Adsorption of Eu(III) on rutile in the presence of complexing inorganic anions: a combined macroscopic and spectroscopic investigation

Knowledge of the geochemical behavior of europium is important for the safe disposal of radioactive wastes. Complexing inorganic anions are ubiquitous in repository environments and can affect europium adsorption behaviors significantly. This work comprehensively studied the Eu(III) adsorption on rutile in the presence of complexing inorganic anions. Our results indicated that sulfate and carbonate had a negligible impact on Eu(III) adsorption, while phosphate could strongly enhance the adsorption. The spectral results suggested that phosphate would enhance Eu(III) adsorption by forming a phosphate-bridged complex on rutile surface under acidic conditions, while promoting adsorption by surface precipitation under alkaline conditions.