Adsorption Behaviors and Mechanism of Single/Multi-Metals by Ion Exchange Resins

Adsorption of Fe(III), Co(II), Cu(II), Zn(II) and K(I) by strong acid resins, Dowex 50WX2 200-400 (H) and Amberlite IRP-69, was studied to investigate the adsorption behaviors and mechanism in single-metal and multi-metal systems. The results showed that 99.9% Fe(III) can be removed by Dowex 50WX2 200-400 (H) in 100 min ([Fe(III)] < 40 mg/L, resin amount = 50 mg, pH = 3.0, 60 degrees C). Mechanism studies revealed that Langmuir model and pseudo-second-order kinetic equation illustrate better fit for the adsorption of Fe(III). Furthermore, the investigations on multi-metal adsorption indicated that resins display a similar adsorption ratio for the same-valence metal ions (Co(II) = Cu(II) = Zn(II)), and a more selective adsorption for high-valence metal ions than low-valence metal ions (Fe(III) > Co(II) > K(I)). The above results can be used for the treatment of wastewater and the recovery of metals from the spent catalysts.