Preparation of hydroxyapatite-based porous materials for absorption of lead ions

In this paper, soybean protein isolate (SPI) was used as template, hydroxyapatite was crystallized on protein chains of SPI by in-situ synthesis, then the obtained inorganic HA/biopolymer SPI composite (HA@SPI) was calcined at suitable temperature, which afforded a novel hydroxyapatite-based porous materials (HApM). The results indicated that the product showed a porous morphology structure and excellent absorption performance for Pb²⁺. HApM maximum removal of lead was attained (96.25%) at an initial pH value of 7.4, temperature of 25 °C and contact time of 30 min with an initial metal concentration of 60 mg/L. In order to identify composition, structure and functional groups involved in the uptake of Pb²⁺, Fourier transform infrared spectrometer (FTIR), thermogravimetric analysis (TG), X-ray diffraction (XRD) scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) analysis were carried out. Therefore, the hydroxyapatite-based porous materials (HApM) is a promising candidate for the treatment of liquid wastes containing toxic Pb²⁺ metal ion, heavy metal ion antidotes and other related fields.