Organic-functionalized Mesoporous Materials Synthesis, Characterization And Adsorption Of Thorium

mesoporous materials with pore size adjustable, large specific surface area, et al,caused by the great interest of scientists. In order to further expand the materials withthe potential applications in separation, adsorption, catalytic. In this article, we chosethe cationic surfactant (CTAB) as template, sythesis of different components oforganic functionalized mesoporous materials. The material were used for theadsorption of thorium radionuclides. These studies provide an useful basis formesoporous materials in adsorption and separation.（1）Introduction, introduces the aspects of the history of the development ofmesoporous materials, synthetic methods, reaction mechanism and application ofmesoporous silica materials.(2) Thorium(Th), as an important natural radioactive element, is receiving anever-increasing interest as nuclear fuel alternatives to uranium in nuclear powerindustry. In view of the extensive application, the development of reliable methods forthe separation, monitoring, and recovery of Th in environmental and geologicalsamples is of particular significance. Herein, a novel sorbent of Th(Ⅳ),phosphonate-functionalized mesoporous silica (NP10), was synthesized, and theadsorption of Th(Ⅳ) from aqueous solution using NP10was studied in batchprocesses under varying operating conditions of pH, temperature, adsorption time andTh(Ⅳ) concentration. The experimental results show that the adsorption of Th(Ⅳ) byNP10is ultra-fast, and the sorption process reaches equilibrium after about30min.The adsorption process can be well described by the Langmuir equation and themaximum sorption capacity is estimated to149mg/g at temperature of14±1℃.When the adsorption temperature is up to40℃, the maximum sorption capacityreaches192mg/g. It is also found that the adsorption percentage of Th(Ⅳ) by NP10 increases rapidly with increasing pH from0.9to4, whereas NaClO4in the solutionshows no obvious effect on the adsorption. Moreover, with the mass of NP10increasing, the adsorption percentage of Th(Ⅳ) by NP10increases until almostcomplete adsorption (>97%).(3) The potential application of thorium (Th) in nuclear power plants as thefuture predominant fuel promotes the development of reliable methods for theremoval and recovery of Th(Ⅳ) from environmental and geological samples. Herein,the phosphonate-amino bifunctionalized mesoporous silica (PAMS) was synthesizedby one-step self-assembly approach and was used as Th (Ⅳ) sorbent. The synthesizedsilica nanoparticles were found to possess ordered mesoporous structure with uniformpore diameter and large surface area, characterized by SEM, XRD, N2adsorption/desorption and13C CP/MAS NMR measurement. The adsorptivity of thePAMS for Th (Ⅳ) from aqueous solution was investigated using batch sorptiontechnique under different experimental conditions. The preliminary results show thatthe Th(Ⅳ) sorption by PAMS is ultrafast with equilibrium time of less than30min,and the sorption capacity is as large as166mg/g at the optimal experimentalconditions. The sorption isotherm has been successfully modeled by the Langmuirisotherm, which reveals a monolayer homogeneous sorption of Th(Ⅳ) in PAMS. TheTh(Ⅳ) soroption by PAMS is pH dependent but ionic strength independent. Besides,the sorbed Th(Ⅳ) can be completely desorbed by using0.2mol/L nitric acid solution.This work highlights the vast opportunities of mesoporous silica as applied in removalor recovery of thorium from environment.