Study On The Preparation And Uranium Adsorption Properties Of Functionalized Graphene Oxide Material

Nuclear energy is a kind of clean energy,which can effectively alleviate the problem of CO₂emission.Uranium is needed for nuclear energy,researchers have set their sights on seawater,which stores large amounts of elemental uranium,1,000 times more than on land,enough to cope with the demand for nuclear energy.However,there are also many difficulties in extracting uranium from seawater.For example,the concentration of uranium in seawater is very low,and the seawater environment is complex,where a variety of microorganisms are enriched and there are many competitive ions.All these will affect the efficiency of extracting uranium from seawater.Therefore,there is a need to design adsorbent materials that are environmentally friendly,with anti-fouling properties and specific selectivity.Graphene oxide（GO）contains abundant active functional groups and is easy to modify.Therefore,in this paper,graphene oxide is chosen as the matrix material and modified to improve its specific selectivity and antifouling properties,etc.In order to improve the adsorption selectivity and antifouling performance of GO based adsorbent,β-1,3-glucan was selected to grafted with GO,and uranyl ion(UO₂²⁺)was used as the target template for imprinting.,the GOG-RE adsorbent material was successfully obtained.After ion-competitive adsorption experiments,it was found to be highly selective for uranyl ions with a K_dvalue of 1.28×10⁵m L·g^-1and a calculated maximum adsorption capacity of806.45 mg·g^-1.The adsorption process was consistent with the pseudo second-order kinetics and the Langmuir isotherm model,indicating a chemically dominated monolayer adsorption.Antibacterial experiments demonstrated that it had significant inhibitory effects on E.coli（Gram-negative）,S.Aureus（Gram-positive）and Pseudoalteromonas marina.To improve the adsorption rate of graphene oxide based adsorbent materials on uranium,GO was co-modified by phosphate zwitterion and polyethylenimide（PEI）,and GMP was synthesized.The material can realize the selective adsorption of uranium and the fast adsorption of uranium with antifouling performance.Contact Angle test showed that the absorbent rate of the synthesized GMP adsorbent was fast,and only 0.15s was needed to achieve complete infiltration.The kinetic experiments show that it only takes 30 min for the adsorption of uranium to reach the adsorption equilibrium.And the adsorption kinetic model was consistent with pseudo second-order kinetics with a correlation coefficient R²up to 0.99.In order to improve the recyclability of GO based adsorption materials,poly（hexamethylene biguanide）hydrochloride（PHMB）was selected to modify GO and give it antifouling performance.The adsorption material（Go-PHMB）_0.4@Gelatin-PAM was synthesized by doping the guanidine modified GO into the double-network hydrogel with gelatin as the first-line network and acrylamide as the second network after N,N-methylene diacrylamide（MBA）crosslinked.Cyclic adsorption and desorption experiments show that after ten cycles,（GO-PHMB）_0.4@Gelatin-PAM still has a uranium removal rate of 66%.The removal rate of uranium is above 75%under simulated seawater conditions.The kinetic adsorption experiment showed that the adsorption equilibrium time was 30 min,and the adsorption process was single layer adsorption dominated by chemical adsorption.