Study On Preparation And Adsorption Of Carbonate Hydroxyapatite

Carbonate hydroxylapatite (CHAP) is a new substitution of hydroxyapatitep (HAP), having the same particular crystal chemistry characteristics. CHAP has better surface properties and ion exchange and adsorption properties than HAP. CHAP has satisfactory treatment effects on heavy metal ions wastewater and organic wastewater by means of multi-sorption.In this dissertation, CHAP was synthesized utilizing the eggshells as material and urea as sintering additive using dynamic hydrothermal synthesis. The ratio of Ca to P and IR of CHAP sample were analyzed. The experimental results indicated that the ratio of Ca to P of CHAP was 2.06, a little higher than the theoretical value 1.67. The IR illustration clearly showed the PO43- and CO32- and OH- wave crest.The adsorption of Pb²⁺,Cd²⁺,Cu²⁺,Zn²⁺ from simulated wastewater and treatment of organic wastewater used the synthesized CHAP were studied emphatically. The affecting factors that might influence the adsorption performance were investigated, such as pH, adsorption period, reaction temperature, the dosage of CHAP and the initial concentration of wastewater, and their adsorption mecha nism preliminary analyzed in theory. The experimental results showed that the removal efficiency of chroma and CODcr of organic wastewater reached to 80% using 18mgCHAP per liter wastewater under the followed reaction conditions: pH was 6, adsorption period was 60 min, and normal temperature, the initial values of chroma and CODcr were 250 and 1610 mg/L of wastewater. The removal efficiencies of adsorbing heavy metal ions such as Pb²⁺,Cd²⁺,Cu²⁺,Zn²⁺ form wastewater by CHAP is more marked, all of them were reached up to 98%. The optimum conditions of adsorbing above-mentioned heavy metal ions using CHAP were: the removal efficiency of Pb²⁺ dosing 0.6g/L CHAP could reach up to 99.90% when the initial concentration of Pb²⁺ in wastewater was 750mg/L,pH value was 6, the adsorption period was 35min and the reaction temperature was 35℃; the removal efficiency of Cd²⁺ dosing 1g/L CHAP could reach up to 99.90% when the initial concentration of Cd²⁺ in wastewater was 30mg/L,pH value was 3.5, the adsorption period was 30min and the reaction temperature was 35℃; the removal efficiency of Cu²⁺ by 5g/L CHAP could reach up to 99.30% when the initial concentration of Cu²⁺ in wastewater was 60mg/L,pH value was 6, the adsorption period was 60min and the reaction temperature was 35℃; the removal efficiency of Zn²⁺ dosing 3g/L CHAP could reach up to 98.75% when the initial concentration of Zn²⁺ in wastewater was 50mg/L,pH value was 3.5, the adsorption period was 60min and the reaction temperature was 35℃. Both Freundlich and Langmuir equation could simulate all the adsorption processes. According to the thermodynamic and the kinetic equation, it could be concluded that the...