高铀/钒吸附容量比纤维吸附剂的研制及吸附机制研究

含偕胺肟基和羧基的纤维吸附剂在海水提铀过程中，存在铀/钒吸附容量比低和钒洗脱条件苛刻导致纤维强度下降等不足之处，严重影响吸附剂的铀吸附性能和循环利用效率。本项目拟选用高强度的超高分子量聚乙烯(UHMWPE)纤维作为基材，利用低能电子束辐射接枝改性的方法，将二氨基马来腈(DAMN)嫁接于UHMWPE纤维上，结合偕胺肟化反应，制备出含DAMO功能分子的UHMWPE纤维吸附剂(UHMWPE-DAMO)。依托模拟海水流动吸附平台和天然海水吸附平台，评估UHMWPE-DAMO纤维吸附剂的铀/钒吸附容量比和铀吸附容量。基于X射线吸收精细结构(XAFS)分析测试手段，研究UHMWPE-DAMO纤维吸附剂与铀、钒的配位方式，阐明其吸附机制。通过优化实验条件，筛选出在天然海水中铀/钒吸附容量比大于5:1和铀吸附容量大于3 mg-U/g-ads(30天)的UHMWPE-DAMO纤维吸附剂。

In the process of extracting uranium from seawater, fibrous adsorbents with amidoximate and carboxyl ligands possess some shortcomings, such as low adsorption capacity ratio of uranium to vanadium and vanadium ions difficult to desorb, which seriously influence its uranium adsorption performance and recycling efficiency. In this project, Ultra-high molecular weight polyethylene (UHMWPE) fiber will be selected as a substrate owing to its high tensile strength. Diaminomaleonitrile (DAMN) will be immobilized onto UHMWPE fiber through low energy electron beam irradiation induced graft polymerization technique. Subsequently, the UHMWPE-DAMO fibrous adsorbent will be fabricated by the amidoximation reaction. The adsorption capacity ratio of uranium to vanadium and uranium adsorption capacity of UHMWPE-DAMO fibrous sorbent will be evaluated via simulated seawater flowing adsorption platform and natural seawater adsorption platform. The coordination mode between UHMWPE-DAMO fibrous adsorbent and uranium/vanadium will be carefully studied based on analysis of X-ray absorption fine structure (XAFS) data, in order to illustrate its adsorption mechanism. The experimental conditions will be systematically optimized in an attempt to achieve the adsorption capacity ratio of uranium to vanadium of 5 to 1 and the uranium adsorption capacity of 3 mg-U/g-ads (30 days) in natural seawater.