Abstract
Hydrothermal synthesis of hydroxyapatite (HAp) using calcium acetate prepared by dissolving scallop shells in acetic acid led to a high adsorption rate of 97% for acidic protein and a low rate of 24% for basic protein. These are advantageous properties for adsorbents used for acid-base separation. The adsorption property was attributed to the needle-like crystalline shape of HAp. The strontium ions and organic compounds present in scallop shells were assumed to be responsible for the needle-like shape of HAp. These components are not present in limestone. Therefore, synthesis of needle-shaped crystals of HAp was not possible under the same hydrothermal synthesis conditions. Results confirmed scallop shells to be beneficial as a raw material for HAp synthesis by hydrothermal reaction.
