Removal of Reactive Blue 204 Dye from Aqueous Solutions by Adsorption Onto Nanohydroxyapatite

The aim of the present paper is to investigate the sorption of Reactive Blue 204 dye on the nanocrystalline hydroxyapatite. The nanohydroxyapatite was prepared by a wet precipitation method by using Ca(NO3)(2)center dot 4H(2)O, and (NH4)(2)HPO4 as main materials. The structure of the nanohydroxyapatite adsorbent was investigated by applying XRD, BET and SEM-EDX methods. The size of hydroxyapatite crystals was smaller than 100 nm. The nanohydroxyapatite samples had a high specific surface area of 325 m(2)/g and 69 m(2)/g for the uncalcined and calcined hydroxyapatite samples, respectively. The batch adsorption experiments were performed by monitoring the following parameters: average adsorbent dosage, contact time, dye solution concentration, solution pH and temperature. Removal rates of Reactive Blue 204 dye about 98.76% and 91.02% for the uncalcined and calcined nanohydroxyapatite, respectively, were obtained. The kinetic studies indicated that the Reactive Blue 204 dye adsorption on both uncalcined and calcined nanohydroxyapatites followed a pseudo-second model.