357 results about "Hydrophobic membranes" patented technology

The present invention relates to filtration media having both hydrophobic (water-repellent) properties. The filtration media are produced using a fluorothermoplastic material, such as a terpolymer of tetrafluoroethylene, vinylidene fluoride, and hexafluoropropylene. The invention also relates to methods of preparing such filtration media using casting solution phase inversion.

The invention provides a three-dimensional oil-water separating material based on the static spinning technology and a preparation method thereof, belonging to the technical field of water treatment. The method specifically comprises the following steps: (a) preparing a static spinning solution; (b) selecting a proper solvent to directly receive static spinning nano fibers to obtain a nano fiber solution; (c) shaping and freezing the nano fiber solution, and drying through a freezing drying machine to obtain the three-dimensional nano fibers; (d) pre-oxidizing, carbonizing and activating the three-dimensional nano fibers to obtain three-dimensional carbon nano fibers; (e) wrapping the three-dimensional carbon nano fiber glue with lipophilic and hydrophobic films so as to obtain the final three-dimensional oil-water separating material. According to the preparation method of the three-dimensional oil-water separating material, the composition and structure of the material are easily controlled; the mechanical performance and hydrophobic performance of the materials can be effectively improved; the oil-water separating effect is good; the material can be recycled and has a wide application prospect in the oil-water separation field.

A method of manufacturing a hydrophilic membrane and hydrophilic membranes having improved antifouling property using a supercritical fluid or a subcritical fluid. The method involves combining a coating solution from a hydrophilic group-containing monomer, an initiator, a cross-linking agent and a supercritical fluid or subcritical fluid in a high pressure solution vessel and transferring the coating solution to a membrane in a high pressure coating vessel, coating the surfaces and micropores of the membranes through cross-linking polymerization reactions. Non-reacted coating material is returned to the high pressure solution vessel. The membranes are removed from the coating vessel, cleaned and dried. The hydrophilic membrane manufactured by the present invention is excellent in properties of hydrophobic membranes such as thermal stability, chemical stability and mechanical strength, and surfaces and micropores of the membranes are uniformly coated.

Composite porous hydrophobic membranes are prepared by forming a perfluorohydrocarbon layer on the surface of a preformed porous polymeric substrate. The substrate can be formed from poly(aryl ether ketone) and a perfluorohydrocarbon layer can be chemically grafted to the surface of the substrate. The membranes can be utilized for a broad range of fluid separations, such as microfiltration, nanofiltration, ultrafiltration as membrane contactors for membrane distillation and for degassing and dewatering of fluids. The membranes can further contain a dense ultra-thin perfluorohydrocarbon layer superimposed on the porous poly(aryl ether ketone) substrate and can be utilized as membrane contactors or as gas separation membranes for natural gas treatment and gas dehydration.

A highly accurate, long life, low cost gas sensor is disclosed, particularly useful for measuring carbon monoxide and other toxic gases in an environment. The gas sensor has a first, sensing electrode and a second, counting electrode. Positioned between the first and second electrodes is an ion conducting, solid electrolyte membrane. In response to the presence of a toxic gas introduced to the first electrode, an electric signal is produced between the first electrode and the second electrode. The electric signal changes in response to changes in the concentration of the toxic gas. Detection circuitry measures the electric signal to determine the concentration of the toxic gas. An electrically conductive, hydrophobic top membrane electrically connects the first electrode to the detection circuitry while preventing liquid water from contacting the first electrode. An electrically conductive, hydrophobic bottom membrane electrically connects the second electrode to the detection circuitry. The top and bottom membranes, though hydrophobic, are preferably also microporous so as to be gas permeable, including permeable to water vapor. Preferably the top and bottom membranes are ion insulating as well. Optionally the sensor is provided with a water reservoir to maintain constant relative humidity at the ion conducting electrolyte membrane. The sensor may also have a heating element. Internal and external self-diagnostic features to ensure that the sensor is functioning normally are disclosed, as well as self-calibration features, so as to ensure sensor accuracy.

The invention discloses a super hydrophobic modification method for polyvinylidene fluoride hydrophobic membranes and belongs to the technical field of membrane separation. The method comprises: preparing membrane casting solution by using polyvinylidene fluoride (PVDF), N,N-dimethylacetamide (DMAC) serving as a solvent and non-solvent low-molecular-weight alcohol and aging the membrane casting solution to form upper membrane solution; preparing membrane casting solution by using PVDF, DMAC, LiCl or/and polyvinyl pyrrolidone (PVP), and aging the membrane casting solution to form lower membrane solution, wherein the PVDF content in the lower membrane solution is higher than that in the upper membrane solution; scraping the lower membrane solution and the upper membrane solution on a glass plate in turn, and placing the glass plate in air at 50 to 75 DEG C and at a water relative humidity of 80 to 100 percent to obtain a primary ecological membrane; and immersing in running water for stripping the membrane and drying to obtain a polyvinylidene fluoride composite film of which the surface is super hydrophobic. In the invention, the method is simple, the process flow is short, the cost is low, and the prepared membrane has high flux and high salt rejection rate.

The invention provides a membrane aeration and membrane separation coupled sewage treatment device and method, wherein the hydrophobic membrane for aeration and the hydrophilic membrane for separation are mounted in a common cylinder shaped reactor, forming a membrane aeration and separation reactor, a bioreactor is also arranged on the reflux line, so as to realize circulatory flow of the treated sewage water between the two reactors, thus achieving the coupling of aeration, membrane separation and biological degradation.

The invention provides a method for removing free moisture or emulsified water by a hydrophobic film. In the method, the hydrophobic film is used as a filtering medium; petroleum products with higher content of water pass through the hydrophobic film under operating pressure which is not exceeding aqueous phase penetrating pressure by hydrophobic nature of the film; then moisture content is intercepted by the hydrophobic film, thus obtaining oil products with lower content of moisture. The method of the invention can be applicable to removal of moisture for many oil products avoiding of the effects of moisture content and temperature. The method of the invention is characterized in that removal of moisture content of the oil products can be carried out in real time in the process of oil delivery without adding any reagents, thus greatly reducing energy consumption, featuring in high dehydration rate and great operational flexibility; the whole manufacturing process is easy and large scale industrialized application of the method can be easily realized.

A method is provided for substantially instantaneously wetting hydrophobic, porous polymeric membranes and for rendering hydrophobic membranes hydrophilic. The method involves treating the membrane with a non-alcoholic aqueous solution of a low molecular weight surfactant, and then drying the treated membrane. The low molecular weight surfactant exhibits high polymer affinity for the hydrophobic membrane substrate as well as high water solubility; a preferred surfactant is sodium dodecylbenzenesulfonate (SDBS). The method is particularly useful for treating hydrophobic membranes such as those made of polyolefins, fluorinated or chlorinated polymers, polysulfone, or polyethersulfone, preferably having a pore size of about 0.01 microns to about 1 micron. A wettable membrane is thus provided as the aqueous surfactant solution is absorbed into the hydrophobic membrane.

The present disclosure relates to improved efficient and effective systems and methods of manufacturing hydrophilic polyethersulfone (PES) membrane suitable for commercial applications and the resultant hydrophilic polyethersulfone (PES) membrane suitable for commercial applications produced thereby and includes methods of manufacturing hydrophilic polyethersulfone (PES) membrane comprising the acts of: providing hydrophobic PES membrane; prewetting the hydrophobic PES membrane in a sufficient amount of a liquid having a sufficiently low surface tension; exposing the wet hydrophobic PES membrane to a sufficient amount of an aqueous solution of oxidizer; and after the exposing act, heating the hydrophobic PES membrane for a sufficient time at a sufficient temperature.

The invention discloses a solar photovoltaic waste heat-joule heat gradient utilization seawater desalination system, and belongs to the field of renewable energy source utilization. The system mainlycomprises a high-transmittance glass cover plate, a solar photovoltaic cell, heat conduction silica gel, a heat conduction aluminum plate, a seawater flow channel, an electric heating layer, a hydrophobic film layer, a condensate flow channel, aheat preservation and insulation layer a seawater storage tank, a condensate collecting tank, a washing tank and an efficient fin radiator. The system iscomposed of multiple layers of seawater desalination devices. The desalination devicesare arranged in the heat preservation and insulation layer, the high-transmittance glass cover plate, the solar photovoltaic cell, the heat conduction silica gel, the heat conduction aluminum plate, the electric heating layer, the hydrophobic film layer, the seawater flow channel, the seawater storage tank and the condensed water collection tank are sequentially arranged in the heat preservation and insulation layer from top to bottom. Waste heat and electric energy generated by power generation of the solarphotovoltaic cell are utilized, energy is utilized in situ or in a gradient mode to participate in sea water desalination, solar energy is utilized to the maximum extent, and meanwhile the evaporationefficiency and the sea water desalination capacity of the system are greatly improved.

The invention relates to a wetting-resisting super-hydrophobic membrane and a preparation method thereof. Combined nanoparticles are coated with a low surface energy solution to form a rough structure, and a PDMS-SiO2-PDMS sandwich compound layer is formed on the surface of the membrane. The compound layer has the advantages of rough structure and low surface energy, the membrane has super hydrophobicity, and the membrane further has high wetting resistance in a membrane distilling process. The membrane can be utilized to perform direct contact type membrane distillation to treat a water bodycontaining a surface active agent, so that membrane distillation operation time is obviously prolonged, stable operation time is 20 times or more of that of a PVDF original membrane, and water production capacity can be improved by 15 times or more.

Method and devices for filtering liquid are provided that rely on pressure difference to filter liquid. In one embodiment, a device for filtering liquid includes a feed chamber, a permeate chamber, and a porous membrane that is at least partially hydrophobic and has one or more pores configured to be permeable to vapor. A pressure of a liquid substance in the feed chamber is increased such that vapor of the liquid substance is transported from the feed chamber to the permeate chamber. The resistance of flow in a hydrophilic layer of the membrane can be controlled to make the membrane defect-tolerant. In another embodiment, a second porous membrane is further included and the second porous membrane is spaced apart from the first porous membrane. Various methods for filtering liquid are also provided.

A method and system for recycling and treating dyeing wastewater are provided. To begin with, the dyeing wastewater is added with an adsorbent for assisted decolorization and filtration. Then, the wastewater is filtered with a first filtration device having hydrophilic membranes. The liquid having passed through the hydrophilic membranes undergoes an RO membrane-base filtration process to produce recycled water and concentrated wastewater. The concentrated wastewater is delivered into a second filtration device having hydrophobic membranes, before a micro-bubbling process is performed on the concentrated wastewater in the second filtration device to turn the concentrated wastewater into a creamy-white nebulized working liquid of high gas content. The steam in the working liquid can readily pass through the hydrophobic membranes to produce an effluent that meets effluent standards.

The invention relates to seepage-proofing and air-permeable sand with super-hydrophobicity and high durability and a preparation method of the seepage-proofing and air-permeable sand. The seepage-proofing and air-permeable sand comprises quartz sand and a hydrophobic film coating the surface of the quartz sand. The seepage-proofing and air-permeable sand is characterized in that the hydrophobic film is obtained through crosslinking and curing of hydrophobic resin, a curing agent, polytetrafluoroethylene and nano SiO2 on the surface of the quartz sand, and a micro-nano two-level rough structureis formed on the surface of the hydrophobic film. Compared with the prior art, the problems of poor seepage-proofing effect, poor durability and surface adhesion of the seepage-proofing and air-permeable sand are solved, and the seepage-proofing and air-permeable sand has characteristics of being simple to prepare and good in super-hydrophobicity, low adhesion and durability and has very wide application prospects.

A membrane distilling process for desalinating seawater includes filtering seawater, bubbling while pressure floating to rmeove seaweeds and solid impurities, bubbling again to mix air with water to become emulsion and making the bubbles contain saturated water vapour, delivering it into a desalinating equipment containing one or more porous hydrophobic membranes to penetrate the emulsion containing a lot of saturated water vapour through the membrane, and condensing the water vapour to obtain fresh water.

Belonging to the technical field of rice storage monitoring, the invention relates to a method for detection of freshness during rice storage. The method includes: firstly using a gas acquisition probe equipped with a heating device and a special filter screen to acquire the volatile gas in grain storage equipment, then employing a 3CCD camera to acquire the sensor array on a hydrophobic membrane and the R, G, B images of rice sample gas before and after reaction, processing the images by a computer, and finally introducing color signal values into a linear discriminant analysis model to calculate the freshness of the output rice sample. The method detects rice freshness through its volatile smell, and is a green, rapid and nondestructive method. Compared with the traditional chemical detection methods, the method provided by the invention is convenient and pollution-free, and has certain consistency with the sensory evaluation of human. Compared with artificial feel, the method has good objectivity and reproducibility. The method provided by the invention has important practical significance for meeting consumers' demands for food quality and safety and enterprises' demands for full use of raw materials and maximum benefits.

The invention discloses a method for cyclic plating of hydrophobic membranes through plasma chemical vapor deposition. The method for cyclic plating of the hydrophobic membranes through plasma chemical vapor deposition comprises the following steps of (1) pretreatment is carried out, specifically, a to-be-coated surface is pretreated; (2) activation is carried out, specifically, the to-be-coated surface is activated in a reaction cavity by means of plasma gas; (3) membrane plating is carried out, specifically, a vaporized hydrophobic material enters the reaction cavity, and a hydrophobic membrane is formed by the hydrophobic material on the to-be-coated surface through plasma chemically-enhanced vapor deposition method; (4) feed of the hydrophobic material is stopped, step (2) and step (3)are carried out again, and another hydrophobic membrane is deposited on the original hydrophobic membrane; (5) step (4) is repeated; and (6) vacuum breaking is carried out in the reaction cavity, sothat a workpiece provided with multiple hydrophobic membranes is obtained. According to the method, the multiple hydrophobic membranes are deposited by means of cyclic plating, so that effective adhesion and close stacking of the membranes are facilitated, the quality of the membranes is improved, the membranes can adhere to and be deposited on the surface of the base material more firmly, and thedurability of the hydrophobic property is ensured.

The invention relates to a preparation method of a high-durability hydrophobing agent, which comprises the following steps: (1) hydrolysis of long-chain fluoroalkyl low-surface-energy substances: adding long-chain fluoroalkyl low-surface-energy substances, a catalyst and water into an organic solvent, and stirring so that the long-chain fluoroalkyl low-surface-energy substances have the activity of reacting with hydroxy group; and (2) extraction: adding a perfluoro solvent into the system, extracting the hydrolyzed long-chain fluoroalkyl low-surface-energy substances into the perfluoro solvent by utilizing favorable solubility of the long-chain fluoroalkyl low-surface-energy substances in the perfluoro solvent, and removing the supernatant liquid, thereby obtaining the hydrophobing agent. The invention also provides a preparation method of hydrophobic glass with high performance, which comprises the following step: preparation of hydrophobic film layer: coating the hydrophobing agent on the surface of the glass to prepare the hydrophobic film layer, thereby obtaining the hydrophobic glass. The perfluoro solvent can improve the solubility of the long-chain fluoroalkyl low-surface-energy substances and prevent the long-chain fluoroalkyl low-surface-energy substances from polymerization and crystallization; and the perfluoro solvent is hardly dissolved in water, thereby avoiding water in the system, enhancing the reaction density between the long-chain fluoroalkyl low-surface-energy substances and the hydroxy group on the glass surface, and improving the durability of the hydrophobic film layer.

The invention discloses a method for preparing an anticorrosion superhydrophobic surface of brass, which prepares the anticorrosion superhydrophobic surface of brass by four steps, namely preparing etching solution, pretreating brass, constructing surface roughness by chemical etching and performing self-assembly of a superhydrophobic membrane on the rough surface of brass. Because mixed liquid of hydrogen peroxide and hydrochloric acid is used to etch the surface of brass to construct the surface roughness, the method for preparing the anticorrosion superhydrophobic surface of brass is simpler, cheaper and easier to control; and the anticorrosion superhydrophobic surface of the brass obtained by the preparation method disclosed by the invention has high anticorrosion performance for the surface of the brass contains certain amount of stearic acid molecules.