Colloidal Behavior Study Of Pu In Clay And Bentonite

Plutonium is a strategic material,nuclear weapons is an important nuclear charge,with strong radioactivity and toxicity.In order to obtain the colloidal behavior and migration mechanism of plutonium,this paper studies the colloid of GMZ-bentonite and Alashan clay to explore the effect of these two kinds of natural mineral colloids on the radionuclide plutonium Adsorption behavior of the two colloids on the adsorption characteristics and regularity of plutonium,and the results of two kinds of artificial mineral colloid-assisted contrast were studied by using a variety of characterization methods and static adsorption methods.The results are as follows:(1)in the colloid characterization:four minerals in the water environment can be formed more stable,good dispersion of colloid.In the aspect of composition analysis,the main components of GMZ-bentonite are montmorillonite,quartz and kaolinite,and the main components of colloid are montmorillonite and kaolinite.The main components of Alashan clay are illite,calcite and Chlorite,and colloidal main components of illite and chlorite,and contains trace calcite,In terms of structure and property analysis,the infrared spectra of four kinds of mineral colloids are basically consistent with their X-ray diffraction results.(2)The distribution coefficient Kd of the four kinds of mineral colloid adsorption increases with the initial concentration of plutonium.In addition to the large specific surface area and the Kd value increases,the other three kinds of mineral colloids After the peak at 3×10-9g/m L-4×10-9g/mL,it began to decrease.Under these conditions,the adsorption capacity of colloid was Alashan clay>>laponite>GMZ-bentonite?saponite.(3)In the acidic environment,the distribution coefficient Kd of four kinds of mineral colloids is very low.With the rise of pH,the Kd values of the four mineral colloids are rising,and the strong alkaline environment begins to decrease.Amongthem,the optimum environment of natural mineral colloid is neutral,and the optimum environment of artificial mineral colloid is about weak alkaline.It is inferred from the pH effect that the mechanism of adsorption of plutonium from natural mineral colloids is the complexation of the hydroxyl groups on the colloidal surface and the hydrolysates of plutonium and plutonium.Fe3+and CO2-3will weaken the adsorption capacity of colloids.The mechanism of Fe3+is the competitive effect of Pu4+and the hydrolysis is acidic.Fe3+increases the Kd value when the concentration increases,The reason may be the formation of Fe(OH)3 colloid;CO2-3by complexing Pu4+Kd value of a sharp decline;Ca2+will make natural mineral colloid stability,hydration capacity,swelling and other properties enhanced,so that colloid The surface activity of the surface groups increases and the specific surface area increases,so that their adsorption capacity is enhanced,and Ca2+has little effect on the adsorption capacity of the artificial mineral colloid.In addition,the presence of humic acid increases the Kd value of the four mineral colloids.