A modified approach towards facile and green conversion of cement kiln dust wastes to efficient hydroxyapatite-carbon nanocomposite water adsorbents.

A new modified approach was used to synthesize hydroxyapatite-carbon nanocomposite (HAP-C) by utilizing cement kiln dust (CKD), which is an industrial waste product, as a source of calcium. Calcium from CKD was first chelated using citric acid, and the chelate was transformed into calcium carbonate and carbon by calcination at 450 °C for 1 h, then reacted with ortho-phosphoric acid using a precipitation method, thus serving as a precursor for the formation of HAP-C. Then, HAP-C was calcined at various temperatures for 2 h after it reached the desired temperature at a heating rate of 10 °C/min.