Samples of synthetic Na-A zeolite, pre-exchanged in Sr form, were heat treated at various temperatures up to 1150◦C, in order to entrap the toxic cation in a non-exchanging ceramic matrix. It has been demonstrated that the Sr-loaded zeolite undergoes the following sequence of transformations: zeolite →amorphous phase (at 900◦C) → hexagonal strontium aluminosilicate (at 1000◦C)→ monoclinic strontium aluminosilicate (above 1100◦C). Strontium retention performances of the above Sr-based compounds were compared to each other, estimating cation leaching either by a back-exchange with NaCl solution or by a prolonged contact with distilled water at different pHs (availability test). Thermal treatments from 900◦C onwards were able to safely immobilize Sr2+. The immobilization level depended on the relevant phase formed and resulted the highest (only 0.14% of theinitial Sr concentration), when monoclinic Sr-aluminosilicate structure (Sr-feldspar) was obtained.
Safe Sr confinement in feldspar structures / Liguori, Barbara; Anaclerio, Sandro; Colella, Carmine. - In: IL NUOVO CIMENTO DELLA SOCIETÀ ITALIANA DI FISICA. B, GENERAL PHYSICS, RELATIVITY, ASTRONOMY AND MATHEMATICAL PHYSICS AND METHODS. - ISSN 1594-9982. - STAMPA. - 10-11:123(2008), pp. 1497-1503.
Safe Sr confinement in feldspar structures
LIGUORI, BARBARA;ANACLERIO, SANDRO;COLELLA, CARMINE
2008
Abstract
Samples of synthetic Na-A zeolite, pre-exchanged in Sr form, were heat treated at various temperatures up to 1150◦C, in order to entrap the toxic cation in a non-exchanging ceramic matrix. It has been demonstrated that the Sr-loaded zeolite undergoes the following sequence of transformations: zeolite →amorphous phase (at 900◦C) → hexagonal strontium aluminosilicate (at 1000◦C)→ monoclinic strontium aluminosilicate (above 1100◦C). Strontium retention performances of the above Sr-based compounds were compared to each other, estimating cation leaching either by a back-exchange with NaCl solution or by a prolonged contact with distilled water at different pHs (availability test). Thermal treatments from 900◦C onwards were able to safely immobilize Sr2+. The immobilization level depended on the relevant phase formed and resulted the highest (only 0.14% of theinitial Sr concentration), when monoclinic Sr-aluminosilicate structure (Sr-feldspar) was obtained.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
