate is dried to form the film or membrane. The dope may also include additional polymers or fillers, such as car-bon nano-tubes, say the inventors.Patent number: WO/2012/166340Inventors: C. Roger, M.A. Garcia-Leiner, J.-A. Laffitte and J. BoyerPublication date: 6 December 2013

Method for washing a filtration membrane using a disinfectant

Applicant: SNU R&DB Foundation, KoreaA method for washing a filtration membrane using a disinfectant has been developed. It is targeted at the water treatment industry, and pro-vides a way of controlling bio-fouling. It includes a step of disinfecting the raw water, in-flow water and the filtration membrane with a solution that includes isocyanurate to minimise damage to the membrane and maintain performance. Micro-organisms which form a bio-film, and cause bio-fouling, are rendered inactive in order to maintain a high rate of salt removal and a stable amount of water penetration.Patent number: WO/2012/165748Inventors: J.-Y. Yoon, J.-H. Yu and Y.-B. BaekPublication date: 6 December 2013

Selective separation and recovery of metal solutes from solutionApplicant: North-West University, South AfricaThis invention relates to a method for the selec-tive separation and recovery of metal solutes

A schematic cross-sectional view of a filtration system detailed by patent WO/2012/165963.

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June 2013 Membrane Technology15

from an acidic aqueous solution using solvent extraction techniques. It further relates to the selective separation and recovery of hafnium and zirconium metal solutes; niobium and tantalum metal solutes; and platinum group metal (PGM) solutes from solution, using membrane-based solvent extraction processes. One application of this invention – a method for the selective separa-tion and recovery of zirconium (Zr) and hafnium (Hf) metal solutes from an acidic aqueous solu-tion – involves a series of steps. An acidic aqueous solution including a source of at least two metal solutes selected from the group consisting of Hf and Zr is provided. An organic medium is con-tacted with an aqueous stripping solution to form a water-in-oil emulsion and this is introduced to the lumen side of a hollow-fibre membrane contactor, while the acidic aqueous solution is introduced to a shell side of the contactor. One or more metal solutes are transferred from the acidic aqueous solution to the water-in-oil emul-sion, and a first metal solute is recovered from the water-in-oil emulsion. Any one or more of these steps described above can be repeated for the recovery of a second and/or further metal solute. The graphs illustrated in the accompanying figure reveal that the extraction increased with time for both Zr and Hf, where Zr was extracted prefer-entially to Hf. After 120 minutes approximately 90% of Zr was extracted, compared with 40% of Hf. During simultaneous recovery, Zr was again preferentially back-extracted into the aque-ous droplets of the emulsion, resulting in the full recovery of Zr with only 40% for Hf after 120 minutes. During the emulsified pertraction the Zr concentration decreased in the aqueous feed-phase (as shown in the top graph) as the metal solutes were transferred to the organic phase, as shown by the initial Zr concentration that increased in the organic phase. However, because of simultaneous back-extraction from the organic phase to the aqueous stripping phase, the latter existing as water droplets in the W/O emulsion, the Zr concentration reached a plateau after 20 minutes of contact before declining through an increase in the back-extraction, as confirmed by the increase in the Zr concentration in the aque-ous stripping phase. The Hf concentration in the aqueous feed solution (as shown in the bottom graph) decreased with a simultaneous increase in Hf concentration in the aqueous stripping phase, while the Hf concentration in the aqueous feed

solution reached an equilibrium after 50 minutes, remaining constant thereafter.Patent number: WO/2012/168915 Inventors: D.J. van der Westhuizen, G. Lachmann and H.M. KriegPublication date: 13 December 2013

Nano-pore formation in solid-state membranes

Applicant: The University of North Carolina at Greensboro; and Carl Zeiss NTS Llc – USAA method of forming nano-pores in solid-state membranes is detailed by this patent. In some embodiments the method of forming an aperture involves placing a solid-state membrane in a cham-ber, and selecting a first dose of ions sufficient to provide an aperture of a predetermined diameter through the membrane. The surface of the mem-brane is exposed to this dose of ions (in a focused ion-beam having a focal-point diameter less than or equal to about 1 nm) to remove material from the membrane, thereby creating the aperture with the required diameter.Patent number: WO/2012/170499

Inventors: A.R. Hall, J. Yang, D.C. Ferranti and C.A SanfordPublication date: 13 December 2013

Membrane production using silicone compositions

Applicant: Dow Corning Corp, USAThis invention relates to silicone compositions that are useful for the production of a membrane which is selectively permeable to at least one com-ponent of a gas mixture. This patent provides a method of forming the membrane and a method of separating components in a feed mixture using it. The membrane includes a reaction product (for example, a cured product) of a silicone composi-tion, including an organopolysiloxane that has at least two unsaturated aliphatic carbon–carbon, bond-containing groups per molecule; a cross-link-ing agent containing at least two silicon-bonded hydrogen atoms per molecule; a hydrosilylation catalyst; a polyether containing at least one unsatu-rated aliphatic carbon–carbon bond-containing group; and a siliceous filler.Patent number: WO/2012/170541Inventors: D. Ahn, J.S. Hrabal, A.J. Greiner and C. WongPublication date: 13 December 2013

Membrane desalination system

Applicant: General Electric Co, USAThe desalination system described comprises a membrane separation device and an adjustment unit. The device is configured to receive a feed stream, including one or more anti-scalants, and produce a permeate stream and a concentrated stream. The adjustment unit is configured to adjust at least a portion of one or more anti-scalants in the concentrated stream from the separation device by decreasing the pH of the con-centrated stream or by increasing its temperature, thereby releasing ions of sparsely soluble salts from their complexes with the anti-scalants. The precipi-tated stream is separated in a concentration device. The concentrated stream is returned to the feed side of the membrane separation device, the pH being increased by means of an activation device.Patent number: WO/2012/170406Inventors: C. Zhang, R. Xiong, Z. Xia and W. CaiPublication date: 13 December 2013

The graphs illustrating the concentration changes that take place in the aqueous feed, organic and the aqueous stripping phases for zirconium and hafnium, in accordance with one example cited in patent WO/2012/168915.