AMIRA Mokrane
مقران أميرة
amira.mokrane@univ-msila.dz
0552376251
- Departement of Physics
- Faculty of Sciences
- Grade PHd
About Me
Sciences de la Matière
Filiere
Physique
Applied Physics
Location
Msila, Msila
Msila, ALGERIA
Code RFIDE- 1992-08-02 00:00:00
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AMIRA Mokrane birthday
- 2025-11-20
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2025-11-20
Effect of temperature on hydroxyapatite prepared by the sol-gel technique for Ca/P ratio = 1.67
This study investigates the impact of high-temperature treatment on the stability of hydroxyapatite (HA) synthesized via the sol-gel method, with a particular focus on a calcium-to-phosphorus (Ca/P) ratio of 1.67. Hydroxyapatite (HA), with the chemical formula Ca₁₀(PO₄)₆(OH)₂, is a vital biomaterial widely used in dental and orthopedic applications due to its close resemblance to the mineral composition of bones and teeth. The sol-gel technique is an effective method for synthesizing hydroxyapatite, as it allows the production of high-purity nanomaterials with uniform particle size distribution. The ideal molar Ca/P ratio of 1.67 in pure hydroxyapatite is crucial for achieving the desired biological properties. Hydroxyapatite (HA) was synthesized using triethyl phosphate (TEP) as the phosphorus precursor and calcium nitrate tetrahydrate as the calcium precursor. A mixture of ethanol and distilled water was used as the solvent. The prepared solution was aged in a closed Teflon container at 90°C for one day. After aging, the gel was allowed to dry for another day. Once dried, all the gels were calcined at 700°C for one hour. Finally, the samples were heat-treated at temperatures of 1100°C, 1200°C, and 1300°C. The structural evolution of the synthesized phases was analyzed using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). The XRD patterns revealed that hydroxyapatite (HA) was the primary phase present in all samples, accompanied by calcium oxide (CaO) as a secondary phase. As the temperature increased, the intensity of the HA peaks increased, while the intensity of the CaO peaks decreased. The FT-IR spectra confirmed the presence of phosphate (PO₄³⁻) groups in all samples, with variations in the intensity and width of the absorption bands, further supporting the XRD findings. Keywords:hydroxyapatite, TEP, sol-gel, CaO.
Citation
Fatima Zohra MEZAHI , Amira Mokrane , MENAD Heraiz , ,(2025-11-20), Effect of temperature on hydroxyapatite prepared by the sol-gel technique for Ca/P ratio = 1.67,2nd National Conference on Physics and its Applications (NCPA'25),Bou-saada
- 2025-11-09
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2025-11-09
Synthesis of hydroxyapatite nanostructures by the sol-gel method: Exploring the effect of Ca/P ratio on physicochemical properties
Synthetic hydroxyapatite (HA) has emerged as a key biomaterial in recent years due to its biocompatibility, bioactivity, and osteoconductivity [1][2]. With a chemical composition of Ca₅(PO₄)₃OH, which closely resembles that of natural bone [3][4], HA effectively bonds with bone tissue and supports regenera-tion, making it widely used in bone grafts, implant coatings, and var-ious medical applications. Its properties are strongly influenced by the calcium to phosphorus (Ca/P) ratio [5][6][7]. This study focuses on synthesizing hydroxyapatite using the sol-gel method with vary-ing Ca/P ratios (1.67, 1.5, 1.45, and 1.4). Triethyl phosphate and cal-cium nitrate tetrahydrate were used as precursors, with ethanol and distilled water serving as solvents. The solutions were aged in a Tef-lon container at 90 °C for one day, followed by one day each for gel-ling and drying. The dried gels were then calcined at 700 °C for one hour. Structural changes in the resulting phases were analyzed using X-ray diffraction (XRD), infrared spectroscopy (FT-IR), and thermal analysis (TG-DSC). XRD analysis revealed two phases in all samples: hydroxyapatite (HA) as the primary phase and calcium oxide (CaO) as a secondary phase. As the Ca/P ratio decreased, the intensity of the CaO peaks also reduced, while the intensity of the HA peaks weakened. In samples with a Ca/P ratio below 1.67, tricalcium phosphate appeared as an additional secondary phase. FT-IR spectra at 700 °C confirmed the presence of phosphate groups, with absorption bands becoming narrower and more intense as the Ca/P ratio increased, consistent with the XRD results. TG-DSC analysis showed a 15% weight loss from 100–200 °C due to the evaporation of water and ethanol, followed by a 35% loss from 200–330 °C due to the combustion of organic components. An exothermic peak observed after 350 °C indicated the crystallization of hydroxyapatite. These findings confirm the material's thermal stability, in alignment with XRD data, and demonstrate that the Ca/P ratio significantly influences the hydroxyapatite content in the synthesized powders.
Citation
Fatima Zohra MEZAHI , Amira Mokrane , MENAD Heraiz , ,(2025-11-09), Synthesis of hydroxyapatite nanostructures by the sol-gel method: Exploring the effect of Ca/P ratio on physicochemical properties,5th International Conference on Mechanics and Materials, ICMM’25,Setif
- 2025-10-29
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2025-10-29
Evaluation of the stability of hydroxyapatite (Ca/P = 1.5) derived from sol-gel at different thermal conditions
This study investigates the high-temperature phase stability of non-stoichiometric hydroxyapatite (HA) with a Ca/P ratio of 1.5 synthesized via the sol-gel method. HA is a significant biomaterial due to its structural similarity to natural bone mineral, and the sol-gel technique was employed for its ability to produce high-purity nanocrystalline powders with uniform morphology. The HA powder was synthesized using triethyl phosphate and calcium nitrate tetrahydrate as precursors in an ethanol-water solvent system. The solution was aged at 90 °C for 24 hours, followed by drying and calcination at 700 °C. Subsequent thermal treatments were conducted at 1100 °C, 1200 °C, and 1300 °C to examine phase stability. Structural evolution was characterized using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). XRD results identified hydroxyapatite as the primary phase in all samples, accompanied by minor phases of calcium oxide (CaO) and β-tricalcium phosphate (β-TCP). As the temperature increased to 1100 °C, the proportion of β-TCP decreased due to its transformation into HA. At higher temperatures (1200 °C and 1300 °C), β-TCP completely disappeared and α-TCP emerged, indicating a phase transition from β to α modification. A consistent increase in HA crystallinity accompanied this transformation. FT-IR analysis confirmed the presence of phosphate (PO₄³⁻) groups in all samples, with spectral variations in intensity and bandwidth supporting the XRD findings regarding structural changes induced by thermal treatment. In summary, the research demonstrates that elevated temperatures promote the conversion of β-TCP to hydroxyapatite up to 1100 °C, while higher temperatures induce a phase transition to α-TCP. These findings provide valuable insights for optimizing the thermal processing of non-stoichiometric HA for biomedical applications.
Citation
Fatima Zohra MEZAHI , Amira Mokrane , MENAD Heraiz , ,(2025-10-29), Evaluation of the stability of hydroxyapatite (Ca/P = 1.5) derived from sol-gel at different thermal conditions,1st National Seminar on Structural Mechanics and Materials (SNMSM’25),M'sila
- 2025-10-21
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2025-10-21
Thermal stability of sol-gel derived hydroxyapatite for Ca/P molar ratio 1.67 and 1.5
Hydroxyapatite (HA: Ca10(PO4)3(OH)2) is a crucial mineral component of bones and teeth 1. It is widely used in biomedical applications due to its excellent biocompatibility 2. Their physical, chemical, and biological properties are significantly influenced by the synthesis parameters, including the initial (Ca/P) ratio and the calcination temperature 3. So, this study investigates the impact of heat treatment on stability of HA, synthesized via the sol-gel method. Two different (Ca/P) molar ratios (1.67 and 1.5) were chosen. HA was synthesized using triethyl phosphate and calcium nitrate tetrahydrate. A mixture of ethanol and distilled water was employed as the solvent. The aging, gelling, and drying process occurred at 90°C for one day. The dried gels were calcined at 700°C for one hour. The samples were then heat-treated at 1100°C, 1200°C, and 1300°C. The structural evolution of the synthesized phases was analyzed using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). XRD patterns indicated HA formation in all samples, along with CaO. Additionally, β-tricalcium phosphate (β-TCP) was observed as a secondary phase in the sample with (Ca/P) ratio of 1.5. At 1100°C, an increase in the intensity of HA peak was remarked, along with a decrease in the intensities of CaO and β-TCP. At 1200°C and 1300°C, β-TCP completely disappeared, and α-TCP emerged, indicating a phase transition from β-TCP to α-TCP. FT-IR spectra confirmed the XRD findings. The formation of biphasic calcium phosphate composites (HA and TCP) enhance the biological activity of these composites and ensure their mechanical stability [4].
Citation
Fatima Zohra MEZAHI , Amira Mokrane , MENAD Heraiz , ,(2025-10-21), Thermal stability of sol-gel derived hydroxyapatite for Ca/P molar ratio 1.67 and 1.5,1st International Hybrid Seminar: Green Chemistry and Artificial Intelligence: Towards Molecular Design,M'sila
- 2024-07-04
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2024-07-04
Structural alterations of sol-gel derived hydroxyapatite versus the volume of ethanol
The aim of this work is to study the effect of the volume of ethanol on the synthesis of hydroxyapatite by sol-gel route. Hydroxyapatite with the chemical formula (Ca5(PO4)3OH) is one of the important biomaterials because of its chemical structure close to the mineral structure of bone and its important biological properties that enable it to be used in medical application as bone replacement 1,2,3. Hydroxyapatite is very used in clinical field as orthopaedic and dental implants as bioactive (high density) and resorbable (porous HA) materials. The bioactive materials form a direct biochemical bonds with living tissues 4-6. This work is to study the effect of solvent type for the preparation of hydroxyapatite (ethanol and or distilled water ) by sol-gel, using triethyl phosphate ((PO(OC2H5)3): TEP) and calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) as phosphor and calcium precursors, respectively. A mixture of distilled water and pure ethanol with different volumes were used as solvent with total volume of 40 ml. Each prepared solution was aged in closed Teflon container at a temperature of 90 °C for one day except one sample was aged for two days. The gelling and drying time was 1 day for each process. All dried gels were calcined at 700 °C for one hour. Different analyses were used in order to follow the structural alterations of formed phases with type of solvent, such as: X- ray diffraction (XRD, Infrared spectroscopy, Raman and the dielectric analyses. X-ray patterns of the prepared samples showed the formation of two phases: HA as a main phase and CaO as second phase for all samples. It was observed that the peak intensity of the CaO increases when the amount of water decreases and the intensity of the HA peaks decreases only for the sample DW5ETH35_1D which was prepared in solvent composed of mixture of 5 ml distilled water and 35 ml ethanol . For this sample, the peak intensity of CaO decreases and the intensity of the HA peaks intensity increases. For the sample aged for 2 days, it was observed the formation of - tricalcium phase as secondary phase. The FT-IR spectra of HA samples at 700 C confirms the presence of phosphate(PO-34) in all spectra, but there is a difference in the intensity and width of the absorption band, It gets narrower as the amount of water decreases, This is confirmed by the results of the X-ray. Also, the dielectric properties were measured in order to compare between the prepared samples. The obtained results showed that the volume of ethanol affect the ratio of HA in the prepared powders.
Citation
Fatima Zohra MEZAHI , Amira Mokrane , ,(2024-07-04), Structural alterations of sol-gel derived hydroxyapatite versus the volume of ethanol,7th International Conference on Smart Materials and Spectroscopy (SMS’2024),Monastir, Tunisie