Adsorption Performance And Experimental Study On Starch-based Materials For U(?)

How to deal with the radioactive pollution in uranium mining and metallurgy effectively,especially the treatment of low concentration uranium-containing wastewater has become one of the hot spots in the current research.Adsorption method has the advantages of high efficiency,good selectivity and wide material source.The key to adsorption is to find a low-cost and efficient adsorbent.The regenerated starch(MS)and amino starch(CAS)were prepared by using corn starch(CS)as raw material and refrigerated solvent exchange and amino modification.The effects of initial p H,dosing amount,initial concentration of uranium and temperature on the adsorption of U(VI)were investigated by static adsorption experiment.And the adsorption data were fitted by adsorption kinetics and thermodynamic model.At the same time,the adsorption mechanism of the two materials was analyzed by X-ray diffraction(XRD),scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FT-IR).The results are as follows:The result show that under the condition of 25?,p H 6.0 and adsorption time of 150 min,the maximum removal rate of 97.8% was achieved with 10mg/L U(VI)solution.The adsorption could be described by Langmuir isothern model and the pseudo-second-order kinetic model and was spontaneous and endothermic.SEM images show that the MS surface is cloudy fluffy porous structure,increasing the specific surface area.FT-IR results show that the presence of active hydroxyl groups in MS plays a major role in the adsorption of U(VI).The consequences indicated that the maximum adsorption of CAS occurred at p H of 6 and the adsorption reached equilibrium within 90 min.and the maximum adsorption capacity is 29.06mg/g.The adsorption process of U(VI)by CAS was in accordance with Langmuir isothermal adsorption model and quasi-second order kinetic model.Chemical adsorption is controlled by kinetics.CAS adsorption U(VI)is a spontaneous endothermic reaction,high temperature is conducive to the progress of the reaction.From the SEM and FT-IR analysis,CAS surface was pleated and loose,and no significant change was observed before and after uranium adsorption.The amino and hydroxyl groups in CAS play a major role in the adsorption of U(VI).The mechanism of adsorption of U(VI)by CAS is surface complex adsorption.Adsorption desorption test showed that CAS has certain practical value.