钠化蛭石对镧(Ⅲ)的吸附行为及机制研究

Adsorption of Lanthanum(Ⅲ) by Sodium-Modified Vermiculite

以碳酸钠(Na_(2)CO_(3))为改性剂制备了钠化蛭石(Na-Ve),利用扫描电镜(SEM)、能谱仪(EDS)、傅里叶变换红外光谱仪(FT-IR)、X射线衍射仪(XRD)等手段对Na-Ve进行了表征与分析,通过静态吸附实验研究了钠化蛭石对La(Ⅲ)的吸附行为。研究结果表明:Na-Ve维持了蛭石原有层状结构,平均孔径增大,对La(Ⅲ)的吸附容量较未改性蛭石有明显提升,最大吸附容量为37.7 mg·g^(-1);增加吸附剂用量、延长吸附时间、增大溶液p H、降低溶液初始浓度、升高温度都能提高Na-Ve对La(Ⅲ)的去除率,在p H值为6,投加量为1.5 g·L^(-1),30℃条件下,La(Ⅲ)去除率可达100%;Na-Ve对La(Ⅲ)的吸附是可自发进行的吸热过程,遵循Langmuir吸附等温线,符合准二级动力学方程。

Sodium-modified vermiculite(Na-Ve)was prepared with Na_(2)CO_(3) solution as modifier.Na-Ve was characterized and analyzed by SEM,EDS,FT-IR,XRD,etc.The adsorption behavior of La(Ⅲ)by Na-Ve was studied by static adsorption experiment.The results show that Na-Ve maintains the lamellar structure of vermicu‐lite,and the average pore size increases.The adsorption capacity of La(Ⅲ)by Na-Ve is significantly higher than unmodified vermiculite,with a maximum adsorption capacity of 37.7 mg·g^(-1).The removal rate of La(Ⅲ)by Na-Ve can been larged with increasing the dosage,adsorption time,p H,temperature,and decreasing the initial concentration of solution.The La(Ⅲ)removal rate can reach 100%at the p H value of 6,the dosage of 1.5 g·L^(-1)and 30℃.The adsorption of La(Ⅲ)by Na-Ve is a spontaneous endothermic process,which follows the Langmuir adsorption isotherm and accords with the quasi-second-order kinetic equation.