Development of Nanoporous Alumino-borosilicate as a Novel Matrix for the Sorption and Stable Immobilization of Cesium Ions

The nanoporous alumino-borosilicate (Al-B-MCM-41) has been developed for the removal of Cesium (Cs) from liquid wastes and further processed for its stable immobilization. The prepared novel sorbent was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), nitrogen porosimetry, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), and transmission electron microscopy (TEM) techniques. The effect of different experimental parameters such as initial pH solution, contact times, temperature, and initial Cs concentration on the sorption capacity of the nanoporous Al-B-MCM-41 was evaluated. According to the obtained results, Al-B-MCM-41 offered the maximum Cs sorption capacity of 119.05 mg g −1 . For stable immobilization of the sorbed Cs ions, the Cs-containing nanoporous Al-B-MCM-41 were subjected to heat treatments at various temperatures. To investigate the leaching of Cs from heat-treated samples, the leach tests were performed using different eluents. Results showed that treating sample at about 1100 °C leads to an effective stabilization of Cs in the Al-B-MCM-41 matrix since only 1.9% of the initially sorbed Cs was leached out. Finally, sorption of Cs-137 from real radioactive waste and its stabilization at the optimal temperature was evaluated.