Calcium pyrophosphate (CPP) was prepared by a simple precipitation method using avian eggshell waste as a low-cost alternative calcium precursor source. The synthesized CPP powder was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM/EDS), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The results indicate that pure β-CPP nanocrystallites (Ca/P = 1.067) were successfully synthesized from avian eggshell waste. The correlation among XRD, SEM/EDS, TGA, and FTIR data is well established. The β-CPP particle exhibited spherical morphology with average crystallite size of 62.3 nm, and can be an important bioceramic for medical applications.

Fish bone is rich in calcium carbonate, which makes it an alternative source of low cost calcium carbonate for the synthesis of calcium phosphate bioceramic for use in bone regeneration. The calcium phosphate bioceramic was prepared by a wet precipitation method with acid and base reactions. The synthesized bioceramic was characterized in terms of X-ray diffraction (XRD), scanning electron microscopy (SEM/EDS), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), average crystallite size and refinement by the Rietveld method for the quantification of crystalline phases. The results indicated the formation of a biphasic calcium phosphate bioceramic comprising 67.6 % of β-calcium pyrophosphate (β-CPP) and 32.1 % of β-tricalcium phosphate (β-TCP). This biphasic calcium phosphate bioceramic synthesized using fish bone waste presented nanostructured nature with an average crystallite size of 69.58 nm, which is very promising for biomedical applications.

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In this work the sintering behavior of a nanostructured b-calcium pyrophosphate (b-CPP) powder derived of avian eggshell waste was investigated. The b-CPP pellets were prepared by uniaxial pressing and sintered in air for 2h at temperatures ranging from 600℃ to 1200℃. The sintering behavior was evaluated in terms of linear shrinkage, water absorption, apparent porosity, apparent density, tensile strength, FTIR (Fourier-transform infrared) analysis, and microstructural analysis via SEM (scanning electron microscopy). The results showed that the nanostructured b-CPP powder presented different behaviors with increasing sintering temperature. It was found that sintering at higher temperatures led to greater densification of the b-CPP pellets (92.56% of theoretical density when sintered at 1000℃). However, SEM micrographs of the fractured surfaces of the sintered β-CCP pellets showed the presence of micro-cracks that negatively impact the mechanical strength. Hence, it was concluded that the sintering temperature of 900℃ was found to be the most suitable in terms of densification, mechanical strength, and sintered microstructure for the production of b-CPP bioceramic pellets derived of avian eggshell waste for potential medical application.