Study On Hydroxyapatite-urea Complex Preparation And Slow-release Characteristic

In this paper, we use the prepared hydroxyapatite as carrier to makehydroxyapatite-urea slow-released fertilizer, characterized by X-raydiffraction, Fourier transform infrared, scanning electron microscopy andother means. And the slow-release characteristics of the preparedcomposites are evaluated by water dissolution, sand column leaching andsoil column leaching method.Firstly, we compose hydroxyapatite by chemical precipitation, establishurea detection method, and complete the methodological study to lay thefoundation for the next step of detection of nitrogen in the complexes. Withurea as a slow-release characteristics, we prepare hydroxyapatite-fertilizer complexes by two methods of adsorption and in-situ synthesis andcharacterize the complexes by scanning electron microscopy (SEM),infrared spectroscopy (FTIR), X-ray diffraction (XRD). And we optimizein-situ synthesis method by using response surface method to draw thebest preparation conditions.Secondly, we inspect the prepared complexes with encapsulationefficiency, drug loading and nutrient release rate as indexes.Finally, we conduct simulation experiment for the prepared complexesunder laboratory conditions by using the methods of water dissolution, sandcolumn leaching and soil column leaching method to study thecontrolled-release characteristics of the HAP-urea complex.