Study On The Preparation And Properties Of Critical Materials For Exploitation Of Marine Resources Of Uranium And Lithium

Limited resources and unrestrained population growth are driving social demand for unconventional industrial metals and fossil energy.With about 1,000 times more uranium in the ocean than on land,and four orders of magnitude more lithium than on land.The ubiquitous seawater could serve as an almost infinite global source of uranium and lithium,and it is a promising source of future energy supply.MOF based nanometer adsorbent is a new type of adsorbent in the field of uranium extraction due to its unique porous structure and ultra-high specific surface area.In addition,according to the currently reported methods of precipitation,adsorption,extraction and electrodialysis,which are applied to seawater lithium extraction under severe conditions.A semi-battery based on solid electrolyte?SSE?structure for electrochemical seawater lithium extraction has been reported recently,which has a high extraction rate of lithium ions,but this field is still limited at present.In this paper,we have developed a super hydrophilic porous nanocomposite membrane with large specific surface area,high binding site,high efficiency and rapid uranium extraction for seawater uranium extraction.And a super-dense?99.2%?garnet SSE with excellent electrochemical properties and ultra-high lithium extraction rate has been prepared for seawater lithium extraction.?1?A new type of MOF-poly?amidoxime?composite porous uranium adsorption film with high permeability was developed.Utilizing the characteristics of polyacrylonitrile?PAN?dissolved in DMF solution,PAN was dissolved in the precursor solution of UIO-66.UIO-66-PAN was synthesized in situ and oxidized to prepare UIO-66-PAO nanocomposites.UIO-66-PAO nanoparticles were dispersed evenly with large layer of graphene oxide?GO?solution,and the mass ratio between GO and UIO-66-PAO is 1:15,and there is no settlement after 4 weeks.UIO-66-PAO porous membrane with high dispersion,strength,toughness and hydrophilicity was prepared by simple and rapid high-pressure filtration method.This method is not only suitable for MOF materials,but also for other nanoparticle materials.The filtered seawater showed the characteristics of rapid and efficient uranium extraction.In 8 ppm simulated seawater,the amount of uranium can reach 510 mg g^-1,and in low-concentration of 60 ppb,the single-layer UIO-66-PAO porous membrane could also achieve the uranium extraction rate of 88.4%.Amidoxime-functionalized membrane structure solves the recovery problem very well,so UIO-66-PAO porous membrane has a good application prospect in the field of seawater uranium extraction and is expected to be a candidate material for uranium adsorption.?2?In this paper,a high density?99.2%?Li_6.75La₃Al_0.25Zr₂O₁₂?LLAZO?cubic garnet solid electrolyte?SSE?was prepared by high-price aluminum doping and spark plasma sintering?SPS?technology.Under the minimum water resistance requirement for lithium extraction from seawater,the lithium ion conductivity of LLAZO is up to 4.8×10^-4S,which is 20 times higher than that of unmodified Li₇La₃Zr₂O₁₂.In natural seawater,the LLAZO SSE based device has a high lithium extraction efficiency of 198?g cm²h^-1and a small voltage fluctuation of 0.01 V.Energy consumption analysis shows that the cost of electrolysis only accounts for 1.0%-3.7%of the output value of lithium metal.Each square meter of LLAZO SSE produces 17.3 Kg of lithium from unconcentrated natural seawater,with a net income of up to$1220-2500 per year.Therefore,the electrochemical device based on LLAZO SSE has a stable,low-cost and high-efficiency application prospect in extracting lithium from seawater,which provides a new research direction in the field of lithium extraction from seawater.