Synthesis of hydroxyapatite nanowires (HAp NWs) from eggshell by solvothermal method using oleic acid as soft-template

Atiek Rostika Noviyanti, Ardanari Wahyu Waardhani, Muhamad Diki Permana, Uji Pratomo, Juliandri, Takahiro Takei, Akrajas Ali Umar
https://doi.org/10.1007/s42247-024-00716-y

Abstract

Hydroxyapatite (HAp) is a bioceramic material that exhibits excellent compatibility with the human body. This characteristic has attracted attention, particularly in medicine and technology. Researchers have recently focused on studying the synthesis of HAp derived from natural sources. This study used eggshell-derived CaO precursors and CaCl₂ to synthesize HAp nanowires (NWs) with different Ca/P ratios, namely 1:2 and 2:3. The nanowire formation process is facilitated by including oleic acid as a soft template. Significantly, all variations of HAp NWs exhibit a crystallite size below 20 nm and a crystallinity exceeding 78%. In this study, the investigation further validates the presence of functional groups related to phosphate (O–P–O) and oleic acid (C–H) on the HAp surface via FTIR spectra analysis. HAp NWs made using chicken eggshell-derived CaO with a Ca/P ratio of 2:3 have the smallest diameter at 174 nm and excellent thermal stability. Even under temperatures surpassing 800 °C, this specific HAp NW variant retains 97.39% of its mass. The results emphasize the significant potential of chicken eggshell-derived CaO HAp NWs, namely the variation with a Ca/P ratio of 2:3, for various applications, highlighting their exceptional thermal stability and unique properties.

Keywords:

Hydroxyapatite; Nanowires; Oleic Acid; Eggshell