Preparation method of silica-coated iron oxide nano-core-shell structural material

Abstract

A preparation method of silica-coated iron oxide nano-core-shell structural material includes: dissolving molysite, acetic acid and polyvinylpyrrolidone in ethanol, and mixing well; moving the solution into a polytetrafluoroethylene reactor, allowing the solution to react at the heating temperature of 160-220 DEG C for 3-48 hours and under the mixing speed of 10-100rpm, and obtaining 0.1-8g / L iron oxide nanoparticle suspension; and adding the ethanol and deionized water into the suspension, allowing the volume ratio of the ethanol to water in the suspension system to be 0.5-10 / 1, adjusting pH value to be 7-12, allowing the mass ratio of tetraethoxysilane to iron oxide nanoparticles to be 1:1-40, slowly adding the tetraethoxysilane under mixing, allowing the mixture to react for 12-70 hours, performing filtering and drying, and calcining at 400-600 DEG C to obtain the silica-coated iron oxide nano-core-shell structural material, wherein the molar concentration of the molysite in solution is 0.01-0.1mol / L, the volume ratio of the acetic acid to the ethanol is 0.002-1:1, and the mass concentration of the polyvinylpyrrolidone in the solution is 1.5-20g / L. The preparation method has the advantages that synthetic process is simple, cost is low, operation is simple, and amplification and synthesis are easy.

Description

Technical field [0001] The invention relates to a preparation method of a silicon dioxide-coated iron oxide nano core-shell structure material. Background technique [0002] Nano-iron oxide is a cheap and environmentally friendly transition metal oxide. Its nano-structured particles have good weather resistance, light resistance, magnetism, and good absorption and shielding effects on ultraviolet rays. It can be widely used in pigments, electronics, high Magnetic recording materials, sensors and catalysts also have good application prospects in the fields of bioengineering and drug release. However, due to the small size and large specific surface area of ​​nanoparticles, the shortcomings of easy agglomeration and instability after separation from the preparation system limit the application of nanoparticles. Silica has good biocompatibility and resistance to decomposition. The surface of iron oxide is coated with a layer of silica to form a core-shell structured nanomaterial no...

AI Technical Summary

Problems solved by technology

However, due to the small size of nanoparticles and large specific surface area, the disadvantages of easy aggregation and instability after separation from the preparation system limit the application of nanoparticles. Silica has good biocompatibility and anti-decomposition ability. Nanomaterials with a core-shell structure coated with a layer of silicon dioxide on the surface of iron oxide are not only conducive to the dispersion and stability of iron oxide nanomaterials, but also improve their biocompatibility. The further functionalization of core-shell composite particles has made them widely used in drug controlled release, biological targeting materials, environmental sewage treatment and iron-based catalyst stabilization, and has attracted widespread attention and has become one of the research hotspots in the preparation of new materials. one

[0003] The surface coating methods of nanoparticles mainly include sol-gel method, microemulsion method, aerosol thermal decomposition method, etc. Among these methods, the sol-gel method has the characteristics of large reaction interval, short time and high yield, and is quite popular At present, a considerable part of the related reports on the surface of iron oxide nanoparticles coated with silicon dioxide have obtained composite particle structures that are not ideal. The synthesized core-shell structure has irregular morphology, poor controllability, and core agglomeration. More serious; the operation process is complicated, for example, the patent CN1477082A "method for preparing ferrite-silica core-shell nanoparticles by ultrasonic treatment" requires steps such as ultrasonic treatment of iron oxide nanoparticles, and the serious agglomeration of the core leads to irregular morphology; the process High cost, difficult to scale up production, etc., which all affect the advancement of the later practical process

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