Removal of lead ions using hydroxyapatite nano-material prepared from phosphogypsum waste

Nano-material of calcium hydroxyapatite (n-CaHAP), with particle size ranging from 50 to 57 nm which was prepared from phosphogypsum waste (PG), was used for the removal of lead ions (Pb (II)) from aqueous solutions. It was investigated in a batch reactor under different experimental conditions. Effects of process parameters such as pH, initial Pb ion concentration and adsorbent dose were studied. Also, various types of kinetic modeling have been studied where the lead uptake was quantitatively evaluated using the Langmuir, Freundlich and Dubinin–Kaganer–Radushkevich (DKR) model. The Pb ions adsorption onto n-CaHAP could best fit the Langmuir isotherm model. The maximum adsorption capacity (qmax) for Pb ions was 769.23 mg/g onto n-CaHAP particles.