亚胺基二乙酸树脂对镉的吸附性能及其机理

Sorption behavior and mechanism of iminodiacetic acid resin for cadmium

研究了用亚胺基二乙酸树脂(D401)吸附镉离子的过程。结果表明,在pH=5.73时树脂对镉的吸附效果最佳,测得树脂的静态饱和吸附容量为363 mg.g-1;用0.5 mol/L HCl作解吸剂,解吸率为100%,表观吸附速率常数k298=2.05×10-5s-1,表观吸附活化能Ea=18.0 kJ/mol,等温吸附服从Freundlich经验式;吸附热力学参数ΔH=3.08 kJ/mol,ΔS=35.9 J/(mol.K),ΔG=-7.62 kJ/mol,树脂功能基与镉离子的配位摩尔比为1∶1。用化学和红外光谱等方法讨论了吸附机理。

The sorption of Cd（Ⅱ） with iminodiacetic acid resin （D401） was investigated, The results show that D401 has a good sorption ability for Cd（Ⅱ） in the HAc - NaAc medium at pH= 5.73. The statically saturated sorption capacity of resin is 363 mg/g and 0.5 mol/L HCl can be used as an eluant; the elution percentage is 100%, the sorption rate constant is k298 =2.05 × 10 ^-5 s^-1 , and the apparent sorption activation energy of D401 for Cd（ Ⅱ ） is 18.0 kJ/mol. The sorption behavior of D401 for Cd（Ⅱ） obeys the Freundlich isotherm. The sorption thermodynamic parameters of D401 for Cd（Ⅱ ） are： enthalpy change △H= 3.08 kJ/mol, free energy change △G = - 7.62 kJ/ mol, entropy change △S =35. 9 J/（mol · K）, respectively. The coordination molar ratio of the functional group of D401 to Cd（ Ⅱ ） is 1 ： 1. The sorption mechanism of D401 for Cd（Ⅱ ）was confirmed by chemical analysis and IR spectrometry.