Ion-Imprinted And Guanidine Functionalized Materials For Selective Sorption Of Uranium

The demand of uranium increase sharply with the fast development of nuclear industry,therefore,sufficient uranium supply and more efficient use of uranium are important safeguards for the sustainable development of the nuclear industry.The ocean contains 4.5 billion tons of uranium,which is thousands of times known on land and can provide a large amount of uranium resources for the nuclear industry.However,there is still a huge challenge to extract uranyl ions efficiently from seawater due to the low concentration,various coexisting ions,and biofouling.On the other hand,a large number of radioactive wastes contain uranium are being produced in the process of nuclear energy production,the extraction and reuse of uranium can greatly increase the efficiency of uranium utilization.Furthermore,uranium is considered one of the main contaminants and a hazard to environment and human due to its radioactive and chemical toxicity.Some challenges are still subsistent for uranium sorption efficiently from radioactive liquid wastes,such as strong acidity,high radioactivity and variety of competing metal ions.Therefore,the development of economical and efficient uranium recovery materials is of great significance for the continued supply of nuclear energy in the future.Specific studies of this paper are as follows:(1)Ion-Imprinted Mesoporous Silica for Selective Removal of Uranium from Highly Acidic and Radioactive EffluentWe demonstrate a novel strategy for selective uranium removal from highly acidic and radioactive media by surface ion-imprinted mesoporous silica(UIMS).The sorbent was prepared by co-condensation method with uranyl as the template ion.The sorption kinetic and isotherm data fit well with the pseudo-second-order model and Langmuir model,respectively,and the sorption equilibrium could be reached within 40 minutes,the maximum adsorption capacity from Langmuir model was 80 mg/g in 1 mol/L HNO3 solution at 298.15 K.The UIMS showed faster sorption kinetics and higher selectivity towards uranium over other ions compared with non-imprinted mesoporous silicas(NIMS).Furthermore,the UIMS sorbent can be used in strong acidic media compared with other ion-imprinted materials,and possesses better selectivity towards uranium in comparison with organophosphorus-functionalized mesoporous silica in strong HNO3 media.In addition,the UIMS exhibited remarkable radioresistance stability and could be regenerated efficiently after five cycles.The results demonstrated that the UIMS can efficiently separate uranium from highly acidic and radioactive media.(2)Guanidine-Functionalized Polypropylene Nonwoven Fabric for Potential Uranium Recovery from Seawater with Antibiofouling PropertyA highly selective guanidine-functionalized polypropylene nonwoven fabric for recovery uranium from seawater with antifouling property was reported here.Specifically,the poly(glycidyl methacrylate)was grafted onto the polypropylene non-woven fabric by radiation grafting technology,and then ring-opening reaction with guanidine hydrochloride,further acylation reaction was performed,and the aldehyde group was finally oximation to obtain an oxime group.The adsorption kinetics study of the material indicated that the adsorption process fit well with the Second-order kinetics model,which dominated that the adsorption process was chemical adsorption.And the adsorption equilibrium could be achieved within 4 h.The adsorption experiments of uranyl ions with coexistent ions showed that the adsorbent have higher selectivity for uranyl ions.In addition,the adsorbent has good antibacterial properties against E.coli and Staphylococcus aureus.