The Experimental Study About Adsorption Of U(?) In Water By Modified MCM-41

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 of nuclear environmental research.Adsorption method of its technical process is simple,high removal rate,widely used in uranium wastewater treatment.Mesoporous molecular sieve MCM-41 has a high degree of orderly arrangement of the pore structure,aperture uniformity,and has a large surface area,high adsorption capacity and good thermal stability and so on.Therefore,MCM-41 molecular template and MCM-41 were used to adsorb U(?)in wastewater.On the one hand,MCM-41 was prepared by hydrothermal method and Fe-MCM-41 composites and Cu-MCM-41 composites were synthesized.On the other hand,the effects of MCM-41-dry and calcined MCM-41-cal on the adsorption of U(?)in water were investigated.Using Fe-MCM-41 and Cu-MCM-41 compares the adsorption effect of U(?)in water.The effects of adsorption U(?)on the adsorption of U(?)were investigated.The adsorption thermodynamics and adsorption kinetics models were established and analyzed by SEM,EDS,BET and FTIR.The effects of pH value,adsorption time,dosage and U(?)initial concentration are used to study the adsorption mechanism of U(?).The adsorption effect of MCM-41-dry material is much higher than that of MCM-41-cal.When the pH is 5,the adsorption time is 180 min and the temperature is 30?,the MCM-41-dry dosage The adsorption rate of U(?)was 99.2% when the initial concentration of U(?)was 0.2g /L and the initial concentration of U(?)was 10mg/L;Langmuir adsorption isothermal model and quasi-second order kinetic equation could fit Adsorption process,when T=303K,the theoretical saturated adsorption capacity of 241.935mg/g,adsorption for the single molecular layer adsorption,mainly chemical adsorption.The BET and FTIR characterization indicated that MCM-41-dry had a hexagonal mesoporous structure that could adsorb U(?),functional hydroxyl groups and amino groups play a significant role.The results showed that when the pH was 5,the temperature was 30?,the adsorption time was 180 min,the dosage of Fe-MCM-41 and Cu-MCM-41 was 0.2g/L,and the maximum adsorption was observed when the concentration of U(?)was 10mg/L(93.02% and 84.21%,respectively),indicating that the adsorption effect of Fe-MCM-41 on U(?)was higher than that of Cu-MCM-41 under the same conditions.Langmuir adsorption isotherm model and quasi-second-order kinetics can be used to fit the adsorption process of Fe-MCM-41 and Cu-MCM-41 on U(?).The theoretical adsorption capacities are 211.935mg/g and 185.935mg/g.,Adsorption for the monolayer adsorption,mainly chemical adsorption.Fe-MCM-41 and Cu-MCM-41 were grafted with transition metal Fe and Cu,respectively,and Fe-MCM-41 and Cu-MCM-41 were successfully characterized by EDS,FTIR and nitrogen adsorption desorption.The basic structure of the MCM-41 was stable before and after adsorption.The Fe-MCM-41 and Cu-MCM-41 after U(?)adsorption were desorbed with 0.1 mol/L HCl,and the adsorption rate was 90% and 80% after adsorption-analysis-adsorption cycle 5 times.It is shown that Fe-MCM-41 and Cu-MCM-41 are adsorbents that can be reused.