Study On The Adsorption Of U(Ⅵ) By Modified Bagasse From Wastewater

With the wide application of uranium in military and nuclear power, our societyneed more and more uranium. To satisfy the demand, uranium mining and metallurgyis developing rapidly. At the same time, the uranium waste and uranium wastewaterincrease greatly. Uranium wastewater pollution is becoming more and more serious.The soluble uranium (U)(Ⅵ) dissolved in water with the current migration, pollutingthe groundwater and rivers on the ground. Uranium can Enrich in the body of animalsand plants, and enrich in hunan body through the enrichment of the food chain finally.Uranium is not only heavy metals but also radioactive metals. It will hurt hunan healthseriously after entering the human body. A large number of studies show that cropstraw can adsorpt uranium from wastewater. It can adsorpt more uranium after beingmodified.In this study, we use the bagasse which was modified by sodium hydroxide as raw material.In the static adsorption experiment, the modification method, solution pH, time, temperature,adsorbent additive amount and initial concentration were studied on adsorption process.Desorption regeneration test and firing recovery test were studied. The adsorption process accordswith the Freundlich equation and Lagergren pseudo-first-order kinetics better. It also accords withThe diffusion equation of particle in high U(Ⅵ) concentration, and using infrared spectrometeranalysis of the change of functional groups in adsorbent.The results show that the modified bagasse is preferably sodium hydroxideadsorption, chemical modification process changes the structure of the originalbagasse. The results showed that optimum condition for adsorption is Ph=4.0,adsorbing temperature55℃，absorbing equilibrium time90minutes and the dosage ofadsorbing material is about1.0g（20g/L）when the Cu2+wastewater whose massconcentration is20mg/L. The adsorption reaction reaches equilibrium in90minutes at the condition which is pH=4.0, adsorbing temperature55℃, solid-to-liquidratio2g/L,and the saturated adsorption capacity is5.61、8.25and11.11mg/g when theInitial concentration is20、50and100mg/L. Correspondingly, the saturatedadsorption capacity is6.41、12.01and14.36mg/g at adsorbing temperature45℃. So,raising the temperature is conducive to improving saturated adsorption capacity. Theadsorption process accords with the Freundlich equation and Lagergrenpseudo-first-order kinetics better. It also accords with The diffusion equation ofparticle in high U(Ⅵ) concentration.The adsorption process includes Physical adsorption on multimolecular layer,maybe includes Chemical adsorption. In analytical test, HCl and HNO3can desorptU from adsorbent better. The desorption rate is above83%. Adsorption processincludes a process which can not be desorpt. Calcination recycling rate is just73.94%,and this recovery method needs to be improved.