Preparation And Application Of Polyphosphate And Polyureas

In this thesis,the preparation of two kinds of polymers,polyphosphate and polyureas,are reported.Furthermore,their uranium adsorption capacities are investigated in detail.The main contents are as the followings:(1)A series of polyureas(PUsX)are successfully synthesized using diamines and bis(trichloromethyl)carbonate as monomers via interfacial polycondensation under mild conditions.The influences of diamine strucrtures,oil phase solvents,stirring speed,and reaction time on the process of polymerization are investigated in detail.FT-IR and 13C NMR measurements are employed to confirm the successful synthesis of polyureas.Meanwhile,FT-IR spectra also indicate the formation or strong bidentate hydrogen bonds between urea groups on adjacent molecular chains.These hydrogen bonds serve as physical cross-linkers,resulting in the formation of crosslinked polyurea networks.In addition,XRD patterns demonstrate that PUsX are semi-crystalline materials.Their unique network structure and semi-crystalline nature of PUsX endow these polymers with high resistance to solvents and excellent thermal stability.Moreover,the influence of chemical structure of polyureas on U(?)adsorption are investigated,indicating that PUs2 exhibits the highest adsorption capacity(86.4 mg g-1).(2)Bis(2-methacryloxyethyl)phosphate is successfully hyper-crosslinked via free radical polymerization.FT-IR and 13C NMR measurements are carried out to characterize the chemical structure of as-prepared polyphosphate(HCPP).The morphology of HCPP is observed by SEM.The influences of pH value,contact time,initial concentration,and competitive ions on U(?)adsorption are investigated.Meanwhile,the adsorption kinetics and adsorption isotherm model of HCPP for uranium adsorption are also studied.Moreover,HCPP exhibits the maximum uranium adsorption capacity up to 800 mg g-1 at pH=6.0 and excellent selectivity for uranium adsorption over coexisting ions in various solutions(including nuclear industrial wastewater and simulated seawater).Further studies indicate the high U(?)adsorption performance of HCPP in both simulated seawater containing high salt concentration and real uranium wastewater.It is noted that HCPP retains a high adsorption efficiency of nearly 90%after 4 adsorption-desorption cycles and the chemical structure of HCPP remains unchanged.In addition,HCPP also displays high REEs adsorption capacity.