Batch kinetics of Cs and Eu radionuclides onto poly-condensed feldspar and perlite based sorbents.

Sorption of fission products onto polycondensed aluminosilicates (PC-AS) is a relatively recent and gets out the mechanisms by which the formers are trapped. Here, PC feldspar (PC-FD), perlite (PC-PR) and their blend (PC-FDPR) were synthesized by the alkaline activation using Na-/K-silicates at Si-modulus of 1.35. XRD patterns revealed the semi-crystalline natures of sorbents. Na- and K-feldspars were detected in PC-FD while Na-based carbonate crystals were detected in others. Components of the poly(sialate-disiloxo) structure were detected in FT-IR spectra. Thermographs were deconvoluted and the amounts of the sticking and zeolitic water were estimated. Kinetic batches for sorption of Cs and Eu onto the elaborated yields were constructed. Ranking of sorbed amounts (q) was varied from Cs (PC-FDPR>PC-FD>PC-PR) to Eu (PC-PR>PC-FD>PC-FDPR). Maximum q was recorded at elevated temperature (323 K) to be 4.28 and 1.45 mg/g for Cs/PC-FDPR and Eu/PC-PR, respectively. Along all batches, chemi-sorption mechanism is common denominator. The effective diffusion coefficients (D) were in the order of 10 m/s. Both PC-FD and PC-FDPR recorded greater D values of Cs than Eu. The low values of E (kJ/mol) reflected the weak adsorbats-adsorbents interactions. While, the high negative values of ∆S suggested that the studied radionuclides were sorbed in associative reaction mechanism.