Adsorption of Phenol from Aqueous Solution by Hydroxyapatite Nanopowders. Part I: Synthesis and Factors Affecting the Adsorption Characteristic Studies

In this study, the nano-hydroxyapatite (n-HAp) powders prepared by chemical precipitation method were used as the adsorbent, and the potential of n-HAp powders for the removal of phenol from aqueous solution was studied. The effect of contact time, initial phenol concentration, pH, adsorbent dosage, solution temperature and adsorbent calcining temperature on the phenol adsorption was investigated. The results showed that the n-HAp powders possessed good adsorption ability to phenol. The adsorption process was fast, and it reached equilibrium in 2 h of contact. The initial phenol concentration, pH and the adsorbent calcining temperature played obvious effects on the phenol adsorption capacity onto n-HAp powders. Increase of the initial phenol concentration could effectively increase the phenol adsorption capacity. At the same time, increase of the pH to high-acidity or to high-alkalinity also resulted in the increase of the phenol adsorption capacity. Increase of the n-HAp dosage could effectively increase the phenol sorption percent. However, the higher calcining temperature of n-HAp powders could obviously decrease the adsorption capacity. The maximum phenol sorption capacity was obtained as 10.33 mg/g for 400 mg/L initial phenol concentrations at pH 6.4 and 60degC.