Synthesis and Characterization of Calcium Phosphate and Its Relation to Cr(vi) Adsorption Properties

Calcium phosphate with hydroxyapatite structure was synthesized and its ability to adsorb Cr(VI) from aqueous solution is presented. XRD, BET, IR, TGA, SEM and EDS techniques were used to characterize the obtained material. A pure phase was obtained through a simple synthesis process. The specific surface area of the synthesized powder was found to be 64.5 m2 g-1. The X-ray diffraction pattern shows that the calcium phosphate formed was nanocrystalline with an average grain size of approximately 75 nm. A fast adsorption was observed and in less than 24 h it was found that 2.41 x 10-4 meq g-1 of Cr(VI) ions were adsorbed on calcium phosphate. Desorption experiments showed that Cr(VI) adsorption decreased to 2.23 x 10-4 meq g-1 of calcium phosphate. This behavior is a consequence of partial dehydration of the synthesized material. Calcium phosphate can be effectively used for removing Cr(VI) from aqueous solutions in treatment processes of metal wastes. Palabras clave: fosfato de calcio, síntesis, caracterización, adsorción de Cr(VI), área superficial, experimentos de adsorción