以NH4H2PO4、Ca(NO3)2·4H2O、Sr(NO3)2和尿素[CO(NH2)2]为原材料,通过水热法合成了一种单分散、由纳米片自组装而成的绣球花状三维(3-D)掺锶碳羟基磷灰石(Sr-CHAp),并用于吸附酸性水溶液中的铅离子(Pb2+).研究了溶液p H、吸附时间、初始浓度对Sr-CHAp材料吸附Pb2+的影响及在其在不同p H条件下的吸附机理.采用XRD、SEM、FI-IR和BET等技术对材料及吸附产物进行表征.结果表明,该吸附剂材料表面具有介孔结构,平均孔隙宽度是11.10 nm,具有较大的比表面积(43.54 m2·g-1),在pH3时对Pb2+具有较高的饱和吸附量(985.1 mg·g-1);其等温线吸附数据符合Langmuir模型,动力学吸附数据符合伪二级动力学模型;在酸性溶液中其对Pb2+的吸附主要表现为溶解/沉淀机理,溶液p H值的大小影响吸附后的产物,强酸性条件下有利于PbHPO4的生成,而p H值为3—6时主要生成Pb10(PO4)6(OH)2.
Using NH4H2PO4,Ca(NO3)2·4H2O,Sr(NO3)2 and urea [CO(NH2)2] as raw materials,monodisperse nanosheets-assembled hydrangea-like three-dimensional(3-D) strontiumdoped carbonate hydroxyapatite(Sr-CHAp) was synthesized by a hydrothermal method,and used as an adsorbent for the removal of lead ions(Pb2+) from acidic aqueous solutions.The effects of p H value,contact time and initial concentration of Pb2+ solutions on the adsorption of the Sr-CHAp material and its adsorption mechanism under different p H were studied.The adsorbent and the products were characterized by XRD,SEM,FI-IR and BET etc..The results show that the obtained Sr-CHAp had a mesoporous structure,of which the average width is 11.10 nm.It had a large specific surface area of 43.54 m2·g-1and a high adsorption capacity(985.1 mg·g-1) towards Pb2+ at p H 3.The isotherm accords with the Langmuir model,and the kinetic data conform to the pseudo-second order kinetic model.The mechanism of Pb2+adsorption was attributed to dissolution/precipitation process in acid solutions.The products were different at different p H value.Strong acidic solution was favorable for the formation of PbHPO4 while Pb10(PO4)6(OH)2 was the main product when p H wasbetween 3—6.