Adsorption Behavior of MWAR Toward Gd(III) in Aqueous Solution

Adsorption and desorption behavior of gd(iii) ion on macroporous weak acid resin(mwar) had been investigated. the influence of operational conditions such as contact time, initialconcentration of gd(iii) ion, initial ph of solution and temperature on the adsorption of gd(iii) ionhad been examined. experimental data were exploited for kinetic and thermodynamic evaluationsrelated to the adsorption processes. adsorption isotherms were attempted to be obtainedthe model parameters at different temperature and to be fitted better to langmuir model than tofreundlich model within the studied concentration range. the maximum adsorption capacity ofgd(iii) ion on mwar was 384 mg/g at 298 k, calculated from langmuir model. the apparentactivation energy was ea = 18.0 kj/mol and adsorption rate constant was k298 = 1.22~10-5 s-1,respectively. thermodynamic parameters such as changes in the enthalpy (δh), entropy (δs) andgibbfs free energy (δg) indicated that gd(iii) ion adsorption by mwar was an endothermic andspontaneous process in nature, and more favorable adsorption was obversed when the ambienttemperature was high gd(iii) can be eluted with the composition of 0.5mol/l hcl and 0.5 mol/lnacl solution.