亚胺基二乙酸树脂对镉的吸附性能及其机理

来源期刊：中国有色金属学报2006年第5期

论文作者：莫建军 熊春华

文章页码：924 - 928

关键词：亚胺基二乙酸树脂； 镉； 动力学； 热力学； 吸附； 机理

Key words：iminodiacetic acid resin; cadmium; kinetics; thermodynamics; sorption; mechanism

摘    要：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^-5 s^-1， 表观吸附活化能E_a=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。

Abstract: 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 ΔH=3.08 kJ/mol, free energy change ΔG =-7.62 kJ/mol, entropy change ΔS=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.