CHARACTERIZATION OF HYDROXYAPATITE-ALUMINA-ZIRCONIA BIOCOMPOSITES PREPARED FROM BIOWASTES (CLAM SHELLS)
Abstract
- Clam shells are the rich source of calcium carbonate. Calcium carbonates of clam shells are converted to hydroxyapatite (HA) by wet precipitation method, and hydroxyapatite was successfully prepared from clam shells by wet precipitation method using Ca (NO3)2, (NH4)2HPO4, and NH4OH as starting materials. All of the carbonate phases in shells were decomposed to calcium oxide at 900 ºC after 6 h heating. The calcined calcium oxide were then treated with nitric acid and crystalized to form Ca (NO3)2.4H2O. To prepare HA powder, (NH4)2HPO4 and prepared Ca (NO3)2.4H2O in ammoniacal media was kept to Ca/P stoichiometry ratio of 1.67 to produce hydroxyapatite (HA). The prepared HA powder before sintering was characterized by EDXRF, XRD, FT IR and SEM. The nano crystalline alumina and commercial zirconia were then mixed with the prepared HA in acetone medium by wet mixing method in different ratios. The prepared HA from clam shells (30 %), Alumina (10 %) and Zirconia (60 %) was designated as CC 1 and the prepared HA from clam shell (30 %), Alumina (60 %) and Zirconia (10 %) was designated as CC 2, respectively. The prepared HA-Alumina-Zirconia biocomposites were characterized by EDXRF, XRD, FT IR, SEM and TEM. From EDXRF analyses, it was observed that CC 1 had the higher relative abundance of zirconium than CC 2. According to XRD analyses, CC 1 is smaller in average crystallite sizes compared to CC 2. Phase analyses were also carried out by XRD analysis. According to these analyses content percent of phase in CC 2 was matched with initial ratio of composition but it was found that CC 1 had Aluminium phase deficiency. Based on the SEM analyses, more agglomerate features were observed in CC 1 than those in CC 2. From transmission electron microscope (TEM), biocomposite in 3: 1: 6 w/w ratio of HA: alumina: zirconia was found to be nano scale 20 nm. CC-2 biocomposite was chosen for further study.
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Year
- 2019
Author
-
Minn Saw Khine
Subject
- Chemistry
Publisher
- Myanmar Academy of Arts and Science (MAAS)