Preparation And Performance Of Silver-incorporated Antibacterial Amidoximated Adsorbents For Uranium Extraction From Seawater

Uranium reserves in seawater are estimated to be as high as 4.5 billion tons,which is almost a thousand times of the current explored uranium reserves on land.If the uranium resources contained in seawater can be effectively utilized,it will not only resolve the current energy crisis,but also ensure the sustainable development of the next hundreds of years.In addition,the environmental friendliness of the extraction process and the simplicity of the separation process make uranium extraction from seawater draw more and more attention of researchers.Uranium extraction from seawater,however,is not an economical means of producing uranium because natural seawater contains only 3.3 ppb of uranium,a feature that not only makes it inefficient and expensive,but also presents a problem that other conventional uranium extraction technologies do not have:biological contamination by marine microorganisms.Due to the extremely low uranium concentration,the experiment time of the adsorbent immersed in seawater is often measured in months.Under such a time scale,the enrichment of organisms will greatly reduce the adsorption performance and service life of the material.Consequently,it is crucial to design and synthesize new adsorption materials with both antibacterial properties and adsorption capacity.In this study,two new antibacterial materials named amidoximated silver-silica core-shell nanoparticles（Ag@Si O₂-AO）and silver nanoparticle incorporated amidoximated polyacryonitrile nanofibers（PAO@Ag NP）were designed and prepared using silver as antibacterial material and amidoxime group as uranium adsorption group.The results of antibacterial experiments presented that both of materials could effectively inhibit high concentration of Escherichia coli and Staphylococcus aureus.95%of Escherichia coli and can be efficiently removed with 50 mg/L of Ag@Si O₂-AO,and 100 mg/L for Staphylococcus aureus.The performance of PAO@Ag NP nanofibers is more excellent,the minimum inhibition concentration for Escherichia coli and Staphylococcus aureus is 200 mg/L,which indicated that the solid-liquid ratio of Ag is only 8 mg/L.In addition,this work also explored the adsorption performance of the two materials through batch experiments,tested the effects of solid-liquid ratio,equilibrium time,p H and other factors on the adsorption performance of the materials,isotermal and kinetic model fittings were also carried out.The results showed that the maximum adsorption capacity of Ag@Si O₂-AO was 47.42 mg/g in labeled natural seawater environment at room temperature;for PAO@Ag NP nanofibers,the maximum adsorption capacity was 11.89 mg/g in labeled natural seawater.Both of the materials exhibited good adsorption ability.