ADSORBABILITY OF HYDROXYPATITE TO PHENOLIC DYES AND HUMIC SUBSTANCES IN WATER

Abstract

We investigated adsorption of phenolic dyes, alizarin and alizarin red S, which are often used as bone-staining agents in histological studies,onto hydroxyapatite(HAP) in water and elucidated their adsorption structures by FT-IR microspectroscopy. The structures were interpreted as a salt form constructed by interaction of vicinal phenolate groups of alizarins with Ca sites on HAP. We further applied the elucidated adsorption theory to adsorption of humic substances onto HAP in water. As a result,effective removal of humic substances was observed. This is possibly due to a lot phenolic groups in humic substances. We hope that HAP is possibly applied as a removal agent in water purification systems.