Effect of process parameters on the synthesis and lead ions removal performance of novel porous hydroxyapatite sheets prepared via non-aqueous precipitation method

Herein, porous hydroxyapatite sheets with high lead ions removal performance are synthesized via self-assembly non-aqueous precipitation method, and the effects of process parameters on the synthesis and lead ions removal performance are systematically investigated. The optimized precursors concentration, the molar ratio of calcium to phosphorus and the calcination temperature are 0.25 mol/L, 1.67 and 650 degrees C, respectively. The refinement XRD, FE-SEM and EDS tests of the optimized samples show that the samples have a porous sheet structure with uniform pore size and wall thickness. The lead ions removal rate of hydroxyapatite sheets has the maximum value of 99.6% when the hydroxyapatite addition amount is 1 g/L. The lead ions removal content is the maximum of 1303.6 mg/g when the initial lead ions concentration is 9 mmol/L. The removal mechanism of lead ions by porous hydroxyapatite sheets prepared in this work is the composite mechanisms of surface adsorption, surface complexation and ions exchange. The hydroxyapatite porous sheet material prepared by optimizing the process parameters in this study has the advantages of high removal capacity and wide adaptability, so it is expected to become a novel adsorbent to solve lead-containing wastewater.