MXene负载纳米零价铁材料对U(Ⅵ)的高效富集和机理分析

Efficient enrichment and mechanism analyses of MXene-supported nanoscale zero-valent iron towards uranium(Ⅵ)

纳米零价铁(NZVI)作为一种新型环境友好材料,因其本身不稳定、易团聚等性质而在环境污染治理等领域有所限制.本研究利用一种新型二维层状材料MXene作为基底,通过支撑与负载作用对NZVI进行改性合成MXFe材料,并将其应用于水环境中U(Ⅵ)的去除.微观表征证明MXFe具有优异的稳定性、较高的比表面积和良好的磁性.批次实验则证明MXFe对U(Ⅵ)的去除过程十分高效,且在实际海水中仍能获得60%的去除效率,充分证明材料的稳定性与实际应用价值.最后,通过结合pH影响研究和反应前后的XPS数据,我们得出MXFe对U(Ⅵ)的作用机理为氧化还原作用与内层表面络合主导的吸附作用相结合的结果.综上所述,MXFe材料拥有出色的理化性质和作用效果,在未来放射性核素U(Ⅵ)或其他污染物的治理中具有巨大潜力和应用价值.

The increasing requirement of nuclear energy greatly improves the potential threat of radionuclide U(Ⅵ)in aqueous environment.Nowadays,nanoscale zero-valent iron(NZVI)shows excellent potential in underground water remediation due to its high reactivity.However,the practical application of NZVI is restricted because of their inherent instability,poor dispersity,and strong reducibility.Herein,matrix supporting is regarded as a facile,highly efficient,and cost-effective route to decorate NZVI.In this study,MXene,a representative class of two-dimensional material,had been employed as a matrix to support NZVI and the composite(MXFe)was applied in U(Ⅵ)decontamination.Moreover,serial characterization techniques(SEM,XRD,FTIR,VSM,BET)were utilized,and the outstanding stability,high surface area,abundant functional group,and magnetism of MXFe were confirmed.The result of batch experiments indicated that the excellent performance of U(Ⅵ)elimination by MXFe,and all pollutant could be removed in 15 min.The elimination efficiency of U(Ⅵ)was maintained well in typical univalent/bivalent ion backgrounds and achieved~60%in a real seawater system.Finally,XPS and p H analyses were applied to explore the removal mechanism of U(Ⅵ)onto MXFe.The result demonstrated that inner-sphere complex adsorption and reduction reactions dominated the U(Ⅵ)elimination.Overall,MXFe possesses outstanding physicochemical properties and excellent performance,which have great applicable potential and research value in radionuclide remediation and environmental management.