Adsorption of Er（ III ） and Its Mechanism on Diglycolamidic Acid Resin
摘要
The adsorption behavior and mechanism of a novel chelate resin, diglycolamidic acid resin (DAAR) for Er( Ⅲ ) were investigated. The optima adsorption condition of DAAR for Er( Ⅲ ) is pH 6.20 in HAc-NaAc medium. The statically saturated adsorption capacity is 189mg·g^-1 resin at 298 K. The Er ( Ⅲ ) adsorbed on DAAR can be eluted reaching 100% by 2 mol·L^-1 HC1 used as eluant. The resin can be regenerated and reused without apparent decreasing of adsorption capacity. The apparent adsorption rate constant is k298 = 1.94 × 10^-5 s^-1. The apparent activation energy is 24.7 kJ·mol^-1. The adsorption behavior of DAAR for Er( Ⅲ ) obeys the Freundlich isotherm. The thermodynamic adsorption parameters, enthalpy change ΔH of DAAR for Er( Ⅲ ) is 24.1 kJ·mol^-1 .The molar coordination ratio of the functional group of DAAR to Er ( Ⅲ ) is 3 : 1. The adsorption mechanism of DAAR for Er ( Ⅲ ) was examined by using chemical method and IR spectrometry. The coordination compound is formed between oxygen atoms in the functional group of DAAR and Er( Ⅲ ).