偕胺肟化FDU-12的制备及对U(Ⅵ)的高效富集研究

Preparation of amidoxime modified FDU-12 and its efficient removal of U(Ⅵ) from aqueous solution

随着核工业的大力发展,铀资源的短缺以及产生的含铀废水严重制约着环境和人类可持续发展,高效铀吸附材料研发对保障能源和环境安全具有重要意义.本研究以Pluronic F127(EO106PO70EO106)为表面活性剂,1,3,5-三甲苯(TMB)为有机膨胀剂,通过四乙氧基硅烷(TEOS)与2-氰乙基三乙氧基硅烷(CPTES)的共缩合及化学还原技术制备了三维笼状介孔分子筛FDU-12(FDU为复旦大学)和偕胺肟化FDU-12(AO@FDU-12)介孔材料.采用光谱分析表征FDU-12和AO@FDU-12的元素组成和微观结构,探究不同物质的量的比投加量对合成材料的物化性质的影响,并考察反应时间、温度、pH、离子强度和共存阴阳离子等环境因素对FDU-12和AO30@FDU-12吸附水溶液中U(Ⅵ)的影响.结果表明,制备过程中TEOS与CPTES的物质的量的比对材料的三维孔结构和铀吸附性能影响较大,随着CPTES物质的量的增加,材料的孔结构由规则变为无序,且以AO30@FDU-12对U(Ⅵ)的吸附效果最优;批量吸附实验研究表明,U(Ⅵ)在FDU-12和AO30@FDU-12吸附过程很快,达到吸附平衡时间分别为20 min和45 min;溶液pH对FDU-12和AO30@FDU-12吸附U(Ⅵ)有很显著影响,而离子强度对两种材料吸附U(Ⅵ)无明显变化;吸附动力学和热力学研究表明,U(Ⅵ)在AO30@FDU-12上的吸附行为是一个化学吸附、自发吸热过程,符合Langmuir单层吸附模型,最大饱和吸附容量可达300.95 mg·g^(-1)(T=298 K,pH=5.0).此外,AO30@FDU-12的还具有良好的放大和循环使用性能,再考虑到AO30@FDU-12对U(Ⅵ)的优异的吸附性能,在净化和富集水溶液中U(Ⅵ)具有巨大的应用潜力.

With rapid development of nuclear technology and peaceful utilization of nuclear energy,the shortage of uranium resources and the generation of uranium-bearing waste water are seriously restricting the sustainable development of environment and the human health.Therefore,the creation of effective uranium adsorbents is crucial for ensuring energy and environmental security.In this study,F127 was used as the surfactant and the organic swelling agent TMB was added via tetraethoxysilane(TEOS) and 2-cyanoethyltriethoxysilane(CPTES).The mesoporous materials FDU-12and AOx@FDU-12 were prepared using co-condensation and chemical reduction methods.The materials were characterized using SAXRD,SEM,TEM,FT-IR,elemental analysis,zeta potentiometer and N2 desorption adsorption.The study investigated the impact of varying loading molar ratios of silanes on the physicochemical properties and the U(Ⅵ) adsorption performance of synthetic FDU-12 and AOx@FDU-12.The results indicate that the molar ratio of TEOS to CPTES significantly affects the material's three-dimensional pore structure.Increasing the amount of CPTES during preparation leads to a transition from a regular to a disordered pore structure.The adsorption of U(Ⅵ) on FDU-12 and AO30@FDU-12 reached equilibrium rapidly,within 20 and 45 minutes,respectively.The pH significantly affects the adsorption of U(Ⅵ) by FDU-12 and AO30@FDU-12,while ionic strength has no evident effect on the adsorption of U(Ⅵ) by the two materials.The adsorption kinetic and thermodynamic studies suggest that the adsorption performance of U(Ⅵ) on AO30@FDU-12 is a chemical adsorption and spontaneous endothermic process,which agrees with the Langmuir monolayer adsorption model.At a temperature of 298 K and a pH of 5.0,the saturated adsorption capacity of AO30@FDU-12 can reach 300.95 mg·g^(-1).Additionally,AO30@FDU-12 exhibits good amplification and recycling properties.Taken together,the synthesized AO30@FDU-12 is an excellent material for the removal and enrichment of U(Ⅵ) in aqueous solutions.