# US 2019/0168172 A1 · Preparation of hand-carry gravity-driven water filter with high throughput and water disinfection performance > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0168172 A1 - Document ID: US20190168172A1 - Status: Published application - Kind: A1 - Application number: 16/323,022 - Filed: 2016-08-08 - Published: 2019-06-06 - Earliest claimed: 2016-08-08 - Assignees: The University of Hong Kong - Applicants: The University of Hong Kong - Inventors: Jianqiang WANG; Xiaonan SHI; Zhe YANG; Chuyang TANG - Web page: https://patentgrep.com/patent/US20190168172A1 ## CPC - B01D 69/1251: {by interfacial polymerisation} - B01D 63/081: {Manufacturing thereof} - B01D 67/00042: {by deposition of fibres, nanofibres or nanofibrils} - B01D 67/00046: {by deposition by filtration through a support or base layer} - B01D 67/0006: {by chemical reactions (in-situ polymerisation, polycondensation, cross-linking or reaction for manufacturing composite membranes B01D69/125)} - B01D 67/0016: {Coagulation} - B01D 67/0079: {Manufacture of membranes comprising organic and inorganic components} - B01D 67/00791: {Different components in separate layers} - B01D 67/0088: {Physical treatment with compounds, e.g. swelling, coating or impregnation} - B01D 69/02: characterised by their properties - B01D 69/1071: {Woven, non-woven or net mesh} - B01D 69/1216: {Three or more layers} - B01D 69/1411: {containing dispersed material in a continuous matrix} - B01D 71/421: {Polyacrylonitrile} - B01D 71/441: {Polyvinylpyrrolidone} - C02F 1/44: by dialysis, osmosis or reverse osmosis {(general membrane separation processes B01D61/00, membrane modules B01D63/00, electrodialysis C02F1/4693, combination of membrane modules and bioreactors C02F3/1268)} - C02F 1/50: by addition or application of a germicide or by oligodynamic treatment {(C02F1/4606, C02F1/467, C02F1/76 take precedence)} - B01D 2313/243: Pumps - B01D 2323/39: Electrospinning - B01D 2323/40: in-situ membrane formation - B01D 2323/48: Influencing the pH - B01D 2325/0283: Pore size - B01D 2325/04: Characteristic thickness - B01D 2325/48: Antimicrobial properties - C02F 2303/04: Disinfection - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes) ## Abstract A hand-carry gravity-driven water filter with high throughput and water disinfection performance is formed. Membranes used for this water filter can be fabricated using electrospun method and non-solvent induced phase inversion method. A novel composite membrane structure (interwoven composite structure) was designed for further enhances water permeability and mechanical strength. The composite membrane can be composed of nanofibers with different diameter from the same polymer or different polymers. Membrane porosity and surface pore size can be controlled. Silver nanoparticles can be in-situ loaded on the surface of the membranes. The developed filter is effective for removal of a wide range of contaminants (e.g., pathogens, suspended solids and heavy metals). The purification process can be carried out under the drive of gravity (with an option for mechanically-enhanced filtration) without electricity. ## Claims ### Claim 1 A composite membrane comprising polymeric nanofibers, the composite membrane having a composite structure of large diameter nanofibers and small diameter nanofibers, the nanofibers all together having a number average diameter in the range of 100-1000 nm, and the polymeric nanofiber membrane having a porosity in the range of 75-95% and a mean pore size in the range of 10-1000 nm. ### Claim 2 (depends on 1) The composite membrane according to claim 1, wherein the composite membrane has a thickness of 50-500 μm. ### Claim 3 (depends on 1) The composite membrane according to claim 1, wherein the large diameter nanofibers have diameters in the range of 200-1000 nm and the small diameter nanofibers have diameters in the range of 100-500 nm. ### Claim 4 (depends on 1) The composite membrane according to claim 1, wherein the polymeric nanofibers comprising different polymeric nanofibers (hydrophobic or hydrophilic). ### Claim 5 (depends on 4) The composite membrane according to claim 4, wherein polymers forming the polymeric nanofibers are selected from a group consisting of poly(acrylonitrile) (PAN), poly(vinyl alcohol) (PVA), poly(vinyl fluoride) (PVDF), chitosan, polysulfone (PSf), polyethersulfone (PES), poly(methyl methacrylate) (PMMA) and poly(vinyl butyral) (PVB). ### Claim 6 (depends on 1) The composite membrane according to claim 1, further comprising nano-beads or microspheres. ### Claim 7 (depends on 6) The composite membrane according to claim 6, wherein the nano-beads or microspheres have an average diameter of 20-2000 nm. ### Claim 8 (depends on 1) The composite membrane according to claim 1, further comprising a polydopamine layer that is a surface coating of polydopamine compounds. ### Claim 9 (depends on 8) The composite membrane according to claim 8, further comprising in-situ surface loaded silver nanoparticles. ### Claim 10 (depends on 9) The composite membrane according to claim 9, wherein the in-situ surface loaded silver nanoparticles are reduced by the polydopamine layer. ### Claim 11 (depends on 9) The composite membrane according to claim 9, wherein the in-situ surface loaded silver nanoparticles have a loading amount of 0 wt. %-5.0 wt. %. ### Claim 12 (depends on 9) The composite membrane according to claim 9, wherein the in-situ surface loaded silver nanoparticles have an average diameter of 0-100 nm. ### Claim 13 (depends on 1) A gravity-driven nano-fibrous membrane filter comprising: a support structure forming an open top volume; and a composite membrane according to claim 1 on at least a bottom of the support structure, said composite membrane having a folded configuration, said filter accepting feed water at the open top and allowing cleaned water to exit below the membrane at the bottom. ### Claim 14 (depends on 13) The gravity-driven nano-fibrous membrane filter according to claim 13, further comprising a mechanically assisted vacuum system for drawing feed water entered at the top of the filter through the membrane. ### Claim 15 (depends on 14) The gravity-driven nano-fibrous membrane filter according to claim 14, wherein the mechanically assisted vacuum system comprises a piston located below the filter and a handle connected to the piston that allows the piston to be pulled down creating a vacuum on the opposite side of the membrane from the feed water. ### Claim 16 (depends on 13) The gravity-driven nano-fibrous membrane filter according to claim 13, wherein silver is loaded onto the composite membrane to provide water purification. ### Claim 17 A process for fabricating a nanofibrous membrane, the process comprising: preparing a solution by mixing and annealing in a sealed container a polymer mixture consisting of a certain amount of polymer and additives in an organic solvent at 50˜90° C. until homogenous, and cooling the polymer mixture to room temperature; applying voltage in the range of 10-30 kV (preferably 15-25 kV) to the solution at room temperature as it is ejected in a stream from a syringe toward a rotating metal drum; feeding the solution from the syringe at the rate 0.5-2.0 mL/h (preferably 1.0-1.5 mL/h); and collecting the stream as nanofibers on a rotating metal drum at a distance of 5.0-20.0 cm (preferably 10-15 cm) from the exit of the syringe to yield a nanofibrous membrane. ### Claim 18 A non-solvent induced phase separation (NIPS) process for fabricating a nanofibrous membrane, the process comprising: preparing a solution by mixing and annealing in a sealed container a polymer mixture consisting of a certain amount of polymer and additives in an organic solvent at 50˜90° C. until homogenous, and cooling the polymer mixture to room temperature; casting with a thickness the solution at room temperature onto a clean and smooth glass plate; quickly and smoothly immersing the glass plate into a coagulation water bath; and after a substrate is formed by phase inversion, removing excess solvent and additives by soaking in DI water to yield a nanofibrous membrane from the substrate. ### Claim 19 (depends on 17) A process for fabricating a composite membrane nanofiber structure, comprising: fabricating a nanofibrous membrane in accordance with the process of claim 17; and subjecting the nanofibrous membrane to interfacial polymerization by bringing it into contact with a polyamine aqueous solution for 1-1200 seconds (preferably 30-600 s), removing the excess polymer solution from the surface of the membrane, immediately bringing the membrane into a TMC n-hexane solution for 1-600 s (preferably 10-300 s), and after desired membrane layers have been formed, rinsing the resulting composite membrane thoroughly with hexane and storing it in DI water at 15-25° C. (preferably 20° C.) before characterization. ### Claim 20 (depends on 19) The method of claim 19, wherein the step of bringing the membrane into contact with the polyamine aqueous solution is performed by pouring it into the polyamine aqueous solution. ### Claim 21 (depends on 19) The method of claim 19, wherein the step of bringing the membrane into the TMC n-hexane solution is performed by pouring it into the TMC n-hexane solution. ### Claim 22 (depends on 19) The method of claim 19, further comprising loading silver nanoparticles in-situ on a surface of the membrane. ### Claim 23 (depends on 22) The method of claim 22, wherein the step of silver loading the membrane comprises: coating DOPA or L-DOPA on the surface of the membrane by simple immersion in a Tris buffer solution; and immersing the membrane into a silver nitrate aqueous solution. ### Claim 24 (depends on 23) The method of claim 23, wherein the step of coating the membrane is carried out with a 0.5-5.0 g/L solution bath of DOPA or L-DOPA for 0.5 hours to 24 hours with a pH of 7.0 to 9.0 for the Tris buffer solution. ### Claim 25 (depends on 23) The method of claim 23, wherein the step of immersing the membrane in the silver nitrate aqueous solution is carried out with a 0.5-10.0 g/L (preferably 1.0-5.0 g/L) silver nitrate aqueous solution for 0.5 hours to 10 hours. ### Claim 26 (depends on 1) The composite membrane of claim 1, wherein the large diameter nanofibers and the small diameter nanofibers are interwoven in a single fiber layer.