Study On Adsorption Of Diatomite And Bentonite For Uranium

The adsorption capability of uranium on natrual diatomite. natrual bentonite . heating diatomite and heating bentonite were studied. The influence of the dosage of sorbent. initial pH. initial concentration of uranium and adsorption time on the adsorption effects were discussed. The research results indicated:Diatomite and bentonite have strong adsorbing capacity. Heating actived with muffle can be improved and enhaced adsorption capacity of diatomite and bentonite; The factors that influence the adsorption of uranium on diatomite and bentonite include: dosage of sorbent , pH, initial concentration of the uranium and adsorption time. With the increment of the sorbent dosage and adsorption time or decrese initial concentration of uranium,the remove rate of uranium was enhanced.The higher of the sorbent dosage ,the less of the adsorption capactiy of uranium on diatomite and bentonite. With the increment of initial concentration of the uranium, the adsorption capacity of uranium increased.pH is an important factor of influencing the adsorbing effect When the pH value being from 3 to 8, the best adsorbing effect was attainted at pH5.The adsorbing effects of the four kinds of sorbent were heating bentonite>natraul bentonite> heating diatomite> natraul diatomite. When the initial concentration of uranium being 20mg/L, pH value being 5, the dosage of sorbent being 0.5g , volume of the solution being 250mL and adsorption time being 90min , the remove rate and adsorption capacity of uranium with heating bentonite. bentonite. heating diatomite and diatomite were 98.05% and 9.81mg/g, 96.00% and 9.60mg/g, 82.50% and 8.25mg/g, 73.50% and 7.35mg/g respectively.The adsorption rate of uranium with the four kinds of sorbent were rapid . the remove rate and adsorption capacity of uranium rised rapidly in 5min.The adsorption equilibrium was nearly reached at 90min.The adsorption dynamics of uranium with the four kinds of sorbent all followed the law of the second-order eqution of Lagergren.The adsorption isotherm of uranium with the four kinds of sorbent all fitted the Freundlich equation. The adsorption mechanism of uranium with diatomite may be ion exchange and suface combination. The adsorption mechanism of uranium with bentonite may be ion exchange, suface combination and inner-layers combination.