THE SYNTHESIS AND PHYSICOCHEMICAL CHARACTERIZATION OF HYDROXYAPATITE (HAP) FROM LOCAL DUCK EGG SHELLS

Hydroxyapatite (HAp) Biocheramics was the main component of remineralisation agent to the hard tissues; it is commonly synthesized from compounds rich with calcium. One of the compounds recommended as a HAp source was eggshells. This study aimed to synthesize the HAp from local duck eggshells containing Calcium 0,8631 ± 0,0015g/g and Phosphor 0,3118 ± 0,0016g/g. The synthesis process of HAp by Base Precipitation methods showed rendement 85,06 ± 1,0135%. The Physicochemical characterization to the HAp showed the Calcium contains 0,4760 ± 0,0027g/g; Phosphor 0,0897 ± 0,0023g/g; Porosity 82,0106 ± 0,4484%; Biodegradability 5,3506 ± 0,0295%; and Swelling ability 5,7678 ± 0,1897%. The results concluded that the local duck egg shells were recommended as HAp sources. Based on characterisation results, the HAp made from it was potentially applied as a remineralization agent. Keyword: Bioceramics, Hydroxyapatite, Remineralisation agent, Local Duck Egg Shells.


INTRODUCTION
Hydroxyapatite bioceramic (HAp) is a type of apatite bioceramic that can be synthesized from calcium-rich compounds such as egg shells [1][2][3][4][5]. The HAp is potentially used as a remineralization agent for the hard tissues because it has a similar structure to the calcium complex that builds the bone and teeth [3][4][5]. The HAp has the chemical name [Ca10(PO4)6(OH)2] [3][4][5][6], also known as Calcium Hydroxyphosphate in trade name [2][3][4]. The research before a report that the HAp is used as a Bone Implant, Bone Graft, and Bone Filer to reparate and remineralization the damaged hard tissues in the human body [2,4] and replace the use of metallic pens (made from steel, iron, cobalt, titanium and platinat) because the metallic pen also caused the bad side effect to the human body [6,7]. In Indonesia, the main materials used to produce Biomaterials, including HAp still imported from abroad [1,7,8]. However, on another side, Indonesia has many raw materials for synthetic and production HAp [9,10], like limestones, animal bones (waste animals bones from markets), and Molluscan shells (snails and clams) from marine and lacustrine [1][2][3][4]. Those raw materials can be synthesized to produce HAp because it is rich in Calcium (Ca) and Phosphorus (P) contains [2,3] the main minerals that build HAp crystal structure [1][2][3]. Indonesia is one of the countries with the higher number of fractures in Asia [7,8];. At the same time, the bone donations (donors and stock) are very limited at once [7][8][9][10], then necessary need to produce the reparating (synthetic) compounds similar to the bone structure like HAp [9,10].
One of the raw materials suitable for becoming raw materials of the HAp synthetic process was the (waste) eggshells [9,10].
The eggshells were predicted to have minerals Ca and P contained in equal positions with another raw material (Molluscan shells, animal bones and limestones) recommended as main compounds in HAp synthetic process [1,4,9,10], but commonly used in HAp synthetic was the Chicken eggshells [9,10] not Duck eggshells [11]. Commonly in Indonesia, eggshells are just applied in simple ways, even potentially applied in advance [12]. The standard and most straightforward applications of the (waste) eggshells in Indonesia nowadays are using it as fertilizer for farming [13][14][15][16]. Especially in Salatiga city, those (waste) eggshells, including Duck eggshells, are easy to find in markets, traditional markets, cake shops, and restaurants and are commonly not used anymore than can be collected in large amounts at low prices, even free of the coast [11,17]

Time and Place
The research was treated from June

Research Instruments
The

Preparation of Eggshells
The eggshells were boiled and washed using water, and Hydrogen peroxide was then separated from the protein fiber inside; after being washed, the eggshells dried at 55 o C in the oven for 24 hours. After dried, the eggshells were crushed into powder form [11,[17][18][19].
The results of synthesis and characterization showed in Table 2.   Table 3. The FTIR Scatter of the eggshell and its HAp showed differences throughout the peak position and intensity of Ca, and P contains. Those two components have the same minerals building the structure but are already different in the chemical position [1,6]. This case showed that the synthetic process's success in changing the eggshells became another different material predicted as HAp. In the eggshells, the Ca and P only showed one peak at each other, but in HAp, the Ca showed two peaks. The two peaks represent one of Ca at the bottom of the crystal structure, and the other peak belongs to Ca in the crystal wall (which binds to PO3).
The Phosphorus (P) peak in HAp is also separated into nine small but significant peaks. One peak belongs to PO4, which bond with Ca at the bottom of the crystal structure, and eight peaks belongs to PO3, which bond with Ca in the wall of crystals. The chemical structure of the HAp showed in Figure 3.  Figure 3, it can be seen that  [17,19,22,32]. In the formula, HAp's role as a remineralization agent also includes abrasive compounds to handle the damage to the tooth enamel layer caused by caries bacteries [18]. The minerals contained in the eggshells are potentially observed deeply [13] to produce the biomaterials like HAp [32,33], and the minerals are the potential to increase the quality and quantity of the HAp [19][20][21]. Because the porosity is still significant, the HAp is recommended to apply as active compounds in toothpaste.