辐射接枝制备聚丙烯纤维基海水提铀吸附剂

摘要

Background:A recent estimate indicates that the land-based uranium sources are only able to last for about a century. Consequently, it is imperative to exploit new uranium resources with an economically feasible method. The uranium dissolved in seawater is about 4.5×109 t, much larger than the terrestrial sources, even though its concentration in seawater is low (about 3.3μg·L?1). Hence, it is essential to develop techniques for mining uranium from seawater in order to satisfy the demand for uranium for nuclear power plants in the future.Purpose:The aim of this work is grafting of poly(amidoxime) (PAO) and poly(acrylic acid) (PAA) onto polypropylene (PP) fibers to prepare the PP-g-P(AO-co-AA) fibrous adsorbents for recovery of uranium from seawater.Methods:The PP-g-P(AO-co-AA) fibrous adsorbents were synthesized by electron beam pre-irradiation induced graft polymerization of AN and AA, followed by amidoximation. The surface morphology, chemical structure and thermal performance of the pristine and modified PP fibers were analyzed by attenuated total reflection Fourier transform infrared (ATR-FTIR), scanning electron microscope (SEM) and thermogravimetric analysis (TGA), respectively. The adsorption capacities of uranium and other metal ions by PP-g-P(AO-co-AA) fibrous adsorbents were evaluated after 68 d of immersion in natural seawater.Results and Conclusion:The uranium adsorption capacity of PP-g-P(AO-co-AA) fibers reached 0.81 mg·g?1 after 68 d of contact with natural seawater, and the uranium adsorption capacity did not show positive correlation with the degree of grafting and AO density of PP-g-P(AO-co-AA) fibers.%采用电子束预辐射接枝法将丙烯腈和丙烯酸接枝于聚丙烯(Polypropylene,PP)纤维上,并探讨了吸收剂量和反应温度对接枝率的影响.随后通过偕胺肟化反应制备出含偕胺肟基和羧基的PP纤维吸附剂.红外光谱数据表明,丙烯腈和丙烯酸成功接枝到PP纤维上,偕胺肟化反应将腈基转化为偕胺肟基,同时对改性前后PP纤维的表面形貌和热性能进行了表征.厦门海域真实海水吸附性能测试结果表明,所制备的PP纤维吸附剂铀吸附容量最高可达到0.81 mg·g?1(吸附时间为68 d),PP纤维吸附剂的铀吸附容量与其接枝率和偕胺肟基密度不呈正相关.