大孔丙烯酸树脂对镧元素的静态与动态吸附研究

Adsorption of Lanthanum(Ⅲ) on Macroporous Acrylic Resin from Aqueous Solutions:Batch and Column Studies

研究了大孔丙烯酸树脂（MAR）对镧离子的吸附与解吸行为。静态吸附研究pH值、接触时间和温度对吸附的影响。结果表明，大孔丙烯酸树脂可以有效地将镧离子从水溶液中去除。吸附平衡的时间为14h。在308K时，缓冲液pH值6．50，由Langmuir等温线模型得出大孔丙烯酸树脂对镧离子的最大吸附量是379mg·g^-1。吸附过程符合液膜扩散动力学（k：4．37×10^-5～5．06×10^-5s^-1）。与Freundlich等温线相比，吸附过程更符合Langrnuir等温线模型。吸附热力学参数分别为：△H=16．7kJ·mol^-1，AS=130J·（tool·K）^-1，△G298K=-22．0kJ·mol^-1。托马斯模型用于确定动态吸附的特征参数以及预测突破曲线。镧离子可以用浓度为0．5mol·L^-1的HCl溶液洗脱。利用红外光谱技术对大孔丙烯酸树脂的表面进行吸附前与吸附后的表征。

The adsorption and desorption behaviors of La（ Ⅲ ） on macroporous acrylic resin （MAR） were investigated in order to optimize the adsorption technological condition of lanthanum. The batch adsorption studies were carried out with pH, contact time and temperature. The results showed that MAR could remove La （Ⅲ ） ions effectively from aqueous solution. The adsorption equilibrium time was observed within 14 h. In the batch system, MAR exhibited the highest La（ Ⅲ ） uptake as 379 mg·g^-1 at 308 K, at an initial pH value of 6.50, calculated from the Langmuir isotherm model. The adsorption kinetics, tested with liquid film diffusion model, gave good fitted （k = 4.37 ×10 -5 s^ -1 to 5.06 × 10 ^-5 s -1 ）. The adsorption data fitted better with Langmuir isotherm than Freundlich isotherm. The adsorption parameters of thermodynamic were AH=16.7 kJ·mol^-1 AS=130 J·（mol·K）^-1 AG298 K=-22.0 kJ·mol^- 1, respectively. The thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design and to predict the breakthrough curves. The La （ Ⅲ ） could be eluted by using the 0.5 mol· L^-1 HCl eluant. The surface characterization of both before-and after adsorption of La （ Ⅲ ） on MAR was undertaken using IR spectroscopic technique.