Efficient and selective immobilization of Pb2+ in highly acidic wastewater using strontium hydroxyapatite nanorods

In this paper, strontium hydroxyapatite (Sr5(PO4)3(OH), SrHAp) nanorods were synthesized by a hydrothermal method and utilized for immobilization of Pb2+ from acidic aqueous solutions. The SrHAp nanorods exhibited a high immobilization capacity of 1482 ± 137 mg g−1 for Pb2+ in acidic solutions (pH = 2.5) within 15 min. The SrHAp nanorods could selectively immobilize Pb2+ with little immobilization effect on other co-existing metal ions when they were used to treat highly acidic nonferrous metallurgy wastewater (pH = 1.1). The XRD, SEM, EDX and XPS results revealed that the immobilization of Pb2+ by the SrHAp nanorods was mainly due to ion exchange and Pb2+ precipitation.

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► Strontium hydroxyapatite nanorods were prepared and used for Pb2+ immobilization.
► The immobilized capacity was 1482 ± 137 mg g−1 for Pb2+ at pH 2.5 from solutions.
► The Pb2+ immobilization is highly selective from the real metallurgy wastewater.