醇胺钛酸酯改性磁化赤泥对Pb(Ⅱ)的吸附性能研究

以工业固体废弃物赤泥(RM)为原料,经还原煅烧和接枝改性,制备得到一种醇胺钛酸酯改性的磁化赤泥吸附材料(ATMMRM)。利用XRD、FT-IR、SEM、BET、VSM等测试方法对RM和ATMMRM进行表征和对比,发现ATMMRM表面成功引入了羟基和胺基官能团,而且其比表面积及饱和磁化强度较RM分别提高6.0倍和9.6倍,这些特性为ATMMRM提供了更多活性吸附位点并赋予了材料磁分离能力。对Pb(Ⅱ)的静态吸附实验结果表明,在pH=6,T=25 ℃条件下,ATMMRM对水体中Pb(Ⅱ)的饱和吸附容量达213 mg·g^-1,吸附过程符合Langmuir等温吸附模型和准二级动力学方程,为自发、吸热、熵增的化学吸附控制过程,吸附机理主要为物理吸附以及ATMMRM表面接枝的羟基和胺基与Pb(Ⅱ)的螯合作用。

Adsorption Property of Pb(Ⅱ)to Magnetic Red Mud Modified by Alcohol-Amine Titanate

Magnetized red mud adsorption material(ATMMRM)modified by alcohol-amine titanate was prepared from industrial solid waste red mud(RM)after reducing calcination and grafting modification.Using XRD,FT-IR,SEM,BET,VSM and other characterization methods to characterize and compare RM and ATMMRM.The results show that the surface of ATMMRM is successfully introduced with hydroxyl and amine groups,and the specific surface area and saturation magnetization of ATMMRM are 6.0 and 9.6 times higher than those before modification,respectively.These properties provide more active adsorption sites for the adsorption of Pb(Ⅱ)by ATMMRM and endow the material with magnetic separation ability.The results of static adsorption experiments show that the saturated adsorption capacity of ATMMRM for Pb(Ⅱ)in aqueous solution reach 213 mg·g^-1 at pH=6 and T=25℃.The adsorption process of Pb(Ⅱ)from aqueous solution by ATMMRM conforms to Langmuir isotherm model and pseudo-second-order kinetic equation,and is controlled by chemisorption process with spontaneous endothermic entropy increase.The main adsorption mechanism are physical adsorption and chelation of Pb(Ⅱ)with hydroxyl and amine groups grafted on the surface of ATMMRM.