Synthesis of β-type Strontium Hydrogen Phosphate Nanosheets and Its Immobilization of Pb2＋ in Acidic Aqueous Solution

Highly crystalline β-type strontium hydrogen phosphate （β-SrHPO4） nanosheets were prepared by a hydro- thermal method and used for the immobilization of lead ions （Pb2＋） from acidic aqueous solution. The effects of various parameters on the immobilization process, including solution pH value, contact time, initial ion concentrations, and coexistent competing cations, were studied to optimize the conditions for maximum immobilization. The β-SrHPO4 nanosheets exhibited a capacity of （1,120 ± 22） mg/g toward Pb2＋ in acidic solution （pH value is 3.0）, and the equilibrium was achieved within 8 rain. The competing cations such as Cu2＋, Zn2＋, Cd2＋, and Co2＋ affected slightly on the selective immobilization of Pb2＋. The results revealed that the removal mechanism of Pb2＋ by the β-SrHPO4 nanosheets was the dissolution/precipitation process in the acidic solution.