Influence of the concentration of phosphoric acid (H3PO4) on the Ca/P ratio in obtaining hydroxyapatite (HAp) from eggshell

The objective of this research was to evaluate the influence of the concentration of phosphoric acid in the impregnation to obtain hydroxyapatite (HAp) from the recycling of the eggshell reduce the residues formed in conventional synthesis; in addition to evaluating the Ca/P ratio in the type of HAp obtained, in order to test the material in the removal of dyes. The material obtained was characterized by Scanning Electron Microscopy, Energy Dispersive Spectroscopy (EDS) to obtainmorphology and elmental composition, Fourier Transform Infrared and Raman Spectroscopy, to determine functional groups and crystalline phases respectively. A carbonated HAp was obtained, increasing the concentration of phosphoric acid (0.5M, 1M, 1.5M, 2M and 2.5M) increases the presence of the phosphate group in the material; therefore, the presence of carbonates decreases. It is important to highlight that by Raman it was not possible to find the presence of phosphates, it is necessary to analyze the material by other characterization techniques. Although, with the other techniques used, it was possible to determine the presence of this in the material.