Preparation Of High-Performance Adsorbing Materials Based On Feather Fiber And Their Adsorption Behavior Of Uranium

With the continuous development of the world ’s emerging economy,the contradiction between the increasing demand for energy and the gradual reduction of traditional fossil energy has become increasingly prominent.Exploring new energy sources has become the key to breaking the energy crisis.As an efficient and clean energy,the development of nuclear energy has become an effective strategy to break the deadlock of the energy crisis.The development of nuclear energy is inseparable from the stable supply of uranium resources.However,China ’s land uranium resources are insufficient,making China ’s uranium resources rely on imports for a long time.In order to reduce our dependence on overseas uranium resources,improve the autonomy of nuclear power development,and ensure the stable supply of uranium resources,it is imperative to develop new ways to obtain uranium resources.There are about 4.5 billion tons of uranium resources in seawater,which is enough to provide raw material guarantee for nuclear power generation for thousands of years.China also clearly put forward the blueprint for the development of uranium extraction from seawater.However,the currently developed adsorbents for uranium extraction from seawater still face the problems of insufficient adsorption performance,low economic competitiveness,and difficulty in application in actual seawater,which limit the industrialization process of uranium extraction from seawater.In order to design and develop high-performance,low-cost and large-scale deployment of seawater uranium extraction adsorption materials,waste feather fiber(FF)was selected as the substrate to construct phosphate ester modified feather fiber(FF-EPI-PT and FF-EGDE-PT),amidoxime modified feather fiber(FF-AO),cuprous oxide composite amidoxime modified feather fiber(FFCu2O/AO)and amidoxime modified feather fiber keratin aerogel(FK-AO aerogel).Through a series of detailed adsorption tests on the above adsorption materials,the adsorption performance of the materials for uranium was studied,and the adsorption law and binding mechanism of the materials for uranium were explored.Combined with actual seawater test and economic accounting,its value in practical application is evaluated,and all adsorption materials are compared and analyzed.The specific contents are as follows:(1)Two adsorbents FF-EPI-PT and FF-EGDE-PT were constructed by grafting phosphate on FF with epichlorohydrin and ethylene glycol glycidyl ether as bridging agents.The efficiency of FF-EPI-PT grafting phosphate ester was higher than that of FF-EGDE-PT.FF-EPI-PT and FF-EGDE-PT have high adsorption capacity(342.84,268.45 mg·g-1)in 8 ppm uranium-containing solution,and both have excellent selectivity.At the same time,the binding mechanism of FF-EPI-PT with uranium was studied.It was found that two phosphate groups on FF-EPI-PT molecule coordinated with one uranyl ion to achieve the adsorption of uranium in solution.In addition,FF-EPI-PT has an adsorption capacity of 3.22 mg·g-1 after 30 days of adsorption in actual seawater.The cost accounting results show that the price of FF-EPI-PT adsorbing uranium from actual seawater is only USD 250.60 per kilogram of uranium,which is lower than most of the adsorption reported in the literature.(2)FF was selected as the substrate,and FF-AO was constructed by grafting modification with amidoxime group.FF-AO had ultra-high adsorption capacity for uranium in uranium-containing solution at pH 7,and the adsorption capacity could reach 612 mg·g-1 when the uranium concentration was 8 ppm.At the same time,FF-AO still has excellent selective adsorption performance for uranium in simulated seawater with high salinity coexisting metal ions.In addition,FF-AO was applied to actual seawater,and 7.73 mg uranium could be extracted per gram of FF-AO after 30 days.Due to the light texture of FF-AO,uranium extraction could be completed without expensive anchoring device in seawater.Based on the preparation cost of FF-AO and the labor cost of its application in actual seawater,it is calculated that FF-AO only needs USD 157.12 to adsorb one kilogram of uranium in actual seawater,which is the lowest adsorption cost among the reported adsorbents for uranium extraction from seawater.Therefore,FF-AO is an economical adsorbent for uranium extraction from seawater with great application potential.(3)Cu2O was synthesized simultaneously with amidoxime-functionalized feather fiber(FF-AO)by in-situ synthesis method.Cu2O particles and amidoxime groups were simultaneously compounded on FF,and a seawater uranium adsorption material FF-Cu2O/AO with anti-bioaccumulation performance was constructed.Compared with FF-AO,FF-Cu2O/AO has higher adsorption capacity and antibacterial properties.Under light conditions,FF-Cu2O/AO has an adsorption capacity of 816 mg·g-1 for uranium in a uranium-containing solution with a concentration of 8 ppm,and maintains excellent selective adsorption performance in simulated seawater with coexisting metal competitive ions and typical marine bacteria.And FF-Cu2O/AO showed excellent antibacterial properties against several different bacteria.Therefore,the excellent adsorption and bioaccumulation resistance of FF-Cu2O/AO make it more typical and applicable in actual seawater,reflecting great application potential.(4)FK-AO aerogel with high specific surface area and high adsorption performance was designed from feather fiber keratin(FK)extracted from waste FF.The cyanide was grafted onto FK by the reaction of acrylonitrile and FK,and then cross-linked with agar to finally obtain cyanide feather keratin aerogel(FKAN aerogel).FK-AN aerogel was reacted with NH2OH to obtain amidoxime,and FK-AO aerogel was prepared.The method is simple,the grafting reaction conditions are mild,and the grafting efficiency is high.The prepared FK-AO aerogel has a high specific surface area of 25.6 m2·g-1 and ultra-strong water absorption capacity FK-AO aerogel has an adsorption capacity of 585.88 mg·g-1 in 8 ppm uranium solution.It has high adsorption capacity and selective adsorption performance in high salinity and low uranium concentration solutions and metal ion coexistence systems.The removal rate of uranium can reach more than 90%when the uranium concentration is less than 2 ppm.Compared with phosphate adsorption materials,amidoxime adsorption materials have greater advantages in the adsorption performance of uranium,greater economic competitiveness and more practical application potential.Among the three amidoxime-based adsorption materials,FF-Cu2O/AO has both ultra-high adsorption capacity and bioaccumulation resistance,which is the most promising among the three,and is expected to realize the industrial application of uranium extraction from seawater.FK-AO aerogel has excellent adsorption performance in high salinity and low uranium concentration,but the preparation cost of FK-AO aerogel is high,and further exploration is needed to reduce its preparation cost in order to be applied in actual seawater.