fractions (from 0.05 ± 0.01 to 0.07 ± 0.01 mg/100 mL), those after treatment with CR20 increased linearly with elution volume (from0.04 ± 0.003 to 0.17 ± 0.01 mg/100 mL). These increasing eluent concentrations reflect gradual saturation of binding sites (Popuri,Vijaya, Boddu, & Abburi, 2009), and indicate that the Cd removal ability of CR11 was higher than that of CR20 when using the column method.