Application Of Containing N Ligands Functionalized Materials For Uranyl Ions Adsorption Removal From Aqueous Solution

Over the past few years, using of nuclear power generation has greatly cased the human demand for electricity, however, it produced a large number of nuclear waster water in the process of uranium water governance, uranium enrichment and nuclear fuel post-processing which brought unprecedented pressure to the earth environment and the human security. Therefore, the using of new materials on the adsorption and separation of radioactive of Th,U,Eu in nuclear waste water is extremely urgent and important. Mesoporous silica have remarkable features such as large surface area and uniform pores with well defined and controlled sizes and shapes, These characteristics make the mesoporous materials a prospective candidate for the removal and entrapment of U(VI) from aqueous solutions.The thesis is mainly focused on the synthesis of functionalized mesoporous silica materials and their applications as adsorbents to extract uranium. In Chapter2and Chapter3the functionalization of mesoporous silicas SBA-15achieved by stepwise post-graft methods. The influence of pH on the synthesis of the SBA-15were investigated. By small angle X-ray powder diffraction (XRD) and N2adsorption-desorption analysis, it was found that the best performing materials can be synthesized under strongly acidic conditions. Then, amide functionalized mesoporous silica materials was synthesis. The concentration of uranium is analyzed through spectrophotometer with azoarsine (Ⅲ) as chromogenic agent. Effects of sorbents content, sorption time, ionic strength, and pH on UO22+sorption to UPTS-SBA-15were investigated. it was found that the removal percent of UO22+increases with increasing sorbent content, the adsorption equilibrium was reached within50mins, moreover, uptake of uranium can be described by pseudo-second order equation model. There was a clear correlation between pH and uranium uptake and the appropriate pH is4.8. The adsorption can be scribed by the Langmuir and Freundlich equation and the largest theoretical adsorption capacity reach75.75mg/ml. Adsorption increased with increased ionic strength and then increased, finally reached equilibrium. In Chapter4, Amino functionalized mesoporous silica materials was synthesised by co-condensed methods. It was characterized by small angle X-ray powder diffraction (XRD), N2adsorption-desorption analysis and Fourier transform infrared Spectra (FT-IR). Effects of sorption time, and pH on UO22+sorption to amino functionalized mesoporous silica materials were investigated. The results suggested that U(VI) adsorptions onto amino functionalized mesoporous silica materials increased with increasing pH, the adsorption was fast in5mins and reached equilibrium within50mins.and the adsorption capacity is about46.89mg/mg calculated from the adsorption isotherms. The functionalization of mesoporous silicas SBA-15achieved by stepwise post-graft methods shows better performer than amino functionalized mesoporous silica materials synthesized by co-condensed methods in pore size, structure and absorption capacity.