Sorption Mechanism And Performance Analysis Of Prussian Blue Analogues For Cs⁺ And Co²⁺ Of Modelling Radioactive Wastewater

Compared with other materials, Prussian blue analogues have some unique advantages. Therefore, it is always a hot research topic that Prussian blue analogues are applied in the field of radioactive wastewater treatment. To selectively use Prussian blue analogues for the different types of radioactive wastewater, three aspects as following was discussed in this paper about its preparation methods and applications in the field of radioactive wastewater treatment.Firstly, the Ni-Fe(II) single metal Prussian blue analogue was prepared by coprecipitation synthesis. Under the condition of static shaking table experiment, 6 equal amounts of the materials were reacted with the solution of Cs Cl with the same initial concentration but different reaction time. Some methods were used to analyze the changes of the metal ions in the solution and the macroscopic and microscopic structure of material before and after adsorption. The results showed that the content of other metal ion had almost no change except for K+ and Cs+ before and after adsorption. The morphology and the symmetry of iron centered octahedral structure had no change after adsorption, but the crystal structure of the material had a serious distortion.Secondly, under the condition of static shaking table experiment, 24 equal amounts of Ni-Fe(II) single metal Prussian blue analogues were reacted with the solution of Cs Cl with the same initial concentration but different contact time, or the same time but different initial concentration, or the same initial concentration and contact time but different p H value, and the same initial concentration in the coexistence of Na+, K+, NH4+, Mg2+, and Ca2+ respectively. The results showed that the sorption isotherms were well described by the Freundlich equation, the sorption kinetics were agree with pseudo-second-order kinetics, and the rate limiting processes were controlled by film diffusion. The distribution coefficient of Cs+(Kd,Cs,) decreased as the following order:NH4+> K+> Na+> Ca2+> Mg2+, When the solution of Cs Cl contains Na+, K+, NH4+, Mg2+, and Ca2+.The Kd,Cs declined with the increase of p H to a minimum value of 5.3 and then increased..Finally, Fe-Ni-Fe(II) double metal Prussian blue analogues were prepared by two different methods, and named as the products 1# and 2# respectively. The Cu-Ni-Fe(II) double metal Prussian blue analogues were prepared by the method of 2#. Under the condition of static shaking table experiment, 9 equal amounts of 1# were reacted with the solution of Co Cl2 with the same initial concentration but different reaction time. The equal amount of 2#,the Ni-Fe(II), Cu-Fe(II), Cu-Ni-Fe(II) Prussian blue analogues were reacted with the solutions of Co Cl2 with the same initial concentration, respectively. The results showed that 2# may be more likely as the Fe-Ni-Fe(II) double metal Prussian blue analogues compared with 1#. The morphology of Fe-Ni-Fe(II) and Cu-Ni-Fe(II) double metal Prussian blue analogues are like a rugby and spherical particle, respectively. After about 4.5 h reacting time, the adsorption of 1# for Co2+ reached equilibrium. Compared with the ionic radius, the ionic potential of Prussian blue analogues has more effect to the adsorption of Co2+.