The experimental adsorption data showed that the Cd2+ removal process follows the pseudo-secondorder law. The results about the effect of initial Cd2+ concentration were evaluated using Langmuir and Freundlich adsorption isotherms. Maximum monolayer adsorption capacity was 103 mg/g. | Vietnam Journal of Chemistry, International Edition, 55(4): 393-399, 2017 DOI: Treatment of Cd2+ ions using aluminum doped hydroxyapatite (AlHAp) powder Nguyen Thi Thom1*, Dinh Thi Mai Thanh2,3, Pham Thi Nam1, Nguyen Thu Phuong1, Cao Thi Hong1, Nguyen Thi Xuyen1, Nguyen Van Trang1, Claudine Buess-Herman4 1 Institute for Tropical Technology, Vietnam Academy of Science and Technology 2 University of Science and Technology of Hanoi, Vietnam Academy of Science and Technology Graduate University of Science and Technology, Vietnam Academy of Science and Technology 3 4 Chimie Analytique et Chimie des Interfaces, Faculté des Sciences, Université Libre de Bruxelles, Belgium Received 16 January 2017; Accepted for publication 28 August 2017 Abstract Pollution of heavy metals in water is an important problem and is attracting the attention of scientists. It affects the health of humans and destroys the environment, therefore removal of heavy metal ions is necessary. This work is about treatment of Cd2+ ions in the water using aluminum doped hydroxyapatite (AlHAp) powder. The effect of some factors such as contact time, initial Cd2+ concentration, pH solution and mass of AlHAp on adsorption capacity and efficiency was investigated. The experimental adsorption data showed that the Cd2+ removal process follows the pseudo-secondorder law. The results about the effect of initial Cd2+ concentration were evaluated using Langmuir and Freundlich adsorption isotherms. Maximum monolayer adsorption capacity was 103 mg/g. Keywords. Aluminum doped hydroxyapatite (AlHAp), Cd2+ ions, adsorption, adsorbent. 1. INTRODUCTION The pollution of heavy metal in water affects the health of humans and destroys the environment. Therefore, treatment heavy metal ions is getting the attention of scientists. The heavy metals such as cadmium (Cd), mercury (Hg), lead (Pb) and arsenic (As) are known as highly toxic elements. All of which appear in the World Health .
