Studies on the Adsorption of Amino Methylene Phosphonic Acid Resin for Holmium(Ⅲ)

The adsorption behavior and mechanism of a novel chelate resin, amino methylene phosphonic acid resin （APAR） for Ho（Ⅲ） were investigated. The statically saturated adsorption capacity is 258 mg·g-1 resin at 298 K in HAc-NaAc medium. The Ho（Ⅲ） adsorbed on APAR can be repeatedly eluted by 3.0 mol·L-1 HCl and the elution percentage is as high as 95.8%. The resin can be regenerated and reused without apparent decrease in adsorption capacity. The apparent adsorption rate constant is k298=1.14×10-5 s-1. The adsorption behavior of APAR for Ho（Ⅲ） obeys the Freundlich isotherm. The thermodynamic adsorption parameter, enthalpy change ΔH of APAR for Ho（Ⅲ） is 11.4 kJ·mol-1. The apparent activation energy is Ea=15.8 kJ·mol-1. The molar coordination ratio of the functional group of APAR to Ho（Ⅲ） is about 2∶1. The adsorption mechanism of APAR for Ho（Ⅲ） was examined by using chemical method and IR spectrometry.