457 results about "Mass transfer resistance" patented technology

An adsorbent material fabricated into a reinforcement-free, self-supported coherent thin sheet and configured for use as a parallel passage contactor element in adsorption/separation applications with gases and liquids is disclosed. The adsorbent sheet material is obtained by enmeshing fine adsorbent particulates in a polymer binder. Particulates include but are not limited to carbon particles, inorganic oxides particles, or ceramic particles, or synthetic polymer resin particles. The adsorbent sheet advantageously contains a large volume percentage of active adsorbent particles. The parallel passage contactor device fabricated from the adsorbent sheet material is characterized by minimal mass transfer resistance and better separation efficiency expressed as height equivalent to a theoretical plate, while it maintains most of the adsorptive properties of the starting particulates, and can be used in gas separation applications with short adsorption cycles, such as rapid pressure swing adsorption, rotary concentrators, rapid electric swing adsorption.

A homogeneous ceria-based mixed-metal oxide, useful as a catalyst support, a co-catalyst and/or a getter, is described. The mixed-metal oxide has a relatively large surface area per weight, typically exceeding 150 m<2>/g, a structure of nanocrystallites having diameters of less than 4 nm, and including pores larger than the nanocrystallites and having diameters in the range of 4 to about 9 nm. The ratio of the pore volumes, VP, to skeletal structure volumes, VS, is typically less than about 2.5, and the surface area per unit volume of the oxide material is greater than 320 m<2>/cm<3>, such that the structural morphology supports both a relatively low internal mass transfer resistance and large effective surface area for reaction activity of interest. The mixed metal oxide is made by co-precipitating a dilute metal salt solution containing the respective metals, which may include Zr, Hf, and/or other metal constituents in addition to Ce, replacing water in the co-precipitate with a water-miscible low surface-tension solvent, and relatively quickly drying and calcining the co-precipitate at moderate temperatures. A highly dispersive catalyst metal, such as Pt, may be loaded on the mixed metal oxide support from a catalyst-containing solution following a selected acid surface treatment of the oxide support. The mixed metal oxide, as catalyst support, co-catalyst or getter, is applied in various reactions, and particularly water gas shift and/or preferential oxidation reactions as associated with fuel processing systems, as for fuel cells and the like.

A carbon nanosphere has at least one opening. The carbon nanosphere is obtained by preparing a carbon nanosphere and treating it with an acid to form the opening. The carbon nanosphere with at least one opening has higher utilization of a surface area and electrical conductivity and lower mass transfer resistance than a conventional carbon nanotube, thus allowing for higher current density and cell voltage with a smaller amount of metal catalyst per unit area of a fuel cell electrode.

The invention discloses a membrane material with ion exchange performance, which is characterized in that the membrane material is in a compact structure or a millipore structure, and is mixed by the polymer with ion exchange performance and the polymer with nonionic exchange performance; wherein, the weight ratio of the polymer with ion exchange performance to the polymer with nonionic exchange performance is 5/95 percent to 95/5 percent. The invention also discloses the application of the membrane material in the separation of anion and cation and the recovery membrane extraction, the removal of the vapor in the gas and the desalination of the water system in the process of driving the positive permeation by non-pressure. The membrane material has the advantages of getting rid of the supporting concept of supporting liquid membrane, enjoying high chemical stability, and low mass transfer resistance to ions. The membrane material not only provides a long-time stability in the separation process of the liquid membrane ions, but also finds application points in other separation fields.

The invention discloses a preparation method and application of a hierarchical pore metal-organic framework loaded heteropolyacid catalyst. The catalyst adopts hydrothermal-extraction method for preparation. The method includes: dissolving an organic ligand, a template agent, a metal salt and Keggin type heteropolyacid in a solvent, conducting hydrothermal synthesis of a crystal product, and thenperforming Soxhlet extraction to obtain a catalyst. The obtained catalyst has a meso-micro hierarchical porous structure, realizes high dispersion of the active component heteropolyacid and ultra-highloading capacity, and at the same time solves the problems of large mass transfer resistance, long diffusion path and small reaction place in microporous materials. The catalyst provided by the invention shows excellent catalytic performance in both photocatalytic degradation of dye wastewater and catalysis of oxidation-extraction desulfurization reaction, the catalysis reaction uses visible light and hydrogen peroxide respectively, the process is clean, environment-friendly and green, and after repeated use, the catalyst still maintains high activity, and has high industrial application value.

The invention relates to a preparation method of covalent organic framework composite microspheres with core-shell structures. The method comprises the following steps: dissolving silicon dioxide microspheres, a first construction element and a second construction element in an organic solvent; and after adding a catalyst, rapidly synthesizing into the composite microspheres with core-shell structures at a certain temperature. In a preparation process, reaction conditions are gentle, the method is simple, and the yield is high; the prepared covalent organic framework composite microspheres have the advantages of good core-shell morphology, high specific surface area, ordered pore structures, good mechanical stability, thermal stability, chemical stability and the like, if the microspheres are used as a chromatographic stationary phase, the chromatographic mass transfer resistance can be reduced effectively, the theoretical plate height is improved, and finally, column efficiency and degree of separation are improved; and if the microspheres are used as solid-phase extracting filler, the enrichment effect can be improved remarkably. The covalent organic framework composite microspheres with core-shell structures have good application prospects in the aspect of separation and enrichment of small organic molecules.

The invention discloses a novel method for preparing a super-hydrophobic membrane for removing dissolved gas in water. Based on a self-cleaning bionic principle, coupling agent modified inorganic nanoparticles with low surface energy and hydrophobic polymer PVDF (Polyvinylidene Fluoride) are blended to obtain a super-hydrophobic flat membrane with good mechanical properties by a phase inversion method. The surface of the super-hydrophobic membrane has a water contact angle of 154+/-1 degrees and a rolling angle of 4+/-1 degrees, so that the has super-hydrophobic membrane good super-hydrophobicity and self-cleaning properties, the mass transfer resistance of the wetted membrane can be obviously reduced, and the separation efficiency of a membrane contactor is improved.

The present invention is a technique to fabricate thin-film composite perm-selective membranes by a transfer method. The composite membranes are useful in separating liquid, vapor or gaseous mixtures by selective permeation and reduce mass transfer resistance of the support layer. Selectivity and flux are improved by reduction of the mass transfer resistance of the support layer.

The invention discloses a micro-interface enhancement reactor reaction rate structure-activity regulation and control model modeling method. Based on the Levenspiel theory, a reaction rate structure-activity model suitable for a micro-interface enhancement reactor is constructed. According to the invention, the reaction rate structure-activity regulation and control model constructed through the method can intuitively make out the effects of the bubble diameter, gas-liquid mass transfer coefficients, the mass transfer resistance and the like on the reaction rate; the bubble diameter of a reaction system, the reaction efficiency (energy efficiency and material efficiency), the physical and chemical properties of the system, micro-interface characteristics, mass transfer characteristics andthe reactor structure are correlated through a mathematic method; the energy efficiency and material efficiency of a reaction process are maximized by adjusting structural parameters and operating parameters; and alternatively, a reaction target (mission), energy consumption and material consumption are given, the efficient reactor structure is designed.

The invention provides a method for preparing a catalyst carrier with macropores and mesopores which are in run-through. The method comprises the following steps of: adding solid cellosilk in the process of preparing or forming the catalyst carrier, so that the solid cellosilk is dispersed in the catalyst carrier; and removing the solid cellosilk by forming and roasting to obtain the catalyst carrier with the run-through macropores and mesopores. The invention also provides a method for preparing a catalyst by further supporting active ingredients by the catalyst carrier and the carrier and the catalyst which are prepared by the method. By the method, the run-through performance of a mesoporous channel of the carrier is improved greatly by adding the solid cellosilk; and the run-through macropore formed by the cellosilk provides a quickly-dispersed channel for reaction molecules, so the mass transfer resistance in the catalytic reaction process is reduced. The method is suitable for preparing various catalysts of which the reaction speed is controlled by internal diffusion, such as a petroleum distillate (particularly heavy oil distillate) hydrogenation catalyst.

The invention relates to a preparation method for a high-gradient porous metal film. The preparation method is characterized by comprising the steps of firstly, carrying out hole blocking treatment on a porous metal matrix by using prepared inorganic powder; then, carrying out metal powder coating; carrying out high temperature sintering under a hydrogen or inert atmosphere to obtain an impurity-containing gradient porous metal film; finally, flushing (carrying out vacuum soaking on) residual impurities in a film matrix by using a chemical reagent or removing the residual impurities in the film matrix by using an ultrasonic technology to obtain the high-gradient porous metal film. According to the high-gradient porous metal film prepared by the preparation method, the powder coating quality is good, the operation is simple and convenient, the residual impurities in a matrix pore passage is easy to be completely removed, and the obtained metal film is good in integrality, high in gradient and low in mass transfer resistance.

The invention belongs to the field of preparation of metal-skeleton organic matters and discloses a small and medium dual-hole HKUST-1 material and a preparation method and application thereof. The method comprises the following steps: respectively dissolving Cu(NO3)2.3H2O and H3BTC into a mixed solution of DMF, ethyl alcohol and water; stirring to obtain a clear solution A and a clear solution B; adding the clear solution A to the clear solution B and mixing evenly; adding 3-aminopropyltrimethoxysilane and stirring; transferring the obtained mixed solution to a stainless steel high-pressure reaction kettle, and carrying out temperature programming; cooling the reaction kettle to room temperature, filtering the product, and drying the product in vacuum; and washing the obtained product with ethyl alcohol for four times, thus obtaining the small and medium dual-hole HKUST-1 material. The product has a single mesoporous and microporous crystal structure, the mass transfer resistance is overcome in reaction, the mass transfer efficiency is improved, and particularly, the product has a relatively good application prospect in the fields of catalysis, adsorption, separation and the like involving macromolecules.

The invention belongs to the field of chemistry, provides a graphene/lignin-based activated carbon preparation method and application in supercapacitors. The method includes the steps that 1, lignin-based activated carbon is prepared; 2, graphite oxide and the activated carbon are mixed, and a graphite oxide/lignin-based activated carbon compound is obtained; 3, pyrolysis reduction is conducted on the compound obtained after alkaline activation is conducted, and graphene/ lignin-based activated carbon composite material is prepared; 4, electrode plates are prepared. Compared with the prior art, the obtained graphene/lignin-based activated carbon has a larger specific surface, lower mass transfer resistance and more excellent electric conductivity. Furthermore, the composite graphene/lignin-based activated carbon is applied to electrode material of the supercapacitors, and the cost and performance are greatly superior to those of existing activated carbon material.

The invention provides an electrode with a progressive structure of a proton exchange membrane fuel cell and a preparation method. The electrode consists of a supporting layer, a leveling layer and a catalyzing layer; a strong-hydrophobic macropore layer is the supporting layer; a weak-hydrophobic mesopore layer is above the strong-hydrophobic macropore layer; a weak-hydrophobic mesopore catalyzing layer is above the weak-hydrophobic mesopore layer; a hydrophile micropore catalyzing layer is above the weak-hydrophobic mesopore catalyzing layer; wherein, the weak-hydrophobic mesopore layer comprises the weak-hydrophobic mesopore catalyzing layer in the leveling layer and the catalyzing layer. The invention has the advantages that the electrode catalyzing layer consists of progressive multilayer structure of hydrophile and hydrophobe, the shortage is overcome of low utilization ratio of catalyst in the hydrophobic catalyzing layer, and the transmission effect of reaction gas, especially an air oxidant in the catalyzing layer is improved; a pore-forming agent which is introduced in the electrode improves the porous structure of the levelling layer and the catalyzing layer of the electrode, forms an progressive structure of pore, reduces the mass transfer resistance in the reaction process, and improves the performance of the electrode.

The invention belongs to the technical field of membrane separation, and particularly relates to a forward osmosis composite membrane based on a two-dimensional nano material and a macroporous substrate and a preparation method and application of the forward osmosis composite membrane. According to the composite membrane, a two-dimensional nano material is deposited on the surface of a macroporoussubstrate to serve as a middle layer, a polyamide separation layer is formed on the surface of the middle layer, and the composite membrane is obtained. The two-dimensional nano material middle layerin the composite membrane prevents polyamide from permeating into the macroporous substrate to damage the original macroporous and mutually communicated pore structure, reduces the mass transfer resistance, and effectively relieves the internal concentration polarization phenomenon in the forward osmosis process, thereby greatly enhancing the separation performance of the polyamide composite membrane and prolonging the service life of the composite membrane. The forward osmosis composite membrane can be widely applied to seawater desalination, juice concentration and other fields.

The invention discloses a preparation method of a carbon loaded bismuth nanoparticle catalyst, and application of the prepared carbon loaded bismuth nanoparticle catalyst to a CO2 electrochemical reduction catalyst. The preparation method uses a water solution chemical reduction method for synthesis. The carbon loaded bismuth nanoparticle catalyst is prepared by the simple water solution chemicalreduction method; by effectively regulating and controlling the addition quantity of a stabilizing agent and the carbon material variety, metal Bi particles of a nanometer structure are obtained; relatively good dispersibility is realized; in the CO2 reduction process, the selectivity on formate is high; the current density can be improved; the electrochemical surface area of the catalyst can be greatly improved; the exposure of CO2 reduction active sites is improved; the electron mass transfer resistance is reduced; the current density of CO2 reduction is increased; the utilization rate and the conversion rate of CO2 are effectively improved; the preparation method is simple; the yield is great; the preparation method is suitable for industrial production.

The invention discloses a preparation method of an immobilized enzyme by applying amphiphilic porous hollow carbon microspheres. The method disclosed by the invention comprises the following steps: mixing amphiphilic porous hollow carbon microspheres and a solution of an enzyme to be immobilized, and reacting for 0.5 to 24 hours at a temperature of between 4 and 45 DEG C to obtain the immobilized enzyme, wherein the amphiphilic porous hollow carbon microspheres are prepared by the following way: carbonizing yeast in an aqueous solution or water at a temperature of between 180 and 240 DEG C to obtain the amphiphilic porous hollow carbon microspheres. The method has the advantages that: (1) enzyme package embedding and carrier preparation are separately carried out to avoid inactivation of the enzyme; (2) non-covalent effect exists between the enzyme and the carrier, the surface group of the carrier is not required to be modified, and the method is simple; (3) damage of strong stirring and other external factors to the enzyme can be effectively avoided, and the operation stability of the immobilized enzyme is improved; (4) the mass transfer resistance is small; (5) the amphiphilic property of the hollow carbon microspheres provides possibility for the application of the hollow carbon microspheres in an organic medium system; (6) the method has universality; and (7) the enzyme carrying capacity is high, and the stability is strong.

The invention discloses a self-dehydration hydrophobic separation membrane and a preparation method. The surface of a hydrophilic membrane is coated with polyvinylidene fluoride particles so as to form the self-dehydration hydrophobic separation membrane with a micro nano grade convex-concave structure. The preparation method comprises the following steps: preparing the polyvinylidene fluoride particles into turbid liquid; performing ultra-filtration so as to enable the the surface of the hydrophilic polyvinylidene fluoride porous membrane-based membrane to be coated with the polyvinylidene fluoride turbid liquid; drying the hydrophilic polyvinylidene fluoride porous membrane-based membrane coated with the polyvinylidene fluoride turbid liquid so as to obtain the self-dehydration hydrophobic separation membrane. The self-dehydration hydrophobic separation membrane is sufficient in mechanical strength and has a self-dehydration function, once being dissociated from an aqueous solution, the surface of the hydrophobic separation membrane can be automatically dried, so that the purpose of drying the hydrophobic separation membrane pores is realized; the hydrophobic layer of the hydrophobic separation membrane is thin, the surface pure water contact angle of the hydrophobic separation membrane is large, the separation mass transfer resistance can be effectively alleviated, the separation efficiency is improved, and the large-scale industrialization application of a membrane separation technique is facilitated.

The invention discloses a system for deep treatment of coking wastewater by means of catalytic ozonation-ceramic membrane filtration, mainly consisting of an ozone generator, an ozone oxidation reactor, a booster pump, a ceramic membrane component, a gas-liquid separator, a tail gas absorbing device, a wastewater reflowing pump, a catalyst reflowing pump, a catalyst adding pump, a catalyst outflowing groove, a catalyst adding groove and corresponding pipe fittings, valves and instruments. According to the system, the application of a powder catalyst in a dynamic reactor can be realized due tothe combination of the catalytic ozonation and the ceramic membrane separation; the ozonation and the catalytic ozonation can be guaranteed to be carried out in a single reactor in a segmental way due to the convection current of the reflowing wastewater and the catalyst slurry and the impact of upcurrent; the mass transfer resistance when the ozonation and the catalytic ozonation are independently used can be reduced; the use ratio of hydroxyl free radical and the removal rate of organic matters can be improved; the aims, such as the COD (chemical oxygen demand), the chroma and the turbidityof the deeply-treated coking wastewater, can be achieved; and the problems that the activity is suddenly reduced when the powder catalyst is formed into particulates, the running needs to be suspended when the mass transfer resistance is increased due to the use of the particulate catalyst and the particulate catalyst is changed and the like can be solved.

The invention discloses a surface self-cleaning carbon nitride Fenton-photocatalytic nanofiltration membrane and a preparation method thereof and belongs to the fields of water treatment membrane materials and preparation processes of the water treatment membrane materials. The method comprises selecting carbon nitride photocatalysts which integrate plasticity of polymer molecules and chemical stability of carbon materials and performing surface modification, chemical modification, Fenton-like agent compounding and the like to prepare a multifunctional water treatment membrane. On the one hand, inter-element triangular nanopores formed by carbon nitride can provide stable natural channels for rapid passage of water molecules; on the other hand, through irradiated catalytic degradation andiron-containing agent Fenton-like oxidation, in-situ degradation of nanofiltration retained pollutants can be achieved. The surface self-cleaning carbon nitride Fenton-photocatalytic nanofiltration membrane provides a new way for solving the problem of membrane contamination difficult for traditional nanofiltration membrane materials and has the advantages of being simple in preparation method, low in cost, resistant to pollution, low in water mass transfer resistance and the like, thereby being applicable to application to the field of water purification.

The invention discloses a bipolar-structured lithium-air battery, which belongs to the technical field of preparation of lithium-air batteries. The bipolar-structured lithium-air battery mainly comprises a cathode, a diaphragm, an anode and a housing, wherein lithium metal as the cathode is arranged inside the housing, and the diaphragm and the anode are sequentially arranged at the upper part of the lithium metal; and the battery does not contain the traditional electrolytic solution layer, and the anode is obtained by preparing a non-volatile electrolytic solution with stable chemical property on a perforated electrode. The bipolar-structured lithium-air battery disclosed by the invention has the advantages of simple structure, small mass transfer resistance, and capabilities of reducing the volatilization of electrolytic solution, decelerating the cathode corrosion, increasing the specific discharge energy capacity and prolonging the cycle life.

The invention belongs to the field of chemistry, and provides a preparation method of graphene/xylogen-based active carbon; the method comprises the following steps: 1) preparing xylogen-based active carbon; 2) mixing graphite oxide with active carbon to obtain graphite oxide/xylogen-based active carbon compound; 3) activating the compound by alkali, treating with pyrolysis and reduction, so as to prepare graphene/xylogen-based active carbon composite material; 4) preparing an electrode slice. Comparing to the prior art, the obtained graphene/xylogen-based active carbon provides a larger specific surface, a smaller mass transfer resistance, and a better conductivity. Additionally, applying the synthesized graphene/xylogen-based active carbon to the electrode material of a super capacitor is much better than the existing active carbon material from cost and performance.