Preparation Of Amidoximated Cross-linked Polyethyleneimine Porous Materials And Uranium Adsorption Properties

Uranium is an important new energy and strategic resource that has been vigorously developed.However,it also brings the problem of uranium-containing wastewater treatment.Direct discharge will cause environmental pollution and waste of resources.Therefore,recycling and reusing uranium-containing wastewater is the best solution at present.Adsorption is one of the most suitable methods for uranium recovery,but the existing adsorbents still have drawbacks such as high cost and difficult recovery.Modified cross-linked high polymers have the advantages of wide source of raw materials,high stability and formability brought by chemical cross-linking structure.They can solve these problems well and tolerate harsh and complex environments.Moreover,the grafting reaction of cross-linking is simple,which makes it more practical.In this study,a flexible porous network adsorbent was prepared by this method,and the effects of ratio and other factors on uranium adsorption were studied.4-cyanobenzaldehyde(PA)was used as a functional monomer to graft modify polyethylene imine.After cross-linking with benzene dimethyl aldehyde(PC),low-cost pliable porous network PEI-PAC-AO adsorbent was obtained through amidoximated.This adsorbent displayed good chemical and thermodynamic stability.Adsorption experiments showed that the adsorbent prepared with a PA to PC ratio of 6:4 had high adsorption performance and selectivity,maintaining a distribution coefficient of 4235 m L/g for uranium even in the presence of interference from other ions at high intensities.After 9 adsorption cycles,the uranium removal rate remained at 80.4%,and the uranium adsorption capacity remained at 91.25 mg/g.Analysis revealed the main adsorption mode to be chelation adsorption of the amino group in amidoxime and polyethylene imine providing valence electrons to the uranium ion,which is chemical adsorption on the surface of the microporous network.The polymer formed by the condensation of benzene dimethyl aldehyde with 1,4-diaminobutene-2-nitrile is cross-linked with polyethyleneimine,PEI-MO-AO porous network polymer material was obtained through amidoximated,and displayed good hydrophilicity and pore structure.Adsorption results showed that the adsorbent prepared with a ratio of long-chain polymer to cross-linking agent of 3:3 had a high adsorption capacity and selectivity,maintaining a distribution coefficient of 8760 m L/g for uranium even in the presence of interference from other ions at high intensities.It still maintained a high uranium removal rate of 83% in highconcentration interfering ions.After 6 adsorption cycles,the uranium removal rate remained at81.6%,and the uranium adsorption capacity remained high at 189.31 mg/g.Analysis revealed that the large number of amidoxime and amino groups in the material resulted in uranium ion adsorption on the surface through chemical coordination,leading to increased selectivity and adsorption capacity in the adsorbent.