Preparation And Characterization Of The Composites Of Mesoporous Hydroxyapatite And Carbon Quantum Dots

Mesoporous hydroxyapatite its special structure and excellent biological performance shows broad application prospects in all aspects of the drug carrier, catalyst and catalyst carrier. Carbon quantum dots(CQDs) is a new type of zero-dimensional carbon nano fluorescent material. Although the absorption in the visible region is weak, CQDs, rear surface modification can achieve strong fluorescence emission and absorption under different wavelengths of sunlight, but also as an electron acceptor or donor to produce light-induced electron transfer. It is a good photocatalytic material. However, carbon quantum dots easy reunion, its performance depends on structural defects, size and surface states and so on.Based on this, This article innovatively having pore structure, high specific surface area and green mesoporous hydroxyapatite composite with modified carbon quantum dots, expanding the following research:1.Mesoporous Hydroxyapatite: Hydrothermal prepared mesoporous hydroxyapatite, a systematic study of the factors that affect the pore size distribution, there is a source of calcium and phosphate sources, the order of dropping, the template and the approach of removing template. By XRD, N2 adsorption- desorption, IR and TEM characterizations,showing calcining HA by CTAB mixed with Na2HPO4 solution dropwise to CaCl2 is most suitable pore structure compositing with CQDs.Carbon Quantum Dots: carbon quantum dots through N and Cl radicals modifing, their fluorescence and photocatalytic tests found that carbon quantum dots N-containing group light emitting is the strongest, carbon quantum dots containing Cl groups photocatalytic is highest efficiency, directing group is mainly due to the photoluminescence and photocatalytic performance.2.The Mesoporous Hydroxyapatite(MHA) and amine-functionalized carbon dots(N-CDs) were combined by ionic bonding under the chemical reaction, resulting in a new composite, i.e. MHA/N-CDs. XRD, IR-spectra and HRTEM revealed that N-CDs were successfully coupled with MHA. The results of Nitrogen adsorption-desorption and TEM suggested that the mesopore size of MHA was about 5 nm. Meanwhile, a certain amount of macropores existed. More importantly, the high photocatalytic activity of the MHA/N-CDs composite was observed upon the degradation of methylene blue(MB) under visible-light irradiation, which was almost two times of N-CDs. Studying on the factors of composite influencing the photocatalytic effect, like the composite manner, the proportion of composites,surface modification group of CDs, pH value of solution and structure of dye.3.Preparing fluorescence hydroxyapatite by hydrothermal, I have studied its luminescent mechanism and metal ion detection performance. The results show that the emission reason of fluorescence hydroxyapatite is hydroxyapatite hydrothermal reaction process adding citrate which generated fluorescent carbon quantum dots; fluorescent hydroxyapatite can detect metal ions Hg and Pb. The fluorescence of hydroxyapatite have potential applications in terms of detection of metal ions.