Study On Preparation And Properties Of 3D And 1D Micro/Nanostructures Of Hydroxyapatite

Hydroxyapatite,as the main component of vertebrate bones and teeth,has good biocompatibility,biological activity and adsorption properties.Therefore,hydroxyapatite has been widely used in bone filling repair materials and adsorbents of heavy metal ions and organic pollutants in recent years.In this paper,three-dimensional and one-dimensional micro/nano structure hydroxyapatite were prepared by hydrothermal method using four water calcium nitrate and diammonium hydrogen phosphate as calcium source and phosphorus source.The influence of the complexing agent,precipitant,the pH value,the concentration of different reactant and the concentration of urea on the morphology and composition of the three and one dimensional micro/nano hydroxyapatite were studied.Scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,X ray diffraction?XRD?,adsorption desorption of N₂,thermogravimetry?TG?and infrared spectroscopy?FTIR?were used to characterize and test the morphology,phase composition and specific surface area of the products.Hydroxyapatite with three dimensional micro/nano structure can be successfully prepared by hydrothermal method with the mixture of ethylenediamine tetra acetic acid disodium salt?EDTA-2Na?as complexing agent and urea as precipitant.With the extension of time,hydroxyapatite changed from the hollow"flower like"structure to"Dandelion"shape,and its specific surface area gradually decreased.When the reaction time is 30 min,the prepared product has a hollow structure with a specific surface area of 52.98 m²/g.The drug loading and releasing experiment was carried out with the model of adriamycin hydrochloride?DOX?as the drug model and the three-dimensional hollow structure hydroxyapatite prepared by the time of hydrothermal reaction of 30 min.The experimental results showed that the hydroxyapatite with three-dimensional hollow structure showed high load rate and prolonged slow release performance.The load rate could reach 47%and the release time could reach 100 h.In the absence of organic templates and organic solvents,one dimensional micro/nano structure?micro/nano-fiber?with super long and flexible hydroxyapatite has been successfully prepared by one step hydrothermal synthesis method.When the pH value of the initial solution is 3.95,the concentration of urea is 1.0 mol/L,the temperature of the hydrothermal reaction is 180?,and the nitric acid is used as the pH regulator,the prepared hydroxyapatite micro/nanoscale length can reach 100?m,the thickness is between 0.01⁰.1?m,with a higher ratio of length to diameter and better flexibility.Hydroxylapatite and cellulose composite paper can be prepared by mixing one dimensional hydroxyapatite micro/nano-fiber material and broad-leaved wood cellulose slurry.The composite paper has good flexibility,can be repeated many times,and has good adsorption properties.When using composite paper to adsorb organic pollutants,acidic lake blue A,the adsorption rate is as high as 91.9%.