Synthesis Of A Silica-Based Hdehp/SiO₂-P Adsorbent And Study On Its Adsorption Behavior Towards Zirconium And Molybdenum

Zr and Mo are two important fission products of used nuclear with relatively high yields,and their concentrations are also relatively high in high-level liquid waste.During the reprocessing of used nuclear fuel such as PUREX process,both of Zr and Mo have negative influence and thus their separation from high-level liquid waste is necessary.Besides,the separation of these two elements is also meaningful because Zr and Mo are also rare resources.A novel silica-based adsorbent was prepared by impregnating HDEHP?Di-?2-ethylhexyl?phosphoric acid?into a macro reticular silica/polymer composite support?SiO₂-P?.The character of adsorbent was evaluated by SEM,TG-DTA,and MIP.The adsorption behavior of Zr and Mo from nitric solution was studied in batch experiments.Experimental results indicated that the HDEHP/SiO₂-P adsorbent showed strong adsorption ability for both Zr and Mo.Kinetic and isotherm of adsorption were in accordance with the pseudo-second order kinetic model and Langmuir isotherm adsorption model,respectively.Besides,the desorption behavior of Zr and Mo from adsorbent was also investigated in batch experiments.It was found that both of the solution of DTPA or oxalic acid are effective for desorption and the desorption rate for zirconium of oxalic acid could reach 98.01%in one hour,and 90.92%in 20 minutes for molybdenum.When DTPA and oxalic was added directly into the solutions,the adsorption characteristics of HDEHP/SiO₂-P towards Zr and Mo will change a lot.The result of column adsorption experiment shows that Zr and Mo can't be separated by the HDEHP/SiO₂-P column.