654 results about "Iron(II,III) oxide" patented technology

The invention belongs to the field of electromagnetic wave absorbing material preparation and relates to a polyaniline / oxidized graphene / ferriferrous oxide composite material and its preparation method. The preparation method comprises the following steps: (1) preparing graphite oxide; (2) preparing ferriferrous oxide nanoparticles; (3) preparing a polyaniline / oxidized graphene / ferriferrous oxide ternary complex; and (4) weighing the polyaniline / oxidized graphene / ferriferrous oxide ternary complex and paraffin, and uniformly mixing to obtain the polyaniline / oxidized graphene / ferriferrous oxide absorbing material. The material provided by the invention has characteristics of low cost, simple preparation technology, strong electromagnetic wave absorbing capability, wide absorption band, low density and the like, has good electromagnetic property, and has important application value in the field of microwave absorption and electromagnetic shielding.

The invention relates to a method for preparing a magnetic nanometer ferroferric oxide-graphene composite catalyst, which includes steps of: 1) dispersing graphite oxide in ethanol and water system; 2) respectively mixing soluble trivalent ferric salt and divalent ferric salt in ethanol; 3) mixing and stirring systems obtained in step 1) and step 2); 4) heating reaction system of 3) at temperature of 50 DEG C to 90 DEG C, and adjusting pH to be 9-11 for reaction by adding ammonia water; and 5) performing magnetic separation on products of step 4), washing through deionized water, and obtaining magnetic nanometer ferroferric oxide-graphene composite catalyst. The method provides a simple and practical coprecipitation method for preparing the nanometer ferroferric oxide-graphene composite catalyst which is uniform in particular sizes, even in dispersing and good in magnetism. The nanometer ferroferric oxide-graphene composite catalyst prepared by the method has excellent catalytic activity and is easy in preparing process and environment-friendly.

The present invention provides the preparation process of super-paramagnetic polymer microsphere. The super-paramagnetic polymer microsphere consists of polyolefin polymerized with lipophilic olefin monomer and organic monomer with hydrophilic functional radical and coated nano magnetic grains of modified ferroferric oxide. The nano magnetic grains with one surface lipophilic layer can be well dispersed in organic matter to form magnetic fluid and dispersed inside polymer microsphere to obtain super-paramagnetism. The microsphere is regular and has size of 0.1-5 micron and has magnetic ferroferric oxide accounting for 0.5-40 wt% of the whole micro microsphere. The present invention has the advantages of simple preparation process, narrow microsphere size, regular appearance, high functional radical content, homogeneous magnetism, stable chemical performance and acid and alkali resistance.

The invention discloses a synthesis method of a metal organic framework composite material which has a sandwich structure, comprises magnetic microsphere ferroferric oxide surface coating polydopamine and takes zirconium ion as central metal ion and application of the material. The synthesis method comprises the following steps: firstly synthesizing ferroferric oxide magnetic microspheres by using a hydrothermal synthesis method; dispersing the magnetic microspheres in an aqueous solution of polydopamine hydrochloride to coat the surfaces of the magnetic microspheres with polydopamine layers; dispersing the magnetic microspheres coated with the polydopamine in an N,N-dimethylformamide mixed solution of zirconium chloride and terephthalic acid to prepare the magnetic metal organic framework composite material with a sandwich structure. The synthesis method is simple and quick; the magnetic metal organic framework composite material obtained by synthesizing is high in specific surface area, good in biocompatibility and applicable to selective enrichment of phosphorylated peptide and MALDI-TOFMS detection in biological samples.

The invention relates to a synthetic method for a magnetic metal organic framework composite material coated by [Cu2(btc)2] on surfaces of ferroferric oxide microspheres and application of the composite material. The method comprises the following steps of: firstly synthesizing ferroferric oxide microspheres by a hydrothermal synthesis method; dispersing magnetic spheres in an ethanol liquid of mercaptoacetic acid, wherein hydroxyls are formed on the surface of the spheres; dispersing mercaptoacetic acid modified magnetic spheres to an ethanol liquid of copper acetate, reacting for 15 minutes at 70 DEG C, and then dispersing the product in an ethanol liquid of trimesic acid and reacting for 30 minutes at 70 DEG C; and performing alternate reaction of magnetic spheres with copper acetate and the ethanol liquid of trimesic acid to finally, obtain the magnetic metal organic framework composite material with a core-shell structure. The material has a metal organic framework shell layer and can be coordinated with peptide fragments with amino groups and carboxylic group so as to enrich low concentration peptide. Meanwhile, the enriching and separating process is fast, simple and convenient due to high paramagnetism of ferroferric oxide. The synthetic method is simple and low in cost, and can be used for enrichment and separation of low abundance peptide fragments less than 1nM and MALDI-TOFMS (Matrix-Assisted Laser Desorption Ionization-Time Of Flight Mass Spectrometer) detection.

The invention discloses a method for preparing carbon-coated superparamagnetic ferroferric oxide gel, which comprises: dissolving ferrocene and surfactant in an acetone solvent; adding solution of hydrogen peroxide into the solution to directly oxidize the ferrocene to synthesize polycrystal uniform magnetic nano balls under a low-temperature (180 to 240 DEG C) solvothermal condition; and allowing the polycrystal uniform magnetic nano balls to react in a magnetic field to prepare a magnetic linear nano material. The polycrystal uniform magnetic nano balls and nano chains are characterized in that: the particle size of the polycrystal uniform magnetic nano balls is limited to a narrow range and controllable; and the nano chains consist of uniform spherical particles and have high stability, and the inter-chain distance is controllable. The superparamagnetic polycrystal uniform nano ball and linear nano chain materials have high superparamagnetism and high chemical stability and gel stability and have promising application prospect in the field of biomedicine, nano self-assembly and the like; the nano balls are grafted by medicaments and can be used as medicament carriers; under the action of the magnetic field, the nano balls can be used as magnetic control photonic crystal; and the nano chains have a promising application prospect in the field of Bragg reflectors, magnetic probes, biomedicine and the like.

The invention provides a method for preparing magnetic ferroferric oxide / conductive polyaniline light-weight composite hollow microspheres, which relates to a method for preparing a magnetic ferroferric oxide / conductive polyaniline composite material. The invention solves the problems of high density and easy agglomeration of the traditional magnetic nanometer particle / conductive polymer composite material. The method comprises the following steps of: regulating ferrous chloride and ferric chloride solutions to be alkaline, adding sodium dodecyl benzene sulfonate and reacting to obtain ferroferric oxide; and modifying hollow glass microspheres by using poly(diallyldimethylammonium chloride) solutions after alkaline cleaning, then reacting the hollow glass microspheres with the ferroferric oxide, sequentially immersing obtained solid particles by using the poly(diallyldimethylammonium chloride) solutions and polystyrene sulfonic acid solutions, then adding the solid particles to aniline solutions, initiating polymerization by using ammonium persulfate, and washing and drying the solid particles to obtain the composite hollow microspheres. The composite hollow microspheres have both conductivity and magnetism, the density is 0.78-0.8g / cm<3>, and the composite hollow microspheres are not easy to agglomerate and are used for fields of military equipment stealth technology and civil anti-electromagnetic radiation.

The invention provides an online self-sharpening metallic bond and super-hard abrasive precision grinding pellet and a preparation method thereof and belongs to the technical field of precision grinding pellets. Raw materials of the precision grinding pellet comprise a super-hard abrasive and a metallic bond, wherein the super-hard abrasive is diamond micro-powder; the diamond concentration falls within a range of 75-100 %; and the metallic bond uses a multicomponent alloy bond whose main components are copper powder, tin powder, aluminum powder, copper-clad ball shaped graphite powder, silicon dioxide and ferroferric oxide powder. The preparation method comprises the following steps: uniformly mixing and stirring the diamond micro-powder as well as the copper powder, the tin powder and the aluminum powder; adding polyvinyl alcohol to a mixture and mixing the polyvinyl alcohol and the mixture; adding the silicon dioxide, the copper-clad ball shaped graphite powder and the ferroferric oxide powder to an obtained mixture and mixing these materials and the obtained mixture; filling the mixture into a graphite mold; maintaining the pressure of the graphite mold for 5-10 minutes after pressurizing the graphite mold to 100-250 MPa; and carrying out hot pressing sintering on the graphite mold in a sintering furnace, wherein the sintering atmosphere is ammonia decomposition gas. Through the adoption of the online self-sharpening metallic bond and super-hard abrasive precision grinding pellet provided by the invention, online automatic sharpening can be achieved without blockage and offline repairing.

The invention provides a preparation method for a molecular imprinting material and the molecular imprinting material prepared through the preparation method. The preparation method comprises the steps that silicon oxide is coated on the surfaces of magnetic ferroferric oxide nanometer particles, the magnetic ferroferric oxide nanometer particles are modified with gamma-(methacryloyl chloride) amino propyl trimethoxy silane to obtain magnetic ferroferric oxide nanometer particles with propenyl on the surfaces, the magnetic ferroferric oxide nanometer particles with the propenyl on the surfaces serve as carriers, estrogen receptors are simulated, functional monomers are optimized, a surface imprinting technology is adopted, and then the molecular imprinting material which can simultaneously identify seven kinds of environmental endocrine disrupting chemicals is prepared. According to the preparation method, the easy separation of a magnetic nanometer material, the good water solubility of a silicon oxide nanometer material, the specific recognition ability of molecular imprinting polymers and the surface imprinting technology are mutually combined, the preparation technology is simple, the conditions are mild, the prepared molecular imprinting material is large in adsorption capacity, fast to respond, high in magnetism, good in chemical stability and high in repeating utilization rate, and the problems that at present, multiple trace, steroid and phenol environmental endocrine disrupting chemicals are difficult to simultaneously identify, separate and enrich are solved.

The invention belonging to the nanometer material field relates to composite material made of carbon nanometer tubes enwrapped by polyaniline and ferroferric oxide and the preparation method thereof. The invention ultrasonically disperses the carbon nanometer tubes in an aqueous solution containing ferric iron ions and ferrous iron ions and obtains carbon nanometer tubes / ferroferric oxide composite material after adding ammonia. After washing and magnetic separation, the carbon nanometer tubes / ferroferric oxide composite material disperses in a mixed liquor containing aniline, phosphoric acid and ammonium persulfate and the composite material of the invention is obtained after agitation. After water and alcohol washing and magnetic separation, finished products are obtained through drying or dispersing in absolute ethyl alcohol. The material which has the functions of electrical conductivity, magnetism, absorption and capability of absorbing and releasing material carrying negative charge in an aqueous solution can be applicable to the fields such as enzyme immobilization, bioactive substance separation, target-oriented medicine preparation, biosensor, environmental protection, etc. The invention which has simple preparation art, low cost and high raw material utilization factor is suitable for volume production.

The invention discloses a method for preparing a ferroferric oxide / carbon nano tube composite material, which is used for solving the technical problem that the nano Fe3O4 particle diameter of the coating prepared by the conventional method for preparing the ferroferric oxide / carbon nano tube composite material is not uniform. According to the technical scheme, multi-wall carbon nano tubes, ammonium ferrous sulfate, ferric chloride and sodium hydroxide are used as raw materials, polyvinyl alcohol is used as a surfactant, the ferroferric oxide / carbon nano tube magnetic nano composite material is obtained by adopting a reverse co-precipitation method, and nano Fe3O4 coatings with different particle diameters are obtained by changing the reaction temperature and the concentration of the reaction solution. The nano Fe3O4 particle diameter of the coating of the ferroferric oxide / carbon nano tube composite material prepared by the method is uniform, the average nano particle diameter is less than 10 nanometers, and the synthesis process and the production equipment are simple.

The invention relates to a carbon / polymer composite material in a specific direction and a preparation method. A ferroferric oxide precursor solution containing 0.05-5% by mass of iron is prepared; a thermally conductive carbon material is uniformly mixed with the ferroferric oxide precursor solution, and reaction, filtration, washing and drying are performed to obtain a magnetic carbon material with ferroferric oxide uniformly dispersed on the surface of the carbon material; the magnetic carbon material is put in a magnetic field of 0.1-1 T, the direction of the magnetic field is from an N pole to an S pole, different magnetic field directions are obtained by regulating relative positions of the N pole and the S pole, and the magnetic carbon material is arranged in the magnetic field direction; and a polymer precursor solution is poured in a directional carbon material array and cured to obtain the carbon / polymer composite material with the carbon material directionally arranged in polymer. The surface of the carbon material is loaded with ferroferric oxide, and the carbon material is directionally arranged in the magnetic field direction in the magnetic field; and the thermal conductivity coefficient of the composite material in the carbon material direction is greater than or equal to 30 W / (m.K).

The invention discloses a magnetic pearlescent pigment and a preparation method thereof. The magnetic pearlescent pigment has black luster and takes a substrate with a particle diameter of 10-60mum as a cladding substrate, and the substrate is clad with Fe3O4. The preparation method of the magnetic pearlescent pigment comprises the following steps: dropwise adding ferric iron salt solution and ferrous iron salt solution to mica suspension at a certain temperature; controlling pH value for coprecipitation to deposit the precipitated ferroferric oxide evenly and compactly on the mica under the protection of inert gas; calcining in an inert atmosphere to prepare the magnetic pearlescent pigment. The prepared magnetic pearlescent pigment has a flat and compact deposition surface, high cladding rate and obvious pearlescent effect. The preparation method helps realize coprecipitation of the ferric iron and the ferrous iron and cause the ferroferric oxide to clad a sericite substrate evenly. The preparation method is suitable for the preparation of various pearlescent pigments, and a coprecipitation method and sintering atmosphere control are introduced to provide the possibility of depositing and cladding the oxides with different valences.

The invention belongs to the technical field of functional material and particularly relates to a magnetic mesoporous titanium dioxide core-shell type compound microsphere as well as a preparation method and applications thereof. The core-shell type compound microsphere takes a ferroferric oxide nano particle cluster as the core and takes mesoporous titanium dioxide with high crystallinity as the shell. The preparation method comprises the following steps: firstly, preparing the ferroferric oxide nano particle cluster with stable citric acid, secondly, wrapping the surface of the cluster with an amorphous titanium dioxide shell through a sol-gel method, and finally, obtaining the magnetic mesoporous titanium dioxide core-shell type compound microsphere through hydro-thermal treatment. By being provided with the mesoporous titanium dioxide shell with high crystallinity, the compound microsphere has the characteristics of high selectivity, high enrichment capacity, high sensitivity and high recovery rate to phosphoeptide; and since a magnetic core exists, the microsphere enriched in phosphoeptide can be separated by magnetism quickly and very conveniently. The method provided by the invention has the advantages that the operation is simple, the process is controllable, and the prepared compound microsphere can be used for analyzing and identifying phosphoeptide with ultra low concentration in a biological sample.

The invention discloses a Fenton-like catalyst of graphene coated ferriferrous oxide (Fe3O4) micro-spheres as well as a preparation method and application thereof. The preparation method comprises the following steps: completely coating Fe3O4 particles by graphene; by taking an aqueous solution of inorganic ferric salt and graphene oxide as a precursor, rapidly preparing graphene oxide coated ferric salt precursor micro-spheres by adopting a spray-drying technology, and performing calcination reduction at a protective atmosphere to obtain a target product. The Fenton-like catalyst of the graphene coated Fe3O4 micro-spheres, disclosed by the invention, has relatively good catalytic efficiency and very good stability under the coordination of a hydrogen peroxide aqueous solution, can also be acquired by virtue of simple external magnetic field separation to be recycled and repeatedly used, can be used for reducing cost, and is an environment-friendly material.

The invention relates to a preparation method for a bismuth vanadate composite photocatalyst loaded with strontium ferrite, and belongs to the field of inorganic catalytic materials. According to the preparation method, bismuth vanadate adopts the structure of scheelite in the monoclinic system; while the degradation rate, of the composite photocatalyst loaded with the strontium ferrite, for methylene blue can reach 93 percent in 5h, the degradation rate, of a similar composite photocatalyst of bismuth vanadate loaded with ferroferric oxide, for the methylene blue can reach 80 percent in 8 h. Moreover, the prepared composite photocatalyst has photocatalysis activity in relatively-wide wavelength range, and can efficiently and cyclically degrade organic pollutants in heteroaromatic dye-type wastewater under the irradiation of ultraviolet light, visible light and natural light through photocatalysis. Meanwhile, the composite catalyst is convenient to recover with the recovery rate not less than 92 percent; the degradation rate, of the recovered composite catalyst, for the methylene blue can reach 60 percent in 5h. The preparation method is simple and has an excellent application prospect.

The invention discloses a method for controlling morphology and performance of a ferriferrous oxide and belongs to the technical field of inorganic materials. The method comprises the following steps of: dissolving ferric trichloride hexahydrate in ethylene glycol to prepare a solution of which the ferric trichloride concentration is 0.15-0.35mol / L; then, adding urea and a surface active agent; fully dissolving to obtain a homogeneous solution; transferring the homogeneous solution into a high-pressure reaction kettle with a polytetrafluoroethylene lining; performing a solvent thermal reaction at the temperature of 170-230 DEG C for 6-72 hours; performing centrifugal separation after the reaction is ended; washing deposits by using deionized water and alcohol; and then, drying in a drying oven to obtain a finished product. The method for controlling the morphology and the performance of the ferriferrous oxide has the advantages that the production cost is low; the preparation technology is safe and simple; the product controllability is strong; and toxic and harmful substances are not generated in the preparation process. The obtained ferriferrous oxide is high in purity and centralized in particle size distribution, and the morphology can be mutually converted among a spherical structure, a microporous structure and a hollow structure.

The invention relates to preparation and application of a magnetic ferroferric oxide nanoparticle modified carbon nanotube composite material. The preparation method includes: mixing a divalent iron salt and a trivalent iron salt, adding NH3.H2O, conducting water bath and centrifugal separation, washing the precipitate, and carrying out drying and grinding to obtain magnetic Fe3O4 nanoparticles; adding concentrated nitric acid and concentrated sulfuric acid into pretreated carbon nanotubes, conducting heating refluxing, carrying out filtering, deionized water washing and vacuum drying, thus obtaining purified multiwalled carbon nanotubes; adding the purified multiwalled carbon nanotubes into a triethylene glycol solution, conducting ultrasonic treatment, adding magnetic Fe3O4 nanoparticles, performing stirring and heating, conducting heat preservation and cooling, separating the product, and conducting vacuum drying, thus obtaining the magnetic Fe3O4 nanoparticle modified carbon nanotube composite material. The composite material is used for detecting the residue amount of organophosphorus pesticides in food. The preparation method utilizes magnetic Fe3O4 nanoparticles to modify carbon nanotubes, and greatly improves the dispersibility and adsorption properties of carbon nanotubes in water. The prepared magnetic Fe3O4 nanoparticle modified carbon nanotube composite material hasgood stability, and the maximum recovery rate can reach 89.6%.

The invention discloses a Fe3O4@SiO2 composite material adsorbent preparation method and application. The method comprises the following steps of: synthesizing ferroferric oxide magnetic micro-spheres by using a chemical co-precipitation method; wrapping silicon dioxide on the surfaces of the ferroferric oxide magnetic micro-spheres by using a sol-gel method; and fixing xanthan gum molecules on the surfaces of the magnetic micro-spheres in a functionalized way to prepare an adsorbent. The adsorbent has large specific surface area under nanoscale, high magnetic separation capacity and good stability due to the wrapped silicon dioxide shell layer, rich active adsorption sites are introduced by the xanthan gum molecules in the functionalized way; the Pb adsorption efficiency is over 90 percent. The adsorbent enriches and separates Pb-containing artificial simulate seawater and is subsequently combined with a graphite furnace atomic absorption spectrometry to measure total lead concentration, so that interference of salinity ions in the background of a seawater sample can be effectively avoided, and a standard curve is satisfactory; the lead concentration in the actual seawater is correspondingly tested, and the recovery rate reaches 85.71 percent.

The invention belongs to the technical field of composite materials, and in particular relates to a magnetic hollow multihole carbon ball with a core-shell structure and a preparation method of the magnetic hollow multihole carbon ball. the core of a core-shell type hollow micro-hole magnetic carbon ball prepared by a microwave hydrothermal method is a magnetic ferroferric oxide nano cluster; and a shell layer is multihole carbon. The preparation method comprises the following steps of: wrapping a template shell layer on the surface of ferroferric oxide by taking the ferroferric oxide nano cluster as a seed through soap-free emulsion polymerization, then wrapping the surface of a ferroferric oxide composite micro ball with phenolic resin through in-situ polymerization according to the microwave hydrothermal method, and finally carbonizing the ferroferric oxide composite micro ball at certain temperature to obtain the magnetic hollow multihole carbon ball with the core-shell structure, wherein the obtained composite carbon ball has the characteristics of uniform granularity, controllable carbon layer thickness and narrow aperture distribution. The preparation method is easy to operate, and a process is controllable; and the carbon ball and the preparation method have a good application prospect.

The invention relates to a magnetic graphene adsorbing material for adsorbing phosphorus in water, a preparation method and an adsorption method. According to the preparation method, firstly, spherical Fe3O4 magnetic nanospheres are supported on the surface of GO with a coprecipitation method under the ultrasonic action, and Fe3O4-supported GO (Fe3O4-GO) is prepared; Fe3O4-GO is reduced by hydrazine hydrate, and Fe3O4-supported graphene(Fe3O4-GNS) is prepared; Fe3O4 is coated with active-amino-terminated PZD with a copolymerizing precipitation method, and PZD-coated Fe3O4-supported graphene (PZD@Fe3O4-GNS) is prepared; a layer of La2O3 nanoparticles are deposited on the surface of PZD@Fe3O4-GNS, and La2O3-PZD@Fe3O4-GNS quaternary nanoparticles are prepared. The preparation conditions are mild, the operation is simple, a product is simple to separate, and the obtained product has excellent adsorption performance on phosphate particles, is free of pollution on the ecological environment and has quite broad application prospect in the aspects of efficient and rapid treatment of a large water area with phosphorus pollution and resource recycling.

The invention belongs to the technical field of inorganic materials and analysis, in particular to a Fe3O4 at SiO2 magnetic silicon ball with the surface being decorated by C8 alkyl chain and the preparation method and application thereof. The magnetic nanometer silicon ball is acquired by synthesizing into the magnetic nanometer material of ferroferric oxide at first, and then synthesizing into the Fe3O4 at SiO2 magnetic micro-ball material with shell structure, and further adopting C8 to conduct surface chemical decorating. The magnetic nanometer particles of the fixing C8 are taken as micro-absorbent, the specific surface is large, the peptide segments in organism are enriched, and the method is simple and effective. The material has good utility value and potential application in proteomics and other fields.

An iron-removing ore dressing technology for potash feldspar includes such steps as washing, breaking, sorting, concentrating, purifying, washing with sulfuric acid and sieving. It has high output (more than 90%), low content of Fe (less than 0.24%) and more by-products (silt, Fe, mica, Fe2O3 and Fe3O4).

The invention discloses a reduced graphene / ferroferric oxide / precious metal nanocomposite and a preparation method and application thereof. The preparation method comprises the specific steps that 1, polyethyleneimine and polyacrylic acid are used as polyelectrolytes, and a reduced graphene nano material supported by magnetic ferroferric oxide is prepared through a self-assembly method; 2, trimethoxysilylpropanethiol is added into the reduced graphene nano material supported by the magnetic ferroferric oxide, and a magnetic graphene material modified by the trimethoxysilylpropanethiol is obtained; 3, precious metal nano particles and the magnetic graphene material modified by the trimethoxysilylpropanethiol are mixed, and the reduced graphene / ferroferric oxide / precious metal nanocomposite is obtained. The obtained composite has the good surface-enhanced Raman activity and electrocatalytic activity, and can be widely applied to the fields of biosensing, electrocatalysis, surface-enhanced Raman detection and the like.

The invention discloses carbon-coated hollow ferriferrous oxide and an application thereof. The preparation method of the carbon-coated hollow ferriferrous oxide comprises the following steps of: (1) adding a ferric salt into a solvent and dissolving the ferric salt, wherein the solvent is a mixture of water and ethanol; implementing a hydrothermal reaction in a sealed hydrothermal kettle for 20-30hours at 100-250 DEG C, and separating to obtain a ferric oxide deposit; and (2) uniformly mixing the ferric oxide deposit with a reducing carbon source, wherein the reducing carbon source is one substance or a combination of multiple substances selected from carbon powder, glucose, polyethylene, acetylene black and starch; and implementing an insulating reaction for 0.5-4hours in a muffle at 200-1000 DEG C, to obtain the carbon-coated hollow ferriferrous oxide. The carbon-coated hollow ferriferrous oxide, used as a lithium ion battery negative electrode material, can remarkably improve electrical conductivity and keeps a stable structure, so that a comparatively high capacity retention ratio is still guaranteed after several charge-discharge cycles.

The invention belongs to the technical field of detection, and particularly relates to a method for manifesting latent fingerprints. The invention provides the method for manifesting the latent fingerprints. A magnetic brush is used to attract magnetic powder; the powder forms a 'magnetic powder ear' under the action of magnetic force; and the latent fingerprints on the surfaces of A4 paper, sheet glass, plastic bottles, pop-top cans, sheet copper, aluminum foils, tables or experiment tables can be manifested by using the tip of the powder ear to slightly brush various object surfaces printed with the latent fingerprints. The method is based on magnetic ferroferric oxide nano-powder and utilizes an phase reversal microemulsion polymerization method to prepare fluorescent magnetic silica gel spheres; and the method jointly coats magnetic granular ferroferric oxide and dye molecules in silicon dioxide microspheres by utilizing the hydrolysis of TEOS under alkaline conditions to perform one-step synthesis of magnetic silica monodisperse gel spheres and dye-doped magnetic fluorescent silica gel spheres to obtain magnetic fluorescent multi-functional powder, can be applied to more conditions and ranges, and has simple operation and no toxic or side effect.

The present invention is composite nano silica / ferroferric oxide grain material and its preparation process. By means of chemical deposition process, nano ferroferric oxide crystal produced in the reaction is compounded and assembled onto the surface of spherical nano silica particle to form the composite grain material in spherical shell shape. The present invention features that through coating silica with nano ferroferric oxide, the features of both the silica and the nano ferroferric oxide are combined together to make the composite material possess light weight, magnetism and low radiance. The composite material may be used in making transparent pigment, stealth material, etc.

The invention discloses a multi-walled carbon nanotube-loaded nano ferrofferic oxide (Fe3O4) catalyst and a preparation method and an application thereof. In the multi-walled carbon nanotube-loaded nano ferrofferic oxide catalyst, ferroferric oxide is distributed on the surface of the outer wall of the multi-walled carbon nanotube. The preparation process is simple, the cost is low, and easiness in industrialized popularization is realized. In the synthesized catalyst, the crystallinity of the Fe3O4 nano particles is high, the particle size is controllable, and the particles distribution is narrow. The catalytic activity of the multi-walled carbon nanotube-loaded nano ferrofferic oxide (Fe3O4) catalyst multi-walled carbon nanotube-loaded nano ferrofferic oxide (Fe3O4) catalyst (Fe3O4-MWCNTs) is high and the Fe3O4-MWCNTs is easy for being repeatedly used through magnetic separation. The Fe3O4-MWCNTs which is prepared by the method can be used as peroxide mimic enzyme and can be used as catalyst for organic pollutants which are difficult to degrade and for organic synthesis.

The invention discloses a ferroferric oxide@carbon / reduced graphene oxide nano composite wave-absorbing material and a preparation method thereof. By using graphene oxide as a template, ferric chloride hexahydrate as a metal salt, terephthalic acid as an organic ligand, and N,N-dimethylformamide as a solvent, the ferroferric oxide@carbon / reduced graphene oxide nano composite material is prepared by a solvothermal-high temperature pyrolysis two-step method. The preparation method is environmentally friendly, generates no toxic by-products, and has a simple preparation process. The prepared nanocomposite material has a good microwave absorption capacity, a wide absorption frequency band, a low thickness, light weight and a low filling ratio, can absorb electromagnetic waves in different wavelength bands by adjusting the addition amount of graphene oxide in a precursor and the thickness of a coating layer, and has an important application value in the field of electromagnetic absorptionand electromagnetic shielding.