Study On Adsorption Properties Of Modified Chitosan And Construction Of 5f Metal Framework Molecules

With the reduction of fossil fuel reserves,people urgently need a new energy source which is green and efficient to replace the fossil fuels.The nuclear energy is the most promising alternative to replace the fossil fuel as the main energy source in the future.To develop nuclear energy,we need a large amount of uranium.Uranium,as a radioactive element,is the main material of nuclear energy.It is unavoidable to cause the uranium contamination in the environment during the development of nuclear energy.So it is necessary to find an effective method to treat uranium-contained wastewater.Among the numerous methods,adsorption causes widespread concern because of the advantages such as the simple operation and the low cost.It is necessary to find a highly efficient,environmentally friendly and cheap adsorbent for treating wastewater by adsorption.As an inexpensive biomass material,chitosan is an ideal adsorbent.However,chitosan need to be modified because of its poor mechanical strength and acid resistance.At the same time,the structure of the chitosan material can be designed to increase the surface area and improve the adsorption capacity.In order to find a uranyl adsorbent with high adsorbability,it is necessary to study the reaction mechanism of the whole adsorption process.There are many reports about the adsorption of uranyl by modified chitosan.While,there are few reports about its adsorption mechanism.Most scholars believe that there may be chemical interactions between uranyl ions and adsorbents in aqueous solution,such as coordination.Therefore,it is useful to look for more efficient and cheap adsorbents and study their adsorption mechanism.Based on the above ideas,it is necessary to proceed from two aspects:develop metal framework complexes and study its coordination mechanism;develop inexpensive,pollution-free and high-efficiency adsorbent materials.Two kinds of modified chitosan were synthesized in this paper.The structure of the two materials was characterized by infrared spectroscopy,thermogravimetry,scanning electron microscopy and PXRD.The effects of pH,adsorption time,adsorbent input and other factors on the adsorption properties were preliminarily discussed.Four kinds of uranyl complexes with different structures were designed and synthesized.The crystal structure was confirmed by X-Ray single crystal diffraction,infrared spectroscopy,UV-vis,thermogravimetry and elemental analysis.Meanwhile,the adsorption properties of complexes on dyes were also studied.