Synthesis Of Amidoxime Funtionalized Hypercrosslinked Polymer And Study On Its Uranium Adsorption Performance

Clean,safe,and efficient are the typical characteristics of nuclear power generation.This energy has been developed more and more rapidly in recent years.Nuclear power,an equivalent of coal,now accounts for 10%of the electricity mix.Uranium is one of the main elements in nuclear power fuel.The long-term sustainable development of nuclear energy are based on exploitation of uranium resources in seawater.In this paper,a hypercrosslinked polymer with ultra-high specific surface area and stability is used as the matrix,and the amidoxime group with high affinity and selectivity for uranyl ions is used as the functional group.Two uranium sorbents with high adsorption capacity and selectivity were synthesized by two different routes.1.The hypercrosslinked polymer skeleton HCP-SQ was synthesized using benzal-dehyde dimethyl acetal as monomer,and the carbonyl group-containing super cross-linked polymer HCP-BJQ was obtained by hydroformylation reaction,Schiff base reaction and amidoximation The reaction modification obtains the hyper-crosslinked polymer HCP-BJQ-AO containing amidoxime groups.The synthesized polymer HCP-BJQ-AO was systematically characterized by FT-IR,SEM,TEM,XRD,TG and BET methods,which proved that the amidoxime functionalized polymer was obtained.At pH=6,the saturated adsorption capacity of uranium can reach 134 mg·g^-1.The uranium adsorption process of HCP-BJQ-AO is better fitted to the pseudo-second-order kinetic model and Langmuir model,that is,the process is monolayer chemisorption.When Na,K,Ca,Ba,Co,Cd,Sr,Pb and other elements coexist,the removal rate of uranium can still reach 66.03%,demonstrating that the adsorbent possesses excellent selectivity.After 5 cycles of adsorption-desorption,the uranium adsorption capacity of HCP-BJQ-AO remain 80.68%of the original,indicating the good recyclability of HCP-BJQ-AO.2.Using benzil containing more carbonyl groups and bisphenol fluorene containing phenolic hydroxyl groups as monomers,the hypercrosslinked polymer HCP-CO with ultra-high specific surface area is synthesized,and the grafting of diaminomaleonitrile are carried out.After the amidoximation reaction,the hypercrosslinked polymer HCP-AO containing amidoxime groups was synthesized.The HCP-AO was systematically characterized by FT-IR,SEM,TEM,XRD,TG and BET methods,which proved the successful modification of amidoxime.At pH=6,the saturated adsorption capacity of uranium can reach 310.3 mg·g^-1.In simulated seawater,the uranium removal rate of HCP-AO can still reach 68.53%,indicating the good selectivity of HCP-AO.After 5 cycles of adsorption-desorption,the adsorption capacity of HCP-AO can still reach 87.4%of the original,indicating the good reproducibility of HCP-AO.Both adsorbents HCP-BJQ-AO and HCP-AO have good adsorption performance and selectivity,and have certain application prospects for uranium extraction from seawater.