Chemisorption of lanthanide ions on succinate-functionalized mesoporous silica: An in situ characterization by fluorescence

LOMBARDO, MA VERÓNICA; MIRENDA, MARTIN; BORDONI, ANDREA V.; WOLOSIUK, ALEJANDRO; REGAZZONI, ALBERTO E.

JOURNAL OF COLLOID AND INTERFACE SCIENCE

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2017 vol. 507 p. 139 - 144

0021-9797

Chemisorption of Eu3+ and Tb3+ on SBA-15 functionalized with succinic groups has been studied by in situ fluorescence measurements. The emission enhancement, and especially the marked increase of the intensity ratio I616/I592 for europium, indicates that both ions adsorb forming inner-sphere surface complexes. Adsorption is a fast process that attains equilibrium in about 5 min. The variation of the peaks maxima (I592 and I616 for europium, and I490 and I545 for terbium) with the total ion concentration is accounted by the sum of the contributions due to the free and adsorbed ions, the latter being langmuirian. At pH 4.5, the respective adsorption constants are 5x105 and 3x105 M-1, the maximum adsorption capacities being 5.10 x10-4 and 5.23 x10-4 mol g−1. The mismatch between the latter values and the number of attached carboxylic groups is discussed. Comparison with other functionalized mesoporous silicas indicates that the anchored succinic groups are very efficient for removing lanthanide ions from aqueous solutions.