以NH4H2P04、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pH、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pH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pH 3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pH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pH值为3-6时主要生成Pb10(P04) 6(OH)2.
Using NH4H2PO4,Ca (NO3) 2· 4H2 O,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 pH value,contact time and initial concentration of Pb2+ solutions on the adsorption of the Sr-CHAp material and its adsorption mechanism under different pH 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-1 and a high adsorption capacity (985.1 mg·g-1) towards Pb2+ at pH 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 pH value.Strong acidic solution was favorable for the formation of PbHPO4 while Pb10(PO4)6(OH)2was the main product when pH was between 3-6.
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