Radiation Synthesis N\P-Containing Cellulose Microsphere For Recovery Of U(?) And Re(?)

The sustainable development,utilization and research of uranium resources is an effective guarantee for global energy security and the development of human civilization.Meanwhile,uranium ore as the main source of uranium,associated with large reserves of rhenium.Therefore,to efficiently recover U(?)and Re(?),combining the advantages of cellulose and functionalized monomers,a series of new cellulose-based adsorbents were prepared using radiation technology.(1)Combining the advantages of both aminotriazole and cellulose,two n-aminotriazole isomers modified cellulose microspheres(n-ATAR,n=3,4)were newly prepared as adsorbents via radiation technology.Batch adsorption experiments showed that n-ATARs possessed good adsorption capacity of U(?)in the order of 3-ATAR>4-ATAR,and the adsorption process followed the Langmuir–Freundlich isotherm model and the pseudo-second-order kinetic model.Both n-ATARs exhibited good selectivity and reusability.Besides,3-ATAR and 4-ATAR were more suitable for the extraction of trace amount of U(?)from the contaminated groundwater and the simulated seawater,respectively.The effect of amino position on triazole ring on adsorption behavior of n-ATAR was studied and explained by DFT calculation.Finally,the adsorption mechanism of U(?)onto n-ATAR was revealed to be inner-sphere complexation via different 1:1 or1:2 coordination models by FTIR,MS,XPS analysis and DFT calculation.(2)A DOPO-based monomer was grafted on cellulose using radiation technique,to synthesize novel DOPO derivative-based adsorbent(x-DOPOR).SEM,FTIR and TG analysis confirmed that the DOPO-based monomer was successfully bonded to the cellulose microspheres.At optimum p H=3.0,the maximum adsorption capacity of U(?)onto m-DOPOR and t-DOPOR is 66.00 mg·g^-1 and 67.56 mg·g^-1,respectively.The introduction of DOPO-based monomers improves the selective adsorption capacity of the adsorbent for U(?).x-DOPOR can effectively separate and remove U(?).Besides,t-DOPOR can adsorb trace amounts of U(?)from simulated contaminated groundwater.Column adsorption experiments show that t-DOPOR can selectively adsorb U(?)from simulated wastewater.The results of XPS analysis show that the adsorption mechanism between t-DOPOR and U(?)is the complexation between U(?)and-OH,-NH and P=O groups.(3)3-ATAR containing an abundant nitrogen content was used as promising adsorbent for the selective recovery Re(?)in the presence of U(?)in acidic solution.A series of batch and column adsorption experiments including monocomponent and binary systems,were designed for evaluating the adsorption and separation performance of Re(?)onto 3-ATAR.The 3-ATAR exhibited a good adsorption capacity(max 146.4 mg·g^-1)of Re(?)and a rapid adsorption rate.In binary solution,the high selectivity coefficients(?_Re/M)indicated that 3-ATAR could separate and recover Re(?)from U(?)and other metal ions(Cu(II),Cr(III),Ni(II),Zn(II)).In particular,it was found that the adsorption of Re was almost unaffected in U/Re-bearing solutions no matter how much the U(?)was changed.When the concentration of U(?)was 40 times higher than that of Re(?),3-ATAR also manifested high Re(?)selectivity over U(?)from a synthetic uranium ore leachate.