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Adsorption of citrate ions on hydroxyapatite synthetized by various methods.

Skwarek E, Janusz W, Sternik D - J Radioanal Nucl Chem (2013)

Bottom Line: The physical properties of the resulting powder were characterized by DTA/TG, XRD, AFM and SEM microscopy.The point of zero charge and the isoelectric point of samples were determined.The points pHpzc and pHIEP for sample 1 are pHpzc 7.5 and pHIEP 3; for sample 2 pHpzc 7.05 and pHIEP 3, for smaple 3 pHpzc 6.7 and pHIEP 3.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Chemistry, Maria Curie-Sklodowska University, Maria Curie-Sklodowska Sq. 5, 20-031 Lublin, Poland.

ABSTRACT

The specific adsorption of citric acid ions at hydroxyapatite interface was investigated by the means of radioisotope method ((14)C) as a function of citric acid ions concentration, NaCl concentration and pH. Application of the hydroxyapatite has become wide in the biomaterial field as the Ca10(OH)2(PO4)6 possess biocompatibility with human hard tissue. Hydroxyapatite was synthesized using three different methods. The physical properties of the resulting powder were characterized by DTA/TG, XRD, AFM and SEM microscopy. Physicochemical qualities characterizing the electrical double layer of the hydroxyapatite/NaCl solution interface were determined. The zeta potential and the adsorption of citric acid molecule were studied as a function of pH. The point of zero charge and the isoelectric point of samples were determined. Electrical double layer parameters of hydroxyapatite/NaCl interface are influenced by a synthesis method. The points pHpzc and pHIEP for sample 1 are pHpzc 7.5 and pHIEP 3; for sample 2 pHpzc 7.05 and pHIEP 3, for smaple 3 pHpzc 6.7 and pHIEP 3. Temperature has weak influence both on pure substance and with citric acid adsorbed, as derivatographic analysis has shown, and characterization of hydroxyapatite structure may be carried out by this thermal analysis. Two phenomena are responsible for citric acid adsorption: phosphate group's replacement at hydroxyapatite surface by citric ions parallel to intraspherical complexes formation.

No MeSH data available.


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AFM micrograph of hydroxyapatite samples 1 (a), 2(b), 3(c)
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Fig1: AFM micrograph of hydroxyapatite samples 1 (a), 2(b), 3(c)

Mentions: Figure 1 shows the AFM micrographs of several hydroxyapatite samples 1, 2, and 3. The examination with an AFM microscope confirms the porosity of the synthesized hydroxyapatites samples of surface. At the pictures you can see the structures built from little crystals with visible pores. Topographic analysis of the hydroxyapatite samples shows that the surface of sample 2 is rougher, the average roughness index is 44 whereas for sample 1 it is 30.4 and for sample 3–21.28. The average roughness for sample 2 is 172 nm, for sample 1-149 nm and for sample 3–142 nm. Sample 2 exhibited the formation of whisker morphologies.Fig. 1


Adsorption of citrate ions on hydroxyapatite synthetized by various methods.

Skwarek E, Janusz W, Sternik D - J Radioanal Nucl Chem (2013)

AFM micrograph of hydroxyapatite samples 1 (a), 2(b), 3(c)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4514589&req=5

Fig1: AFM micrograph of hydroxyapatite samples 1 (a), 2(b), 3(c)
Mentions: Figure 1 shows the AFM micrographs of several hydroxyapatite samples 1, 2, and 3. The examination with an AFM microscope confirms the porosity of the synthesized hydroxyapatites samples of surface. At the pictures you can see the structures built from little crystals with visible pores. Topographic analysis of the hydroxyapatite samples shows that the surface of sample 2 is rougher, the average roughness index is 44 whereas for sample 1 it is 30.4 and for sample 3–21.28. The average roughness for sample 2 is 172 nm, for sample 1-149 nm and for sample 3–142 nm. Sample 2 exhibited the formation of whisker morphologies.Fig. 1

Bottom Line: The physical properties of the resulting powder were characterized by DTA/TG, XRD, AFM and SEM microscopy.The point of zero charge and the isoelectric point of samples were determined.The points pHpzc and pHIEP for sample 1 are pHpzc 7.5 and pHIEP 3; for sample 2 pHpzc 7.05 and pHIEP 3, for smaple 3 pHpzc 6.7 and pHIEP 3.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Chemistry, Maria Curie-Sklodowska University, Maria Curie-Sklodowska Sq. 5, 20-031 Lublin, Poland.

ABSTRACT

The specific adsorption of citric acid ions at hydroxyapatite interface was investigated by the means of radioisotope method ((14)C) as a function of citric acid ions concentration, NaCl concentration and pH. Application of the hydroxyapatite has become wide in the biomaterial field as the Ca10(OH)2(PO4)6 possess biocompatibility with human hard tissue. Hydroxyapatite was synthesized using three different methods. The physical properties of the resulting powder were characterized by DTA/TG, XRD, AFM and SEM microscopy. Physicochemical qualities characterizing the electrical double layer of the hydroxyapatite/NaCl solution interface were determined. The zeta potential and the adsorption of citric acid molecule were studied as a function of pH. The point of zero charge and the isoelectric point of samples were determined. Electrical double layer parameters of hydroxyapatite/NaCl interface are influenced by a synthesis method. The points pHpzc and pHIEP for sample 1 are pHpzc 7.5 and pHIEP 3; for sample 2 pHpzc 7.05 and pHIEP 3, for smaple 3 pHpzc 6.7 and pHIEP 3. Temperature has weak influence both on pure substance and with citric acid adsorbed, as derivatographic analysis has shown, and characterization of hydroxyapatite structure may be carried out by this thermal analysis. Two phenomena are responsible for citric acid adsorption: phosphate group's replacement at hydroxyapatite surface by citric ions parallel to intraspherical complexes formation.

No MeSH data available.


Related in: MedlinePlus