Anti-fouling Solution Blown Amidoxime Based Nanofibers For Uranium Extraction From Seawater

Nuclear energy is the most promising clean energy,widely used in military,industrial,aerospace and other fields.As the most important nuclear material,uranium mining and enrichment is of great significance.The global ocean contains about 4.5 billion tons of uranium,which is 1000 times of the total amount of uranium ore on land.Therefore,it is particularly important to enrich uranium from seawater.However,bacteria and algae in seawater will adhere to the surface of the material,causing biofouling,blocking the pores and reducing the adsorption capacity of the material for uranium.Therefore,it is important to prepare anti biofouling uranium extraction materials.Among many biofouling problems,biofilm fouling is the most serious.The formation of biofilm on materials can be divided into three stages:molecular fouling stage in the early stage,extracellular polysaccharide adhesion stage in the middle stage and mature three-dimensional tower stage in the late stage.At present,most of the existing anti fouling uranium extraction materials play a role in the early stage,which can slow down the process of biofilm formation,but can not prevent the final formation of biofilm,let alone release biofouling.Thus,it is expected to promote the process of uranium industrialization to develop high adsorption performance seawater uranium extraction materials with biological fouling resistance.Amidoxime group is the most widely used chelating group because of its high specificity and high efficiency.The development of Amidoxime based adsorbents has a broad prospect.In this study,we combined amidoxime group to prepare nanofibers（AOP）.In order to solve the problem of serious biological fouling and the need to improve the adsorption performance of uranium extraction materials in real seawater,it is proposed to introduce anti biological fouling ions and groups into the substrate and design dynamic self-renewal surface to improve the comprehensive performance of the materials.In this paper,two kinds of uranium extraction materials with high adsorption properties were prepared,and their structure,adsorption performance and anti biological fouling performance of the materials were characterized.Poly（ethylene glycol methyl ether）-b-Poly（L-arginine）（PPLA）diblock copolymers containing guanidine group were synthesized by ring opening polymerization and guanidination.It is produced by solution blow molding（SBS）.In order to improve the adsorption capacity of uranium,the synergistic effect of guanidine group and amidoxime group was used.Cationic guanidine can inhibit the proliferation of bacteria by electrostatic interaction with anionic groups on the surface of bacteria,which will lead to the damage of bacterial membrane and dysfunction of function or metabolism,resulting in the death of bacteria.The results showed that AP₁₅fiber had significant damage to bacterial biofilm,with inhibition rate of 60%to E.coli,57%to S.aureus and 78%to P.aeruginosa.Ap₁₅fiber showed high uranium adsorption capacity in the p H range of 4.0-8.0,and the maximum adsorption capacity in Langmuir model was 1659 mg/g.in unfiltered natural seawater,the adsorption equilibrium capacity could reach 10.31 mg/g within 35 days.Inspired by the high specific surface area and tunability of metal organic frameworks（MOFs）,dynamic surface self-renewal materials were prepared.AOP@ZIF-8/TA fiber not only has the ability to resist biofilm formation and kill microorganisms in biofilm,but also has the ability to remove biofilm colonization on the surface of adsorbent.Therefore,the adsorption performance and antibacterial persistence were greatly improved,and the inhibition rate of bacteria and algae was 92%and 83%,respectively.The saturated adsorption capacity of the fiber in 8 ppm simulated seawater is 2702.35 mg/g,and in natural seawater,the adsorption equilibrium capacity can reach 11.17 mg/g within 25 days.