941results about How to "Achieve degradation" patented technology

The invention discloses an easily-soluble magnesium alloy material which comprises the following elements such as Al, Li, Ca, Zn, In, Ga, Si, Zr, and the like. The invention further discloses a preparation method of the easily-soluble magnesium alloy material. The easily-soluble magnesium alloy material is used for producing products such as a ball sealer, a target, and the like, has technical characteristic of being easy to dissolve or quick to degrade, and can be designed into an oil exploitation underground component or an underground component which is used for performing a temporary function or is temporarily needed. Compared with the prior art, the easily-soluble magnesium alloy material has the advantages as follows: a high operation cost problem for secondary drilling or milling is solved or avoided, and technical and economic effects with low cost and high efficiency are obtained. Meanwhile, the magnesium alloy density is proper, molten slag or corrosion products of the magnesium alloy satisfy flow-back operation technical requirements, and technical effects with multiple advantages of being simple, efficient, environment-friendly, energy-saving, and the like, can be obtained.

A full-biodegradable plastic membrane, which uses thermoplastic starch with diameter of 1-9 mu m, biodegradable polymer and auxiliary component as raw material, processed by screw extruding apparatus and membrane producing apparatus. The raw material comprises 30-70 parts by weight of thermoplastic starch with diameter of 1-9 mu m, 10-40 parts by weight of biodegradable polymer, 5-10 parts by weight of compatible modified component, 3-5 parts by weight of complex plasticized component, 10-30 parts by weight of lubricant. These materials are mixed and processed by screw extruding apparatus and membrane producing apparatus, wherein the lubricant is at least adding into other materials for mixture before process by screw extruding apparatus and during melt blending, and the adding amount of lubricant before process by screw extruding apparatus is not more than 1 / 3 of the total amount thereof. By highly increasing dosage of lubricant and changing mixing way, thermoplastic degree of starch is increased, rheological property of the system and processing quality of product are dramatically improved, mechanical property of the product is enhanced.

The invention discloses a rapidly degradable magnesium alloy material. The material comprises the following components: elements such as Al, Li, Ca, Y, Si, Ni, Cu and Fe. The invention also discloses a preparation method and the application of the rapidly degradable magnesium alloy material. Compared with the prior art, the rapidly degradable magnesium alloy material has the advantages that the problems of failure in resisting high temperatures and failure in meeting high-temperature and high-bearing operation requirements of the existing easily degradable materials or easily degradable magnesium alloy materials and products thereof are solved, meanwhile, the material is controllable in density, the slag or the corrosion product of the material meets the requirements of flowback operations, and multiple technical effects of simplicity and high efficiency, low cost, energy conservation, environmental protection and the like can be achieved.

The invention discloses a method for degrading organic pollutants in a water body through an activator composite material and activating persulfate, belonging to the technical field of water pollution control. According to the method, the activator composite material comprises nano zero-valent iron and biochar; the activator composite material and persulfate react with the organic pollutants when being existent at the same time so as to degrade the organic pollutants in the water body. The method comprises the following concrete steps: 1, adding persulfate into the water body containing the organic pollutants, wherein the molar ratio of persulfate to the organic pollutants is (20 : 1) to (200 : 1); 2, adding the activator composite material while stirring, wherein the molar ratio of the activator composite material and persulfate is 1 : 1. The method has the advantages that generated free radicals are good in oxidation property, a reaction system is stable, the pH range is wide, the utilization rate of an oxidant is high, and the like; in addition, the method has wide application prospects on aspect of repairing the organic polluted water body.

The invention relates to an environment-friendly composite microbial preparation, preparation thereof, and application thereof to aquaculture. An environment-friendly composite microbial water purifying agent comprises the following components in percentage by weight: 20 to 40 percent of bacillus subtilis, 10 to 20 percent of bacillus licheniformis, 10 to 15 percent of bacillus megaterium, 10 to 15 percent of brevibacillus laterosporus, 5 to 10 percent of bacillus pumilus, 5 to 20 percent of bacillus coagulans and 2 percent of biological activating agent. The high-concentration composite microbial preparation is prepared by screening eight strains of probiotics by simulating the physiological functions of normal microbial flora in an aquaculture environment and through scientific compatibility, so that division and cooperation amount the bacterial strains can be realized, a biological enhancement technology can be combined with an indigenous flora activating technology, complex problems in a culture water body can be solved completely, the using amount is small, the cost is low, and the competitive advantage is remarkable.

The invention relates to a preparation method for magnetic nano biological microspheres for remedying soil polluted by organic chloride durably. The preparation method comprises the following steps of: (1) preparing nano Fe3O4 particles with the surfaces adsorbing amino by a coprecipitation method; (2) dissolving chitosan into an acetic acid solution to form a homogeneous transparent colloidal solution, and mixing and stirring the solution and the nano Fe3O4 particles to obtain the magnetic nano-particles; (3) adding the prepared magnetic nano-particles into a buffering solution of citric acid and performing ultrasonic dispersion to obtain magnetic fluid; and (4) adding the magnetic fluid into a bacterial solution, adding cross-linked fluid dropwise, performing adsorption-cross-linking, and performing solid liquid separation under the action of an external magnetic field to obtain the magnetic nano biological microspheres. The method is quick, simple, convenient and low in cost. The prepared magnetic nano biological microspheres have the characteristics of homogenous shape, large specific surface area, high microbial activity and the like and are applicable to degradation of organic chloride pollutant and in-situ remediation of polluted soil.

The invention relates to a reductive degradable stabilizer for heavy metal and / or organic matter polluted soil as well as a preparation method and use of the stabilizer. The reductive degradable stabilizer can be used for quickly and efficiently stabilizing the heavy metals and the organic matters in the polluted soil by virtue of a synergistic effect of a plurality of active ingredients, and can also be used for further lowering the content of the organic matters, so that the purpose of lowering leaching toxicity of pollutants and health risk is realized; therefore, the reductive degradable stabilizer is a novel and efficient stabilizer which has the advantages of being wide in treatment substrate, capable of reducing the total amount of the organic matters, good in stabilizing effect, convenient to operate and the like, and has a wide range of application in the governance fields including polluted soil, bottom mud, sludge and the like.

The invention discloses an anti-electrostatic degradable film material and a preparation method thereof. The film material is prepared from the following raw materials: LDPE, LLDPE, starch-based degradable plastic materials and anti-electrostatic master batch. The preparation method comprises the following steps: uniformly mixing the raw materials at a high speed; and obtaining a product by extruding, swelling and stretching. The anti-electrostatic degradable film material has good anti-electrostatic effect, is degradable and does not pollute the environment; and the preparation method of the anti-electrostatic degradable film material has simple process and low cost and can prepare finished products with good quality.

The invention pertains to the technical field of environment protection, which provides a method for treating black-odor rivers and lakes with microbiological preparations and comprises the following steps of: (1) pre-treatment of the rivers or the lakes; (2) biofilm colonization treatment; (3) microorganism augmentation treatment by direct application; (4) water ecology recovery and oxidation reduction of reductive sludge at the bottom; and (5) protection and further improvement of water environment. The method for treating black-odor rivers and lakes with microbiological preparations employs a plurality of microbiological preparations to treat the black-odor rivers and lakes, realizes the decomposition of organic pollutants in the water body, improves water ecological balance, and oxidizes, and reduces the reductive sludge at the bottoms of the rivers and lakes.

The invention relates to an electrochemical device for wastewater treatment and a method for treating wastewater by using the same. The electrochemical device consists of a power supply, a primary electrolytic bath B, an electrolytic bath A, an electrolytic bath C, a cathode, a permeable isolation material part, an anode, a raw water tank, a purified water collector and a concentrated solution collecting tank. The electrochemical device can simultaneously remove common negative ions such as nitrate radicals, phosphate radicals, chloride ions, fluorine ions and the like and organic substances, does not need to add any agent, can avoid second pollution to the effluent, is convenient to operate, and has high treatment efficiency and low energy consumption.

The invention discloses a modified blue-green algae biochar composite and application thereof to treatment of electroplating wastewater, and belongs to the technical field of preparation of biochar composite preparation. Blue-green algae in Taihu lake are dried, ground and sieved, then mixed with an activating agent and then subjected to thermal cracking to obtain modified blue-green algae biochar; the modified blue-green algae biochar is soaked in an iron-containing solution for further modification to obtain the modified blue-green algae biochar composite. The prepared modified blue-green algae biochar composite has the adsorption and catalysis capacity. The composite can efficiently remove metal ions in the wastewater through adsorption and Fenton-like reaction during the treatment of the electroplating wastewater. The composite is high in stability and can be repeatedly used.

The invention relates to titanium dioxide powder with ultrahigh water dispersion and high photocatalytic activity and a preparation method thereof. The method comprises the following steps: adding titanium salt in alcohol solvent to prepare precursor, performing low-temperature non-aqueous solvent heat treatment to the precursor, washing the product with ethanol, centrifuging, and drying to obtain titanium dioxide powder with ultrahigh water dispersion and high photocatalytic activity. The obtained titanium dioxide belongs to anatase polycrystal and consists of 5-10nm of particles; the isoelectric point of titanium dioxide is 6.3; when the pH value is less than 5 or more than 6.5, the absolute value of the Zeta potential is more than 30 millivolts; the weight percentage of titanium dioxide is 0.1%-50%, the aqueous dispersion can remain stable for at least 48 hours; and the pollutants can be completely degraded in 1 hour under the simulated sunlight. The method of the invention has simple synthetic route, controllable technological process, low reaction temperature, accessible raw materials, low cost and high yield which is up to 97% and is suitable for industrial mass production.

The invention discloses a tobacco stalk biochar soil conditioner capable of reducing the content of heavy metals in tobacco, improving the tobacco quality and improving the soil environment, as well as an improvement method for tobacco field soil. The tobacco stalk biochar soil conditioner is prepared by mixing the following raw materials in parts by weight: 40-60 parts of tobacco stalk biochar and 40-60 g of a passivant. The tobacco stalk biochar soil conditioner is easy to obtain raw materials, simple in preparation method and low in cost, can effectively reduce the content of heavy metals in tobacco, and can improve the quality of tobacco field soil; a large number of waste tobacco stalks generated in tobacco growing areas are adopted as the raw material, the resource recycling of waste materials is realized, the sustainable development of the tobacco industry is facilitated, and the tobacco stalk biochar soil conditioner is suitable for large-scale popularization and application in the field of tobacco growing.

The invention discloses a method for treating arsenic-containing wastewater by using a multiphase Fenton system based on iron oxide. The method is characterized in that firstly, the pH of the arsenic-containing wastewater is adjusted to range from 2.0 to 9.0, then an iron oxide catalyst and a hydrogen peroxide oxidizing agent are added, so that an organic arsenic compound completes form transformation from organic arsenic to inorganic arsenic in the multiphase Fenton system based on the iron oxide, meanwhile, released inorganic arsenic forms Fe-As chemical coordinate bonds through binding state iron central atoms on the surface of the iron oxide to be effectively adsorbed, and the arsenic pollutant in the arsenic-containing wastewater is removed. Degradation from organic arsenic to inorganic arsenic and adsorption of the inorganic arsenic can be finished simultaneously in one step, the iron oxide serves as an efficient adsorption material of the inorganic arsenic as well as a Fenton reaction catalyst for degrading the organic arsenic to the inorganic arsenic, and the treatment cost of the organic arsenic wastewater is effectively reduced while the reaction efficiency and the operation simplicity are greatly improved.

This invention discloses a method for treating azo-dye wastewater. The method comprises: (1) introducing azo-dye wastewater into a wastewater pool; (2) fixing an ultrasonic wave generator, and a visible light source; (3) opening the ultrasonic wave generator and the visible light source simultaneously, ultrasonicating and irradiating the azo-dye wastewater; (4) examming the dye decomposition result, and terminating the treatment when the decomposition reaches saturation. The method has such advantages as high decomposition rate, no toxic intermediates, low cost, no addition of other chemical substances, no pollution, and adequate utilization of ultrasonic wave energy.

The invention discloses a completely-degradable bamboo-plastic composite material with super-high toughness and a preparation method of the completely-degradable bamboo-plastic composite material. The completely-degradable bamboo-plastic composite material comprises the following components by weight: 20 to 60 parts of degradable plastic, 30 to 50 parts of superfine bamboo powder, 10 to 30 parts of natural plant fiber, 3 to 7 parts of compatilizer, 0.1 to 0.6 part of antioxidant, and 1 to 6 parts of lubricant. The preparation method comprises the following steps: blending all the raw materials except the natural plant fiber in a dry way; feeding the mixed raw materials into a twin-screw extruder; feeding the natural plant fibers into the extruder through a forcible feeder; melting and extruding; and pelleting to obtain the composite material. Compared with the commonly-marketed bamboo-plastic composite material, the bamboo-plastic composite material disclosed by the invention has the advantages that the impact toughness is improved by 5 to 10 times, and the bamboo-plastic composite material can be completely degraded within one year under soil burial condition and cannot be automatically degraded under natural use condition, so that the safety in long-term use can be ensured; and the melt index can reach 5 to 10g / 10min, so that the injection molding can be adopted for forming.

The invention discloses a genetic engineering bacterium for PET plastic degrading. The genetic engineering bacterium is acquired by transferring a gene segment used for expressing PET hydrolase and MHET hydrolase into a host bacterium in the manner of double-plasmid double expression or single-plasmid double expression. The genetic engineering bacterium provided by the invention is capable of simultaneously expressing PET hydrolase and MHET hydrolase and secreting out of cells; the PET hydrolase is capable of degrading PET plastic to oligomer or low polymer state; the MHET hydrolase is capableof degrading PET plastic from oligomer or low polymer state to phthalic acid and glycol monomer, so as to realize full degradation of PET plastic. The invention provides an effective biodegradation method for full degradation of PET plastic.

The invention provides a degradable rare earth magnesium alloy medical biomaterial which is prepared by taking magnesium as a base alloy and adding a rare earth, zinc and zirconium according to a certain proportion relationship; the degradable rare earth magnesium alloy comprises the chemical composition by the mass percentage: 0.5-2.0 wt.% of Y, 0.1-0.5 wt.% of Dy, 0.8-1.2 wt.% of Zn, 0.35-0.55 wt.% of Zr, and the balance Mg and inevitable impurities. At the same time, the invention provides a preparation method of the degradable rare earth magnesium alloy medical biomaterial. The degradable rare earth magnesium alloy medical biomaterial has the following advantages: 1, the degradable rare earth magnesium alloy medical biomaterial has good mechanical properties and processing performance, and can meet the need of medical implant materials; 2, the degradable rare earth magnesium alloy medical biomaterial has good corrosion resistance, not only can be completely degraded, but also can ensure an appropriate corrosion speed; and 3, toxicity of alloying elements has strict limitation. The degradable rare earth magnesium alloy medical biomaterial is mainly used in medical metal materials.

A biomass carbon source release combination type ecological floating bed water purifying device comprises an ecological floating bed comprising a floating frame and a basket for planting an emergent aquatic plant, a packing groove comprising a groove body and a groove bottom board, and a bottom groove used for planting a submerged plant and internally provided with the packing groove, wherein each of the four corners in a groove body of the bottom groove for planting the submerged plant is provided with a bottom groove suspending ring at the upper end of a bottom groove suspending rod extending out of an upper port of the bottom groove body, each of the four corners in the groove body of the packing groove is provided with a groove body suspending rod extending out of an upper port of the packing groove, a groove body suspending ring at the upper end and the opposite part of the floating frame are respectively bonded by the two ends of an inner cable and an outer cable, the bottom groove used for planting the submerged plant and the packing groove are both made of a board uniformly provided with holes, an artificial water plant or / and a cob is / are suspended at the bottom part of a basket body of the basket for planting the emergent aquatic plant, a zeolite layer, a cob layer, a wheat straw layer and a coal cinder layer are respectively paved between vertical partition boards in the packing groove, and a rope provided with an anchor at the other end is bonded on a vertical floating tube on each of the two sides of the floating frame. The biomass carbon source release combination type ecological floating bed water purifying plant is applicable to open riverways, lakes or landscape water bodies.

The invention discloses a wet catalytic oxidation catalyst for phenolic wastewater and a preparation method thereof, and a phenolic wastewater treatment method. The catalyst uses activated carbon as a support, and contains non-metal and non-noble metal elements as active components, wherein the non-metal element is N, and the non-noble metal element is Fe. In the phenolic wastewater treatment process, the catalyst is added into the phenolic wastewater, and the conditions are as follows: the volumetric space velocity is 3-30 / hour, the phenol content in the wastewater is 500-5000 mg / L, the reaction pressure is 0.2-2.0 MPa, and the reaction temperature is 100-250 DEG C. By using the non-noble metal as the active component, the cost of the catalyst can be lowered. The catalyst can implement degradation of high-concentration phenol wastewater under the conditions of lower temperature and oxygen pressure. The nitrogen element is introduced into the activated carbon support surface, and the synergistic action of the nitrogenous functional group on the activated carbon surface and the non-noble metal active component is utilized to enhance the catalytic activity of the catalyst.

The invention relates to a microchannel type photocatalytic microreactor based on a nanorod array and a preparation method thereof. The photocatalytic microreactor uses a quartz capillary as a photocatalytic region microchannel, uses a semiconductor nanorod array which vertically grows on the inner surface of the microchannel as a photocatalyst, uses a polytetrafluoroethylene micropipe as a fluidconveying and receiving channel, uses an ultraviolet lamp as a light source, and uses a micro-injection pump to convey organic substances into the microchannel, thereby achieving the purpose of continuous, quick and efficient photocatalytic degradation of the organic substances. By adjusting the pushing speed of the micro-injection pump, the complete degradation of the organic substances is realized; and moreover, the microchannel type photocatalytic microreactor still has high photocatalytic activity after being continuously used for 100 hours, and the degradation rate for the organic substances is still more than 80%.

The present invention discloses a micro-ecological preparation for improving milk yields of dairy cows, and belongs to the preparation for improving the milk yields of the dairy cows. The micro-ecological preparation uses a method combining statistical methods with culture-independent technology to screen dominant bacteria in rumens of high-yielding dairy cows; pure strains are obtained from the dominant bacteria by using pure culture technology; and the micro-ecological preparation is prepared through fermenting, culturing, combining and mixing the pure strains. The micro-ecological preparation is prepared by following specific steps: (1) sequencing, (2) screening, (3) separating and purifying strains, (4) culturing, (5) fermenting (6) mixing and (7) packaging. The micro-ecological preparation contains Bacteroidaceae and Ruminococcus helpful for decomposing polysaccharide and cellulose, can improve Bacteroidaceae and Ruminococcus contents in rumen bacteria of the high-yielding dairy cows in order to ensure the advantage position and improve the utilization of the cellulose and the polysaccharide, thus improving absorption and utilization of feed nutrient components for the dairy cows, increase the milk yields and bring economic benefits. The Bacteroidaceae can help the host absorb the polysaccharide, improve nutrition utilization rates and host's immunity, and maintain gastrointestinal micro-ecological balance. The micro-ecological preparation has a strong pertinence and specificity.

The embodiment of the invention discloses a non-petroleum base complete degradation master batch which comprises the following components in percentage by weight: 30%-50% of carrier, 20%-70% of pigment and 0-60% of stuffing, wherein the carrier is a biological base complete degradation polymer; the biological base complete degradation polymer comprises one or two of hydroxy fatty acid ester PHA series, polylactic acid PLA and polydiethylene glycol sebacate PBS. The master batch prepared by the invention contains no petroleum base and no degradable addition agent; and the needed carrier is derived from renewable resources, thereby realizing the complete degradation in the true sense and more effectively promoting the application of a degradable material and the protection of environments.

The invention belongs to the technical fields of material preparation and environmental pollution improvement, and provides a preparation method for a novel magnetic induction C3N4 / Fe3O4 composite film. The preparation method comprises the following steps: step 1, preparing a C3N4 / Fe3O4 composite photocatalyst; and step 2, performing magnetic induction on a C3N4 / Fe3O4 composite material to preparethe photocatalytic film. The catalytic film prepared by utilizing the magnetic induction method provided by the invention can effectively overcome the shortcoming that a catalyst is easy to imbed ina traditional blend film, achieves high-efficiency catalytic degradation of target pollutants, and has the advantages of simple synthesis, high degradation efficiency and the like.

The invention discloses a biodegradable tableware which contains the following components in weight percentage: 30-60% of starch, 2.5-7% of low-density polyethylene, 20-42% of polyethylene, 1-3% of polyethylene wax, 1-2% of glyceryl monostearate, 3-5% of ethylene-vinyl acetate copolymer, 1-3% of titanium white powder, 2-6% of light calcium carbonate, 1-3% of talc powder, 0.2-0.5% of Al-Ti composite coupler, 0.01-0.02% of modifier, 0.1-0.2% of anti-oxygen agent and 0.04-0.06 of antioxidant. The invention also discloses a method for processing the biodegradable tableware. The method comprises the steps of proportioning, mixing and melting at high speed, extruding and tabletting, molding under positive pressure, trimming and finishing, etc. The invention modifies the formulation and the corresponding production process, so that the biodegradable tableware is not fragile and has high mechanical strength. The biodegradable tableware has water-proof and oil-proof functions without needing inner coating, and can be degraded completely in a short degradation period.

The invention provides a visible light photocatalyst Bi12O17Cl2 and a preparation method of the photocatalyst. The preparation method comprises the following steps of: dissolving bismuth nitrate pentahydrate and potassium chloride in water to prepare a mixed solution, wherein the molar ratio of bismuth nitrate pentahydrate to potassium chloride is 1:1; and adjusting the pH value of the mixed solution to 12.5-13, then carrying out hydrothermal treatment at 160-180 DEG C on the solution to obtain a solid product, and washing and drying the solid product to obtain the Bi12O17Cl2 product, which is nano sheets with length of a few hundreds of nanometers and width of a few hundreds of nanometers. Under the irradiation of visible light, the photocatalyst can realize that more than 99.5% and approximate 100% of target pollutant pentachlorophenol is degraded within 45 minutes. The method is simple in synthetic route, easy in whole process control, easy in raw material obtaining, low in cost, and high in yield (up to 90%), and is suitable for industrial large-scale production.

The invention relates to the technical field of medicines, in particular to a novel electret microneedle transdermal drug delivery system. The system comprises an isolation layer and a drug-containing pressure-sensitive adhesive layer arranged on the inner side of the isolation layer, wherein an electret layer made from an electret material is arranged on the outer side of the isolation layer; a controlled-release membrane layer is arranged on the inner side of the drug-containing pressure-sensitive adhesive layer; the electret layer, the isolation layer, the drug-containing pressure-sensitive adhesive layer and the controlled-release membrane layer are arranged in sequence from outside to inside to form a reservoir type patch; a microneedle array layer is arranged on the inner side of the reservoir type patch and comprises a microneedle array formed by a plurality of microneedles; each microneedle is 20-50 microns in diameter; and the spacing between every two adjacent microneedles is 1-1.5mm. According to the system, a drug can conveniently penetrate the skin by optimizing microneedle structure and arrangement; and when the system is used, the microneedles act on the skin firstly, the drug quickly penetrates the skin through the needle holes of the microneedles, and the electret layer accelerates drug penetration to achieve a treatment effect.

The invention relates to wastewater treatment application technologies and aims to provide a method for decolorizing printing and dyeing wastewater by adopting co-immobilized white-rot fungi. The method comprises the following steps: inoculating a seed solution containing any two or more white-rot fungi into a liquid culture medium with an immobilization carrier at a volume ratio of 5-20%, and then performing shake culture at 25-30 DEG C for 5-7 days; after covering the immobilization carrier with thalli, performing separation to obtain a carrier fixed with the white-rot fungus thalli, and putting the carrier into the printing and dyeing wastewater, thereby realizing decolorization treatment. The method fully utilizes enzymes generated by the white-rot fungi with different species and complementary enzyme systems to degrade and decolorize the printing and dyeing wastewater, can realize complete degradation of printing and dyeing wastewater pollutants, and can realize repeated decolorization. The method can be used for decolorization treatment of the printing and dyeing wastewater containing dyes with different structure types, and is high in decolorization efficiency. As the pollutants are degraded by the white-rot fungi, degradation products do not cause secondary pollution to a water body.

The invention discloses application of activating mono-persulfate based on copper ferrite nano-powder. Nanometer copper ferrite particles are put into a solution containing persistent organic pollutants, then, mono-persulfate is put to perform a reaction, after the reaction is ended, and a magnetic separation method is performed for recycling an activating agent. Compared with other activating systems, such as metal ions (Fe2+ / Cu2+) or nanometer copper oxide, the adopted nanometer copper ferrite is higher in activating efficiency, the mono-persulfate can be efficiently and continuously activated for generating sulfate radials and hydroxyl radicals, and the purpose of degrading the persistent organic pollutants is achieved.

The invention belongs to the technical field of dendrobium polysaccharide preparation and discloses ultralow-molecular-weight dendrobium polysaccharides as well as preparation and application thereof.The method comprises the following steps: (1) inoculating an activated aspergillus tubingensis strain into a liquid seed culture medium, and culturing to obtain seed liquid; (2) fetching the seed liquid and inoculating into a fermentation culture medium of a fermentation tank; adjusting the pH of the liquid in the fermentation tank to 4.0-7.0; fermenting at 25-35 DEG C to obtain fermented liquid,wherein the fermentation culture medium contains broken herba dendrodii officinalis; (3) inactivating the fermented liquid; (4) purifying and concentrating the inactivated fermented liquid, adding anexcipient, performing high-pressure homogenization, and drying to obtain the dendrobium polysaccharides. The method disclosed by the invention is simple, safe and pollution-free, and the yield and purity of the polysaccharides are high; in the obtained dendrobium polysaccharides, the polysaccharides with less than 10kDa of weight-average molecular weight account for 98% or above of total polysaccharides; therefore, the obtained dendrobium polysaccharides are ultralow-molecular-weight dendrobium polysaccharides.