Removal of Eu(III) from aqueous solution using ZSM-5 zeolite

ZSM-5 zeolite is characterized by XRD, FT-IR and acid-base titration in detail. The results show that the sorption site distribution of ZSM-5 zeolite is affected by ionic strength obviously; the main sorption sites are =XNa, =SOH and =SO- in all pH ranges. The sorption experiments of Eu(III) on ZSM-5 zeolite indicate that the sorption is strongly dependent on pH value and on ionic strength (ranged from I = 0.001 to 0.05 mol/L NaClO4) under ambient conditions. The sorption edges of Eu(III) on ZSM-5 zeolite in 0.1 and 0.01 mol/L NaClO4 and the sorption isotherm in 0.01 mol/L NaClO4, respectively, were modeled using a quasi-mechanistic sorption model (1-site protolysis non electrostatic surface complexation and cation exchange (1-SPNE SC/CE) model). The EU(III) sorption edges in different ionic strengths Could be modeled in the pH range 3-10 using cation exchange reactions for Eu3+/Na+ and three surface complexation reactions on the sorption sites by forming =SOEu, =SCEu(OH)(+) and =SOEu(OH)(2) inner-sphere surface complexes successively. The Eu(III)/ZSM-5 zeolite EXAFS analysis indicates that Eu(Ill) on ZSM-5 zeolite can be simulated (R = 0.045) by assuming a number of coordination oxygen N = 7.7(5) at d(Eu-O) 2.31 angstrom (sigma = 0.001 angstrom). (c) 2009 Elsevier Inc. All rights reserved.