178 results about "Membrane flux" patented technology

The invention discloses a GO (graphene oxide) and g-C3N4 composite modified membrane material. A preparation method includes steps: activating an original membrane to recover original membrane flux; adding a surfactant into GO and g-C3N4 mixed dispersion liquid to obtain mixed liquid; soaking the activated original membrane into the mixed liquid to realize ultrafiltration adsorption, and soaking the membrane into aniline hydrochloric acid solution; taking out after soaking is finished, and soaking in hydrochloric acid solution of ammonium persulfate immediately to enable interface polymerization reaction; finally, drying the membrane to obtain the composite modified membrane material. By an ultrafiltration adsorption and interface polymerization combined modification method, GO and g-C3N4are combined for surface composite modification of the membrane material, and a visible light responsive catalytic modified membrane is developed. The novel modified membrane is low in preparation cost and recyclable, pollution resistance is remarkably improved, firmness in modifying agent and photocatalyst loading is achieved, the visible catalytic performance and hydrophilic performance are remarkably enhanced, the forbidden bandwidth of a membrane function layer is decreased, the problem of secondary pollution is avoided, and a promising application prospect is achieved.

The invention relates to a method for hydrolyzing the surface of a polyacrylonitrile ultrafiltration membrane, and belongs to the technical field of membrane separation. The prior soakage method is easy to make the inner surface and the outer surface of the membrane and the insides of membrane pores all perform hydrolysis reaction, so that the mechanical strength and the flux of the membrane are severely reduced. The invention realizes the surface hydrolysis of the polyacrylonitrile ultrafiltration membrane by adopting the following technical proposal: filling a transitional solvent-ethanol into the membrane pores; using a filling solvent-cyclohexane to substitute the ethanol; making a single surface of the membrane contact an alkaline solution for hydrolysis; using the ethanol to substitute the cyclohexane in the membrane pores; and using water to substitute the ethanol in the membrane pores. When the method is adopted to modify the polyacrylonitrile ultrafiltration membrane, the hydrolysis reaction is only performed on the surface of the membrane and not performed in the membrane pores, so that the method improves the pollution resistance and the biocompatibility of the polyacrylonitrile ultrafiltration membrane and simultaneously guarantees the mechanical strength and the flux of the membrane.

The invention discloses an online monitoring method and system for MBR membrane pollution, and the method comprises the steps: obtaining MBR membrane pollution influence parameters in incoming water at a current moment, inputting the MBR membrane pollution influence parameters at the current moment into a current optimal LSTM recurrent neural network model, obtaining a membrane flux prediction result at the current moment, and judging the pollution and blockage conditions of an MBR; wherein the LSTM recurrent neural network model is mainly established on the basis of a training data set formedby MBR membrane pollution influence factors and historical data of membrane flux according to principal component analysis and an LSTM recurrent neural network algorithm. According to the method, theredundancy in the MBR membrane flux judgment process is reduced through a principal component analysis algorithm, the dimensionality of a training sample is reduced, and the calculation speed is increased; aiming at the time characteristic of MBR membrane pollution, the LSTM recurrent neural network solves the problem of time serialization. According to the method, a nonlinear relationship between membrane pollution factors and membrane flux representing the membrane pollution degree is well established, and the pollution and blockage conditions of the membrane are predicted in advance.

The invention discloses a preparation method of a self-assembly nanofiltration separation membrane for high salinity and high ammonia nitrogen wastewater, and the nanofiltration separation membrane is used for the treatment of high ammonia nitrogen and high salinity wastewater. Polysulfone ultrafiltration membrane is used as a basic membrane; static layer-by-layer self-assembly technique is employed; and a PST surface modifier of nanofiltration membrane material aiming at desalination of high salinity and high ammonia nitrogen wastewater and recycling of ammonia nitrogen components is developed; and poly diallyl dimethyl ammonium chloride (PDADMAC) / sodium polystyrene sulfonate (PSS) multilayer polyelectrolyte nanofiltration membrane is prepared. Aiming at the influences of species, concentration and self-assembly layer of ions on separation performance, charge property and hydrophilicity of the membrane, the surface properties of nanofiltration membrane are adjusted; and according to the retention rate of nanofiltration membrane on different ions in waste water under different operation conditions and change of membrane flux and recovery rate, targeted membrane material and technology for desalination of high salinity alkali wastewater and separation of ammonia nitrogen are developed.

The invention provides a gas drive membrane separation method. When a membrane works, continuous bubbles are introduced into one side or two sides of the membrane so that the membrane is vibrated within a definite frequency spectrum range. The invention also provides a membrane separation device. When the method and the device are applied, the prior process flow and the prior operating devices are not needed to be improved greatly, and a membrane device can be subjected to dirt removing operation during the running of the membrane only by increasing a bubble generating and controlling device so as to reduce membrane pollution, reduce plugging ratio, increase membrane flux, keep long-time continuous and stable operation during membrane separation, prolong the service life of the membrane, and improve the water yield of the membrane.

The invention discloses a method and a device for cleaning a high-efficiency water-saving medicine-saving membrane unit. The method comprises the following steps: allowing reclaimed water subjected to MBR treatment to pass through three bubble pools, a clean-water reservoir and two dosing pools, adding 1000kg of 13 mass percent of sodium hypochlorite solution and 25+/-0.1kg of industrial sodium hydroxide, and stirring until the sodium hydroxide is completely dissolved; moving the membrane unit into the clean-water reservoir, mixing the reclaimed water and gas to perform continuous and effective air scrubbing and water scrubbing on membranes which are difficultly cleaned in a membrane box, and cleaning organic matters such as activated sludge attached to the membranes on the surface of the membrane box and in the membrane unit; transferring the membrane unit into the dosing pools, performing bottom aeration, jittering to blow out the sludge on the membranes in the membrane unit, and effectively cleaning the membranes through air bubbles generated by air aeration. According to the method and device, the waste of dose is effectively reduced, the membrane flux is improved, and the effluent amount and water quality stability of the MBR process are guaranteed.

The invention discloses a nozzle for preparing a tubular nanofiltration membrane, a membrane spraying device and a system. One end of the nozzle is closed, and the other end is open. The inside of the nozzle is radially divided into water-phase regions, oil-phase regions and hot-air regions that do not communicate with each other. The walls of the nozzles in each region are axially penetrated with micropores. The membrane spraying device for preparing the tubular nanofiltration membrane comprises the above-mentioned spray tube, a power mechanism and a sliding support mechanism for driving the spray tube to rotate. The system for preparing tubular nanofiltration membranes includes a membrane fixing device, a membrane spraying device, a feeding device and a hot air device. The water phase medium and the oil phase medium are sprayed onto the inner wall of the tubular membrane through the feeding device and the spraying device for interfacial polymerization. , heat treatment through a hot air device to complete the preparation of the tubular nanofiltration membrane. The invention solves the technical defect of the traditional method that the inner and outer walls of the tube membrane are prone to interfacial polymerization at the same time during the soaking process; reduces the amount of medicament used and the amount of waste liquid in the interfacial polymerization process, and forms a thinner dense separation layer at the same time, increasing the membrane flux.

The invention discloses pectin and an extraction method and a preparation method thereof. The extraction method comprises the steps: adding organic weak acid salt into an acidic pectin extracting solution, uniformly mixing, carrying out membrane filtration on the extracting solution treated by the organic weak acid salt, carrying out alcohol precipitation or salting-out on the extracting solution,and separating to obtain the pectin, wherein the addition amount of the organic weak acid salt in the mixed solution is 0.2-1 mg/mL. Due to the fact that a proper amount of organic weak acid salt isadded before membrane filtration, pectin colloid is further stabilized, pectin is not prone to precipitation on the surface of a membrane during membrane concentration, meanwhile, pigments, saccharides, calcium, magnesium and other salts in the pectin can be removed, the membrane flux can be increased, and membrane pollution is effectively relieved. Besides, in the salting-out process, low-valencesalt can be used as a precipitating agent, complexing of high-valence cations in a salt solution and the pectin is avoided, pectin desalination is easy to carry out, and thus the problems that pectinis low in extraction rate, heavy in color and low in purity are solved, and the ash content of the pectin is not high.

A method for or producing an organic-inorganic hybrid membrane by enzyme induction belongs to the technical field of membrane separation and comprises steps: firstly, assembling a plurality of layers of cationic polyelectrolyte and anionic polyelectrolyte alternately on the surface of a treated membrane to obtain a membrane 1; secondly assembling a plurality of layers of cationic polyelectrolyte, calcium salt and anionic polyelectrolyte and urease alternately on the surface of the membrane 1 to obtain a membrane 2; and finally soaking the membrane 2 in a urea solution, catalyzing urea in the urea solution by the urease in the membrane 2 to generate carbon dioxide, and then reacting with calcium salt on the surface of the membrane 2 to obtain calcium carbonate particles. The obtained calcium carbonate particles can effectively enhance the hydrophilic performance of the surface of the membrane, so that the membrane flux is increased.

The invention discloses a high-stability and high-flux polydopamine nanoparticle modified membrane as well as a preparation method and application thereof. The preparation method comprises the following steps: carrying out vacuum filtration on a mixed solution of polydopamine/polyethyleneimine nanoparticles and polyethyleneimine macromolecules, loading the nanoparticles in a polydopamine/polyethyleneimine co-deposited film, and further reacting to prepare the polydopamine/polyethyleneimine co-deposited film. In the vacuum filtration process, the nano-particles with covalent bonds formed inside are selectively adhered to dead corner areas in membrane holes, so that fluid in the nano-particles in the membrane is prevented from being washed away, and macromolecules on the surfaces of the nano-particles are prevented from being eroded by the fluid. In addition, the nano-particles cannot block through pore channels in the membrane, and the hydrophilicity of the membrane is enhanced after the particles are loaded, so that the membrane flux is further increased, and the membrane has better anti-pollution performance.

The invention relates to a method used for improving an organic nanofiltration membrane separating property, and belongs to the technical field of membrane separation. Aiming at the limitation in a membrane separating technology, the invention provides a method for improving organic nanofiltration membrane separating property by utilizing the photo-thermal effect of a metal nano particle. According to the method, laser is used for irradiating the upper surface of a nanometer inorganic-inorganic compound nanofiltration membrane during filtering, and the part of a filter unit between a laser transmitting terminal and the nanometer inorganic-inorganic compound nanofiltration membrane is made of transparent material, so that laser can pass through the filter unit to irradiate the upper surface of the nanometer inorganic-inorganic compound nanofiltration membrane. According to the invention, the improvement of the separating property of the membrane is caused by temperature increment of the membrane and does not derive from the modification of any membrane or the formation of membrane holes, so that the membrane flux of the organic nano filter membrane can be greatly improved under the condition that the retention rate is not obviously changed, and an 'inverse effect' of the membrane flux and the retention rate is overcome.

The invention relates to a method for synchronously improving the flux and the anti-pollution performance of a polyamide reverse osmosis composite membrane. The method comprises the steps that first,1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride is used for activating carboxyl group on the surface of the polyamide reverse osmosis composite membrane to react with primary amine, secondary amine or hydroxyl group to introduce a tertiary amine group; then the tertiary amine group reacts with sultone on the surface of the membrane to achieve the purpose of introducing amphoteric molecules in the form of chemical bonds; on the other hand, due to the protection of a water molecular layer, the condition that membrane fouling is caused due to the fact pollutants in feed liquid are deposited on the membrane surface is avoided; and in addition, the method is post-processing and does not affect the overall consistency of a polyamide separation layer so as to simultaneously improve the permeability and the anti-pollution performance of a commercial polyamide reverse osmosis composite membrane without sacrificing the retention performance of the polyamide reverse osmosis compositemembrane, and good application prospects are achieved.

The invention provides a preparation process of a nanofiltration composite membrane, wherein the preparation process comprises the steps: firstly, compounding an aqueous phase solution on a non-woven fabric composite bottom membrane, and then compounding an oil phase solution to obtain a semi-finished product; performing heat treatment on the semi-finished product obtained in the step 1 through a drying oven, and controlling the membrane surface temperature of an outlet of the drying oven after heat treatment by adjusting the air speed and temperature of the drying oven to obtain the nanofiltration composite membrane, wherein the temperature of the membrane surface at the outlet of the drying oven is 20-30 DEG C. According to the preparation process, the membrane flux can be remarkably improved under the condition that the desalination rate of the composite nanofiltration membrane is not greatly reduced, and the problems that the water flux is generally low and the separation efficiency cannot be effectively improved in an existing NF membrane are effectively solved. Meanwhile, according to the preparation process provided by the invention, a reaction system is not greatly changed as much as possible, the variation of related matching parameters is small, the debugging period is short, the process application prospect is good, and the preparation process is more suitable for industrial production and application.

The invention relates to a preparation method of a high molecular ultra-filtration membrane. The preparation method specifically comprises the steps of adding a fusiform solid pore-forming agent into a high molecular basement membrane material solution for ultrasonic oscillation and dispersion; carrying out vacuum defoamation treatment to form a casting solution; consolidation-forming the casting solution to prepare a membrane; dissolving the pore-forming agent in the prepared membrane; and forming fusiform pores to obtain the high molecular ultra-filtration membrane with a fusiform micropore structure. When the liquid is separated and filtered, the flow resistance of the liquid in the micropores of the high molecular ultra-filtration membrane is small, the pressure loss is less, the membrane flux is high. The ultra-filtration membrane is especially suitable for treating thick liquid and has wide application value.

The invention belongs to the technical field of chemical engineering, and particularly relates to an ultrafiltration membrane cleaning agent and a cleaning method thereof. The invention provides an ultrafiltration membrane cleaning agent and a cleaning method thereof in order to effectively remove ultrafiltration membrane pollution retentate, recover membrane flux, reduce operation resistance andremarkably improve the cleaning effect. The cleaning agent comprises a component A and a component B, wherein the component A is an aqueous solution of sodium hydroxide and sodium hypochlorite, and the component B is an aqueous solution of citric acid. The cleaning method comprises the following steps of feeding the component A into an ultrafiltration membrane, carrying out circulating alkali washing, and then washing with water, and feeding the component B into an ultrafiltration membrane, carrying out cyclic acid washing, and washing with water again. The pressure at the operation inlet endof the ultrafiltration membrane device can be reduced to the maximum extent, the membrane flux is recovered, the cleaning period is prolonged, and a good cleaning effect is achieved.

The invention relates to a method for preparing a composite ultrafiltration membrane, and belongs to the technical field of water treatment. The composite ultrafiltration membrane is prepared by a sol-gel method. Silica and titanium dioxide are added to a casting solution, and the phase splitting process in the film formation process is controlled by means of the unique chain structure of the silica and the hydroxyl group on the surface thereof. The blending of nano titanium dioxide and a membrane material can enhance the hydrophilicity of the membrane, increase the membrane flux, improve theroughness of the membrane surface, delay membrane fouling, prolong the service life of the membrane, and reduce the operating cost of the membrane device. The porosity of the composite ultrafiltrationmembrane is gradually increased, and the water flux is gradually increased. A hydrogen bond may also be formed between polyvinylidene fluoride and cellulose micro/nano crystal, which enables the cellulose micro/nano crystal to be uniformly dispersed in a polyvinylidene fluoride solution, and have good interface bonding with the polyvinylidene fluoride, so that the composite membrane has certain strength and toughness, and thus the composite membrane exhibits good mechanical properties.

The invention relates to a preparation method of a pollution-resistant modified porous membrane, which utilizes C-Cl bonds in a vinylidene fluoride-chlorotrifluoroethylene copolymer and polyvinyl chloride polymer molecules to react with micromolecular monoamino hydrophilic compounds to realize functionalization of a membrane material so as to improve the pollution resistance and blood compatibility of the porous membrane. The method is simple in grafting reaction process, mild in reaction condition and easy to implement. Chemical grafting modification is adopted, the formed modified material cannot fall off from the membrane material, meanwhile, the problem that membrane holes are blocked due to conventional grafted macromolecules can be avoided, the membrane flux is not reduced, and the negatively charged or electrically neutral anti-pollution and high-blood-compatibility porous membrane can be obtained.

The invention provides a magnetic response oil-water separation membrane, a preparation method and a self-cleaning method thereof. The magnetic response oil-water separation membrane comprises a basemembrane and magnetic composite nanoparticles chemically grafted on the surface of the base membrane. The oil-water separation membrane provided by the invention can realize self-cleaning of the membrane surface by utilizing periodic transformation of an external magnetic field; meanwhile, the oil-water separation membrane provided by the invention can well prevent oil macromolecules from being incontact with a membrane contact channel to pollute pore channels, so that the oil-water separation membrane can keep a certain membrane flux and stable separation efficiency, and has a good application prospect.

The invention relates to a high-flux super-hydrophilic/underwater super-oleophobic Janus membrane modification method, which is characterized in that a dopamine and polyethyleneimine co-deposition technology is adopted to coat a hydrophilic carbon nanotube on the surface of one side of a hydrophobic membrane, and a stable hydrophilic carbon nanotube coating is synthesized, so that one side of the membrane keeps the original characteristics, and the other side of the membrane has excellent super-hydrophilic/underwater super-oleophobic characteristics; the membrane flux is increased, and the oil pollution resistance of the membrane is improved; a synthesis method comprises the following steps: coating the surface of the membrane with a carbon nano tube ethanol solution in a negative pressure vacuum manner, and then stably fixing the coated carbon nano tube in a dopamine and polyethyleneimine codeposition manner, so that the obtained modified Janus membrane has the pore diameter of 0.2-0.25 [mu]m, the water contact angle of 9 degrees and the oil contact angle of 180 degrees, and the membrane has extremely high hydrophilicity and super-oleophobic characteristics. The method is simple and efficient, and the prepared super-hydrophilic/underwater super-oleophobic janus membrane is high in flux and resistant to oil pollution.

The invention relates to a cleaning method of a membrane bioreactor for treating wastewater in the gum dipping glove industry. The cleaning method comprises the following steps: S1, removing a membrane component, and lifting the membrane component out of a reaction tank; S2, cleaning and scouring the membrane component with vaporous water to remove activated sludge after lifting; S3, acid pickling; preparing an acid pickling agent in the acid pickling tank, and completely immersing the membrane module in the acid pickling agent for cleaning; S4, backwashing with clean water for the first time;S5, alkali washing; preparing an alkaline washing agent in the alkaline washing pool, and completely immersing the membrane module in the alkaline washing agent for cleaning; S6, backwashing with clean water for the second time; and S7, installation and recovery: resetting and installing the membrane module, and recovering production. With application of the membrane cleaning method, the cleaningtime can be shortened, cleaning is thorough, the membrane flux can be fully recovered, and the membrane cleaning frequency can be reduced. The influence of pollutants on the membrane is reduced, themembrane attenuation is reduced and the service life of the membrane assembly is prolonged.