Performance investigation of Pb(II) removal by synthesized hydroxyapatite based ceramic ultrafiltration membrane: Bench scale study

Abstract In this study, a low pressure novel ultrafiltration membrane has been developed using synthesized hydroxyapatite nanoparticle over low cost clay-alumina based porous ceramic substrate with multichannel configuration. The nanoparticles and membrane were characterized by FESEM, EDX, XRD, BET, FTIR analyses. The FESEM and EDX images revealed a crack free uniform hydroxyapatite coating layer over porous support with maximum presence of Ca and P at top of the active layer compared to other ceramic elements. The nominal pore size of the membrane was measured as 2.8 nm (BET analysis). Bench scale membrane separation process was performed for the removal of toxic Pb(II) from spiked aqueous solution using 500 mm long synthesized hydroxyapatite ceramic membrane. The clean water permeability and the flux were 79.8 L m−2h−1 bar−1 and 28.4 L m−2h−1 (at 0.5 bar pressure), respectively. The developed membrane showed 99.6% rejections of Pb(II) from 5 mg L−1 solutions at 1 bar pressure. Furthermore, pH effect on rejection efficiency was also studied and it demonstrated maximum rejections at pH 7.4. The probable mechanism of high rejection was established by XPS analysis as complexation reaction. The membrane was regenerated and subsequently reused. However, this study highlights on designing, fabrication and performance evaluation of novel hydroxyapatite clay-alumina ceramic ultrafiltration membrane in bench scale via simple method that can be potentially applied for industrial purposes.