Study on sorption of D155 resin for gadolinium

The sorption behavior and mechanism of a Macroporous weak acid resin, (D155 resin,) for Gd(III) were investigated. The statically saturated sorption capacity is 283 mg/g resin at 298 K in HAc-NaAc medium. The Gd(III) adsorbed on macroporous weak acid resin, (D155 resin,) could be reductively eluted with the mixed solution of HCl and NaCl, and the elution percentage was as high as 100%. The resin could be regenerated and reused without remarkable decrease in sorption capacity. The apparent sorption rate constant was k(298)=1.98x10(-5) s(-1). The apparent activation energy was E-a=2.78 kJ/mol. The sorption behavior of D155 resin for Gd(III) obeyed the Langmuir isotherm. The thermodynamic sorption parameters were Delta H=33.0 kJ/mol, Delta S=192 J/mol/K, and Delta G(298)=-24.3 kJ/mol. The sorption mechanism of D155 resin for Gd(III) was examined by using chemical method and IR spectrometry. The coordination compound was formed between oxygen atoms in the functional group of D155 resin and Gd (III).