267 results about "Fe3o4 nanoparticle" patented technology

The invention discloses a preparation method of magnetic beads by extracting nucleic acid. The surfaces of magnetic nanoparticles Fe3O4 are coated with silicon hydroxyl and then are dispersed into a 0.02% NaN3 aqueous solution; the prepared silicon-based magnetic bead is of a core-shell structure and comprises a Fe3O4 nanoparticle core and a SiO2 shell layer, wherein the outer surfaces of a plurality of Fe3O4 nano-particles are coated with the SiO2 shell layer; the silicon-based magnetic bead has the secondary particle size of 400nm-1 micron, measured by a nanometer laser particle analyzer, and has the saturation magnetization of 43.0-74.5emu / g after being subjected to ultrasonic dispersion for 1h; the prepared silicon-based magnetic bead can be widely applied to nucleic acid extraction and purification of biomaterials such as fresh animal tissues, animal tissue paraffin sections, plant leaves, seeds, whole blood, free serum, hairs, fingernails, stubs, saliva, bacteria or viruses. The method is simple in process flow, convenient to operate, and low in raw material cost and is suitable for being used in industrial mass production.

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 preparation method of an amino functional magnetic silicon dioxide adsorption material. The method comprises the following preparation process that firstly, solid Fe3O4 nanoparticles are prepared by a solvothermal method; then, the solid Fe3O4 nano particles are put into a mixed solution of absolute ethyl alcohol and water; a certain quantity of ammonia water is added; after ultrasonic dispersion, ethyl orthosilicate is added drop by drop at normal temperature; after stirring reaction is performed for a period of time, a certain quantity of different kinds of amino-silane coupling agents are added; continuous stirring is performed for reaction for a period of time; after the product is subjected to magnetic separation, washing and vacuum drying, an amino functional Fe3O4@SiO2 composite adsorbing material with a core-shell structure is prepared. The prepared amino functional Fe3O4@SiO2 composite adsorbing material has good adsorption performance on virulent contaminants Cr(VI) in wastewater; particularly, the significant advantages of fast adsorption kinetics is realized; after one-hour adsorption, the adsorption is balanced; the characteristic of fast separation after the adsorbent adsorbs the contaminants is realized.

The invention relates to a method for preparing a magneto-optical difunctional two parallel strand composite nanofiber bundle, and belongs to the technical field of nanomaterial preparation. The method comprises the following four steps of: (1) preparing Fe3O4 nanoparticles by using a hydrothermal method; (2) preparing a Eu(BA)3phen complex by using a precipitation method; (3) preparing spinning solutions, namely preparing a spinning solution from a mixed solution of the Eu(BA)3phen complex, polyvinyl pyrrolidone (PVP) and dimethyl formamide (DMF), and preparing a spinning solution from a mixed solution of the Fe3O4 nanoparticles, PVP and DMF; and (4) preparing a Fe3O4 / PVP / / Eu(BA)3phen / PVP magneto-optical difunctional two parallel strand composite nanofiber bundle by adopting an electrostatic spinning technology and using parallel double spinning nozzles. The prepared Fe3O4 / PVP / / Eu(BA)3phen / PVP magneto-optical difunctional two parallel strand composite nanofiber bundle has a smooth surface and has good magnetism and luminosity, and the diameter of a single stranded nanofiber is 380nm. The two parallel strand composite nanofiber bundle with magneto-optical double functions and a novel structure can be importantly applied to future nanostructure devices and medical diagnosis and treatment. The method is simple and feasible, is suitable for mass production and has a wide application prospect.

The invention discloses a preparation method and application of a polydopamine-modified magnetic nanoparticle, belonging to the technical field of magnetic nanoparticle modification. The preparation method comprises the following steps: preparing Fe3O4 nanoparticles from FeCl3.6H2O, Na3C6H5O7.2H2O and CH3COONa; adjusting the pH value of a Tris solution to 8.0-8.5 by using dilute hydrochloric acidso as to obtain a Tris-HCl buffer solution; adding the Fe3O4 nanoparticles into the Tris-HCl buffer solution for ultrasonic dispersion treatment for 5-10 min so as to obtain a solution A; adding dopamine hydrochloride into the Tris-HCl buffer solution for ultrasonic dispersion treatment for 1-2 min to obtain a solution B; adding the solution B into the solution A, performing a reaction for 10 to 24 h under stirring so as to obtain Fe3O4@PDA particles, collecting the nano-Fe3O4@PDA particles via an external magnetic field, separately washing the nano-Fe3O4@PDA particles with deionized water andethanol twice or more times, and carrying out drying under vacuum to obtain the polydopamine-modified magnetic nanoparticle. The polydopamine-modified magnetic nanoparticle, as a heavy metal adsorbent, has good biocompatibility, high stability, high adsorption capacity and superparamagnetism.

The invention discloses a method for preparing a Fe3O4 nanoparticle / graphene composite material by a sol electrostatic self-assembly process, which comprises the following steps: (1) preparing a Fe(OH)3 sol solution of which the surface is positively charged; (2) preparing a graphene oxide sol of which the surface is negatively charged; and (3) mixing the graphene oxide sol and the Fe(OH)3 sol, magnetically stirring to generate a brownish black precipitate, separating, pouring out the supernate to obtain a Fe(OH)3 / graphene oxide composite, and reducing the composite at 300-800 DEG C in a nitrogen atmosphere to obtain the Fe3O4 / graphene nano composite material. The composite of the Fe(OH)3 colloidal particles and graphene oxide is performed in the water solution, and thus, the method has the advantages of low cost, energy saving, environment friendliness and simple technique, and can easily implement industrial mass production; and the preparation process of the Fe(OH)3 colloidal particle / graphene oxide composite material has obvious solution variation, and the solution becomes turbid from clear and finally precipitates, so that the supernate can be directly poured out.

The invention relates to a preparation method of magnetic Fe3O4 nanoparticles and application thereof in adsorption and separation of heavy metal ions, belonging to the technical field of nanomaterials as well as adsorption and separation treatment application of heavy metal ions in industrial and agricultural wastewater. The preparation method comprises the following steps: firstly preparing a ferric chloride solution with water used as a solvent by using a hydrothermal synthesis method, and then adding ascorbic acid to obtain a solution; and adding hydrazine hydrate to the resulting solution, then transferring to a stainless steel reaction kettle to react, after the reaction is finished, centrifugally separating, and washing and drying the obtained precipitate to obtain the magnetic Fe3O4 nanoparticles. The preparation method provided by the invention has the advantages of inexpensive and easily available raw materials and simple synthesis method; Fe3O4 prepared by the preparation method has good adsorption property to As and Cr metal ions, and the removal rate can be more than 90%; and the obtained magnetic Fe3O4 nanoparticles can be widely used in adsorption and separation of As and Cr in the industrial and agricultural wastewater.

The invention discloses a graphene oxide covalently bonded and coated magnetic nanoparticle composite material and a preparation method thereof. According to the preparation method, Fe3O4 nanoparticles are prepared, the Fe3O4 nanoparticles are subjected to surface modification and functional group introduction to generate Fe3O4@SiO2-NH2 particles, and the Fe3O4@SiO2-NH2 particles react with graphene oxide so as to coat the Fe3O4@SiO2-NH2 particle surface with the graphene oxide through covalent bonding. Compared to the reported graphene oxide-Fe3O4 composite material, the composite material of the present invention has the following advantages that the structure is improved, the stability is substantially enhanced, and the defects that the Fe3O4 is electrostatically coated with graphene oxide and the Fe3O4 deposits in the graphene oxide sheet layer composite layer are overcome, According to the present invention, the graphene oxide-Fe3O4 composite material prepared through the method has excellent adsorption property for heavy metals, can be reused, and has broad application prospects in the fields of heavy metal sewage treatment and the like, wherein the adsorption process is simple, green, and environmental protection.

The invention discloses a preparation method and application of polyethylenimine-modifed magnetic microspheres. The preparation method comprises the following steps: firstly synthesizing ferroferric oxide magnetic microspheres, then performing ultrasonic dispersion on the prepared Fe3O4 nanoparticles in a Tris-HCI solution and then dropwise adding a dopamine-dissolved Tris-HCl solution; reacting under the action of mechanical stirring and drying to obtain dry Fe3O4@PEI magnetic microspheres; finally dispersing the prepared Fe3O4@PEI nanoparticles in the Tris-HCI solution, slowly adding a PEI aqueous solution, reacting under water bath conditions and drying to obtain the dry Fe3O4@PDA@PEI magnetic microspheres. The preparation method disclosed by the invention is simple, effective and goodin reproducibility; the prepared magnetic microspheres are uniform in particle size, larger in specific area, controllable in size, quick in response to an external magnetic field, good in selectivity, capable of producing an electrostatic effect with a negatively-charged sulfonic acid group in a pigment, easy for pigment absorption, good in stability, renewable and reusable.

The invention discloses an immobilized biological adsorbent containing phanerochete chrysosporium, the surface of which is uniformly wrapped by a layer of carrier Fe3O4 nanoparticles for fixation. The method comprises the steps of: first adding Fe3O4 nanoparticles into a phanerochete chrysosporium liquid medium containing tween 80, then inoculating a phanerochete chrysosporium spore suspension, conducting shaking cultivation so as to obtain the immobilized biological adsorbent. The invention also discloses application of the adsorbent in dye wastewater treatment. The biological adsorbent of the invention has high adsorption efficiency and large adsorption capacity, and can be effectively used for treating neutral red and lead in dye wastewater. The preparation technology and treatment technology in the invention are characterized by simplicity and low cost.

The invention relates to a preparation method of nano magnesium ferrite, which comprises the following steps: mixing FeCl3.6H2O and FeCl2.4H2O in a mol ratio of 1:1, dropwisely adding a 2 mol / L NaOH solution, and preparing magnetic Fe3O4 nanoparticles by a chemical coprecipitation process; putting the magnetic Fe3O4 nanoparticles into a muffle furnace, and roasting at 500 DEG C for 3-4 hours to obtain nano Fe2O3; putting magnesium powder in a beaker, adding deionized water, and putting the beaker in an ultrasonic cleaner to treat for 5-8 hours, thereby obtaining a white turbid liquid; putting the supernatant of the turbid liquid in a clean beaker, drying in a drying box at constant temperature, and grinding the product to obtain Mg(OH)2; roasting the nano Mg(OH)2 in a muffle furnace at 350 DEG C for 3-4 hours, and roasting the Fe3O4 nanoparticles in a muffle furnace at 500 DEG C for 3-4 hours; respectively obtaining nano MgO and nano Fe2O3; and taking the nano Fe2O3 and the nano MgO, mixing the nano Fe2O3 and the nano MgO in a mol ratio of 1:1, adding deionized water, treating in an ultrasonic cleaner for 10-12 hours to obtain a red turbid liquid, sucking the supernatant of the turbid liquid into a clean beaker, drying the beaker in a drying box at constant temperature, and grinding the product to obtain the nano magnesium ferrite. The nano magnesium ferrite prepared by the method provided by the invention has the advantages of low cost, high purity, uniform appearance, environmental protection and no pollution.

The invention relates to a preparation method of carboxyl functionalized hyperbranched magnetic mesoporous silica composite microspheres which are suitable for packaging anticancer drugs and loading noble metal nano-catalysts. By selecting magnetic Fe3O4 nanoparticles prepared by a hydrothermal method as a magnetic core, a surfactant CTAB (Cetyltrimethyl Ammonium Bromide) as a template and TEOS (Tetraethyl Orthosilicate) as a silicon source, magnetic double-shell mesoporous silica composite microspheres with relatively high magnetic responsiveness, strong stability and high specific surface area and pore volume are successfully prepared through a conventional hydrolysis method. Application of the microspheres in aspects of loading and controlled release of DOX (Doxorubicin), loading of noble metal nano-catalysts and the like is studied, thereby representing an expected superior effect. According to the preparation method provided by the invention, in consideration of hyperbranched structures and terminal carboxyl functional groups with the stereo-hindrance effect contained in mesoporous ducts, the material has important meaning in cancer therapy and organic synthesis of the noble metal nano-catalysts.

The invention relates to a preparation method and an application of a carbon-coated Fe3O4 nanoparticle lithium ion battery negative electrode material, and relates to an electrode used in a lithium storage battery and formed based on an oxide active material; the preparation method is a method for preparing the carbon-coated Fe3O4 nanoparticle lithium ion battery negative electrode material by a hydrothermal method and a high temperature calcination process and comprises the steps: preparation of precursor carbon-coated Fe2O3 nanoparticles, preparation of a carbon-coated Fe3O4 nanoparticle powder, and preparation of the carbon-coated Fe3O4 nanoparticle lithium ion battery negative electrode material. The carbon-coated Fe3O4 nanoparticle lithium ion battery negative electrode material is applied as a lithium ion battery negative electrode piece for assembly of a semi-battery. The defects that carbon-coated Fe3O4 nanoparticles prepared in the prior art have larger particle size, the microtopography and the structure are difficult to control, a lithium ion battery negative electrode material prepared by the carbon-coated Fe3O4 nanoparticles has not good electrochemical performance, the preparation process is complex and the production cost is high are overcome.

The invention provides a targeted adriamycin-loaded magnetic nanoparticles and a preparation method and application, and belongs to the magnetic nanoparticles and preparation thereof. The targeted adriamycin-loaded magnetic nanoparticles are formed by taking the magnetic Fe3O4 nanoparticles formed by using dopamine to wrap as a core, and an EGFR antibody covalently coupled on the surface of the magnetic Fe3O4 nanoparticles through 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride or N-hydroxysuccinimide, and adriamycin non-covalently coupled to the surface of the nanoparticles. The nanoparticles provided by the invention have good target recognition capacity to the colon cancer cell DLD-1, can effectively enter the internal of the DLD-1 cell, has excellent photo-thermal killing ability on the DLD-1 cell, can be used for the photo-thermal treatment and medicine chemotherapy of the colon cancer cell, and has a good magnetic resonance imaging function.

The invention discloses magnetic composite hydroxyapatite nanoparticles. The magnetic composite hydroxyapatite nanoparticles are composed of Fe3O4 nanoparticles and hydroxyapatite nanoparticles, wherein the molar ratio of the Fe3O4 to the hydroxyapatite is (1-10): 1; the magnetic composite hydroxyapatite nanoparticles are spherical aggregate or agglomerate in which the Fe3O4 nanoparticles and the hydroxyapatite nanoparticles are distributed evenly and alternately. The preparation method of the magnetic composite hydroxyapatite nanoparticles is simple; the nanoparticles are capable of efficiently removing heavy metal ions in sewage, and in the later treatment period, quick magnetic separation can be realized; the nanoparticles have the adsorbing capacity of 440mg / g to lead ions, the adsorbing capacity of 238mg / g to cadmium ions, the adsorbing capacity of 139mg / g to zinc ions and the adsorbing capacity of 135mg / g to copper ions in the sewage; the magnetic composite hydroxyapatite nanoparticles have a rapid magnetic response characteristic, and are capable of realizing rapid solid-liquid separation with an external magnetic field, and the separation process is high in separation efficiency, and simple and efficient to operate; and besides, the nanoparticles are not residual in water and do not cause secondary pollution to the water and the environment.

The invention relates to the field of functional composite materials, in particular to a low-reflection high shielding electromagnetic shielding composite material with a gradient structure and a preparation method of the low-reflection high shielding electromagnetic shielding composite material. The low reflection and high shielding characteristics of the electromagnetic shielding material are achieved by controlling gradient distribution of different filler. Firstly, tetragonal acicular zinc oxide whisker nanoparticles with a special spatial structure and a wave-absorbing property are adopted as carriers, and a metal silver layer is deposited on the surface of the carriers by using a chemical deposition method so as to obtain tetragonal acicular zinc oxide whisker nanoparticles-loaded silver nanoparticles with excellent electrical conductivity and a special spatial structure; graphene-loaded Fe3O4 nanoparticles with balanced electrical conductivity and magnetic performance are prepared by using a co-precipitation method; and finally, blending and casting are performed on the two electrically conductive filler and water-soluble polyurethane which is adopted as a matrix so as to prepare the electromagnetic shielding composite material.

The invention relates to a method for preparing an RGD peptide targeted ultra-small ferriferrous oxide MRI positive nanoprobe. The method comprises the steps of: conducting a one-step solvothermal synthesis method to obtain surface sodium citrate stabilized ultra-small Fe3O4 nanoparticles, then modifying NH2-PEG-RGD to the nanoparticle surface to obtain the RGD targeted ultra-small ferriferrous oxide MRI positive molecular probe. The PEG-RGD modified ultra-small ferriferrous oxide nanoprobe has long cycle time in mice, and realizes targeting T1-weighted enhancement MRI on the surface of cancer cells with alphavbeta3 integrin high expression (U87MG cells, human brain glioma cells) and subcutaneously transplanted tumor on animal level and cellular level. The Fe3O4 nanoparticles prepared by the invention can be in stably dispersed in an aqueous solution for a long time, and do not agglomerate. The preparation method provided by the invention has the advantages of simpleness, low cost and potential in industrialization and commercialization.

The invention discloses a preparation method of a hollow Fe / Fe3O4@SiO2 nanostructure with adjustable wave-absorbing property. The preparation method comprises the following steps of: preparing 340-nanometer hollow Fe3O4 nanoparticles by a simple solvothermal method; performing ultrasonic treatment on Fe3O4 in hydrochloric acid, and separating and washing; dispersing the Fe3O4, which is treated with hydrochloric acid, into absolute ethanol and aqueous solution, adjusting the pH value to 10, dropwise adding ethyl orthosilicate step by step at room temperature, reacting while stirring, washing with distilled water and performing vacuum drying to obtain a Fe3O4 / SiO2 nanocomposite material with a core-shell structure; and heating the Fe3O4 / SiO2 composite material in a tube furnace to 723 K, reducing for 6 hours under heat insulating condition, and cooling to room temperature to obtain the hollow Fe / Fe3O4@SiO2 nanostructure with adjustable wave-absorbing property. Equipment required by the method is simple, easy to operate, suitable for industrial production and convenient to recover.

The invention discloses a polyethylene glycol modified magnetic nanoparticle and an application thereof. The method comprises the steps as follows: firstly, a solvothermal method is adopted to prepare the magnetic Fe3O4 nanoparticle; then, a layer of grafted copolymer dopamine / polyacrylic acid / polyethylene glycol (DA-PAA-PEG) is decorated on the surface of the magnetic Fe3O4 nanoparticle through chelation of hydroxide radicals and iron ions on dopamine so as to obtain a polyethylene glycol modified magnetic Fe3O4 nanoparticle (Fe3O4-DA-PAA-PEG); and finally, photosensitive molecules are loaded through the chelation of hydroxide radicals and iron ions on the photosensitive molecules to obtain the polyethylene glycol modified magnetic nanoparticle. The prepared polyethylene glycol modified magnetic nanoparticle has good water solubility and biocompatibility as well as excellent in-vivo magnetic targeting performance, and can generate singlet oxygen under the laser irradiation, so that cancer cells can be killed efficiently, and accordingly, the a polyethylene glycol modified magnetic nanoparticle can be applied to preparation of an in vivo fluorescence and magnetic resonance bimodal imaging developer and a photo-thermal therapeutic agent for treating cancers.

The invention provides a preparation method of an anode material Fe3O4 / MoS2 for a lithium ion battery. The preparation method comprises the following steps of; dispersing prepared MoS2 nanoparticles in a mixed solution of alkali and triethanolamine to obtain a mixed alkali liquid; respectively dissolving ferrous sulfate and ferric sulfate in an equal amount of deionized water according to a mole ratio of 4:3; respectively mixing half of the mixed alkali liquid with the ferrous sulfate solution and with the ferric sulfate solution; carrying out a reaction for 20 hours at a constant temperature of 100 DEG C after mixing; and centrifugally separating a black product, cleaning and drying to obtain the anode material Fe3O4 / MoS2 for the lithium ion battery. The prepared MoS2 layered structure is in in-situ composited in a Fe3O4 substrate, the theoretical capacity of the Fe3O4 is effectively improved with the addition of the MoS2, the volume change of a composite material during the charging and discharging circulation is effectively relieved with the combination of the Fe3O4 and the MoS2, the Fe3O4 nanoparticles are also effectively prevented from being agglomerated, and the electrochemical performance of the composite anode material is improved.

The invention provides a method for processing chromium-containing tanning wastewater by using a magnetic coagulation method. The method comprises the steps of: preparing Fe3O4 nanoparticles with superparamagnetism by using a chemical coprecipitation method; adding a coagulant, the Fe3O4 nanoparticles and a flocculant to the chromium-containing tanning wastewater and stirring; and putting the mixed wastewater in a magnetic field, and completing the separation of flocculate-containing tanning wastewater under the control of the magnetic field. The method has the advantages that the operation is convenient, the equipment is simple, and harmful substances, particularly heavy metal chromium, in the tanning wastewater can be effectively reduced; the disadvantages of the traditional chemical coagulation method are overcome, the amount of precipitated residues is greatly reduced, the precipitation time is obviously shortened, and the separation effect is obviously enhanced; and the method has broad application prospects in the industrial application field of heavy metal polluted wastewater treatment.

The invention relates to magnetic composite nanoparticles with a multilayer nuclear-shell structure and Fe3O4 nanoparticles being wrapped by triblock copolymer as well as the application of the magnetic nanoparticles which are taken as drug carriers. A first block of the triblock copolymer is methoxyl polyethylene glycol, a second block of the triblock copolymer is random copolymer of crylic acidand acrylic ester, or random copolymer of methacrylic acid and methacrylic acid ester; and a third block of the triblock copolymer is polyacrylic acid monoglyceride or polymethylacrylic acid monoglyceride, wherein the third-block polymer is combined with the surface of the Fe3O4 nanoparticles; drugs with amino groups or amido groups, such as amycin, can be loaded on a polyanion layer at the sub-outer layer of the composite nanoparticles; and the loaded drugs are not released under the neutral conditions and released when the pH value is below 5.5.

The invention relates to a preparation method of magnetic Fe3O4@SiO2-NH2 nanoparticles. The preparation method of the magnetic Fe3O4@SiO2-NH2 nanoparticles comprises the step of synthesizing of magnetic Fe3O4 nanoparticles, magnetic Fe3O4@SiO2 nanoparticles and the magnetic Fe3O4@SiO2-NH2 nanoparticles, wherein the magnetic Fe3O4 nanoparticles are spherical, even in particle size and good in dispersibility, the particle sizes of the magnetic Fe3O4 nanoparticles are 5-10 nm, and the heat stability is good. The magnetic Fe3O4@SiO2-NH2 nanoparticles are good in crystal structure, have unique magnetic property and can be used in various biotechnological fields such as magnetofluid, contrast agents, immunodetection, cell separation, biosensors, separation and purification of protein and nucleic acid, diagnostic reagents and enzyme immobilization.

The invention relates to the field of magnetic resonance contrast agents and nuclear magnetic resonance sensors and discloses ferroferric oxide-silicon dioxide-thymine nanoparticles which have water solubility, good monodispersity and superparamagnetism, and the average particle size is 10-20nm. The preparation method comprises the steps of preparing the Fe3O4 nanoparticles by high-temperature pyrolysis, wrapping silicon dioxide, connecting with amino groups, and further connecting with thymine. The nanoparticles can be used for preparing the magnetic resonance contrast agents and preparing the nuclear magnetic resonance sensors for detecting mercury ions.

The invention relates to a preparation method of a targeted MRI (magnetic resonance imaging) contrast medium based on folic acid modified iron oxide nanoparticles. The method comprises the following steps of: connecting FA to NH2-PEG-COOH to form COOH-PEG-FA; synthesizing PEI coated Fe3O4 nanoparticles (Fe3O4-PEI) by a hydrothermal method; performing surface modification on the Fe3O4-PEI nanoparticles by use of fluorescein isothiocyanate (FI); connecting COOH-PEG-FA to the surface of the Fe3O4 nanoparticles; and finally performing acetylation modification of the residual PEI aminos on the surface of the Fe3O4 nanoparticles to improve the biocompatibility for MRI diagnosis. The preparation method provided by the invention has simple technology and mild reaction conditions, and is easy to operate; and the prepared Fe3O4 magnetic nanoparticles have good colloidal stability, biocompatibility and tumor targeting performance as well as potential application value in the field of in-vivo tumor targeted diagnosis.

The invention discloses a preparation method and application of a magnetic modified sodium alginate flocculating agent. The preparation method comprises the following steps: grafting partially oxidized sodium alginate by using thiosemicarbazide, and performing reaction with Fe3O4 nanoparticles of which the surfaces are modified by amino groups to obtain a magnetic thiosemicarbazide-sodium alginate flocculating agent with a special effect. The method mainly comprises the following three reaction processes of (1) reacting the partially oxidized sodium alginate with the thiosemicarbazide to generate a Schiff base, and reacting the Schiff base with NaBH4 to generate stable amine; (2) preparing the magnetic Fe3O4 nanoparticles by using a co-precipitation method, and performing surface modification on the Fe3O4 nanoparticles by using gamma-aminopropyltriethoxysilane (KH-550); (3) reacting thiosemicarbazide-sodium alginate with the modified Fe3O4 nanoparticles to obtain the magnetic sodium alginate flocculating agent (ST-Fe) at room temperature in the presence of a catalyst EDC / NHS. The obtained product can be applied to sewage treatment and precious metal recovery, has the advantages of efficient adsorption, high sedimentation speed, simplicity in separation, low cost, biodegradability, no secondary pollution and the like, and has wide industrial application prospect.

The invention relates to a composite adsorption material applied to the fields of sewage treatment, environmental governance and the like, and in particular relates to a magnetic cellulose / graphene oxide composite adsorbent and a preparation method thereof. The magnetic cellulose / graphene oxide composite adsorbent is prepared by mixing cellulose, graphene oxide and Fe3O4 nanoparticles, and has the advantages of convenience in recycling after absorbing, simple equipment, low cost, easiness in industrialization and the like, thus being applied to the fields of sewage treatment, environmental governance and the like.

The invention discloses a boric acid type magnetic COFs (covalent organic frameworks) material, a preparation method and application. The boric acid type magnetic COFs material comprises nanoparticleswith core-shell structures, wherein a core is an Fe3O4 nanoparticle; a shell is COFs; the COFs are modified by boric acid groups, so as to obtain the boric acid type magnetic COFs material. The preparation method comprises the following steps of synthesizing the core-shell Fe3O4@TpBD(NO2)2 nanoparticle by a solvent thermal method via in situ growth, and modifying the function groups on a surfaceby a monomer containing phenylboronic acid groups, so as to obtain the novel boric acid type magnetic COFs material. The separation material has the characteristics that the adsorption capacity is high, and the stability and selectivity are good;material, can be used for the separation and enrichment and content analysis of a trace monoamine type neurotransmitter substance in urine, the interference of a complicated matrix can be eliminated, and the separation and enrichment efficiency is improved.

The invention discloses a preparation method of a Ag / Fe3O4 / nano-cellulose tri-element composite material. Nano-cellulose is used in the preparation method and plays a role as a reducing agent, and improving of binding strength between Ag and Fe3O4 nanoparticles is facilitated. The preparation method is environment-friendly, pollution-free and high in reaction selectivity and reaction efficiency; water is used as a solvent, so that the preparation method is wide in raw material source and low in cost, and production cost is lowered. The Ag / Fe3O4 / nano-cellulose tri-element composite material can be prepared through a hydrothermal method and a microwave hydrothermal method, so that industrialization is facilitated.